core.git: Branch 'libreoffice-24-2' - vcl/skia

[Patrick Luby (via logerrit)]

 vcl/skia/gdiimpl.cxx |   20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

New commits:
commit d5ffb72e00e528796c07d51b3ed9d7a28ad12668
Author:     Patrick Luby <guibmac...@gmail.com>
AuthorDate: Fri Apr 26 20:25:03 2024 -0400
Commit:     Christian Lohmaier <lohmaier+libreoff...@googlemail.com>
CommitDate: Thu May 16 19:56:34 2024 +0200

    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 <guibomac...@gmail.com>
    Tested-by: Jenkins
    (cherry picked from commit 05d3a99aa687ee4e1706f9403651379b7ebdad89)
    Reviewed-on: https://gerrit.libreoffice.org/c/core/+/166722
    Reviewed-by: Christian Lohmaier <lohmaier+libreoff...@googlemail.com>

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();