github.com/srwiley/oksvg v0.0.0-20221011165216-be6e8873101c, patched for lys-lib

A copy of github.com/srwiley/oksvg at be6e8873101c (BSD 3-Clause, LICENSE), its non-test sources only, carried as a package of the lys-lib module and imported as github.com/stubbedev/lys-lib/third_party/oksvg. render rasterizes SVG icons and OT-SVG glyphs through it.

Why it lives inside the module

Go ignores a dependency's replace directives, so a patched copy wired in through go.mod would reach lys-lib's own builds and none of its consumers'. As a package of the lys-lib module, the patches reach every application importing lys-lib.

Patches

Strokes scale with the transform

svg_path.go, SvgPath.DrawTransformed: upstream hands the dasher stroke-width, stroke-dasharray and stroke-dashoffset as device pixels while the path itself goes through the full transform (viewBox fit and element transforms), so a stroke kept its user-unit width at any icon size. The patch scales all three by the transform's area scale, sqrt(|det|), exact for uniform scales and rotations (lys-ui#189).

Stroke defaults are SVG's

path_style.go, DefaultStyle: upstream defaults stroke-width to 2 and stroke-linejoin to bevel; SVG's initial values are 1 and miter (stubbedev/lys-ui#191).

userSpaceOnUse gradients follow the transform

svg_path.go, SvgPath.DrawTransformed: upstream builds gradient paints with rasterx's GetColorFunction, the identity transform, so a gradientUnits="userSpaceOnUse" gradient was placed at its user-space coordinates read as device pixels. The patch passes the path's full transform to GetColorFunctionUS. rasterx maps the gradient's geometry forward through it, which is exact for scales and translations (the viewBox fit) but not for a radial gradient under a rotation or skew (stubbedev/lys-ui#190).

Products round the same on every architecture

svg_path.go, public.go, utils.go, draw.go: the Go spec lets the compiler fuse x*y + z into one FMA instruction, which skips the rounding of the product, and it does so on arm64 and not on amd64. Each such product is now converted first, as in third_party/rasterx, which also has the numbers. amd64's results are unchanged. Pinned by the family's goldens and by just no-fused. Imports third_party/rasterx in place of github.com/srwiley/rasterx.

Upstream status

Each patch is offered upstream; once one is merged, the copy is rebased onto it and the patch dropped.

• Strokes scale with the transform: srwiley/oksvg#54
• Stroke defaults are SVG's: srwiley/oksvg#55
• userSpaceOnUse gradients follow the transform: srwiley/oksvg#56