fix: use clientX/Y for mouse coordinates#696
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mattgodbolt merged 3 commits intoMay 13, 2026
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Calculate mouse coordinates using evt.clientX/clientY against the screen canvas rect directly, rather than mixing evt.offsetX/offsetY with bounding rect positions. The previous approach failed when the canvas was inset within the monitor image (e.g., with display filters that add non-zero canvasLeft/canvasTop). The new calculation correctly handles all display filter scenarios. Fixes mattgodbolt#631
mattgodbolt
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May 12, 2026
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Thank you! And for the lovely tests - just a couple tweaks, I don't think we should test the old behaviour though I appreciate you demonstrating it was broken in test form; and I think we should test the code we execute and not a copy paste of it. Thnk you!
Extract calculateMouseCoordinates into a shared module so tests exercise the actual production code. Remove old-behavior tests.
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OK removed old tests && extracted shared module. |
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Fixes #631.
Mouse coordinates were calculated incorrectly when the canvas was inset within the monitor image (e.g., with display filters that add non-zero canvasLeft/canvasTop). The previous approach mixed evt.offsetX/offsetY with bounding rect positions, which failed in these scenarios.
Switched to calculating mouse coordinates using evt.clientX/clientY against the screen canvas rect directly. This correctly handles all display filter scenarios and eliminates the incorrect mixing of coordinate systems.
Includes a regression test that reproduces the original issue.