Add angle to TextArea to control text rotation#1
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Add `angle` (degrees) and `rotation_origin` fields to TextArea, enabling text rotation in the vertex shader via a 2D rotation matrix applied in screen space before NDC conversion. Changes: - TextArea: new `angle: f32` and `rotation_origin: Option<[f32; 2]>` fields - GlyphToRender: new `angle` and `rotation_origin` per-instance vertex data - Shader: rotation matrix applied around rotation_origin before NDC transform - Cache: sampler switched to Linear filtering for smooth rotated glyphs - Atlas: 1px padding on glyph allocations to prevent linear filter bleed - Bounds clipping skipped for rotated text (axis-aligned clips are incorrect) Based on the approach from jonmmease#1, adapted for glyphon 0.9.0. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
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This PR adds an
angle: f32property toTextAreato control the rotation of the text in text area. This angle is routed through toGlyphToRenderand to the shader where it's used to construct a 2d rotation matrix which is applied to the vertex positions.To make the text look smooth when rotated, the sampler mode was changed from
FilterMode::NearesttoFilterMode::Linear.When text is rotated, linear interpolation can cause artifacts on glyph borders due to interpolation against neighboring glyphs in the texture atlas. To fix this, a one pixel buffer was added to the glyph width and height when positioning the glyph in the text atlas.