Update pyproject.toml

Replaced chunked rendering approach with direct canvas drawing for mask preview, then applying to main canvas. Added "Mask Opacity" slider.

js/Canvas.js

@@ -61,6 +61,15 @@ export class Canvas {
         });
         this.offscreenCanvas = offscreenCanvas;
         this.offscreenCtx = offscreenCtx;
+        // Create overlay canvas for brush cursor and other lightweight overlays
+        const { canvas: overlayCanvas, ctx: overlayCtx } = createCanvas(0, 0, '2d', {
+            alpha: true,
+            willReadFrequently: false
+        });
+        if (!overlayCtx)
+            throw new Error("Could not create overlay canvas context");
+        this.overlayCanvas = overlayCanvas;
+        this.overlayCtx = overlayCtx;
         this.canvasContainer = null;
         this.dataInitialized = false;
         this.pendingDataCheck = null;

js/CanvasInteractions.js

@@ -3,16 +3,33 @@ import { snapToGrid, getSnapAdjustment } from "./utils/CommonUtils.js";
 const log = createModuleLogger('CanvasInteractions');
 export class CanvasInteractions {
     constructor(canvas) {
+        // Bound event handlers to enable proper removeEventListener and avoid leaks
+        this.onMouseDown = (e) => this.handleMouseDown(e);
+        this.onMouseMove = (e) => this.handleMouseMove(e);
+        this.onMouseUp = (e) => this.handleMouseUp(e);
+        this.onMouseEnter = (e) => { this.canvas.isMouseOver = true; this.handleMouseEnter(e); };
+        this.onMouseLeave = (e) => { this.canvas.isMouseOver = false; this.handleMouseLeave(e); };
+        this.onWheel = (e) => this.handleWheel(e);
+        this.onKeyDown = (e) => this.handleKeyDown(e);
+        this.onKeyUp = (e) => this.handleKeyUp(e);
+        this.onDragOver = (e) => this.handleDragOver(e);
+        this.onDragEnter = (e) => this.handleDragEnter(e);
+        this.onDragLeave = (e) => this.handleDragLeave(e);
+        this.onDrop = (e) => { this.handleDrop(e); };
+        this.onContextMenu = (e) => this.handleContextMenu(e);
+        this.onBlur = () => this.handleBlur();
+        this.onPaste = (e) => this.handlePasteEvent(e);
         this.canvas = canvas;
         this.interaction = {
             mode: 'none',
             panStart: { x: 0, y: 0 },
             dragStart: { x: 0, y: 0 },
-            transformOrigin: {},
+            transformOrigin: null,
             resizeHandle: null,
             resizeAnchor: { x: 0, y: 0 },
             canvasResizeStart: { x: 0, y: 0 },
             isCtrlPressed: false,
+            isMetaPressed: false,
             isAltPressed: false,
             isShiftPressed: false,
             isSPressed: false,
@@ -32,18 +49,29 @@ export class CanvasInteractions {
             view: this.canvas.getMouseViewCoordinates(e)
         };
     }
+    getModifierState(e) {
+        return {
+            ctrl: this.interaction.isCtrlPressed || e?.ctrlKey || false,
+            shift: this.interaction.isShiftPressed || e?.shiftKey || false,
+            alt: this.interaction.isAltPressed || e?.altKey || false,
+            meta: this.interaction.isMetaPressed || e?.metaKey || false,
+        };
+    }
     preventEventDefaults(e) {
         e.preventDefault();
         e.stopPropagation();
     }
     performZoomOperation(worldCoords, zoomFactor) {
-        const rect = this.canvas.canvas.getBoundingClientRect();
         const mouseBufferX = (worldCoords.x - this.canvas.viewport.x) * this.canvas.viewport.zoom;
         const mouseBufferY = (worldCoords.y - this.canvas.viewport.y) * this.canvas.viewport.zoom;
         const newZoom = Math.max(0.1, Math.min(10, this.canvas.viewport.zoom * zoomFactor));
         this.canvas.viewport.zoom = newZoom;
         this.canvas.viewport.x = worldCoords.x - (mouseBufferX / this.canvas.viewport.zoom);
         this.canvas.viewport.y = worldCoords.y - (mouseBufferY / this.canvas.viewport.zoom);
+        // Update stroke overlay if mask tool is drawing during zoom
+        if (this.canvas.maskTool.isDrawing) {
+            this.canvas.maskTool.handleViewportChange();
+        }
         this.canvas.onViewportChange?.();
     }
     renderAndSave(shouldSave = false) {
@@ -64,29 +92,39 @@ export class CanvasInteractions {
         }
     }
     setupEventListeners() {
-        this.canvas.canvas.addEventListener('mousedown', this.handleMouseDown.bind(this));
-        this.canvas.canvas.addEventListener('mousemove', this.handleMouseMove.bind(this));
-        this.canvas.canvas.addEventListener('mouseup', this.handleMouseUp.bind(this));
-        this.canvas.canvas.addEventListener('mouseleave', this.handleMouseLeave.bind(this));
-        this.canvas.canvas.addEventListener('wheel', this.handleWheel.bind(this), { passive: false });
-        this.canvas.canvas.addEventListener('keydown', this.handleKeyDown.bind(this));
-        this.canvas.canvas.addEventListener('keyup', this.handleKeyUp.bind(this));
+        this.canvas.canvas.addEventListener('mousedown', this.onMouseDown);
+        this.canvas.canvas.addEventListener('mousemove', this.onMouseMove);
+        this.canvas.canvas.addEventListener('mouseup', this.onMouseUp);
+        this.canvas.canvas.addEventListener('wheel', this.onWheel, { passive: false });
+        this.canvas.canvas.addEventListener('keydown', this.onKeyDown);
+        this.canvas.canvas.addEventListener('keyup', this.onKeyUp);
         // Add a blur event listener to the window to reset key states
-        window.addEventListener('blur', this.handleBlur.bind(this));
-        document.addEventListener('paste', this.handlePasteEvent.bind(this));
-        this.canvas.canvas.addEventListener('mouseenter', (e) => {
-            this.canvas.isMouseOver = true;
-            this.handleMouseEnter(e);
-        });
-        this.canvas.canvas.addEventListener('mouseleave', (e) => {
-            this.canvas.isMouseOver = false;
-            this.handleMouseLeave(e);
-        });
-        this.canvas.canvas.addEventListener('dragover', this.handleDragOver.bind(this));
-        this.canvas.canvas.addEventListener('dragenter', this.handleDragEnter.bind(this));
-        this.canvas.canvas.addEventListener('dragleave', this.handleDragLeave.bind(this));
-        this.canvas.canvas.addEventListener('drop', this.handleDrop.bind(this));
-        this.canvas.canvas.addEventListener('contextmenu', this.handleContextMenu.bind(this));
+        window.addEventListener('blur', this.onBlur);
+        document.addEventListener('paste', this.onPaste);
+        this.canvas.canvas.addEventListener('mouseenter', this.onMouseEnter);
+        this.canvas.canvas.addEventListener('mouseleave', this.onMouseLeave);
+        this.canvas.canvas.addEventListener('dragover', this.onDragOver);
+        this.canvas.canvas.addEventListener('dragenter', this.onDragEnter);
+        this.canvas.canvas.addEventListener('dragleave', this.onDragLeave);
+        this.canvas.canvas.addEventListener('drop', this.onDrop);
+        this.canvas.canvas.addEventListener('contextmenu', this.onContextMenu);
+    }
+    teardownEventListeners() {
+        this.canvas.canvas.removeEventListener('mousedown', this.onMouseDown);
+        this.canvas.canvas.removeEventListener('mousemove', this.onMouseMove);
+        this.canvas.canvas.removeEventListener('mouseup', this.onMouseUp);
+        this.canvas.canvas.removeEventListener('wheel', this.onWheel);
+        this.canvas.canvas.removeEventListener('keydown', this.onKeyDown);
+        this.canvas.canvas.removeEventListener('keyup', this.onKeyUp);
+        window.removeEventListener('blur', this.onBlur);
+        document.removeEventListener('paste', this.onPaste);
+        this.canvas.canvas.removeEventListener('mouseenter', this.onMouseEnter);
+        this.canvas.canvas.removeEventListener('mouseleave', this.onMouseLeave);
+        this.canvas.canvas.removeEventListener('dragover', this.onDragOver);
+        this.canvas.canvas.removeEventListener('dragenter', this.onDragEnter);
+        this.canvas.canvas.removeEventListener('dragleave', this.onDragLeave);
+        this.canvas.canvas.removeEventListener('drop', this.onDrop);
+        this.canvas.canvas.removeEventListener('contextmenu', this.onContextMenu);
     }
     /**
      * Sprawdza czy punkt znajduje się w obszarze któregokolwiek z zaznaczonych layerów
@@ -124,9 +162,10 @@ export class CanvasInteractions {
     handleMouseDown(e) {
         this.canvas.canvas.focus();
         const coords = this.getMouseCoordinates(e);
+        const mods = this.getModifierState(e);
         if (this.interaction.mode === 'drawingMask') {
             this.canvas.maskTool.handleMouseDown(coords.world, coords.view);
-            this.canvas.render();
+            // Don't render here - mask tool will handle its own drawing
             return;
         }
         if (this.canvas.shapeTool.isActive) {
@@ -135,11 +174,11 @@ export class CanvasInteractions {
         }
         // --- Ostateczna, poprawna kolejność sprawdzania ---
         // 1. Akcje globalne z modyfikatorami (mają najwyższy priorytet)
-        if (e.shiftKey && e.ctrlKey) {
+        if (mods.shift && mods.ctrl) {
             this.startCanvasMove(coords.world);
             return;
         }
-        if (e.shiftKey) {
+        if (mods.shift) {
             // Clear custom shape when starting canvas resize
             if (this.canvas.outputAreaShape) {
                 // If auto-apply shape mask is enabled, remove the mask before clearing the shape
@@ -163,7 +202,7 @@ export class CanvasInteractions {
             }
             return;
         }
-        if (e.button !== 0) { // Środkowy przycisk
+        if (e.button === 1) { // Środkowy przycisk
             this.startPanning(e);
             return;
         }
