From 78637759218de6dd24f5cf13ed95c62afbae24ba Mon Sep 17 00:00:00 2001
From: Quantum <quantum2048@gmail.com>
Date: Sun, 24 Apr 2022 02:13:45 -0400
Subject: [PATCH] Negate opacity channel on ImageMagick 7
In ImageMagick 7, the semantics of the opacity channel is flipped.
---
win2xcur/shadow.py | 12 ++++++++++--
1 file changed, 10 insertions(+), 2 deletions(-)
diff --git a/win2xcur/shadow.py b/win2xcur/shadow.py
index 1f75101..8791754 100644
--- a/win2xcur/shadow.py
+++ b/win2xcur/shadow.py
@@ -7,8 +7,10 @@ from win2xcur.cursor import CursorFrame
if 'copy_opacity' in COMPOSITE_OPERATORS:
COPY_ALPHA = 'copy_opacity' # ImageMagick 6 name
+ NEEDS_NEGATE = False
else:
COPY_ALPHA = 'copy_alpha' # ImageMagick 7 name
+ NEEDS_NEGATE = True
def apply_to_image(image: BaseImage, *, color: str, radius: float, sigma: float, xoffset: float,
@@ -18,8 +20,14 @@ def apply_to_image(image: BaseImage, *, color: str, radius: float, sigma: float,
new_width = image.width + 3 * xoffset
new_height = image.height + 3 * yoffset
+ if NEEDS_NEGATE:
+ channel = image.channel_images['opacity'].clone()
+ channel.negate()
+ else:
+ channel = image.channel_images['opacity']
+
opacity = Image(width=new_width, height=new_height, pseudo='xc:white')
- opacity.composite(image.channel_images['opacity'], left=xoffset, top=yoffset)
+ opacity.composite(channel, left=xoffset, top=yoffset)
opacity.gaussian_blur(radius * image.width, sigma * image.width)
opacity.negate()
opacity.modulate(50)
@@ -28,8 +36,8 @@ def apply_to_image(image: BaseImage, *, color: str, radius: float, sigma: float,
shadow.composite(opacity, operator=COPY_ALPHA)
result = Image(width=new_width, height=new_height, pseudo='xc:transparent')
+ result.composite(shadow)
result.composite(image)
- result.composite(shadow, operator='difference')
trimmed = result.clone()
trimmed.trim(color=Color('transparent'))