Consolidates shape mask controls into a styled container, improves UI logic for showing/hiding sub-options, and updates slider initialization to reflect current values. Mask removal now always uses a hard-edged shape, even if feathering was previously applied, ensuring complete erasure of feathered areas. The mask application logic also clears the maximum possible mask area before applying the new mask to prevent artifacts from previous slider values. Checkbox and slider labels are updated for clarity.
Implements a real-time blue outline preview when adjusting the expansion and feather sliders in the custom shape mask UI. The preview updates dynamically while dragging, and applies the mask only on mouse release. Adds a viewport change listener to keep the preview in sync during zooming or panning. Refactors mask expansion/contraction to use fast morphological operations for sharp edges and updates mask drawing to handle holes correctly.
Introduces a CustomShapeMenu UI component for managing custom output area shape masks, including options for auto-applying the mask, expansion/contraction, and feathering. Updates Canvas and MaskTool to support these new mask operations, and ensures the menu is shown or hidden based on shape presence. Adds distance transform-based algorithms for accurate mask expansion and feathering.
