generic Skia workaround for VCL sending empty size (tdf#140288)

There have already been commits to handle this, but the case
of getting the wrong size the first was still broken (or was
fixed in the past and got broken again). Try to be generic
by forcing these to be always considered to be offscreen
and force non-zero size there.

Change-Id: Ie366a296f7f6645333630fa31e9fe18d54c7fba8
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/111528
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

3 files changed, 24 insertions, 13 deletions

diff --git a/vcl/skia/gdiimpl.cxx b/vcl/skia/gdiimpl.cxx
index 950010183cb1..d8ddf48536c0 100644
--- a/vcl/skia/gdiimpl.cxx
+++ b/vcl/skia/gdiimpl.cxx
@@ -334,14 +334,24 @@ void SkiaSalGraphicsImpl::createWindowSurface(bool forceRaster)
 #endif
 }
 
+bool SkiaSalGraphicsImpl::isOffscreen() const
+{
+    if (mProvider == nullptr || mProvider->IsOffScreen())
+        return true;
+    // HACK: Sometimes (tdf#131939, tdf#138022, tdf#140288) VCL passes us a zero-sized window,
+    // and zero size is invalid for Skia, so force offscreen surface, where we handle this.
+    if (GetWidth() <= 0 || GetHeight() <= 0)
+        return true;
+    return false;
+}
+
 void SkiaSalGraphicsImpl::createOffscreenSurface()
 {
     SkiaZone zone;
     assert(isOffscreen());
     assert(!mSurface);
     assert(!mWindowContext);
-    // When created (especially on Windows), Init() gets called with size (0,0), which is invalid size
-    // for Skia. May happen also in rare cases such as shutting down (tdf#131939).
+    // HACK: See isOffscreen().
     int width = std::max(1, GetWidth());
     int height = std::max(1, GetHeight());
     switch (SkiaHelper::renderMethodToUse())
@@ -460,17 +470,7 @@ void SkiaSalGraphicsImpl::checkSurface()
     }
     else if (GetWidth() != mSurface->width() || GetHeight() != mSurface->height())
     {
-        if (avoidRecreateByResize())
-            return;
-
-        if (!GetWidth() || !GetHeight())
-        {
-            SAL_WARN("vcl.skia", "recreate(" << this << "): can't create empty surface "
-                                             << Size(GetWidth(), GetHeight())
-                                             << " => keeping old one!");
-            return;
-        }
-
+        if (!avoidRecreateByResize())
         {
             Size oldSize(mSurface->width(), mSurface->height());
             // Recreating a surface means that the old SkSurface contents will be lost.
@@ -503,6 +503,14 @@ void SkiaSalGraphicsImpl::checkSurface()
     }
 }
 
+bool SkiaSalGraphicsImpl::avoidRecreateByResize() const
+{
+    // Keep the old surface if VCL sends us a broken size (see isOffscreen()).
+    if (GetWidth() == 0 || GetHeight() == 0)
+        return true;
+    return false;
+}
+
 void SkiaSalGraphicsImpl::flushDrawing()
 {
     if (!mSurface)
diff --git a/vcl/skia/win/gdiimpl.cxx b/vcl/skia/win/gdiimpl.cxx
index 054555ca6e41..8467b1d80765 100644
--- a/vcl/skia/win/gdiimpl.cxx
+++ b/vcl/skia/win/gdiimpl.cxx
@@ -38,6 +38,7 @@ void WinSkiaSalGraphicsImpl::createWindowContext(bool forceRaster)
 {
     SkiaZone zone;
     sk_app::DisplayParams displayParams;
+    assert(GetWidth() > 0 && GetHeight() > 0);
     displayParams.fSurfaceProps = *SkiaHelper::surfaceProps();
     switch (forceRaster ? SkiaHelper::RenderRaster : SkiaHelper::renderMethodToUse())
     {
diff --git a/vcl/skia/x11/gdiimpl.cxx b/vcl/skia/x11/gdiimpl.cxx
index 29fb15d27140..2ef186ad78d0 100644
--- a/vcl/skia/x11/gdiimpl.cxx
+++ b/vcl/skia/x11/gdiimpl.cxx
@@ -108,6 +108,8 @@ X11SkiaSalGraphicsImpl::createWindowContext(Display* display, Drawable drawable,
 
 bool X11SkiaSalGraphicsImpl::avoidRecreateByResize() const
 {
+    if (SkiaSalGraphicsImpl::avoidRecreateByResize())
+        return true;
     if (!mSurface || isOffscreen())
         return false;
     // Skia's WindowContext uses actual dimensions of the X window, which due to X11 being