Regression from 9.0.1 to 9.1.0 in polygon rasterization

[rockandsalt]

What did you do?

@mikedh and I noticed that the polygon rasterization wasn't clean in certain case. The regression seems to have occured in 9.1.0 since version before that one works fine. @mikedh made a comment here

What are your OS, Python and Pillow versions?

• OS: Windows
• Python: 3.8
• Pillow: 9.1.0

Here's the minimum code to reproduce it.

from PIL import Image, ImageDraw

if __name__ == '__main__':
    curve = [270, 114, 269, 114, 269, 114, 268, 115, 268, 115, 267, 116, 267, 116, 266, 117, 266, 117, 265, 117, 265, 117, 264, 118, 264, 118, 263, 119, 263, 119, 262, 119, 262, 119, 261, 120, 261, 120, 260, 121, 260, 121, 259, 121, 259, 121, 258, 122, 258, 122, 257, 123, 257, 123, 256, 123, 256, 123, 255, 124, 255, 124, 254, 125, 254, 125, 253, 125, 253, 125, 252, 126, 252, 126, 251, 126, 251, 126, 250, 127, 250, 127, 249, 128, 249, 128, 248, 128, 247, 128, 246, 129, 246, 129, 245, 129, 245, 129, 244, 130, 244, 130, 243, 130, 243, 130, 242, 131, 242, 131, 241, 131, 241, 131, 240, 132, 240, 132, 239, 132, 239, 132, 238, 133, 238, 133, 237, 133, 237, 133, 235, 134, 235, 134, 234, 134, 234, 134, 233, 135, 233, 135, 232, 135, 232, 135, 231, 136, 231, 136, 230, 136, 230, 136, 229, 136, 229, 136, 228, 137, 228, 137, 226, 137, 226, 137, 225, 137, 225, 137, 224, 138, 224, 138, 223, 138, 223, 138, 222, 139, 222, 139, 221, 139, 221, 139, 219, 139, 219, 139, 218, 139, 218, 139, 217, 140, 217, 140, 216, 140, 216, 140, 215, 140, 215, 140, 214, 141, 213, 141, 212, 141, 212, 141, 211, 141, 211, 141, 210, 141, 210, 141, 209, 142, 209, 142, 208, 142, 207, 142, 206, 142, 206, 142, 205, 142, 205, 142, 204, 142, 204, 142, 203, 143, 203, 143, 201, 143, 201, 143, 200, 143, 200, 143, 199, 143, 199, 143, 198, 143, 198, 143, 197, 143, 197, 143, 195, 143, 195, 143, 194, 143, 194, 143, 193, 144, 193, 144, 192, 144, 192, 144, 190, 144, 190, 144, 189, 144, 189, 144, 188, 144, 188, 144, 187, 144, 187, 144, 186, 144, 186, 144, 184, 144, 184, 144, 183, 144, 183, 144, 182, 144, 182, 144, 181, 144, 181, 144, 179, 144, 179, 144, 178, 144, 178, 144, 177, 144, 177, 144, 176, 144, 176, 144, 174, 143, 174, 143, 174, 143, 174, 143, 173, 143, 173, 143, 171, 143, 171, 143, 168, 143, 168, 143, 163, 143, 163, 142, 153, 142, 144, 141, 143, 141, 134, 140, 133, 140, 132, 140, 113, 138, 111, 138, 92, 136, 89, 136, 71, 134, 68, 134, 50, 133, 50, 133, 40, 132, 39, 132, 29, 131, 29, 131, 19, 130, 11, 129, 11, 129, 11, 129, 11, 129, 10, 129, 10, 129, 9, 129, 