qnloft
/
ComfyUI
mirror of https://github.com/comfyanonymous/ComfyUI.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Fix alpha in PorterDuffImageComposite. (#3411) 

There were two bugs in PorterDuffImageComposite.

The first one is the fact that it uses the mask input directly as alpha, missing the conversion (`1-a`). The fix is similar to c16f5744.

The second one is that all color composition formulas assume alpha premultiplied values, while the input is not premultiplied.

This change fixes both of these issue.
This commit is contained in:
Denys Smirnov 2024-06-04 23:37:11 +03:00 committed by GitHub
parent cb8d0ebccc
commit 20447e9ec9
No known key found for this signature in database
GPG Key ID: B5690EEEBB952194
1 changed files with 16 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
comfy_extras/nodes_compositing.py
View File

@ -28,6 +28,14 @@ class PorterDuffMode(Enum):
def porter_duff_composite(src_image: torch.Tensor, src_alpha: torch.Tensor, dst_image: torch.Tensor, dst_alpha: torch.Tensor, mode: PorterDuffMode): def porter_duff_composite(src_image: torch.Tensor, src_alpha: torch.Tensor, dst_image: torch.Tensor, dst_alpha: torch.Tensor, mode: PorterDuffMode):
# convert mask to alpha
src_alpha = 1 - src_alpha
dst_alpha = 1 - dst_alpha
# premultiply alpha
src_image = src_image * src_alpha
dst_image = dst_image * dst_alpha
# composite ops below assume alpha-premultiplied images
if mode == PorterDuffMode.ADD: if mode == PorterDuffMode.ADD:
out_alpha = torch.clamp(src_alpha + dst_alpha, 0, 1) out_alpha = torch.clamp(src_alpha + dst_alpha, 0, 1)
out_image = torch.clamp(src_image + dst_image, 0, 1) out_image = torch.clamp(src_image + dst_image, 0, 1)
@ -35,7 +43,7 @@ def porter_duff_composite(src_image: torch.Tensor, src_alpha: torch.Tensor, dst_
out_alpha = torch.zeros_like(dst_alpha) out_alpha = torch.zeros_like(dst_alpha)
out_image = torch.zeros_like(dst_image) out_image = torch.zeros_like(dst_image)
elif mode == PorterDuffMode.DARKEN: elif mode == PorterDuffMode.DARKEN:
out_alpha = src_alpha + dst_alpha - src_alpha * dst_alpha out_alpha = src_alpha + dst_alpha - src_alpha * dst_alpha
out_image = (1 - dst_alpha) * src_image + (1 - src_alpha) * dst_image + torch.min(src_image, dst_image) out_image = (1 - dst_alpha) * src_image + (1 - src_alpha) * dst_image + torch.min(src_image, dst_image)
elif mode == PorterDuffMode.DST: elif mode == PorterDuffMode.DST:
out_alpha = dst_alpha out_alpha = dst_alpha
@ -84,8 +92,13 @@ def porter_duff_composite(src_image: torch.Tensor, src_alpha: torch.Tensor, dst_
out_alpha = (1 - dst_alpha) * src_alpha + (1 - src_alpha) * dst_alpha out_alpha = (1 - dst_alpha) * src_alpha + (1 - src_alpha) * dst_alpha
out_image = (1 - dst_alpha) * src_image + (1 - src_alpha) * dst_image out_image = (1 - dst_alpha) * src_image + (1 - src_alpha) * dst_image
else: else:
out_alpha = None return None, None
out_image = None
# back to non-premultiplied alpha
out_image = torch.where(out_alpha > 1e-5, out_image / out_alpha, torch.zeros_like(out_image))
out_image = torch.clamp(out_image, 0, 1)
# convert alpha to mask
out_alpha = 1 - out_alpha
return out_image, out_alpha return out_image, out_alpha