[Libreoffice-commits] core.git: vcl/skia

[Luboš Luňák (via logerrit)]

 vcl/skia/gdiimpl.cxx |   15 +++++++++++++++
 1 file changed, 15 insertions(+)

New commits:
commit c3b044abc2906bbb56a0f359f89ee7c1eb400c93
Author:     Luboš Luňák <l.lunak at collabora.com>
AuthorDate: Wed Apr 15 12:33:17 2020 +0200
Commit:     Luboš Luňák <l.lunak at collabora.com>
CommitDate: Wed Apr 15 15:10:21 2020 +0200

    keep old contents of resized windows with Skia (tdf#131952)
    
    It seems this is necessary in rare cases.
    
    Change-Id: Id7557a069bc0adf61b34068f00761e16b961fbc5
    Reviewed-on: https://gerrit.libreoffice.org/c/core/+/92258
    Tested-by: Jenkins
    Reviewed-by: Luboš Luňák <l.lunak at collabora.com>

diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index 6f7c2b70b1df..e20d63018747 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -432,7 +432,22 @@ void SkiaSalGraphicsImpl::checkSurface()
         if (!avoidRecreateByResize())
         {
             Size oldSize(mSurface->width(), mSurface->height());
+            // Recreating a surface means that the old SkSurface contents will be lost.
+            // But if a window has been resized the windowing system may send repaint events
+            // only for changed parts and VCL would not repaint the whole area, assuming
+            // that some parts have not changed (this is what seems to cause tdf#131952).
+            // So carry over the old contents for windows, even though generally everything
+            // will be usually repainted anyway.
+            sk_sp<SkImage> snapshot;
+            if (!isOffscreen())
+                snapshot = mSurface->makeImageSnapshot();
             recreateSurface();
+            if (snapshot)
+            {
+                SkPaint paint;
+                paint.setBlendMode(SkBlendMode::kSrc); // copy as is
+                mSurface->getCanvas()->drawImage(snapshot, 0, 0, &paint);
+            }
             SAL_INFO("vcl.skia.trace", "recreate(" << this << "): old " << oldSize << " new "
                                                    << Size(mSurface->width(), mSurface->height())
                                                    << " requested "