Subpixel rendering
Slap yourself if
You think subpixel rendering is just 'fractional pixels' or assume it always improves visual quality.
Why this exists
Because subpixel behavior explains blurry text, jittery animations, and cross-browser inconsistencies that teams misdiagnose as font or GPU bugs.
Mental model
Subpixel rendering exploits the physical layout of display pixels, but it is constrained by transforms, compositing, and color pipelines. Precision is conditional, not guaranteed.
- Layout and transforms can position content at fractional pixel boundaries.
- Rasterization may snap or preserve subpixel positions depending on context.
- Text and shapes can be rendered with subpixel precision or grayscale.
- Compositing and scaling can discard subpixel information.
- Animating elements at fractional positions and seeing jitter.
- Assuming subpixel text rendering survives transforms.
- Blaming fonts when compositing caused the blur.
- Expecting consistent behavior across devices and OSes.
Subpixel rendering allows fractional positioning and text precision, but it is often lost during transforms or compositing, leading to blur or snapping.
- Claims subpixel rendering is always enabled.
- Ignores the role of compositing layers.
- Treats blur as a font issue only.
- Assumes browser consistency.
Deep dive
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