@@ -179,7 +218,7 @@ export class CanvasInteractions {
             return;
         }
         // 4. Domyślna akcja na tle (lewy przycisk bez modyfikatorów)
-        this.startPanningOrClearSelection(e);
+        this.startPanning(e, true); // clearSelection = true
     }
     handleMouseMove(e) {
         const coords = this.getMouseCoordinates(e);
@@ -199,7 +238,7 @@ export class CanvasInteractions {
         switch (this.interaction.mode) {
             case 'drawingMask':
                 this.canvas.maskTool.handleMouseMove(coords.world, coords.view);
-                this.canvas.render();
+                // Don't render during mask drawing - it's handled by mask tool internally
                 break;
             case 'panning':
                 this.panViewport(e);
@@ -221,6 +260,10 @@ export class CanvasInteractions {
                 break;
             default:
                 this.updateCursor(coords.world);
+                // Update brush cursor on overlay if mask tool is active
+                if (this.canvas.maskTool.isActive) {
+                    this.canvas.canvasRenderer.drawMaskBrushCursor(coords.world);
+                }
                 break;
         }
         // --- DYNAMICZNY PODGLĄD LINII CUSTOM SHAPE ---
@@ -232,6 +275,7 @@ export class CanvasInteractions {
         const coords = this.getMouseCoordinates(e);
         if (this.interaction.mode === 'drawingMask') {
             this.canvas.maskTool.handleMouseUp(coords.view);
+            // Render only once after drawing is complete
             this.canvas.render();
             return;
         }
@@ -315,8 +359,17 @@ export class CanvasInteractions {
             this.performZoomOperation(coords.world, zoomFactor);
         }
         else {
-            // Layer transformation when layers are selected
-            this.handleLayerWheelTransformation(e);
+            // Check if mouse is over any selected layer
+            const isOverSelectedLayer = this.isPointInSelectedLayers(coords.world.x, coords.world.y);
+            if (isOverSelectedLayer) {
+                // Layer transformation when layers are selected and mouse is over selected layer
+                this.handleLayerWheelTransformation(e);
+            }
+            else {
+                // Zoom operation when mouse is not over selected layers
+                const zoomFactor = e.deltaY < 0 ? 1.1 : 1 / 1.1;
+                this.performZoomOperation(coords.world, zoomFactor);
+            }
         }
         this.canvas.render();
         if (!this.canvas.maskTool.isActive) {
@@ -324,14 +377,15 @@ export class CanvasInteractions {
         }
     }
     handleLayerWheelTransformation(e) {
+        const mods = this.getModifierState(e);
         const rotationStep = 5 * (e.deltaY > 0 ? -1 : 1);
         const direction = e.deltaY < 0 ? 1 : -1;
         this.canvas.canvasSelection.selectedLayers.forEach((layer) => {
-            if (e.shiftKey) {
-                this.handleLayerRotation(layer, e.ctrlKey, direction, rotationStep);
+            if (mods.shift) {
+                this.handleLayerRotation(layer, mods.ctrl, direction, rotationStep);
             }
             else {
-                this.handleLayerScaling(layer, e.ctrlKey, e.deltaY);
+                this.handleLayerScaling(layer, mods.ctrl, e.deltaY);
             }
         });
     }
@@ -376,7 +430,7 @@ export class CanvasInteractions {
         }
     }
     calculateGridBasedScaling(oldHeight, deltaY) {
-        const gridSize = 64;
+        const gridSize = 64; // Grid size - could be made configurable in the future
         const direction = deltaY > 0 ? -1 : 1;
         let targetHeight;
         if (direction > 0) {
@@ -401,6 +455,8 @@ export class CanvasInteractions {
     handleKeyDown(e) {
         if (e.key === 'Control')
             this.interaction.isCtrlPressed = true;
+        if (e.key === 'Meta')
+            this.interaction.isMetaPressed = true;
         if (e.key === 'Shift')
             this.interaction.isShiftPressed = true;
         if (e.key === 'Alt') {
@@ -418,11 +474,12 @@ export class CanvasInteractions {
             return;
         }
         // Globalne skróty (Undo/Redo/Copy/Paste)
-        if (e.ctrlKey || e.metaKey) {
+        const mods = this.getModifierState(e);
+        if (mods.ctrl || mods.meta) {
             let handled = true;
             switch (e.key.toLowerCase()) {
                 case 'z':
-                    if (e.shiftKey) {
+                    if (mods.shift) {
                         this.canvas.redo();
                     }
                     else {
@@ -449,7 +506,7 @@ export class CanvasInteractions {
         }
         // Skróty kontekstowe (zależne od zaznaczenia)
         if (this.canvas.canvasSelection.selectedLayers.length > 0) {
-            const step = e.shiftKey ? 10 : 1;
+            const step = mods.shift ? 10 : 1;
             let needsRender = false;
             // Używamy e.code dla spójności i niezależności od układu klawiatury
             const movementKeys = ['ArrowLeft', 'ArrowRight', 'ArrowUp', 'ArrowDown', 'BracketLeft', 'BracketRight'];
@@ -485,6 +542,8 @@ export class CanvasInteractions {
     handleKeyUp(e) {
         if (e.key === 'Control')
             this.interaction.isCtrlPressed = false;
+        if (e.key === 'Meta')
+            this.interaction.isMetaPressed = false;
         if (e.key === 'Shift')
             this.interaction.isShiftPressed = false;
         if (e.key === 'Alt')
@@ -504,6 +563,7 @@ export class CanvasInteractions {
     handleBlur() {
         log.debug('Window lost focus, resetting key states.');
         this.interaction.isCtrlPressed = false;
+        this.interaction.isMetaPressed = false;
         this.interaction.isAltPressed = false;
         this.interaction.isShiftPressed = false;
         this.interaction.isSPressed = false;
@@ -525,6 +585,11 @@ export class CanvasInteractions {
         }
     }
     updateCursor(worldCoords) {
+        // If actively rotating, show grabbing cursor
+        if (this.interaction.mode === 'rotating') {
+            this.canvas.canvas.style.cursor = 'grabbing';
+            return;
+        }
         const transformTarget = this.canvas.canvasLayers.getHandleAtPosition(worldCoords.x, worldCoords.y);
         if (transformTarget) {
             const handleName = transformTarget.handle;
@@ -572,7 +637,9 @@ export class CanvasInteractions {
     }
     prepareForDrag(layer, worldCoords) {
         // Zaktualizuj zaznaczenie, ale nie zapisuj stanu
-        if (this.interaction.isCtrlPressed) {
+        // Support both Ctrl (Windows/Linux) and Cmd (macOS) for multi-selection
+        const mods = this.getModifierState();
+        if (mods.ctrl || mods.meta) {
             const index = this.canvas.canvasSelection.selectedLayers.indexOf(layer);
             if (index === -1) {
                 this.canvas.canvasSelection.updateSelection([...this.canvas.canvasSelection.selectedLayers, layer]);
@@ -590,10 +657,9 @@ export class CanvasInteractions {
         this.interaction.mode = 'potential-drag';
         this.interaction.dragStart = { ...worldCoords };
     }
-    startPanningOrClearSelection(e) {
-        // Ta funkcja jest teraz wywoływana tylko gdy kliknięto na tło bez modyfikatorów.
-        // Domyślna akcja: wyczyść zaznaczenie i rozpocznij panoramowanie.
-        if (!this.interaction.isCtrlPressed) {
+    startPanning(e, clearSelection = true) {
+        // Unified panning method - can optionally clear selection
+        if (clearSelection && !this.interaction.isCtrlPressed) {
             this.canvas.canvasSelection.updateSelection([]);
         }
         this.interaction.mode = 'panning';
@@ -642,19 +708,16 @@ export class CanvasInteractions {
         this.canvas.render();
         this.canvas.saveState();
     }
-    startPanning(e) {
-        if (!this.interaction.isCtrlPressed) {
-            this.canvas.canvasSelection.updateSelection([]);
-        }
-        this.interaction.mode = 'panning';
-        this.interaction.panStart = { x: e.clientX, y: e.clientY };
-    }
     panViewport(e) {
         const dx = e.clientX - this.interaction.panStart.x;
         const dy = e.clientY - this.interaction.panStart.y;
         this.canvas.viewport.x -= dx / this.canvas.viewport.zoom;
         this.canvas.viewport.y -= dy / this.canvas.viewport.zoom;
         this.interaction.panStart = { x: e.clientX, y: e.clientY };
+        // Update stroke overlay if mask tool is drawing during pan
+        if (this.canvas.maskTool.isDrawing) {
+            this.canvas.maskTool.handleViewportChange();
+        }
         this.canvas.render();
         this.canvas.onViewportChange?.();
     }
@@ -709,7 +772,7 @@ export class CanvasInteractions {
             mouseY = Math.abs(mouseY - snapToGrid(mouseY)) < snapThreshold ? snapToGrid(mouseY) : mouseY;
         }
         const o = this.interaction.transformOrigin;
-        if (o.rotation === undefined || o.width === undefined || o.height === undefined || o.centerX === undefined || o.centerY === undefined)
+        if (!o)
             return;
         const handle = this.interaction.resizeHandle;
         const anchor = this.interaction.resizeAnchor;
@@ -856,7 +919,7 @@ export class CanvasInteractions {
         if (!layer)
             return;
         const o = this.interaction.transformOrigin;
-        if (o.rotation === undefined || o.centerX === undefined || o.centerY === undefined)
+        if (!o)
             return;
         const startAngle = Math.atan2(this.interaction.dragStart.y - o.centerY, this.interaction.dragStart.x - o.centerX);
         const currentAngle = Math.atan2(worldCoords.y - o.centerY, worldCoords.x - o.centerX);