9, 129, 8, 129, 8, 129, 8, 129, 7, 128, 7, 128, 6, 128, 6, 128, 6, 128, 5, 127, 5, 127, 5, 127, 4, 127, 4, 127, 4, 126, 4, 126, 3, 126, 3, 125, 3, 125, 2, 125, 2, 124, 2, 124, 2, 124, 2, 123, 1, 123, 1, 123, 1, 123, 1, 122, 1, 122, 1, 121, 1, 121, 0, 120, 0, 120, 0, 120, 0, 120, 0, 120, 0, 119, 0, 119, 0, 118, 0, 118, 0, 117, 0, 117, 0, 114, 0, 72, 0, 70, 0, 27, 0, 27, 0, 26, 0, 26, 0, 25, 0, 25, 0, 24, 0, 24, 0, 24, 0, 23, 0, 23, 1, 23, 1, 22, 1, 22, 1, 22, 1, 21, 1, 21, 2, 20, 2, 20, 2, 20, 2, 19, 2, 19, 3, 19, 3, 18, 3, 18, 4, 18, 4, 17, 4, 17, 5, 17, 5, 17, 5, 17, 5, 16, 6, 16, 6, 16, 7, 16, 7, 16, 7, 15, 8, 15, 8, 15, 8, 15, 9, 15, 9, 15, 9, 15, 10, 15, 10, 15, 11, 15, 11, 15, 11, 15, 11, 15, 19, 14, 20, 14, 29, 13, 30, 13, 40, 12, 41, 12, 50, 11, 53, 11, 71, 9, 89, 8, 92, 8, 93, 7, 112, 6, 114, 6, 133, 4, 142, 3, 143, 3, 153, 2, 153, 2, 154, 2, 163, 1, 168, 1, 168, 1, 171, 1, 171, 1, 173, 0, 173, 0, 174, 0, 174, 0, 176, 0, 176, 0, 177, 0, 177, 0, 178, 0, 178, 0, 179, 0, 179, 0, 180, 0, 181, 0, 182, 0, 182, 0, 183, 0, 183, 0, 184, 0, 184, 0, 185, 0, 185, 0, 187, 0, 187, 0, 188, 0, 188, 0, 189, 0, 189, 0, 190, 0, 190, 0, 192, 0, 192, 0, 193, 0, 193, 0, 194, 0, 194, 0, 195, 0, 195, 0, 196, 1, 196, 1, 198, 1, 198, 1, 199, 1, 199, 1, 200, 1, 200, 1, 201, 1, 201, 1, 203, 1, 203, 1, 204, 1, 204, 1, 205, 2, 205, 2, 206, 2, 206, 2, 207, 2, 207, 2, 209, 2, 209, 2, 210, 2, 210, 2, 211, 3, 211, 3, 212, 3, 212, 3, 213, 3, 213, 3, 214, 3, 215, 3, 216, 4, 216, 4, 217, 4, 217, 4, 218, 4, 218, 4, 219, 5, 219, 5, 220, 5, 220, 5, 222, 5, 222, 5, 223, 6, 223, 6, 224, 6, 224, 6, 225, 6, 225, 6, 226, 7, 226, 7, 227, 7, 227, 7, 228, 7, 229, 7, 230, 8, 230, 8, 231, 8, 231, 8, 232, 9, 232, 9, 233, 9, 233, 9, 234, 10, 234, 10, 235, 10, 235, 10, 236, 10, 236, 10, 238, 11, 238, 11, 239, 11, 239, 11, 240, 12, 240, 12, 241, 12, 241, 12, 242, 13, 242, 13, 243, 13, 243, 13, 244, 14, 244, 14, 245, 14, 245, 15, 246, 15, 246, 15, 247, 16, 247, 16, 248, 16, 248, 16, 249, 17, 249, 17, 251, 17, 251, 17, 252, 18, 252, 18, 253, 19, 253, 19, 254, 19, 254, 19, 255, 20, 255, 20, 256, 20, 256, 20, 257, 21, 257, 21, 258, 22, 258, 22, 259, 22, 259, 22, 260, 23, 260, 23, 261, 24, 261, 24, 262, 24, 262, 24, 263, 25, 263, 25, 264, 26, 264, 26, 265, 26, 265, 26, 266, 27, 266, 27, 267, 28, 267, 28, 268, 29, 268, 29, 268, 29, 269, 29, 269, 30, 269, 30, 270, 31, 270, 31, 271, 32, 271, 32, 272, 32, 272, 32, 273, 33, 273, 33, 274, 34, 274, 34, 275, 35, 275, 35, 276, 36, 276, 36, 277, 36, 277, 37, 278, 37, 278, 37, 278, 38, 278, 