Fix intersection calculation bug in rect_paint_needed - #52
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The intersection rectangle calculation had two copy-paste errors where the x2 and y2 values were incorrectly using x1/y1 instead of x2/y2 in the ternary operators: x2 = (ignore_reg->x2 < reg->x2) ? ignore_reg->x1 : reg->x1; y2 = (ignore_reg->y2 < reg->y2) ? ignore_reg->y1 : reg->y1; This produced incorrect intersection dimensions, which could cause w*h to be negative or wrong, leading to the ignore region being computed incorrectly and windows that should be painted being skipped.
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Summary
Fixes two copy-paste errors in the intersection rectangle calculation that could cause windows to be incorrectly skipped during painting.
Problem
The intersection rectangle calculation in
rect_paint_needed()had two copy-paste errors:This produced incorrect intersection dimensions, which could cause
w*hto be negative or wrong, leading to the ignore region being computed incorrectly and windows that should be painted being skipped.Solution
Correct the ternary operators to use
x2andy2respectively:Scope
comp_rect.cis touched (2 lines)make clean && makeproduces zero warnings, zero errorsImpact
Fixes a correctness bug in the occlusion culling logic. On certain window layouts (overlapping windows with specific positions), this could cause visible windows to not be painted.