Qt Text quality on TBitmap
Original Reporter info from Mantis: Blaazen @Blaazen
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Reporter name: Vojtech Cihak
Original Reporter info from Mantis: Blaazen @Blaazen
- Reporter name: Vojtech Cihak
Description:
I noticed that text quality in Qt is worse when text is drawn to Bitmap.Canvas (via TextOut method) and then copied to native Canvas (PaintBox.Canvas.Draw).
Text quality is fine when it is drawn directly (PaintBox.Canvas.TextOut).
After some observation (using Spectacle and Krita) I found the reason: Qt does wrong sub-pixel rendering for Bitmap.Canvas.
This does not happen in GTK2.
Steps to reproduce:
Run demo project. In this demo, as well as in screenshots, the upper half is drawn directly to PaintBox while the lower half is drawn to Bitmap and then copied to PaintBox.
You can see that subpixel rendering on the lower half of QtTextOutDetailZoom.png is monochromatic, which is wrong.
Additional information:
Lazarus 2.1.0 r60425M FPC 3.3.1 x86_64-linux-qt
Mantis conversion info:
- Mantis ID: 35108
- OS: Linux
- OS Build: Chakra 64-bit
- Build: 60425
- Platform: amd64
- Version: 2.1 (SVN)