38, 279, 39, 279, 39, 280, 40, 280, 40, 281, 41, 281, 41, 282, 42, 282, 42, 283, 42, 283, 42, 283, 43, 284, 43, 284, 44, 284, 44, 285, 45, 285, 45, 286, 46, 286, 46, 287, 47, 287, 47, 287, 48, 288, 48, 288, 49, 288, 49, 289, 50, 289, 50, 290, 51, 290, 51, 291, 52, 291, 52, 291, 53, 291, 53, 292, 53, 292, 54, 293, 54, 293, 54, 293, 55, 293, 55, 294, 56, 294, 56, 295, 57, 295, 57, 296, 58, 296, 58, 296, 59, 296, 59, 297, 60, 297, 60, 298, 61, 298, 61, 298, 62, 298, 62, 299, 63, 299, 63, 299, 64, 300, 65, 300, 66, 300, 66, 301, 67, 301, 67, 301, 67, 301, 67, 301, 67, 301, 67, 301, 67, 301, 68, 301, 68, 301, 68, 302, 68, 302, 68, 302, 69, 302, 69, 302, 69, 302, 70, 302, 70, 302, 70, 302, 70, 302, 71, 302, 71, 302, 71, 302, 71, 302, 72, 302, 72, 302, 72, 302, 72, 302, 73, 302, 73, 302, 73, 302, 73, 302, 74, 302, 74, 302, 74, 302, 74, 302, 75, 302, 75, 302, 75, 302, 75, 302, 75, 302, 76, 302, 76, 301, 76, 301, 77, 301, 77, 301, 77, 301, 77, 301, 77, 300, 78, 300, 78, 300, 79, 300, 79, 299, 80, 299, 80, 298, 81, 298, 81, 298, 82, 298, 82, 297, 83, 297, 83, 296, 84, 296, 84, 296, 85, 296, 85, 295, 86, 295, 86, 294, 87, 294, 87, 294, 88, 294, 88, 293, 89, 293, 89, 292, 90, 292, 90, 291, 91, 291, 91, 291, 92, 291, 92, 290, 93, 290, 93, 289, 94, 289, 94, 288, 95, 288, 95, 288, 96, 288, 96, 287, 97, 287, 97, 286, 98, 286, 98, 285, 99, 285, 99, 284, 99, 284, 99, 284, 100, 284, 100, 283, 101, 283, 101, 282, 102, 282, 102, 281, 103, 281, 103, 280, 104, 280, 104, 279, 105, 279, 105, 279, 106, 279, 106, 278, 106, 278, 106, 277, 107, 277, 107, 276, 108, 276, 108, 275, 109, 275, 109, 274, 110, 274, 110, 273, 110, 273, 110, 272, 111, 272, 111, 271, 112, 271, 112, 271, 113, 271, 113, 270, 114, 270, 114]

    result = Image.new(mode='1', size=[400,400])
    draw = ImageDraw.Draw(result)
    draw.polygon(curve, fill=1)
    result.save('scanline_defect.png')

[radarhere]

Is it possible to get an example with a smaller number of co-ordinates?

[rockandsalt]

Sure, I can try

[radarhere]

I've managed to reduce curve down to this - [(67, 66), (66, 67), (18, 67), (18, 40), (93, 40)]. That is sufficient to demonstrate a dent in the polygon.

[radarhere]

I've created PR #6303 to resolve this.

[mikedh]

Awesome thanks! Fixes mikedh/trimesh#1569

[opeide]

In which version is this fix included?

[hugovk]

It was released in 9.2.0 in July 2022.

• https://pypi.org/project/Pillow/9.2.0/
• https://pillow.readthedocs.io/en/stable/releasenotes/9.2.0.html
• https://github.com/python-pillow/Pillow/releases/tag/9.2.0