Editor GPU: Support rendering strikethrough

[Tyriar]

Fixes #233992

[Copilot]

Pull request overview

This PR adds strikethrough rendering support to the GPU-accelerated editor renderer. The implementation includes CSS validation for text-decoration properties, decoration style caching for strikethrough attributes, and canvas-based rendering of the strikethrough line.

Key Changes:

• Added support for text-decoration CSS properties (text-decoration, text-decoration-line, text-decoration-style, text-decoration-color, text-decoration-thickness)
• Extended decoration style cache to track strikethrough state and thickness
• Implemented strikethrough rendering in the glyph rasterizer using canvas fillRect

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/vs/editor/browser/gpu/viewGpuContext.ts	Added text-decoration CSS properties to supported rules list and implemented validation logic for strikethrough-specific values
src/vs/editor/browser/gpu/renderStrategy/viewportRenderStrategy.ts	Added strikethrough and strikethroughThickness variables, parsing logic for text-decoration properties, and updated cache entry creation
src/vs/editor/browser/gpu/renderStrategy/fullFileRenderStrategy.ts	Applied same strikethrough handling as viewport strategy to maintain consistency between render strategies
src/vs/editor/browser/gpu/raster/glyphRasterizer.ts	Implemented canvas-based strikethrough rendering with positioning and thickness calculations
src/vs/editor/browser/gpu/css/decorationStyleCache.ts	Extended interface and cache implementation to include strikethrough and strikethroughThickness properties

[Copilot]

Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.