js/CanvasRenderer.js

@@ -7,6 +7,9 @@ export class CanvasRenderer {
         this.lastRenderTime = 0;
         this.renderInterval = 1000 / 60;
         this.isDirty = false;
+        // Initialize overlay canvases
+        this.initOverlay();
+        this.initStrokeOverlay();
     }
     /**
      * Helper function to draw text with background at world coordinates
@@ -102,10 +105,12 @@ export class CanvasRenderer {
         if (maskImage && this.canvas.maskTool.isOverlayVisible) {
             ctx.save();
             if (this.canvas.maskTool.isActive) {
+                // In draw mask mode, use the previewOpacity value from the slider
                 ctx.globalCompositeOperation = 'source-over';
-                ctx.globalAlpha = 0.5;
+                ctx.globalAlpha = this.canvas.maskTool.previewOpacity;
             }
             else {
+                // When not in draw mask mode, show mask at full opacity
                 ctx.globalCompositeOperation = 'source-over';
                 ctx.globalAlpha = 1.0;
             }
@@ -158,6 +163,11 @@ export class CanvasRenderer {
             this.canvas.canvas.height = this.canvas.offscreenCanvas.height;
         }
         this.canvas.ctx.drawImage(this.canvas.offscreenCanvas, 0, 0);
+        // Ensure overlay canvases are in DOM and properly sized
+        this.addOverlayToDOM();
+        this.updateOverlaySize();
+        this.addStrokeOverlayToDOM();
+        this.updateStrokeOverlaySize();
         // Update Batch Preview UI positions
         if (this.canvas.batchPreviewManagers && this.canvas.batchPreviewManagers.length > 0) {
             this.canvas.batchPreviewManagers.forEach((manager) => {
@@ -583,4 +593,243 @@ export class CanvasRenderer {
             padding: 8
         });
     }
+    /**
+     * Initialize overlay canvas for lightweight overlays like brush cursor
+     */
+    initOverlay() {
+        // Setup overlay canvas to match main canvas
+        this.updateOverlaySize();
+        // Position overlay canvas on top of main canvas
+        this.canvas.overlayCanvas.style.position = 'absolute';
+        this.canvas.overlayCanvas.style.left = '0px';
+        this.canvas.overlayCanvas.style.top = '0px';
+        this.canvas.overlayCanvas.style.pointerEvents = 'none';
+        this.canvas.overlayCanvas.style.zIndex = '20'; // Above other overlays
+        // Add overlay to DOM when main canvas is added
+        this.addOverlayToDOM();
+        log.debug('Overlay canvas initialized');
+    }
+    /**
+     * Add overlay canvas to DOM if main canvas has a parent
+     */
+    addOverlayToDOM() {
+        if (this.canvas.canvas.parentElement && !this.canvas.overlayCanvas.parentElement) {
+            this.canvas.canvas.parentElement.appendChild(this.canvas.overlayCanvas);
+            log.debug('Overlay canvas added to DOM');
+        }
+    }
+    /**
+     * Update overlay canvas size to match main canvas
+     */
+    updateOverlaySize() {
+        if (this.canvas.overlayCanvas.width !== this.canvas.canvas.clientWidth ||
+            this.canvas.overlayCanvas.height !== this.canvas.canvas.clientHeight) {
+            this.canvas.overlayCanvas.width = Math.max(1, this.canvas.canvas.clientWidth);
+            this.canvas.overlayCanvas.height = Math.max(1, this.canvas.canvas.clientHeight);
+            log.debug(`Overlay canvas resized to ${this.canvas.overlayCanvas.width}x${this.canvas.overlayCanvas.height}`);
+        }
+    }
+    /**
+     * Clear overlay canvas
+     */
+    clearOverlay() {
+        this.canvas.overlayCtx.clearRect(0, 0, this.canvas.overlayCanvas.width, this.canvas.overlayCanvas.height);
+    }
+    /**
+     * Initialize a dedicated overlay for real-time mask stroke preview
+     */
+    initStrokeOverlay() {
+        // Create canvas if not created yet
+        if (!this.strokeOverlayCanvas) {
+            this.strokeOverlayCanvas = document.createElement('canvas');
+            const ctx = this.strokeOverlayCanvas.getContext('2d');
+            if (!ctx) {
+                throw new Error('Failed to get 2D context for stroke overlay canvas');
+            }
+            this.strokeOverlayCtx = ctx;
+        }
+        // Size match main canvas
+        this.updateStrokeOverlaySize();
+        // Position above main canvas but below cursor overlay
+        this.strokeOverlayCanvas.style.position = 'absolute';
+        this.strokeOverlayCanvas.style.left = '1px';
+        this.strokeOverlayCanvas.style.top = '1px';
+        this.strokeOverlayCanvas.style.pointerEvents = 'none';
+        this.strokeOverlayCanvas.style.zIndex = '19'; // Below cursor overlay (20)
+        // Opacity is now controlled by MaskTool.previewOpacity
+        this.strokeOverlayCanvas.style.opacity = String(this.canvas.maskTool.previewOpacity || 0.5);
+        // Add to DOM
+        this.addStrokeOverlayToDOM();
+        log.debug('Stroke overlay canvas initialized');
+    }
+    /**
+     * Add stroke overlay canvas to DOM if needed
+     */
+    addStrokeOverlayToDOM() {
+        if (this.canvas.canvas.parentElement && !this.strokeOverlayCanvas.parentElement) {
+            this.canvas.canvas.parentElement.appendChild(this.strokeOverlayCanvas);
+            log.debug('Stroke overlay canvas added to DOM');
+        }
+    }
+    /**
+     * Ensure stroke overlay size matches main canvas
+     */
+    updateStrokeOverlaySize() {
+        const w = Math.max(1, this.canvas.canvas.clientWidth);
+        const h = Math.max(1, this.canvas.canvas.clientHeight);
+        if (this.strokeOverlayCanvas.width !== w || this.strokeOverlayCanvas.height !== h) {
+            this.strokeOverlayCanvas.width = w;
+            this.strokeOverlayCanvas.height = h;
+            log.debug(`Stroke overlay resized to ${w}x${h}`);
+        }
+    }
+    /**
+     * Clear the stroke overlay
+     */
+    clearMaskStrokeOverlay() {
+        if (!this.strokeOverlayCtx)
+            return;
+        this.strokeOverlayCtx.clearRect(0, 0, this.strokeOverlayCanvas.width, this.strokeOverlayCanvas.height);
+    }
+    /**
+     * Draw a preview stroke segment onto the stroke overlay in screen space
+     * Uses line drawing with gradient to match MaskTool's drawLineOnChunk exactly
+     */
+    drawMaskStrokeSegment(startWorld, endWorld) {
+        // Ensure overlay is present and sized
+        this.updateStrokeOverlaySize();
+        const zoom = this.canvas.viewport.zoom;
+        const toScreen = (p) => ({
+            x: (p.x - this.canvas.viewport.x) * zoom,
+            y: (p.y - this.canvas.viewport.y) * zoom
+        });
+        const startScreen = toScreen(startWorld);
+        const endScreen = toScreen(endWorld);
+        const brushRadius = (this.canvas.maskTool.brushSize / 2) * zoom;
+        const hardness = this.canvas.maskTool.brushHardness;
+        const strength = this.canvas.maskTool.brushStrength;
+        // If strength is 0, don't draw anything
+        if (strength <= 0) {
+            return;
+        }
+        this.strokeOverlayCtx.save();
+        // Draw line segment exactly as MaskTool does
+        this.strokeOverlayCtx.beginPath();
+        this.strokeOverlayCtx.moveTo(startScreen.x, startScreen.y);
+        this.strokeOverlayCtx.lineTo(endScreen.x, endScreen.y);
+        // Match the gradient setup from MaskTool's drawLineOnChunk
+        if (hardness === 1) {
+            this.strokeOverlayCtx.strokeStyle = `rgba(255, 255, 255, ${strength})`;
+        }
+        else {
+            const innerRadius = brushRadius * hardness;
+            const gradient = this.strokeOverlayCtx.createRadialGradient(endScreen.x, endScreen.y, innerRadius, endScreen.x, endScreen.y, brushRadius);
+            gradient.addColorStop(0, `rgba(255, 255, 255, ${strength})`);
+            gradient.addColorStop(1, `rgba(255, 255, 255, 0)`);
+            this.strokeOverlayCtx.strokeStyle = gradient;
+        }
+        // Match line properties from MaskTool
+        this.strokeOverlayCtx.lineWidth = this.canvas.maskTool.brushSize * zoom;
+        this.strokeOverlayCtx.lineCap = 'round';
+        this.strokeOverlayCtx.lineJoin = 'round';
+        this.strokeOverlayCtx.globalCompositeOperation = 'source-over';
+        this.strokeOverlayCtx.stroke();
+        this.strokeOverlayCtx.restore();
+    }
+    /**
+     * Redraws the entire stroke overlay from world coordinates
+     * Used when viewport changes during drawing to maintain visual consistency
+     */
+    redrawMaskStrokeOverlay(strokePoints) {
+        if (strokePoints.length < 2)
+            return;
+        // Clear the overlay first
+        this.clearMaskStrokeOverlay();
+        // Redraw all segments with current viewport
+        for (let i = 1; i < strokePoints.length; i++) {
+            this.drawMaskStrokeSegment(strokePoints[i - 1], strokePoints[i]);
+        }
+    }
+    /**
+     * Draw mask brush cursor on overlay canvas with visual feedback for size, strength and hardness
+     * @param worldPoint World coordinates of cursor
+     */
+    drawMaskBrushCursor(worldPoint) {
+        if (!this.canvas.maskTool.isActive || !this.canvas.isMouseOver) {
+            this.clearOverlay();
+            return;
+        }
+        // Update overlay size if needed
+        this.updateOverlaySize();
+        // Clear previous cursor
+        this.clearOverlay();
+        // Convert world coordinates to screen coordinates
+        const screenX = (worldPoint.x - this.canvas.viewport.x) * this.canvas.viewport.zoom;
+        const screenY = (worldPoint.y - this.canvas.viewport.y) * this.canvas.viewport.zoom;
+        // Get brush properties
+        const brushRadius = (this.canvas.maskTool.brushSize / 2) * this.canvas.viewport.zoom;
+        const brushStrength = this.canvas.maskTool.brushStrength;
+        const brushHardness = this.canvas.maskTool.brushHardness;
+        // Save context state
+        this.canvas.overlayCtx.save();
+        // If strength is 0, just draw outline
+        if (brushStrength > 0) {
+            // Draw inner fill to visualize brush effect - matches actual brush rendering
+            const gradient = this.canvas.overlayCtx.createRadialGradient(screenX, screenY, 0, screenX, screenY, brushRadius);
+            // Preview alpha - subtle to not obscure content
+            const previewAlpha = brushStrength * 0.15; // Very subtle preview (max 15% opacity)
+            if (brushHardness === 1) {
+                // Hard brush - uniform fill within radius
+                gradient.addColorStop(0, `rgba(255, 255, 255, ${previewAlpha})`);
+                gradient.addColorStop(1, `rgba(255, 255, 255, ${previewAlpha})`);
+            }
+            else {
+                // Soft brush - gradient fade matching actual brush
+                gradient.addColorStop(0, `rgba(255, 255, 255, ${previewAlpha})`);
+                if (brushHardness > 0) {
+                    gradient.addColorStop(brushHardness, `rgba(255, 255, 255, ${previewAlpha})`);
+                }
+                gradient.addColorStop(1, `rgba(255, 255, 255, 0)`);
+            }
+            this.canvas.overlayCtx.beginPath();
+            this.canvas.overlayCtx.arc(screenX, screenY, brushRadius, 0, 2 * Math.PI);
+            this.canvas.overlayCtx.fillStyle = gradient;
+            this.canvas.overlayCtx.fill();
+        }
+        // Draw outer circle (SIZE indicator)
+        this.canvas.overlayCtx.beginPath();
+        this.canvas.overlayCtx.arc(screenX, screenY, brushRadius, 0, 2 * Math.PI);
+        // Stroke opacity based on strength (dimmer when strength is 0)
+        const strokeOpacity = brushStrength > 0 ? (0.4 + brushStrength * 0.4) : 0.3;
+        this.canvas.overlayCtx.strokeStyle = `rgba(255, 255, 255, ${strokeOpacity})`;
+        this.canvas.overlayCtx.lineWidth = 1.5;
+        // Visual feedback for hardness
+        if (brushHardness > 0.8) {
+            // Hard brush - solid line
+            this.canvas.overlayCtx.setLineDash([]);
+        }
+        else {
+            // Soft brush - dashed line
+            const dashLength = 2 + (1 - brushHardness) * 4;
+            this.canvas.overlayCtx.setLineDash([dashLength, dashLength]);
+        }
+        this.canvas.overlayCtx.stroke();
+        // Center dot for small brushes
+        if (brushRadius < 5) {
+            this.canvas.overlayCtx.beginPath();
+            this.canvas.overlayCtx.arc(screenX, screenY, 1, 0, 2 * Math.PI);
+            this.canvas.overlayCtx.fillStyle = `rgba(255, 255, 255, ${strokeOpacity})`;
+            this.canvas.overlayCtx.fill();
+        }
+        // Restore context state
+        this.canvas.overlayCtx.restore();
+    }
+    /**
+     * Update overlay position when viewport changes
+     */
+    updateOverlayPosition() {
+        // Overlay canvas is positioned absolutely, so it doesn't need repositioning
+        // Just ensure it's the right size
+        this.updateOverlaySize();
+    }
 }

js/CanvasView.js

@@ -554,6 +554,25 @@ async function createCanvasWidget(node, widget, app) {
                         setTimeout(() => canvas.render(), 0);
                     }
                 }),
+                $el("div.painter-slider-container.mask-control", { style: { display: 'none' } }, [
+                    $el("label", { for: "preview-opacity-slider", textContent: "Mask Opacity:" }),
+                    $el("input", {
+                        id: "preview-opacity-slider",
+                        type: "range",
+                        min: "0",
+                        max: "1",
+                        step: "0.05",
+                        value: "0.5",
+                        oninput: (e) => {
+                            const value = e.target.value;
+                            canvas.maskTool.setPreviewOpacity(parseFloat(value));
+                            const valueEl = document.getElementById('preview-opacity-value');
+                            if (valueEl)
+                                valueEl.textContent = `${Math.round(parseFloat(value) * 100)}%`;
+                        }
+                    }),
+                    $el("div.slider-value", { id: "preview-opacity-value" }, ["50%"])
+                ]),
                 $el("div.painter-slider-container.mask-control", { style: { display: 'none' } }, [
                     $el("label", { for: "brush-size-slider", textContent: "Size:" }),
                     $el("input", {

