Use exact trig values for rotation transform in OnRotate#169
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This pull request refactors the rotation transformation logic in FlutterTizenView::OnRotate by replacing an if-else structure with a switch statement that uses hardcoded matrices for cardinal angles (0, 90, 180, 270). This change aims to improve precision for common rotations. The reviewer suggests normalizing the input degree to the [0, 360) range to ensure that equivalent angles consistently trigger the optimized switch cases rather than falling through to the default trigonometric calculation.
cos/sin of pi multiples leaves ~1e-16 dust on entries that mathematically equal 0 or +-1. The dust scales y=1080 to 1079.99999... and shifts the bottom/right edge by 1 px in rasterizer paths that floor the transformed vertex. SendInitialGeometry calls OnRotate(degree=0) at startup, so non-rotating Skia + GLES apps were also affected and the player overlay (avplay videohole) appeared 1-2 px below adjacent Flutter widgets at the screen's bottom edge. Impeller's GLES backend short-circuits near-identity transforms and did not exhibit the shift. Use exact 0 / +-1 / width / height entries for the cardinal angles (0, 90, 180, 270), and keep the cos/sin computation in the default branch so arbitrary rotation degrees remain supported.
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xiaowei-guan
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xiaowei-guan
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cos/sin of pi multiples leaves ~1e-16 dust on entries that mathematically equal 0 or +-1. The dust scales y=1080 to 1079.99999... and shifts the bottom/right edge by 1 px in rasterizer paths that floor the transformed vertex. SendInitialGeometry calls OnRotate(degree=0) at startup, so non-rotating Skia + GLES apps were also affected and the player overlay (avplay videohole) appeared 1-2 px below adjacent Flutter widgets at the screen's bottom edge. Impeller's GLES backend short-circuits near-identity transforms and did not exhibit the shift.
Use exact 0 / +-1 / width / height entries for the cardinal angles (0, 90, 180, 270), and keep the cos/sin computation in the default branch so arbitrary rotation degrees remain supported.
flutter-tizen/flutter-tizen#764