Cleanup QPicture dpi scaling workarounds #58122
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Move to a single function in QgsPainting
This hides the messy scaling workaround details
nyalldawson
added
API
troopa81
reviewed
Jul 16, 2024
| // Then when being drawn, it scales the painter. The following call | ||
| // negates the effect. There is no way of setting QPicture's DPI. | ||
| // See QTBUG-20361 | ||
| const double xScale = static_cast< double >( QgsPainting::qtDefaultDpiX() ) / painter->device()->logicalDpiX(); |
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Why not calling applyScaleFixForQPictureDpi and using save/restore instead ?
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There's considerable overhead in save/restore calls, and it's trivial to avoid them here.
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OK.
Just out of curiosity, do you have any discussion/information about this?
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Just my own experiences profiling QGIS rendering. And it makes sense -- saving / restoring QPainter state requires storing a lot of properties, especially when clip masks are in place. In comparison scaling is an almost zero-cost operation.
troopa81
approved these changes
Jul 17, 2024
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Unifies the various QPicture DPI scaling workaround implementations, and adds high level methods to make this simpler to handle