Rendering arbitrary-scale emojis using the Slug algorithm (leduyquang753.name.vn)

The post explains how to adapt Eric Lengyel’s Slug GPU algorithm to render vector color fonts—like emojis—at arbitrary scales. It describes a HarfBuzz GPU pipeline for single-color glyphs (using fragment-shader coverage of curve outlines), then extends the approach to COLRv0 flat layered colors and COLRv1’s render-tree features such as clipping, gradients, affine transforms, and blending. The author outlines how glyph outlines and (for gradients) gradient definitions and transforms can be encoded into GPU buffers so colors can be computed per pixel during rendering.