otfried
Fix tiling pattern and image rendering bottleneck
Currently, images of large resolutions and tiling patterns render inefficiently. See the attached ipe file, which is barely usable due to this issue.
tiling_pattern_and_image_test.ipe.zip
Image Rendering
This PR proposes using CAIRO_FILTER_FAST instead of CAIRO_FILTER_GOOD when rendering images inside the UI (but not when exporting). The visual difference is imperceptible (at least for me) and the speedup is drastic.
Tiling Pattern Rendering
Currently, rendering tiling patterns (if they fill a moderately large part of the screen buffer) is painfully slow. This is due to an apparent issue in cairo. If we do not render the tiling pattern using a repeating texture with resolution 32x32, but, say 512x512, the bottleneck disappears and rendering is orders of magnitudes faster.
To keep file exports stemming from cairo efficient (e.g., svg), only use a larger texture when drawing the ui, not exporting.
