rounded_rectangle raises an "y1 should be > y0" even when coordinates are correctly ordered

[ZRunner]

What did you do?

I recently updated one of my programs from 9.4 to 9.5 and got this new ValueError when drawing rounded rectangles on an image.

After some trials and error, I think the bug only happens when the rectangle height equals 1 + 2*radius. I'm not 200% confident about that, but that's all I got so far.

The exact lines causing the error are

Pillow/src/PIL/ImageDraw.py

Lines 378 to 383 in 2a274a4

	left = [x0, y0, x0 + r, y1]
	if corners[0]:
	left[1] += r + 1
	if corners[3]:
	left[3] -= r + 1
	self.draw.draw_rectangle(left, fill, 1)

What did you expect to happen?

Well, PIL should be able to correctly calculate positions and draw my rounded corners.

What actually happened?

Traceback (most recent call last):
  File "/.../test.py", line 17, in <module>
    main()
  File "/.../test.py", line 14, in main
    draw.rounded_rectangle(coordinates, radius=3, fill=(0, 0, 0))
  File "/.../env/lib/python3.9/site-packages/PIL/ImageDraw.py", line 385, in rounded_rectangle
    self.draw.draw_rectangle(left, fill, 1)
ValueError: y1 must be greater than or equal to y0

What are your OS, Python and Pillow versions?

• OS: macOS 13.3.1
• Python: 3.9.16
• Pillow: 9.5.0

from PIL import Image, ImageDraw

def main():
    # get a 1021x340 image
    img = Image.new('RGB', (20, 20), color=(255, 255, 255))
    # draw a rounded rectangle on it
    draw = ImageDraw.Draw(img)
    coordinates = (
        (5, 0),
        (15, 7)
    )
    # here's the bug:
    # on ImageDraw.py line 383, y1 from "left" will be 1px less than y0
    draw.rounded_rectangle(coordinates, radius=3, fill=(0, 0, 0))

if __name__ == '__main__':
    main()

[radarhere]

I've created PR #7151 to resolve this.

[sandydunlop]

I'm getting the same error from Pillow after updating the Minecraft Overviewer app to 0.19.10...

  File "/usr/local/lib/python3.11/site-packages/Minecraft_Overviewer-0.19.10-py3.11-macosx-13-x86_64.egg/overviewer_core/textures.py", line 4072, in repeater
    ImageDraw.Draw(torch).rectangle((0,24,10,15),outline=(0,0,0,0),fill=(0,0,0,0))
  File "/usr/local/lib/python3.11/site-packages/PIL/ImageDraw.py", line 294, in rectangle
    self.draw.draw_rectangle(xy, fill, 1)
ValueError: y1 must be greater than or equal to y0

[radarhere]

The first line you mention is https://github.com/overviewer/Minecraft-Overviewer/blob/13c1bddaf65dfaaf6c4c7a396c94db75bed4c089/overviewer_core/textures.py#L4072, so I would suggest raising an issue with https://github.com/overviewer/Minecraft-Overviewer

[Shaobo-Zhao]

dear ZRunner,did you solved this problem?

[radarhere]

@Shaobo-Zhao the problem should have been solved by #7151 in Pillow 10.0.0. If you upgrade to that version or later, it should be fixed.

[leleogere]

It seems that the problem was not completely fixed in #7151 as it still exists in version 10.2.0:

from PIL import Image, ImageDraw, __version__

print(__version__)

img = Image.new("RGBA", (1000, 10000), (0, 0, 0, 0))
draw = ImageDraw.Draw(img)

x, y, w, h = 294.5454545454545, 7103.020833333333, 32.727272727272805, 3.4895833333339397
draw.rounded_rectangle((x, y, x + w, y + h), radius=1)

Error:

10.2.0
Traceback (most recent call last):
  File "/home/user/.config/JetBrains/PyCharm2023.3/scratches/scratch_1.py", line 7, in <module>
    draw.rounded_rectangle((x, y, x + w, y + h), fill=(255, 255, 255, 255), outline=(0, 0, 0, 255), radius=1)
  File "/home/user/anaconda3/envs/env/lib/python3.11/site-packages/PIL/ImageDraw.py", line 394, in rounded_rectangle
    self.draw.draw_rectangle(left, fill, 1)
ValueError: y1 must be greater than or equal to y0

[radarhere]

I've created #7881 for this.