core.git: Branch 'libreoffice-7-6-7' - vcl/skia

[Patrick Luby (via logerrit)]

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

New commits:
commit 01fa786b27ac08aff7eb896653103b36bae6bbfe
Author:     Patrick Luby <guibmac...@gmail.com>
AuthorDate: Fri Apr 26 21:29:10 2024 -0400
Commit:     Patrick Luby <guibomac...@gmail.com>
CommitDate: Mon May 6 19:14:58 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: Iabe9078e416b0dde003ee61c88817ff970cc8d39
    Reviewed-on: https://gerrit.libreoffice.org/c/core/+/166721
    Tested-by: Patrick Luby <guibomac...@gmail.com>
    Reviewed-by: Michael Stahl <michael.st...@allotropia.de>
    Reviewed-by: Patrick Luby <guibomac...@gmail.com>
    Reviewed-by: Ilmari Lauhakangas <ilmari.lauhakan...@libreoffice.org>

diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index a6e030924ab6..eb6faeaa99d2 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -1489,6 +1489,26 @@ 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, -0.25);
+            getDrawCanvas()->concat(aMatrix);
+        }
+#endif
     }
     getDrawCanvas()->drawPath(aPath, aPaint);
     postDraw();