js/MaskTool.js

@@ -3,11 +3,15 @@ import { createCanvas } from "./utils/CommonUtils.js";
 const log = createModuleLogger('Mask_tool');
 export class MaskTool {
     constructor(canvasInstance, callbacks = {}) {
+        // Track strokes during drawing for efficient overlay updates
+        this.currentStrokePoints = [];
         this.ACTIVE_MASK_UPDATE_DELAY = 16; // ~60fps throttling
         this.SHAPE_PREVIEW_THROTTLE_DELAY = 16; // ~60fps throttling for preview
         this.canvasInstance = canvasInstance;
         this.mainCanvas = canvasInstance.canvas;
         this.onStateChange = callbacks.onStateChange || null;
+        // Initialize stroke tracking for overlay drawing
+        this.currentStrokePoints = [];
         // Initialize chunked mask system
         this.maskChunks = new Map();
         this.chunkSize = 512;
@@ -28,8 +32,9 @@ export class MaskTool {
         this.isOverlayVisible = true;
         this.isActive = false;
         this.brushSize = 20;
-        this.brushStrength = 0.5;
-        this.brushHardness = 0.5;
+        this._brushStrength = 0.5;
+        this._brushHardness = 0.5;
+        this._previewOpacity = 0.5; // Default 50% opacity for preview
         this.isDrawing = false;
         this.lastPosition = null;
         const { canvas: previewCanvas, ctx: previewCtx } = createCanvas(1, 1, '2d', { willReadFrequently: true });
@@ -79,8 +84,27 @@ export class MaskTool {
             this.canvasInstance.canvas.parentElement.appendChild(this.previewCanvas);
         }
     }
+    // Getters for brush properties
+    get brushStrength() {
+        return this._brushStrength;
+    }
+    get brushHardness() {
+        return this._brushHardness;
+    }
+    get previewOpacity() {
+        return this._previewOpacity;
+    }
     setBrushHardness(hardness) {
-        this.brushHardness = Math.max(0, Math.min(1, hardness));
+        this._brushHardness = Math.max(0, Math.min(1, hardness));
+    }
+    setPreviewOpacity(opacity) {
+        this._previewOpacity = Math.max(0, Math.min(1, opacity));
+        // Update the stroke overlay canvas opacity when preview opacity changes
+        if (this.canvasInstance.canvasRenderer && this.canvasInstance.canvasRenderer.strokeOverlayCanvas) {
+            this.canvasInstance.canvasRenderer.strokeOverlayCanvas.style.opacity = String(this._previewOpacity);
+        }
+        // Trigger canvas render to update mask display opacity
+        this.canvasInstance.render();
     }
     initMaskCanvas() {
         // Initialize chunked system
@@ -671,16 +695,17 @@ export class MaskTool {
         this.brushSize = Math.max(1, size);
     }
     setBrushStrength(strength) {
-        this.brushStrength = Math.max(0, Math.min(1, strength));
+        this._brushStrength = Math.max(0, Math.min(1, strength));
     }
     handleMouseDown(worldCoords, viewCoords) {
         if (!this.isActive)
             return;
         this.isDrawing = true;
         this.lastPosition = worldCoords;
-        // Activate chunks around the drawing position for performance
-        this.updateActiveChunksForDrawing(worldCoords);
-        this.draw(worldCoords);
+        // Initialize stroke tracking for live preview
+        this.currentStrokePoints = [worldCoords];
+        // Clear any previous stroke overlay
+        this.canvasInstance.canvasRenderer.clearMaskStrokeOverlay();
         this.clearPreview();
     }
     handleMouseMove(worldCoords, viewCoords) {
@@ -689,14 +714,69 @@ export class MaskTool {
         }
         if (!this.isActive || !this.isDrawing)
             return;
-        // Dynamically update active chunks as user moves while drawing
-        this.updateActiveChunksForDrawing(worldCoords);
-        this.draw(worldCoords);
+        // Add point to stroke tracking
+        this.currentStrokePoints.push(worldCoords);
+        // Draw interpolated segments for smooth strokes without gaps
+        if (this.lastPosition) {
+            // Calculate distance between last and current position
+            const dx = worldCoords.x - this.lastPosition.x;
+            const dy = worldCoords.y - this.lastPosition.y;
+            const distance = Math.sqrt(dx * dx + dy * dy);
+            // If distance is small, just draw a single segment
+            if (distance < this.brushSize / 4) {
+                this.canvasInstance.canvasRenderer.drawMaskStrokeSegment(this.lastPosition, worldCoords);
+            }
+            else {
+                // Interpolate points for smooth drawing without gaps
+                const interpolatedPoints = this.interpolatePoints(this.lastPosition, worldCoords, distance);
+                // Draw all interpolated segments
+                for (let i = 0; i < interpolatedPoints.length - 1; i++) {
+                    this.canvasInstance.canvasRenderer.drawMaskStrokeSegment(interpolatedPoints[i], interpolatedPoints[i + 1]);
+                }
+            }
+        }
         this.lastPosition = worldCoords;
     }
+    /**
+     * Interpolates points between two positions to create smooth strokes without gaps
+     * Based on the BrushTool's approach for eliminating dotted lines during fast drawing
+     */
+    interpolatePoints(start, end, distance) {
+        const points = [];
+        // Calculate number of interpolated points based on brush size
+        // More points = smoother line
+        const stepSize = Math.max(1, this.brushSize / 6); // Adjust divisor for smoothness
+        const numSteps = Math.ceil(distance / stepSize);
+        // Always include start point
+        points.push(start);
+        // Interpolate intermediate points
+        for (let i = 1; i < numSteps; i++) {
+            const t = i / numSteps;
+            points.push({
+                x: start.x + (end.x - start.x) * t,
+                y: start.y + (end.y - start.y) * t
+            });
+        }
+        // Always include end point
+        points.push(end);
+        return points;
+    }
+    /**
+     * Called when viewport changes during drawing to update stroke overlay
+     * This ensures the stroke preview scales correctly with zoom changes
+     */
+    handleViewportChange() {
+        if (this.isDrawing && this.currentStrokePoints.length > 1) {
+            // Redraw the entire stroke overlay with new viewport settings
+            this.canvasInstance.canvasRenderer.redrawMaskStrokeOverlay(this.currentStrokePoints);
+        }
+    }
     handleMouseLeave() {
         this.previewVisible = false;
         this.clearPreview();
+        // Clear overlay canvases when mouse leaves
+        this.canvasInstance.canvasRenderer.clearOverlay();
+        this.canvasInstance.canvasRenderer.clearMaskStrokeOverlay();
     }
     handleMouseEnter() {
         this.previewVisible = true;
@@ -706,10 +786,15 @@ export class MaskTool {
             return;
         if (this.isDrawing) {
             this.isDrawing = false;
+            // Commit the stroke from overlay to actual mask chunks
+            this.commitStrokeToChunks();
+            // Clear stroke overlay and reset state
+            this.canvasInstance.canvasRenderer.clearMaskStrokeOverlay();
+            this.currentStrokePoints = [];
             this.lastPosition = null;
             this.currentDrawingChunk = null;
             // After drawing is complete, update active canvas to show all chunks
-            this.updateActiveMaskCanvas(true); // forceShowAll = true
+            this.updateActiveMaskCanvas(true); // Force full update
             this.completeMaskOperation();
             this.drawBrushPreview(viewCoords);
         }
@@ -724,6 +809,38 @@ export class MaskTool {
         // This prevents unnecessary recomposition during drawing
         this.updateActiveCanvasIfNeeded(this.lastPosition, worldCoords);
     }
+    /**
+     * Commits the current stroke from overlay to actual mask chunks
+     * This replays the entire stroke path with interpolation to ensure pixel-perfect accuracy
+     */
+    commitStrokeToChunks() {
+        if (this.currentStrokePoints.length < 2) {
+            return; // Need at least 2 points for a stroke
+        }
+        log.debug(`Committing stroke with ${this.currentStrokePoints.length} points to chunks`);
+        // Replay the entire stroke path with interpolation for smooth, accurate lines
+        for (let i = 1; i < this.currentStrokePoints.length; i++) {
+            const startPoint = this.currentStrokePoints[i - 1];
+            const endPoint = this.currentStrokePoints[i];
+            // Calculate distance between points
+            const dx = endPoint.x - startPoint.x;
+            const dy = endPoint.y - startPoint.y;
+            const distance = Math.sqrt(dx * dx + dy * dy);
+            if (distance < this.brushSize / 4) {
+                // Small distance - draw single segment
+                this.drawOnChunks(startPoint, endPoint);
+            }
+            else {
+                // Large distance - interpolate for smooth line without gaps
+                const interpolatedPoints = this.interpolatePoints(startPoint, endPoint, distance);
+                // Draw all interpolated segments
+                for (let j = 0; j < interpolatedPoints.length - 1; j++) {
+                    this.drawOnChunks(interpolatedPoints[j], interpolatedPoints[j + 1]);
+                }
+            }
+        }
+        log.debug("Stroke committed to chunks successfully with interpolation");
+    }
     /**
      * Draws a line between two world coordinates on the appropriate chunks
      */
@@ -767,13 +884,13 @@ export class MaskTool {
         chunk.ctx.moveTo(startLocal.x, startLocal.y);
         chunk.ctx.lineTo(endLocal.x, endLocal.y);
         const gradientRadius = this.brushSize / 2;
-        if (this.brushHardness === 1) {
-            chunk.ctx.strokeStyle = `rgba(255, 255, 255, ${this.brushStrength})`;
+        if (this._brushHardness === 1) {
+            chunk.ctx.strokeStyle = `rgba(255, 255, 255, ${this._brushStrength})`;
         }
         else {
-            const innerRadius = gradientRadius * this.brushHardness;
+            const innerRadius = gradientRadius * this._brushHardness;
             const gradient = chunk.ctx.createRadialGradient(endLocal.x, endLocal.y, innerRadius, endLocal.x, endLocal.y, gradientRadius);
-            gradient.addColorStop(0, `rgba(255, 255, 255, ${this.brushStrength})`);
+            gradient.addColorStop(0, `rgba(255, 255, 255, ${this._brushStrength})`);
             gradient.addColorStop(1, `rgba(255, 255, 255, 0)`);
             chunk.ctx.strokeStyle = gradient;
         }
@@ -805,28 +922,17 @@ export class MaskTool {
         return true; // For now, always draw - more precise intersection can be added later
     }
     /**
-     * Updates active canvas when drawing affects chunks with throttling to prevent lag
-     * During drawing, only updates the affected active chunks for performance
+     * Updates active canvas when drawing affects chunks
+     * Since we now use overlay during drawing, this is only called after drawing is complete
      */
     updateActiveCanvasIfNeeded(startWorld, endWorld) {
-        // Calculate which chunks were affected by this drawing operation
-        const minX = Math.min(startWorld.x, endWorld.x) - this.brushSize;
-        const maxX = Math.max(startWorld.x, endWorld.x) + this.brushSize;
-        const minY = Math.min(startWorld.y, endWorld.y) - this.brushSize;
-        const maxY = Math.max(startWorld.y, endWorld.y) + this.brushSize;
-        const affectedChunkMinX = Math.floor(minX / this.chunkSize);
-        const affectedChunkMinY = Math.floor(minY / this.chunkSize);
-        const affectedChunkMaxX = Math.floor(maxX / this.chunkSize);
-        const affectedChunkMaxY = Math.floor(maxY / this.chunkSize);
-        // During drawing, only update affected chunks that are active for performance
-        if (this.isDrawing) {
-            // Use throttled partial update for active chunks only
-            this.scheduleThrottledActiveMaskUpdate(affectedChunkMinX, affectedChunkMinY, affectedChunkMaxX, affectedChunkMaxY);
-        }
-        else {
+        // This method is now simplified - we only update after drawing is complete
+        // The overlay handles all live preview, so we don't need complex chunk activation
+        if (!this.isDrawing) {
             // Not drawing - do full update to show all chunks
             this.updateActiveMaskCanvas(true);
         }
+        // During drawing, we don't update chunks at all - overlay handles preview
     }
     /**
      * Schedules a throttled update of the active mask canvas to prevent excessive redraws
@@ -903,18 +1009,12 @@ export class MaskTool {
     }
     drawBrushPreview(viewCoords) {
         if (!this.previewVisible || this.isDrawing) {
-            this.clearPreview();
+            this.canvasInstance.canvasRenderer.clearOverlay();
             return;
         }
-        this.clearPreview();
-        const zoom = this.canvasInstance.viewport.zoom;
-        const radius = (this.brushSize / 2) * zoom;
-        this.previewCtx.beginPath();
-        this.previewCtx.arc(viewCoords.x, viewCoords.y, radius, 0, 2 * Math.PI);
-        this.previewCtx.strokeStyle = 'rgba(255, 255, 255, 0.8)';
-        this.previewCtx.lineWidth = 1;
-        this.previewCtx.setLineDash([2, 4]);
-        this.previewCtx.stroke();
+        // Use overlay canvas instead of preview canvas for brush cursor
+        const worldCoords = this.canvasInstance.lastMousePosition;
+        this.canvasInstance.canvasRenderer.drawMaskBrushCursor(worldCoords);
     }
     clearPreview() {
         this.previewCtx.clearRect(0, 0, this.previewCanvas.width, this.previewCanvas.height);

pyproject.toml

@@ -1,7 +1,7 @@
 [project]
 name = "layerforge"
 description = "Photoshop-like layered canvas editor to your ComfyUI workflow. This node is perfect for complex compositing, inpainting, and outpainting, featuring multi-layer support, masking, blend modes, and precise transformations. Includes optional AI-powered background removal for streamlined image editing."
-version = "1.5.4"
+version = "1.5.5"
 license = { text = "MIT License" }
 dependencies = ["torch", "torchvision", "transformers", "aiohttp", "numpy", "tqdm", "Pillow"]
 

src/Canvas.ts

@@ -84,6 +84,8 @@ export class Canvas {
     node: ComfyNode;
     offscreenCanvas: HTMLCanvasElement;
     offscreenCtx: CanvasRenderingContext2D | null;
+    overlayCanvas: HTMLCanvasElement;
+    overlayCtx: CanvasRenderingContext2D;
     onHistoryChange: ((historyInfo: { canUndo: boolean; canRedo: boolean; }) => void) | undefined;
     onViewportChange: (() => void) | null;
     onStateChange: (() => void) | undefined;
@@ -122,6 +124,16 @@ export class Canvas {
         });
         this.offscreenCanvas = offscreenCanvas;
         this.offscreenCtx = offscreenCtx;
+        
+        // Create overlay canvas for brush cursor and other lightweight overlays
+        const { canvas: overlayCanvas, ctx: overlayCtx } = createCanvas(0, 0, '2d', {
+            alpha: true,
+            willReadFrequently: false
+        });
+        if (!overlayCtx) throw new Error("Could not create overlay canvas context");
+        this.overlayCanvas = overlayCanvas;
+        this.overlayCtx = overlayCtx;
+        
         this.canvasContainer = null;
 
         this.dataInitialized = false;

src/CanvasInteractions.ts

@@ -10,15 +10,36 @@ interface MouseCoordinates {
     view: Point;
 }
 
+interface ModifierState {
+    ctrl: boolean;
+    shift: boolean;
+    alt: boolean;
+    meta: boolean;
+}
+
+interface TransformOrigin {
+    x: number;
+    y: number;
+    width: number;
+    height: number;
+    rotation: number;
+    centerX: number;
+    centerY: number;
+    originalWidth?: number;
+    originalHeight?: number;
+    cropBounds?: { x: number; y: number; width: number; height: number };
+}
+
 interface InteractionState {
     mode: 'none' | 'panning' | 'dragging' | 'resizing' | 'rotating' | 'drawingMask' | 'resizingCanvas' | 'movingCanvas' | 'potential-drag' | 'drawingShape';
     panStart: Point;
     dragStart: Point;
-    transformOrigin: Partial<Layer> & { centerX?: number, centerY?: number };
+    transformOrigin: TransformOrigin | null;
     resizeHandle: string | null;
     resizeAnchor: Point;
     canvasResizeStart: Point;
     isCtrlPressed: boolean;
+    isMetaPressed: boolean;
     isAltPressed: boolean;
     isShiftPressed: boolean;
     isSPressed: boolean;
@@ -35,17 +56,35 @@ export class CanvasInteractions {
     public interaction: InteractionState;
     private originalLayerPositions: Map<Layer, Point>;
 
