GNOME Bugzilla – Bug 583029
The gdk_pixbuf_composite_color function uses wrong checkboard offset
Last modified: 2018-05-22 13:10:16 UTC
From the description of gdk_pixbuf_composite_color:
Creates a transformation of the source image src by scaling by scale_x and scale_y then translating by offset_x and offset_y, then composites the rectangle (dest_x ,dest_y, dest_width, dest_height) of the resulting image with a checkboard of the colors color1 and color2 and renders it onto the destination image.
There is also a note about the origin of the checkboard in the description of check_x parameter:
origin of checkboard is at -check_x, -check_y
However gdk_pixbuf_composite_color is implemented so, that the checkboard is shifted by dest_x and dest_y before composition with the source image. So the actual position of the checkboard's origin is (dest_x-check_x, dest_y-check_y) when composition is performed.
Created attachment 134854 [details]
test for verify correctness of checkboard offset
If checkboard offset is not depend from dest_x and dest_y parameters, then both resulting images should be the same.
Reproduce with 2.31
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