Files
Bjornulf_custom_nodes/image_to_grayscale.py

39 lines
1.2 KiB
Python

import torch
class GrayscaleTransform:
@classmethod
def INPUT_TYPES(s):
return {
"required": {
"image": ("IMAGE",),
"preserve_alpha": ("BOOLEAN", {"default": False}),
},
}
RETURN_TYPES = ("IMAGE",)
FUNCTION = "transform_to_grayscale"
CATEGORY = "Bjornulf"
def transform_to_grayscale(self, image, preserve_alpha):
# Check if the image has an alpha channel
has_alpha = image.shape[3] == 4
# Extract RGB channels
rgb = image[:, :, :, :3]
# Convert to grayscale using the luminosity method
# Weights are based on human perception of color
grayscale = 0.2989 * rgb[:,:,:,0] + 0.5870 * rgb[:,:,:,1] + 0.1140 * rgb[:,:,:,2]
# Expand dimensions to match original shape
grayscale = grayscale.unsqueeze(-1).repeat(1, 1, 1, 3)
if has_alpha and preserve_alpha:
# If the original image had an alpha channel and we want to preserve it
alpha = image[:, :, :, 3:4]
result = torch.cat([grayscale, alpha], dim=3)
else:
result = grayscale
return (result,)