+    // Bound event handlers to enable proper removeEventListener and avoid leaks
+    private onMouseDown = (e: MouseEvent) => this.handleMouseDown(e);
+    private onMouseMove = (e: MouseEvent) => this.handleMouseMove(e);
+    private onMouseUp = (e: MouseEvent) => this.handleMouseUp(e);
+    private onMouseEnter = (e: MouseEvent) => { this.canvas.isMouseOver = true; this.handleMouseEnter(e); };
+    private onMouseLeave = (e: MouseEvent) => { this.canvas.isMouseOver = false; this.handleMouseLeave(e); };
+    private onWheel = (e: WheelEvent) => this.handleWheel(e);
+    private onKeyDown = (e: KeyboardEvent) => this.handleKeyDown(e);
+    private onKeyUp = (e: KeyboardEvent) => this.handleKeyUp(e);
+    private onDragOver = (e: DragEvent) => this.handleDragOver(e);
+    private onDragEnter = (e: DragEvent) => this.handleDragEnter(e);
+    private onDragLeave = (e: DragEvent) => this.handleDragLeave(e);
+    private onDrop = (e: DragEvent) => { this.handleDrop(e); };
+    private onContextMenu = (e: MouseEvent) => this.handleContextMenu(e);
+    private onBlur = () => this.handleBlur();
+    private onPaste = (e: ClipboardEvent) => this.handlePasteEvent(e);
+
     constructor(canvas: Canvas) {
         this.canvas = canvas;
         this.interaction = {
             mode: 'none',
             panStart: { x: 0, y: 0 },
             dragStart: { x: 0, y: 0 },
-            transformOrigin: {},
+            transformOrigin: null,
             resizeHandle: null,
             resizeAnchor: { x: 0, y: 0 },
             canvasResizeStart: { x: 0, y: 0 },
             isCtrlPressed: false,
+            isMetaPressed: false,
             isAltPressed: false,
             isShiftPressed: false,
             isSPressed: false,
@@ -68,13 +107,21 @@ export class CanvasInteractions {
         };
     }
 
+    private getModifierState(e?: MouseEvent | WheelEvent | KeyboardEvent): ModifierState {
+        return {
+            ctrl: this.interaction.isCtrlPressed || (e as any)?.ctrlKey || false,
+            shift: this.interaction.isShiftPressed || (e as any)?.shiftKey || false,
+            alt: this.interaction.isAltPressed || (e as any)?.altKey || false,
+            meta: this.interaction.isMetaPressed || (e as any)?.metaKey || false,
+        };
+    }
+
     private preventEventDefaults(e: Event): void {
         e.preventDefault();
         e.stopPropagation();
     }
 
     private performZoomOperation(worldCoords: Point, zoomFactor: number): void {
-        const rect = this.canvas.canvas.getBoundingClientRect();
         const mouseBufferX = (worldCoords.x - this.canvas.viewport.x) * this.canvas.viewport.zoom;
         const mouseBufferY = (worldCoords.y - this.canvas.viewport.y) * this.canvas.viewport.zoom;
 
@@ -84,6 +131,11 @@ export class CanvasInteractions {
         this.canvas.viewport.x = worldCoords.x - (mouseBufferX / this.canvas.viewport.zoom);
         this.canvas.viewport.y = worldCoords.y - (mouseBufferY / this.canvas.viewport.zoom);
         
+        // Update stroke overlay if mask tool is drawing during zoom
+        if (this.canvas.maskTool.isDrawing) {
+            this.canvas.maskTool.handleViewportChange();
+        }
+        
         this.canvas.onViewportChange?.();
     }
 
@@ -106,34 +158,49 @@ export class CanvasInteractions {
     }
 
     setupEventListeners(): void {
-        this.canvas.canvas.addEventListener('mousedown', this.handleMouseDown.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('mousemove', this.handleMouseMove.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('mouseup', this.handleMouseUp.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('mouseleave', this.handleMouseLeave.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('wheel', this.handleWheel.bind(this) as EventListener, { passive: false });
-        this.canvas.canvas.addEventListener('keydown', this.handleKeyDown.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('keyup', this.handleKeyUp.bind(this) as EventListener);
+        this.canvas.canvas.addEventListener('mousedown', this.onMouseDown as EventListener);
+        this.canvas.canvas.addEventListener('mousemove', this.onMouseMove as EventListener);
+        this.canvas.canvas.addEventListener('mouseup', this.onMouseUp as EventListener);
+        this.canvas.canvas.addEventListener('wheel', this.onWheel as EventListener, { passive: false });
+        this.canvas.canvas.addEventListener('keydown', this.onKeyDown as EventListener);
+        this.canvas.canvas.addEventListener('keyup', this.onKeyUp as EventListener);
 
         // Add a blur event listener to the window to reset key states
-        window.addEventListener('blur', this.handleBlur.bind(this));
+        window.addEventListener('blur', this.onBlur);
 
-        document.addEventListener('paste', this.handlePasteEvent.bind(this));
+        document.addEventListener('paste', this.onPaste as unknown as EventListener);
 
-        this.canvas.canvas.addEventListener('mouseenter', (e: MouseEvent) => {
-            this.canvas.isMouseOver = true;
-            this.handleMouseEnter(e);
-        });
-        this.canvas.canvas.addEventListener('mouseleave', (e: MouseEvent) => {
-            this.canvas.isMouseOver = false;
-            this.handleMouseLeave(e);
-        });
+        this.canvas.canvas.addEventListener('mouseenter', this.onMouseEnter as EventListener);
+        this.canvas.canvas.addEventListener('mouseleave', this.onMouseLeave as EventListener);
 
-        this.canvas.canvas.addEventListener('dragover', this.handleDragOver.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('dragenter', this.handleDragEnter.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('dragleave', this.handleDragLeave.bind(this) as EventListener);
-        this.canvas.canvas.addEventListener('drop', this.handleDrop.bind(this) as unknown as EventListener);
+        this.canvas.canvas.addEventListener('dragover', this.onDragOver as EventListener);
+        this.canvas.canvas.addEventListener('dragenter', this.onDragEnter as EventListener);
+        this.canvas.canvas.addEventListener('dragleave', this.onDragLeave as EventListener);
+        this.canvas.canvas.addEventListener('drop', this.onDrop as unknown as EventListener);
 
-        this.canvas.canvas.addEventListener('contextmenu', this.handleContextMenu.bind(this) as EventListener);
+        this.canvas.canvas.addEventListener('contextmenu', this.onContextMenu as EventListener);
+    }
+
+    teardownEventListeners(): void {
+        this.canvas.canvas.removeEventListener('mousedown', this.onMouseDown as EventListener);
+        this.canvas.canvas.removeEventListener('mousemove', this.onMouseMove as EventListener);
+        this.canvas.canvas.removeEventListener('mouseup', this.onMouseUp as EventListener);
+        this.canvas.canvas.removeEventListener('wheel', this.onWheel as EventListener);
+        this.canvas.canvas.removeEventListener('keydown', this.onKeyDown as EventListener);
+        this.canvas.canvas.removeEventListener('keyup', this.onKeyUp as EventListener);
+
+        window.removeEventListener('blur', this.onBlur);
+        document.removeEventListener('paste', this.onPaste as unknown as EventListener);
+
+        this.canvas.canvas.removeEventListener('mouseenter', this.onMouseEnter as EventListener);
+        this.canvas.canvas.removeEventListener('mouseleave', this.onMouseLeave as EventListener);
+
+        this.canvas.canvas.removeEventListener('dragover', this.onDragOver as EventListener);
+        this.canvas.canvas.removeEventListener('dragenter', this.onDragEnter as EventListener);
+        this.canvas.canvas.removeEventListener('dragleave', this.onDragLeave as EventListener);
+        this.canvas.canvas.removeEventListener('drop', this.onDrop as unknown as EventListener);
+
+        this.canvas.canvas.removeEventListener('contextmenu', this.onContextMenu as EventListener);
     }
 
     /**
@@ -177,10 +244,11 @@ export class CanvasInteractions {
     handleMouseDown(e: MouseEvent): void {
         this.canvas.canvas.focus();
         const coords = this.getMouseCoordinates(e);
+        const mods = this.getModifierState(e);
 
         if (this.interaction.mode === 'drawingMask') {
             this.canvas.maskTool.handleMouseDown(coords.world, coords.view);
-            this.canvas.render();
+            // Don't render here - mask tool will handle its own drawing
             return;
         }
 
@@ -192,11 +260,11 @@ export class CanvasInteractions {
         // --- Ostateczna, poprawna kolejność sprawdzania ---
 
         // 1. Akcje globalne z modyfikatorami (mają najwyższy priorytet)
-        if (e.shiftKey && e.ctrlKey) {
+        if (mods.shift && mods.ctrl) {
             this.startCanvasMove(coords.world);
             return;
         }
-        if (e.shiftKey) {
+        if (mods.shift) {
             // Clear custom shape when starting canvas resize
             if (this.canvas.outputAreaShape) {
                 // If auto-apply shape mask is enabled, remove the mask before clearing the shape
@@ -222,7 +290,7 @@ export class CanvasInteractions {
             }
             return;
         }
-        if (e.button !== 0) { // Środkowy przycisk
+        if (e.button === 1) { // Środkowy przycisk
             this.startPanning(e);
             return;
         }
@@ -241,7 +309,7 @@ export class CanvasInteractions {
         }
         
         // 4. Domyślna akcja na tle (lewy przycisk bez modyfikatorów)
-        this.startPanningOrClearSelection(e);
+        this.startPanning(e, true); // clearSelection = true
     }
 
     handleMouseMove(e: MouseEvent): void {
@@ -264,7 +332,7 @@ export class CanvasInteractions {
         switch (this.interaction.mode) {
             case 'drawingMask':
                 this.canvas.maskTool.handleMouseMove(coords.world, coords.view);
-                this.canvas.render();
+                // Don't render during mask drawing - it's handled by mask tool internally
                 break;
             case 'panning':
                 this.panViewport(e);
@@ -286,6 +354,10 @@ export class CanvasInteractions {
                 break;
             default:
                 this.updateCursor(coords.world);
+                // Update brush cursor on overlay if mask tool is active
+                if (this.canvas.maskTool.isActive) {
+                    this.canvas.canvasRenderer.drawMaskBrushCursor(coords.world);
+                }
                 break;
         }
 
