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Speed up and simplify GIF optimization #10074

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Merged
radarhere merged 2 commits into from
Sep 28, 2026
+9 −30
Merged

Speed up and simplify GIF optimization #10074

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b1ec2e0
Speed up and simplify GIF optimization
akx Sep 28, 2026
5fbb13c
Use 'each'
radarhere Sep 28, 2026
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39 changes: 9 additions & 30 deletions src/PIL/GifImagePlugin.py
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Original file line number Diff line number Diff line change
Expand Up @@ -43,8 +43,6 @@
Image,
ImageChops,
ImageFile,
ImageMath,
ImageOps,
ImagePalette,
ImageSequence,
)
Expand Down Expand Up @@ -735,37 +733,18 @@ def _write_multiple_frames(
pass
if "transparency" in encoderinfo:
# When the delta is zero, fill the image with transparency
diff_frame = im_frame.copy()
fill = Image.new("P", delta.size, encoderinfo["transparency"])
if delta.mode == "RGBA":
# Each pixel is unchanged only if all four bands are zero
r, g, b, a = delta.split()
mask = ImageMath.lambda_eval(
lambda args: args["convert"](
args["max"](
args["max"](
args["max"](args["r"], args["g"]), args["b"]
),
args["a"],
)
* 255,
"1",
),
r=r,
g=g,
b=b,
a=a,
)
else:
if delta.mode == "P":
# Convert to L without considering palette
delta_l = Image.new("L", delta.size)
delta_l.putdata(delta.get_flattened_data())
delta = delta_l
mask = ImageMath.lambda_eval(
lambda args: args["convert"](args["im"] * 255, "1"),
im=delta,
delta = ImageChops.lighter(
ImageChops.lighter(r, g),
ImageChops.lighter(b, a),
)
diff_frame.paste(fill, mask=ImageOps.invert(mask))
# Map zero pixels (palette indices, for "P")
# to a "1" mask without consulting the palette.
unchanged = delta.point([255, *(0,) * 255], "1")
diff_frame = im_frame.copy()
diff_frame.paste(encoderinfo["transparency"], mask=unchanged)
else:
bbox = None
previous_im = im_frame
Expand Down
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