gui_toolkit 0.4.0

Added

• 2D affine transforms in draw: Affine (CSS matrix(a, b, c, d, e, f) convention), push_transform /
  pop_transform, current_transform, and the helpers affine_mul, affine_translate, affine_scale,
  affine_rotate, affine_skew, affine_around, affine_apply, affine_apply_vector, affine_inverse,
  affine_bounds, affine_determinant, affine_scale_factor, affine_is_identity, affine_is_scale_translate,
  affine_from_xform. Rects (rounded, borders, shadows), gradients, text and images follow the transform; rotated and
  skewed shapes are evaluated in local space in the pixel shader (exact corners, 1 px antialiasing). Scaled text is
  re-rasterized at its on-screen size.
• Rounded / transformed clips: draw.push_clip_rounded(dc, r, radii) (per-pixel, antialiased, nests up to 8
  deep); push_clip under rotation or skew clips the exact rect. draw.current_clip.
• Images: render.create_texture_rgba, update_texture_rgba (sRGB, straight alpha in; stored premultiplied in
  linear light), destroy_texture, texture_size, max_texture_size; mip chains regenerated after updates.
  draw.image, draw.image_corners (rounded corners, sub-rectangles, tint) and draw.image_tiled (seamless
  repeat). Images and glyphs share batches.
• examples/transforms (build.bat transforms): animated demo, --stress=N / --bench=N load test.
• -define:GPU_TIMING=true + render.gpu_ms: GPU time of the frame (timestamp queries).
• Unit tests for the affine helpers: odin test tests/affine.
• docs/draw.md: transforms, clips, images, costs and limits.

Changed

• render.Rect_Inst is 144 bytes (adds xform, clip, flags); use_tex takes KIND_SHAPE / KIND_GLYPH /
  KIND_IMAGE. render.Batch gains image; render.frame_submit takes the optional transform and clip tables.
• draw.Context.clips holds draw.Clip (scissor + shape) and xforms holds draw.Transform (an Affine).
  push_scale / pop_xform keep their behaviour; the existing examples render pixel-identical to 0.3.2.
• Soft shapes (soft > 1) drawn under push_scale scale their blur with the rest of the shape.