@@ -300,6 +372,7 @@ export class CanvasInteractions {
         
         if (this.interaction.mode === 'drawingMask') {
             this.canvas.maskTool.handleMouseUp(coords.view);
+            // Render only once after drawing is complete
             this.canvas.render();
             return;
         }
@@ -397,8 +470,17 @@ export class CanvasInteractions {
             const zoomFactor = e.deltaY < 0 ? 1.1 : 1 / 1.1;
             this.performZoomOperation(coords.world, zoomFactor);
         } else {
-            // Layer transformation when layers are selected
-            this.handleLayerWheelTransformation(e);
+            // Check if mouse is over any selected layer
+            const isOverSelectedLayer = this.isPointInSelectedLayers(coords.world.x, coords.world.y);
+            
+            if (isOverSelectedLayer) {
+                // Layer transformation when layers are selected and mouse is over selected layer
+                this.handleLayerWheelTransformation(e);
+            } else {
+                // Zoom operation when mouse is not over selected layers
+                const zoomFactor = e.deltaY < 0 ? 1.1 : 1 / 1.1;
+                this.performZoomOperation(coords.world, zoomFactor);
+            }
         }
         
         this.canvas.render();
@@ -408,14 +490,15 @@ export class CanvasInteractions {
     }
 
     private handleLayerWheelTransformation(e: WheelEvent): void {
+        const mods = this.getModifierState(e);
         const rotationStep = 5 * (e.deltaY > 0 ? -1 : 1);
         const direction = e.deltaY < 0 ? 1 : -1;
 
         this.canvas.canvasSelection.selectedLayers.forEach((layer: Layer) => {
-            if (e.shiftKey) {
-                this.handleLayerRotation(layer, e.ctrlKey, direction, rotationStep);
+            if (mods.shift) {
+                this.handleLayerRotation(layer, mods.ctrl, direction, rotationStep);
             } else {
-                this.handleLayerScaling(layer, e.ctrlKey, e.deltaY);
+                this.handleLayerScaling(layer, mods.ctrl, e.deltaY);
             }
         });
     }
@@ -462,7 +545,7 @@ export class CanvasInteractions {
     }
 
     private calculateGridBasedScaling(oldHeight: number, deltaY: number): number {
-        const gridSize = 64;
+        const gridSize = 64; // Grid size - could be made configurable in the future
         const direction = deltaY > 0 ? -1 : 1;
         let targetHeight;
 
@@ -487,6 +570,7 @@ export class CanvasInteractions {
 
     handleKeyDown(e: KeyboardEvent): void {
         if (e.key === 'Control') this.interaction.isCtrlPressed = true;
+        if (e.key === 'Meta') this.interaction.isMetaPressed = true;
         if (e.key === 'Shift') this.interaction.isShiftPressed = true;
         if (e.key === 'Alt') {
             this.interaction.isAltPressed = true;
@@ -505,11 +589,12 @@ export class CanvasInteractions {
         }
         
         // Globalne skróty (Undo/Redo/Copy/Paste)
-        if (e.ctrlKey || e.metaKey) {
+        const mods = this.getModifierState(e);
+        if (mods.ctrl || mods.meta) {
             let handled = true;
             switch (e.key.toLowerCase()) {
                 case 'z':
-                    if (e.shiftKey) {
+                    if (mods.shift) {
                         this.canvas.redo();
                     } else {
                         this.canvas.undo();
@@ -536,7 +621,7 @@ export class CanvasInteractions {
 
         // Skróty kontekstowe (zależne od zaznaczenia)
         if (this.canvas.canvasSelection.selectedLayers.length > 0) {
-            const step = e.shiftKey ? 10 : 1;
+            const step = mods.shift ? 10 : 1;
             let needsRender = false;
             
             // Używamy e.code dla spójności i niezależności od układu klawiatury
@@ -571,6 +656,7 @@ export class CanvasInteractions {
 
     handleKeyUp(e: KeyboardEvent): void {
         if (e.key === 'Control') this.interaction.isCtrlPressed = false;
+        if (e.key === 'Meta') this.interaction.isMetaPressed = false;
         if (e.key === 'Shift') this.interaction.isShiftPressed = false;
         if (e.key === 'Alt') this.interaction.isAltPressed = false;
         if (e.key.toLowerCase() === 's') this.interaction.isSPressed = false;
@@ -590,6 +676,7 @@ export class CanvasInteractions {
     handleBlur(): void {
         log.debug('Window lost focus, resetting key states.');
         this.interaction.isCtrlPressed = false;
+        this.interaction.isMetaPressed = false;
         this.interaction.isAltPressed = false;
         this.interaction.isShiftPressed = false;
         this.interaction.isSPressed = false;
@@ -615,6 +702,12 @@ export class CanvasInteractions {
     }
 
     updateCursor(worldCoords: Point): void {
+        // If actively rotating, show grabbing cursor
+        if (this.interaction.mode === 'rotating') {
+            this.canvas.canvas.style.cursor = 'grabbing';
+            return;
+        }
+
         const transformTarget = this.canvas.canvasLayers.getHandleAtPosition(worldCoords.x, worldCoords.y);
 
         if (transformTarget) {
@@ -663,7 +756,9 @@ export class CanvasInteractions {
 
     prepareForDrag(layer: Layer, worldCoords: Point): void {
         // Zaktualizuj zaznaczenie, ale nie zapisuj stanu
-        if (this.interaction.isCtrlPressed) {
+        // Support both Ctrl (Windows/Linux) and Cmd (macOS) for multi-selection
+        const mods = this.getModifierState();
+        if (mods.ctrl || mods.meta) {
             const index = this.canvas.canvasSelection.selectedLayers.indexOf(layer);
             if (index === -1) {
                 this.canvas.canvasSelection.updateSelection([...this.canvas.canvasSelection.selectedLayers, layer]);
@@ -681,14 +776,13 @@ export class CanvasInteractions {
         this.interaction.dragStart = {...worldCoords};
     }
 
-    startPanningOrClearSelection(e: MouseEvent): void {
-        // Ta funkcja jest teraz wywoływana tylko gdy kliknięto na tło bez modyfikatorów.
-        // Domyślna akcja: wyczyść zaznaczenie i rozpocznij panoramowanie.
-        if (!this.interaction.isCtrlPressed) {
+    startPanning(e: MouseEvent, clearSelection: boolean = true): void {
+        // Unified panning method - can optionally clear selection
+        if (clearSelection && !this.interaction.isCtrlPressed) {
             this.canvas.canvasSelection.updateSelection([]);
         }
         this.interaction.mode = 'panning';
-        this.interaction.panStart = {x: e.clientX, y: e.clientY};
+        this.interaction.panStart = { x: e.clientX, y: e.clientY };
     }
 
     startCanvasResize(worldCoords: Point): void {
@@ -743,20 +837,18 @@ export class CanvasInteractions {
         this.canvas.saveState();
     }
 
-    startPanning(e: MouseEvent): void {
-        if (!this.interaction.isCtrlPressed) {
-            this.canvas.canvasSelection.updateSelection([]);
-        }
-        this.interaction.mode = 'panning';
-        this.interaction.panStart = { x: e.clientX, y: e.clientY };
-    }
-
     panViewport(e: MouseEvent): void {
         const dx = e.clientX - this.interaction.panStart.x;
         const dy = e.clientY - this.interaction.panStart.y;
         this.canvas.viewport.x -= dx / this.canvas.viewport.zoom;
         this.canvas.viewport.y -= dy / this.canvas.viewport.zoom;
         this.interaction.panStart = {x: e.clientX, y: e.clientY};
+        
+        // Update stroke overlay if mask tool is drawing during pan
+        if (this.canvas.maskTool.isDrawing) {
+            this.canvas.maskTool.handleViewportChange();
+        }
+        
         this.canvas.render();
         this.canvas.onViewportChange?.();
     }
@@ -818,7 +910,7 @@ export class CanvasInteractions {
         }
 
         const o = this.interaction.transformOrigin;
-        if (o.rotation === undefined || o.width === undefined || o.height === undefined || o.centerX === undefined || o.centerY === undefined) return;
+        if (!o) return;
         
         const handle = this.interaction.resizeHandle;
         const anchor = this.interaction.resizeAnchor;
@@ -974,7 +1066,7 @@ export class CanvasInteractions {
         if (!layer) return;
 
         const o = this.interaction.transformOrigin;
-        if (o.rotation === undefined || o.centerX === undefined || o.centerY === undefined) return;
+        if (!o) return;
         const startAngle = Math.atan2(this.interaction.dragStart.y - o.centerY, this.interaction.dragStart.x - o.centerX);
         const currentAngle = Math.atan2(worldCoords.y - o.centerY, worldCoords.x - o.centerX);
         let angleDiff = (currentAngle - startAngle) * 180 / Math.PI;

src/CanvasRenderer.ts

@@ -8,12 +8,19 @@ export class CanvasRenderer {
     lastRenderTime: any;
     renderAnimationFrame: any;
     renderInterval: any;
+    // Overlay used to preview in-progress mask strokes (separate from cursor overlay)
+    strokeOverlayCanvas!: HTMLCanvasElement;
+    strokeOverlayCtx!: CanvasRenderingContext2D;
     constructor(canvas: any) {
         this.canvas = canvas;
         this.renderAnimationFrame = null;
         this.lastRenderTime = 0;
         this.renderInterval = 1000 / 60;
         this.isDirty = false;
+        
+        // Initialize overlay canvases
+        this.initOverlay();
+        this.initStrokeOverlay();
     }
 
     /**
@@ -141,9 +148,11 @@ export class CanvasRenderer {
             ctx.save();
 
             if (this.canvas.maskTool.isActive) {
+                // In draw mask mode, use the previewOpacity value from the slider
                 ctx.globalCompositeOperation = 'source-over';
-                ctx.globalAlpha = 0.5;
+                ctx.globalAlpha = this.canvas.maskTool.previewOpacity;
             } else {
+                // When not in draw mask mode, show mask at full opacity
                 ctx.globalCompositeOperation = 'source-over';
                 ctx.globalAlpha = 1.0;
             }
@@ -205,6 +214,12 @@ export class CanvasRenderer {
         }
         this.canvas.ctx.drawImage(this.canvas.offscreenCanvas, 0, 0);
 
