From 528f74855bf2d7c772106900f66414d7116bb640 Mon Sep 17 00:00:00 2001 From: Patrick Luby Date: Fri, 26 Apr 2024 20:25:03 -0400 Subject: tdf#153306 prevent subpixel shifting of X coordinate HACK: for some unknown reason, if the X coordinate of the path's bounds is more than 1024, SkBlendMode::kExclusion will shift by about a half a pixel to the right with Skia/Metal on a Retina display. Weirdly, if the same polygon is repeatedly drawn, the total shift is cumulative so if the drawn polygon is more than a few pixels wide, the blinking cursor in Writer will exhibit this bug but only for one thin vertical slice at a time. Apparently, shifting drawing a very tiny amount to the left seems to be enough to quell this runaway cumulative X coordinate shift. Change-Id: Ic1ac8a390df51c4aa1cc3183590dce72059af6b6 Reviewed-on: https://gerrit.libreoffice.org/c/core/+/166766 Reviewed-by: Patrick Luby Tested-by: Jenkins (cherry picked from commit 05d3a99aa687ee4e1706f9403651379b7ebdad89) Reviewed-on: https://gerrit.libreoffice.org/c/core/+/166722 Reviewed-by: Christian Lohmaier --- vcl/skia/gdiimpl.cxx | 20 ++++++++++++++++++++ 1 file changed, 20 insertions(+) (limited to 'vcl') diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx index f4ad57f715b0..5a04a08b6438 100644 --- a/vcl/skia/gdiimpl.cxx +++ b/vcl/skia/gdiimpl.cxx @@ -1490,6 +1490,26 @@ void SkiaSalGraphicsImpl::invert(basegfx::B2DPolygon const& rPoly, SalInvert eFl aPaint.setShader( aBitmap.makeShader(SkTileMode::kRepeat, SkTileMode::kRepeat, SkSamplingOptions())); } + +#ifdef SK_METAL + // tdf#153306 prevent subpixel shifting of X coordinate + // HACK: for some unknown reason, if the X coordinate of the + // path's bounds is more than 1024, SkBlendMode::kExclusion will + // shift by about a half a pixel to the right with Skia/Metal on + // a Retina display. Weirdly, if the same polygon is repeatedly + // drawn, the total shift is cumulative so if the drawn polygon + // is more than a few pixels wide, the blinking cursor in Writer + // will exhibit this bug but only for one thin vertical slice at + // a time. Apparently, shifting drawing a very tiny amount to + // the left seems to be enough to quell this runaway cumulative + // X coordinate shift. + if (isGPU()) + { + SkMatrix aMatrix; + aMatrix.set(SkMatrix::kMTransX, -0.001); + getDrawCanvas()->concat(aMatrix); + } +#endif } getDrawCanvas()->drawPath(aPath, aPaint); postDraw(); -- cgit