- At any zoom level (via trackpad gesture or shortcut or GUI controls) selection-frame & ruler-markers are always perfectly aligned.
- But the zoomed-up pixels on the canvas are misaligned. The pixels are not where they are supposed to be. They have a totally irregular offset which accumulates. Only every n-th pixel is aligned with the ruler/selection-grid.
- Making reliable selection, cut, copy, paste operations is impossible that way.
- The developer and some community members tried all possible configurations: It always works fine on newer Macs, and it just never works on the affected Mac.
- GraphicConverter uses standard Apple technologies for rendering the canvas.
- With a very high probability this is a bug in the graphics drivers of Macs of that generation and graphics card series (MacBookPro 15'', Mid 2014, NVIDIA GeForce GT 750M 2 GB) on macOS Big Sur. Maybe the graphics drivers on elder macOS versions still work fine in that regard with GraphicConverter, that was not tested.
——— Original bug report ↓ ———
Use Case: You want to perform a pixel-exact selection.
Problem: When zoomed in, the selection border goes halfway through the pixels.
- The visualization of the border box is not aligned with the pixel grid.
- If you drag the selection boundaries, you see the offset accumulates (e.g. 10% per pixel), so only at every n-th pixel (e.g. every 10th pixel) the borderline aligns clearly with the visible pixels.
- That way it is impossible to work pixel exact.
- Graphic Converter 11.6.1
- macOS 11.6.5-6 Big Sur
- MacBook Pro, Retina 15" (Mid 2015)
- NVIDIA GeForce GT 750M 2 GB
- PNG of normal resolution (72dpi aka @1x)
- On a normal resolution screen.
- This is not an issue of subpixel operations not possible within a @2x or @3x resolution file in an editor which works with on the operational pixel level only as is the case with some image editors as e.g. documented here: How to operate (cut/move) on a subpixel level in @2x double or @3d triple resolution files in Snagit
- I do not confuse these two issues.
- I really think this is a bug or a misconfiguration (although I did not touch the display resolution preferences in the Preferences)