+        // Ensure overlay canvases are in DOM and properly sized
+        this.addOverlayToDOM();
+        this.updateOverlaySize();
+        this.addStrokeOverlayToDOM();
+        this.updateStrokeOverlaySize();
+
         // Update Batch Preview UI positions
         if (this.canvas.batchPreviewManagers && this.canvas.batchPreviewManagers.length > 0) {
             this.canvas.batchPreviewManagers.forEach((manager: any) => {
@@ -710,4 +725,290 @@ export class CanvasRenderer {
             padding: 8
         });
     }
+
+    /**
+     * Initialize overlay canvas for lightweight overlays like brush cursor
+     */
+    initOverlay(): void {
+        // Setup overlay canvas to match main canvas
+        this.updateOverlaySize();
+        
+        // Position overlay canvas on top of main canvas
+        this.canvas.overlayCanvas.style.position = 'absolute';
+        this.canvas.overlayCanvas.style.left = '0px';
+        this.canvas.overlayCanvas.style.top = '0px';
+        this.canvas.overlayCanvas.style.pointerEvents = 'none';
+        this.canvas.overlayCanvas.style.zIndex = '20'; // Above other overlays
+        
+        // Add overlay to DOM when main canvas is added
+        this.addOverlayToDOM();
+        
+        log.debug('Overlay canvas initialized');
+    }
+
+    /**
+     * Add overlay canvas to DOM if main canvas has a parent
+     */
+    addOverlayToDOM(): void {
+        if (this.canvas.canvas.parentElement && !this.canvas.overlayCanvas.parentElement) {
+            this.canvas.canvas.parentElement.appendChild(this.canvas.overlayCanvas);
+            log.debug('Overlay canvas added to DOM');
+        }
+    }
+
+    /**
+     * Update overlay canvas size to match main canvas
+     */
+    updateOverlaySize(): void {
+        if (this.canvas.overlayCanvas.width !== this.canvas.canvas.clientWidth ||
+            this.canvas.overlayCanvas.height !== this.canvas.canvas.clientHeight) {
+            
+            this.canvas.overlayCanvas.width = Math.max(1, this.canvas.canvas.clientWidth);
+            this.canvas.overlayCanvas.height = Math.max(1, this.canvas.canvas.clientHeight);
+            
+            log.debug(`Overlay canvas resized to ${this.canvas.overlayCanvas.width}x${this.canvas.overlayCanvas.height}`);
+        }
+    }
+
+    /**
+     * Clear overlay canvas
+     */
+    clearOverlay(): void {
+        this.canvas.overlayCtx.clearRect(0, 0, this.canvas.overlayCanvas.width, this.canvas.overlayCanvas.height);
+    }
+
+    /**
+     * Initialize a dedicated overlay for real-time mask stroke preview
+     */
+    initStrokeOverlay(): void {
+        // Create canvas if not created yet
+        if (!this.strokeOverlayCanvas) {
+            this.strokeOverlayCanvas = document.createElement('canvas');
+            const ctx = this.strokeOverlayCanvas.getContext('2d');
+            if (!ctx) {
+                throw new Error('Failed to get 2D context for stroke overlay canvas');
+            }
+            this.strokeOverlayCtx = ctx;
+        }
+
+        // Size match main canvas
+        this.updateStrokeOverlaySize();
+
+        // Position above main canvas but below cursor overlay
+        this.strokeOverlayCanvas.style.position = 'absolute';
+        this.strokeOverlayCanvas.style.left = '1px';
+        this.strokeOverlayCanvas.style.top = '1px';
+        this.strokeOverlayCanvas.style.pointerEvents = 'none';
+        this.strokeOverlayCanvas.style.zIndex = '19'; // Below cursor overlay (20)
+        // Opacity is now controlled by MaskTool.previewOpacity
+        this.strokeOverlayCanvas.style.opacity = String(this.canvas.maskTool.previewOpacity || 0.5);
+
+        // Add to DOM
+        this.addStrokeOverlayToDOM();
+        log.debug('Stroke overlay canvas initialized');
+    }
+
+    /**
+     * Add stroke overlay canvas to DOM if needed
+     */
+    addStrokeOverlayToDOM(): void {
+        if (this.canvas.canvas.parentElement && !this.strokeOverlayCanvas.parentElement) {
+            this.canvas.canvas.parentElement.appendChild(this.strokeOverlayCanvas);
+            log.debug('Stroke overlay canvas added to DOM');
+        }
+    }
+
+    /**
+     * Ensure stroke overlay size matches main canvas
+     */
+    updateStrokeOverlaySize(): void {
+        const w = Math.max(1, this.canvas.canvas.clientWidth);
+        const h = Math.max(1, this.canvas.canvas.clientHeight);
+        if (this.strokeOverlayCanvas.width !== w || this.strokeOverlayCanvas.height !== h) {
+            this.strokeOverlayCanvas.width = w;
+            this.strokeOverlayCanvas.height = h;
+            log.debug(`Stroke overlay resized to ${w}x${h}`);
+        }
+    }
+
+    /**
+     * Clear the stroke overlay
+     */
+    clearMaskStrokeOverlay(): void {
+        if (!this.strokeOverlayCtx) return;
+        this.strokeOverlayCtx.clearRect(0, 0, this.strokeOverlayCanvas.width, this.strokeOverlayCanvas.height);
+    }
+
+    /**
+     * Draw a preview stroke segment onto the stroke overlay in screen space
+     * Uses line drawing with gradient to match MaskTool's drawLineOnChunk exactly
+     */
+    drawMaskStrokeSegment(startWorld: { x: number; y: number }, endWorld: { x: number; y: number }): void {
+        // Ensure overlay is present and sized
+        this.updateStrokeOverlaySize();
+
+        const zoom = this.canvas.viewport.zoom;
+        const toScreen = (p: { x: number; y: number }) => ({
+            x: (p.x - this.canvas.viewport.x) * zoom,
+            y: (p.y - this.canvas.viewport.y) * zoom
+        });
+
+        const startScreen = toScreen(startWorld);
+        const endScreen = toScreen(endWorld);
+
+        const brushRadius = (this.canvas.maskTool.brushSize / 2) * zoom;
+        const hardness = this.canvas.maskTool.brushHardness;
+        const strength = this.canvas.maskTool.brushStrength;
+
+        // If strength is 0, don't draw anything
+        if (strength <= 0) {
+            return;
+        }
+
+        this.strokeOverlayCtx.save();
+        
+        // Draw line segment exactly as MaskTool does
+        this.strokeOverlayCtx.beginPath();
+        this.strokeOverlayCtx.moveTo(startScreen.x, startScreen.y);
+        this.strokeOverlayCtx.lineTo(endScreen.x, endScreen.y);
+        
+        // Match the gradient setup from MaskTool's drawLineOnChunk
+        if (hardness === 1) {
+            this.strokeOverlayCtx.strokeStyle = `rgba(255, 255, 255, ${strength})`;
+        } else {
+            const innerRadius = brushRadius * hardness;
+            const gradient = this.strokeOverlayCtx.createRadialGradient(
+                endScreen.x, endScreen.y, innerRadius,
+                endScreen.x, endScreen.y, brushRadius
+            );
+            gradient.addColorStop(0, `rgba(255, 255, 255, ${strength})`);
+            gradient.addColorStop(1, `rgba(255, 255, 255, 0)`);
+            this.strokeOverlayCtx.strokeStyle = gradient;
+        }
+        
+        // Match line properties from MaskTool
+        this.strokeOverlayCtx.lineWidth = this.canvas.maskTool.brushSize * zoom;
+        this.strokeOverlayCtx.lineCap = 'round';
+        this.strokeOverlayCtx.lineJoin = 'round';
+        this.strokeOverlayCtx.globalCompositeOperation = 'source-over';
+        this.strokeOverlayCtx.stroke();
+        
+        this.strokeOverlayCtx.restore();
+    }
+
+    /**
+     * Redraws the entire stroke overlay from world coordinates
+     * Used when viewport changes during drawing to maintain visual consistency
+     */
+    redrawMaskStrokeOverlay(strokePoints: { x: number; y: number }[]): void {
+        if (strokePoints.length < 2) return;
+
+        // Clear the overlay first
+        this.clearMaskStrokeOverlay();
+
+        // Redraw all segments with current viewport
+        for (let i = 1; i < strokePoints.length; i++) {
+            this.drawMaskStrokeSegment(strokePoints[i - 1], strokePoints[i]);
+        }
+    }
+
+    /**
+     * Draw mask brush cursor on overlay canvas with visual feedback for size, strength and hardness
+     * @param worldPoint World coordinates of cursor
+     */
+    drawMaskBrushCursor(worldPoint: { x: number, y: number }): void {
+        if (!this.canvas.maskTool.isActive || !this.canvas.isMouseOver) {
+            this.clearOverlay();
+            return;
+        }
+
+        // Update overlay size if needed
+        this.updateOverlaySize();
+        
+        // Clear previous cursor
+        this.clearOverlay();
+        
+        // Convert world coordinates to screen coordinates
+        const screenX = (worldPoint.x - this.canvas.viewport.x) * this.canvas.viewport.zoom;
+        const screenY = (worldPoint.y - this.canvas.viewport.y) * this.canvas.viewport.zoom;
+        
+        // Get brush properties
+        const brushRadius = (this.canvas.maskTool.brushSize / 2) * this.canvas.viewport.zoom;
+        const brushStrength = this.canvas.maskTool.brushStrength;
+        const brushHardness = this.canvas.maskTool.brushHardness;
+        
+        // Save context state
+        this.canvas.overlayCtx.save();
+        
+        // If strength is 0, just draw outline
+        if (brushStrength > 0) {
+            // Draw inner fill to visualize brush effect - matches actual brush rendering
+            const gradient = this.canvas.overlayCtx.createRadialGradient(
+                screenX, screenY, 0,
+                screenX, screenY, brushRadius
+            );
+            
+            // Preview alpha - subtle to not obscure content
+            const previewAlpha = brushStrength * 0.15; // Very subtle preview (max 15% opacity)
+            
+            if (brushHardness === 1) {
+                // Hard brush - uniform fill within radius
+                gradient.addColorStop(0, `rgba(255, 255, 255, ${previewAlpha})`);
+                gradient.addColorStop(1, `rgba(255, 255, 255, ${previewAlpha})`);
+            } else {
+                // Soft brush - gradient fade matching actual brush
+                gradient.addColorStop(0, `rgba(255, 255, 255, ${previewAlpha})`);
+                if (brushHardness > 0) {
+                    gradient.addColorStop(brushHardness, `rgba(255, 255, 255, ${previewAlpha})`);
+                }
+                gradient.addColorStop(1, `rgba(255, 255, 255, 0)`);
+            }
+            
+            this.canvas.overlayCtx.beginPath();
+            this.canvas.overlayCtx.arc(screenX, screenY, brushRadius, 0, 2 * Math.PI);
+            this.canvas.overlayCtx.fillStyle = gradient;
+            this.canvas.overlayCtx.fill();
+        }
+        
+        // Draw outer circle (SIZE indicator)
+        this.canvas.overlayCtx.beginPath();
+        this.canvas.overlayCtx.arc(screenX, screenY, brushRadius, 0, 2 * Math.PI);
+        
+        // Stroke opacity based on strength (dimmer when strength is 0)
+        const strokeOpacity = brushStrength > 0 ? (0.4 + brushStrength * 0.4) : 0.3;
+        this.canvas.overlayCtx.strokeStyle = `rgba(255, 255, 255, ${strokeOpacity})`;
+        this.canvas.overlayCtx.lineWidth = 1.5;
+        
+        // Visual feedback for hardness
+        if (brushHardness > 0.8) {
+            // Hard brush - solid line
+            this.canvas.overlayCtx.setLineDash([]);
+        } else {
+            // Soft brush - dashed line
+            const dashLength = 2 + (1 - brushHardness) * 4;
+            this.canvas.overlayCtx.setLineDash([dashLength, dashLength]);
+        }
+        
+        this.canvas.overlayCtx.stroke();
+        
+        // Center dot for small brushes
+        if (brushRadius < 5) {
+            this.canvas.overlayCtx.beginPath();
+            this.canvas.overlayCtx.arc(screenX, screenY, 1, 0, 2 * Math.PI);
+            this.canvas.overlayCtx.fillStyle = `rgba(255, 255, 255, ${strokeOpacity})`;
+            this.canvas.overlayCtx.fill();
+        }
+        
+        // Restore context state
+        this.canvas.overlayCtx.restore();
+    }
+
+    /**
+     * Update overlay position when viewport changes
+     */
+    updateOverlayPosition(): void {
+        // Overlay canvas is positioned absolutely, so it doesn't need repositioning
+        // Just ensure it's the right size
+        this.updateOverlaySize();
+    }
 }

src/CanvasView.ts

@@ -640,6 +640,24 @@ $el("label.clipboard-switch.mask-switch", {
                         setTimeout(() => canvas.render(), 0);
                     }
                 }),
+                $el("div.painter-slider-container.mask-control", {style: {display: 'none'}}, [
+                    $el("label", {for: "preview-opacity-slider", textContent: "Mask Opacity:"}),
+                    $el("input", {
+                        id: "preview-opacity-slider",
+                        type: "range",
+                        min: "0",
+                        max: "1",
+                        step: "0.05",
+                        value: "0.5",
+                        oninput: (e: Event) => {
+                            const value = (e.target as HTMLInputElement).value;
+                            canvas.maskTool.setPreviewOpacity(parseFloat(value));
+                            const valueEl = document.getElementById('preview-opacity-value');
+                            if (valueEl) valueEl.textContent = `${Math.round(parseFloat(value) * 100)}%`;
+                        }
+                    }),
+                    $el("div.slider-value", {id: "preview-opacity-value"}, ["50%"])
+                ]),
                 $el("div.painter-slider-container.mask-control", {style: {display: 'none'}}, [
                     $el("label", {for: "brush-size-slider", textContent: "Size:"}),
                     $el("input", {

src/MaskTool.ts

@@ -21,9 +21,10 @@ interface MaskChunk {
 }
 
 export class MaskTool {
-    private brushHardness: number;
-    private brushSize: number;
-    private brushStrength: number;
+    private _brushHardness: number;
+    public brushSize: number;
+    private _brushStrength: number;
+    private _previewOpacity: number;
     private canvasInstance: Canvas & { canvasState: CanvasState, width: number, height: number };
     public isActive: boolean;
     public isDrawing: boolean;
@@ -31,6 +32,9 @@ export class MaskTool {
     private lastPosition: Point | null;
     private mainCanvas: HTMLCanvasElement;
     
+    // Track strokes during drawing for efficient overlay updates
+    private currentStrokePoints: Point[] = [];
+    
     // Chunked mask system
     private maskChunks: Map<string, MaskChunk>; // Key: "x,y" (chunk coordinates)
     private chunkSize: number;
@@ -72,6 +76,9 @@ export class MaskTool {
         this.mainCanvas = canvasInstance.canvas;
         this.onStateChange = callbacks.onStateChange || null;
         
