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fix(android): correct cover-fill scaling in SinkSurface vertices #249

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Merged
parkergrt merged 1 commit into from
Sep 26, 2026
Merged

fix(android): correct cover-fill scaling in SinkSurface vertices #249

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14 changes: 11 additions & 3 deletions src/sink/sink_surface.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -382,9 +382,17 @@ void SinkSurface::UpdateDisplayVertices() {
scaled_width = inset_framebuffer_width / view_width_;
scaled_height = inset_framebuffer_height / view_height_;
} else if (fill_mode_ == FillMode::PreserveAspectRatioAndFill) {
// Preserve aspect ratio and scale to fill, may crop
scaled_width = view_width_ / inset_framebuffer_height;
scaled_height = view_height_ / inset_framebuffer_width;
// Preserve aspect ratio and scale to fill, may crop.
//
// The inscribed fit above touches the view on one axis and falls short on
// the other; cover-fill scales it up uniformly until it spans both, letting
// the long axis overflow (i.e. crop). Dividing by view_* converts back to
// the normalised device coordinates the vertices below are expressed in.
float cover_w = view_width_ / inset_framebuffer_width;
float cover_h = view_height_ / inset_framebuffer_height;
float cover = cover_w > cover_h ? cover_w : cover_h;
scaled_width = inset_framebuffer_width * cover / view_width_;
scaled_height = inset_framebuffer_height * cover / view_height_;
}
// In Stretch mode, scaled_width and scaled_height remain 1.0

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