Performance issue with rendering large images using Vello Classic
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- Dominant language
- Rust
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Description
Hi :) I'm having a performance issue with Vello Classic. I'm filling a full-screen rectangle with a 1835 by 8192 image on an iPad Pro 2025 13", and I'm unable to sustain 120 FPS. I'm not doing anything else with the GPU.
If I scale the image down (proportionally) to a height of 4096, the frame rate recovers to 120 (the display's refresh rate). However if I scale it to 4097, the problem persists, suggesting some kind of threshold at 4096 pixels. What could be going wrong here?
Two other less significant issues:
- `ImageQuality::High` does not yield bicubic filtering.
- Image sizes of more than 8192 silently fail to render. I'd expect an error somewhere.
Tested with revision Vello commit `ea2a935d4c502c` and `--release`.
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Research direction
Start by reproducing the full-screen image case in Vello Classic at heights of 4096 and 4097, using commit ea2a935d4c502c and a --release build. Investigate the behavior around ImageQuality::High and images above 8192; done means explaining the threshold and addressing the confirmed performance, filtering, and error-reporting issues.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- rust
- Domain
- computer-graphics, performance
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Quiet
- Clarity
- Needs clarification
- Newbie friendliness
- 45/100