+        // Initialize stroke tracking for overlay drawing
+        this.currentStrokePoints = [];
+        
         // Initialize chunked mask system
         this.maskChunks = new Map();
         this.chunkSize = 512;
@@ -96,8 +103,9 @@ export class MaskTool {
         this.isOverlayVisible = true;
         this.isActive = false;
         this.brushSize = 20;
-        this.brushStrength = 0.5;
-        this.brushHardness = 0.5;
+        this._brushStrength = 0.5;
+        this._brushHardness = 0.5;
+        this._previewOpacity = 0.5; // Default 50% opacity for preview
         this.isDrawing = false;
         this.lastPosition = null;
 
@@ -156,8 +164,31 @@ export class MaskTool {
         }
     }
 
+    // Getters for brush properties
+    get brushStrength(): number {
+        return this._brushStrength;
+    }
+
+    get brushHardness(): number {
+        return this._brushHardness;
+    }
+
+    get previewOpacity(): number {
+        return this._previewOpacity;
+    }
+
     setBrushHardness(hardness: number): void {
-        this.brushHardness = Math.max(0, Math.min(1, hardness));
+        this._brushHardness = Math.max(0, Math.min(1, hardness));
+    }
+
+    setPreviewOpacity(opacity: number): void {
+        this._previewOpacity = Math.max(0, Math.min(1, opacity));
+        // Update the stroke overlay canvas opacity when preview opacity changes
+        if (this.canvasInstance.canvasRenderer && this.canvasInstance.canvasRenderer.strokeOverlayCanvas) {
+            this.canvasInstance.canvasRenderer.strokeOverlayCanvas.style.opacity = String(this._previewOpacity);
+        }
+        // Trigger canvas render to update mask display opacity
+        this.canvasInstance.render();
     }
 
     initMaskCanvas(): void {
@@ -867,7 +898,7 @@ export class MaskTool {
     }
 
     setBrushStrength(strength: number): void {
-        this.brushStrength = Math.max(0, Math.min(1, strength));
+        this._brushStrength = Math.max(0, Math.min(1, strength));
     }
 
     handleMouseDown(worldCoords: Point, viewCoords: Point): void {
@@ -875,10 +906,12 @@ export class MaskTool {
         this.isDrawing = true;
         this.lastPosition = worldCoords;
         
-        // Activate chunks around the drawing position for performance
-        this.updateActiveChunksForDrawing(worldCoords);
+        // Initialize stroke tracking for live preview
+        this.currentStrokePoints = [worldCoords];
+        
+        // Clear any previous stroke overlay
+        this.canvasInstance.canvasRenderer.clearMaskStrokeOverlay();
         
-        this.draw(worldCoords);
         this.clearPreview();
     }
 
@@ -888,16 +921,83 @@ export class MaskTool {
         }
         if (!this.isActive || !this.isDrawing) return;
         
-        // Dynamically update active chunks as user moves while drawing
-        this.updateActiveChunksForDrawing(worldCoords);
+        // Add point to stroke tracking
+        this.currentStrokePoints.push(worldCoords);
+        
+        // Draw interpolated segments for smooth strokes without gaps
+        if (this.lastPosition) {
+            // Calculate distance between last and current position
+            const dx = worldCoords.x - this.lastPosition.x;
+            const dy = worldCoords.y - this.lastPosition.y;
+            const distance = Math.sqrt(dx * dx + dy * dy);
+            
+            // If distance is small, just draw a single segment
+            if (distance < this.brushSize / 4) {
+                this.canvasInstance.canvasRenderer.drawMaskStrokeSegment(this.lastPosition, worldCoords);
+            } else {
+                // Interpolate points for smooth drawing without gaps
+                const interpolatedPoints = this.interpolatePoints(this.lastPosition, worldCoords, distance);
+                
+                // Draw all interpolated segments
+                for (let i = 0; i < interpolatedPoints.length - 1; i++) {
+                    this.canvasInstance.canvasRenderer.drawMaskStrokeSegment(
+                        interpolatedPoints[i], 
+                        interpolatedPoints[i + 1]
+                    );
+                }
+            }
+        }
         
-        this.draw(worldCoords);
         this.lastPosition = worldCoords;
     }
 
+    /**
+     * Interpolates points between two positions to create smooth strokes without gaps
+     * Based on the BrushTool's approach for eliminating dotted lines during fast drawing
+     */
+    private interpolatePoints(start: Point, end: Point, distance: number): Point[] {
+        const points: Point[] = [];
+        
+        // Calculate number of interpolated points based on brush size
+        // More points = smoother line
+        const stepSize = Math.max(1, this.brushSize / 6); // Adjust divisor for smoothness
+        const numSteps = Math.ceil(distance / stepSize);
+        
+        // Always include start point
+        points.push(start);
+        
+        // Interpolate intermediate points
+        for (let i = 1; i < numSteps; i++) {
+            const t = i / numSteps;
+            points.push({
+                x: start.x + (end.x - start.x) * t,
+                y: start.y + (end.y - start.y) * t
+            });
+        }
+        
+        // Always include end point
+        points.push(end);
+        
+        return points;
+    }
+
+    /**
+     * Called when viewport changes during drawing to update stroke overlay
+     * This ensures the stroke preview scales correctly with zoom changes
+     */
+    handleViewportChange(): void {
+        if (this.isDrawing && this.currentStrokePoints.length > 1) {
+            // Redraw the entire stroke overlay with new viewport settings
+            this.canvasInstance.canvasRenderer.redrawMaskStrokeOverlay(this.currentStrokePoints);
+        }
+    }
+
     handleMouseLeave(): void {
         this.previewVisible = false;
         this.clearPreview();
+        // Clear overlay canvases when mouse leaves
+        this.canvasInstance.canvasRenderer.clearOverlay();
+        this.canvasInstance.canvasRenderer.clearMaskStrokeOverlay();
     }
 
     handleMouseEnter(): void {
@@ -908,11 +1008,18 @@ export class MaskTool {
         if (!this.isActive) return;
         if (this.isDrawing) {
             this.isDrawing = false;
+            
+            // Commit the stroke from overlay to actual mask chunks
+            this.commitStrokeToChunks();
+            
+            // Clear stroke overlay and reset state
+            this.canvasInstance.canvasRenderer.clearMaskStrokeOverlay();
+            this.currentStrokePoints = [];
             this.lastPosition = null;
             this.currentDrawingChunk = null;
             
             // After drawing is complete, update active canvas to show all chunks
-            this.updateActiveMaskCanvas(true); // forceShowAll = true
+            this.updateActiveMaskCanvas(true); // Force full update
             
             this.completeMaskOperation();
             this.drawBrushPreview(viewCoords);
@@ -932,6 +1039,44 @@ export class MaskTool {
         this.updateActiveCanvasIfNeeded(this.lastPosition, worldCoords);
     }
 
+    /**
+     * Commits the current stroke from overlay to actual mask chunks
+     * This replays the entire stroke path with interpolation to ensure pixel-perfect accuracy
+     */
+    private commitStrokeToChunks(): void {
+        if (this.currentStrokePoints.length < 2) {
+            return; // Need at least 2 points for a stroke
+        }
+        
+        log.debug(`Committing stroke with ${this.currentStrokePoints.length} points to chunks`);
+        
+        // Replay the entire stroke path with interpolation for smooth, accurate lines
+        for (let i = 1; i < this.currentStrokePoints.length; i++) {
+            const startPoint = this.currentStrokePoints[i - 1];
+            const endPoint = this.currentStrokePoints[i];
+            
+            // Calculate distance between points
+            const dx = endPoint.x - startPoint.x;
+            const dy = endPoint.y - startPoint.y;
+            const distance = Math.sqrt(dx * dx + dy * dy);
+            
+            if (distance < this.brushSize / 4) {
+                // Small distance - draw single segment
+                this.drawOnChunks(startPoint, endPoint);
+            } else {
+                // Large distance - interpolate for smooth line without gaps
+                const interpolatedPoints = this.interpolatePoints(startPoint, endPoint, distance);
+                
+                // Draw all interpolated segments
+                for (let j = 0; j < interpolatedPoints.length - 1; j++) {
+                    this.drawOnChunks(interpolatedPoints[j], interpolatedPoints[j + 1]);
+                }
+            }
+        }
+        
+        log.debug("Stroke committed to chunks successfully with interpolation");
+    }
+
     /**
      * Draws a line between two world coordinates on the appropriate chunks
      */
@@ -982,15 +1127,15 @@ export class MaskTool {
         
         const gradientRadius = this.brushSize / 2;
         
-        if (this.brushHardness === 1) {
-            chunk.ctx.strokeStyle = `rgba(255, 255, 255, ${this.brushStrength})`;
+        if (this._brushHardness === 1) {
+            chunk.ctx.strokeStyle = `rgba(255, 255, 255, ${this._brushStrength})`;
         } else {
-            const innerRadius = gradientRadius * this.brushHardness;
+            const innerRadius = gradientRadius * this._brushHardness;
             const gradient = chunk.ctx.createRadialGradient(
                 endLocal.x, endLocal.y, innerRadius,
                 endLocal.x, endLocal.y, gradientRadius
             );
-            gradient.addColorStop(0, `rgba(255, 255, 255, ${this.brushStrength})`);
+            gradient.addColorStop(0, `rgba(255, 255, 255, ${this._brushStrength})`);
             gradient.addColorStop(1, `rgba(255, 255, 255, 0)`);
             chunk.ctx.strokeStyle = gradient;
         }
@@ -1029,29 +1174,17 @@ export class MaskTool {
     }
 
     /**
-     * Updates active canvas when drawing affects chunks with throttling to prevent lag
-     * During drawing, only updates the affected active chunks for performance
+     * Updates active canvas when drawing affects chunks
+     * Since we now use overlay during drawing, this is only called after drawing is complete
      */
     private updateActiveCanvasIfNeeded(startWorld: Point, endWorld: Point): void {
-        // Calculate which chunks were affected by this drawing operation
-        const minX = Math.min(startWorld.x, endWorld.x) - this.brushSize;
-        const maxX = Math.max(startWorld.x, endWorld.x) + this.brushSize;
-        const minY = Math.min(startWorld.y, endWorld.y) - this.brushSize;
-        const maxY = Math.max(startWorld.y, endWorld.y) + this.brushSize;
-        
-        const affectedChunkMinX = Math.floor(minX / this.chunkSize);
-        const affectedChunkMinY = Math.floor(minY / this.chunkSize);
-        const affectedChunkMaxX = Math.floor(maxX / this.chunkSize);
-        const affectedChunkMaxY = Math.floor(maxY / this.chunkSize);
-
-        // During drawing, only update affected chunks that are active for performance
-        if (this.isDrawing) {
-            // Use throttled partial update for active chunks only
-            this.scheduleThrottledActiveMaskUpdate(affectedChunkMinX, affectedChunkMinY, affectedChunkMaxX, affectedChunkMaxY);
-        } else {
+        // This method is now simplified - we only update after drawing is complete
+        // The overlay handles all live preview, so we don't need complex chunk activation
+        if (!this.isDrawing) {
             // Not drawing - do full update to show all chunks
             this.updateActiveMaskCanvas(true);
         }
+        // During drawing, we don't update chunks at all - overlay handles preview
     }
 
     /**
@@ -1142,20 +1275,13 @@ export class MaskTool {
 
     drawBrushPreview(viewCoords: Point): void {
         if (!this.previewVisible || this.isDrawing) {
-            this.clearPreview();
+            this.canvasInstance.canvasRenderer.clearOverlay();
             return;
         }
 
-        this.clearPreview();
-        const zoom = this.canvasInstance.viewport.zoom;
-        const radius = (this.brushSize / 2) * zoom;
-
-        this.previewCtx.beginPath();
-        this.previewCtx.arc(viewCoords.x, viewCoords.y, radius, 0, 2 * Math.PI);
-        this.previewCtx.strokeStyle = 'rgba(255, 255, 255, 0.8)';
-        this.previewCtx.lineWidth = 1;
-        this.previewCtx.setLineDash([2, 4]);
-        this.previewCtx.stroke();
+        // Use overlay canvas instead of preview canvas for brush cursor
+        const worldCoords = this.canvasInstance.lastMousePosition;
+        this.canvasInstance.canvasRenderer.drawMaskBrushCursor(worldCoords);
     }
 
     clearPreview(): void {