actually prefer DrawTransformedBitmap() if it's known to be fast

This partially reverts the logic of change 9d89d98d3349502b56d,
which always made DrawTransformedBitmap() get changed to DrawBitmapEx
if only translation+scaling was involved. But since that one
may call BitmapEx::Mirror() that'll do pixel-shuffling, trust
the DrawTransformedBitmap() implementation to do the right and
efficient thing if it says so.

Change-Id: If25b3d189ddd46b235e122e5e8d6f8079ec09f7f
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/111248
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

3 files changed, 12 insertions, 20 deletions

diff --git a/vcl/inc/salgdi.hxx b/vcl/inc/salgdi.hxx
index 494f03eef5a5..175123342318 100644
--- a/vcl/inc/salgdi.hxx
+++ b/vcl/inc/salgdi.hxx
@@ -588,6 +588,7 @@ protected:
                                     double fAlpha) = 0;
 
     /// Used e.g. by canvas to know whether to cache the drawing.
+    /// See also tdf#138068.
     virtual bool hasFastDrawTransformedBitmap() const = 0;
 
     /** Render solid rectangle with given transparency
diff --git a/vcl/inc/salgdiimpl.hxx b/vcl/inc/salgdiimpl.hxx
index 8b310c586e1a..94505b1a83f6 100644
--- a/vcl/inc/salgdiimpl.hxx
+++ b/vcl/inc/salgdiimpl.hxx
@@ -198,6 +198,7 @@ public:
                 double fAlpha) = 0;
 
     /// Used e.g. by canvas to know whether to cache the drawing.
+    /// See also tdf#138068.
     virtual bool hasFastDrawTransformedBitmap() const = 0;
 
     virtual bool drawAlphaRect(
diff --git a/vcl/source/outdev/bitmap.cxx b/vcl/source/outdev/bitmap.cxx
index 563989cc366d..426366580c4d 100644
--- a/vcl/source/outdev/bitmap.cxx
+++ b/vcl/source/outdev/bitmap.cxx
@@ -1265,17 +1265,16 @@ void OutputDevice::DrawTransformedBitmapEx(
     const bool bInvert(RasterOp::Invert == meRasterOp);
     const bool bBitmapChangedColor(mnDrawMode & (DrawModeFlags::BlackBitmap | DrawModeFlags::WhiteBitmap | DrawModeFlags::GrayBitmap ));
     const bool bTryDirectPaint(!bInvert && !bBitmapChangedColor && !bMetafile);
+    // tdf#130768 CAUTION(!) using GetViewTransformation() is *not* enough here, it may
+    // be that mnOutOffX/mnOutOffY is used - see AOO bug 75163, mentioned at
+    // ImplGetDeviceTransformation declaration
+    basegfx::B2DHomMatrix aFullTransform(ImplGetDeviceTransformation() * rTransformation);
 
     // First try to handle additional alpha blending, either directly, or modify the bitmap.
     if(!rtl::math::approxEqual( fAlpha, 1.0 ))
     {
         if(bTryDirectPaint)
         {
-            // tdf#130768 CAUTION(!) using GetViewTransformation() is *not* enough here, it may
-            // be that mnOutOffX/mnOutOffY is used - see AOO bug 75163, mentioned at
-            // ImplGetDeviceTransformation declaration
-            const basegfx::B2DHomMatrix aFullTransform(ImplGetDeviceTransformation() * rTransformation);
-
             if(DrawTransformBitmapExDirect(aFullTransform, bitmapEx, fAlpha))
             {
                 // we are done
@@ -1292,6 +1291,9 @@ void OutputDevice::DrawTransformedBitmapEx(
     if(rtl::math::approxEqual( fAlpha, 1.0 ))
         fAlpha = 1.0; // avoid the need for approxEqual in backends
 
+    if(bTryDirectPaint && mpGraphics->HasFastDrawTransformedBitmap() && DrawTransformBitmapExDirect(aFullTransform, bitmapEx))
+        return;
+
     // decompose matrix to check rotation and shear
     basegfx::B2DVector aScale, aTranslate;
     double fRotate, fShearX;
@@ -1326,18 +1328,10 @@ void OutputDevice::DrawTransformedBitmapEx(
         return;
     }
 
-    if(bTryDirectPaint)
+    if(bTryDirectPaint && DrawTransformBitmapExDirect(aFullTransform, bitmapEx))
     {
-        // tdf#130768 CAUTION(!) using GetViewTransformation() is *not* enough here, it may
-        // be that mnOutOffX/mnOutOffY is used - see AOO bug 75163, mentioned at
-        // ImplGetDeviceTransformation declaration
-        const basegfx::B2DHomMatrix aFullTransform(ImplGetDeviceTransformation() * rTransformation);
-
-        if(DrawTransformBitmapExDirect(aFullTransform, bitmapEx))
-        {
-            // we are done
-            return;
-        }
+        // we are done
+        return;
     }
 
     // take the fallback when no rotate and shear, but mirror (else we would have done this above)
@@ -1370,10 +1364,6 @@ void OutputDevice::DrawTransformedBitmapEx(
     const double fOrigArea(rOriginalSizePixel.Width() * rOriginalSizePixel.Height() * 0.5);
     const double fOrigAreaScaled(fOrigArea * 1.44);
     double fMaximumArea(std::clamp(fOrigAreaScaled, 1000000.0, 4500000.0));
-    // tdf#130768 CAUTION(!) using GetViewTransformation() is *not* enough here, it may
-    // be that mnOutOffX/mnOutOffY is used - see AOO bug 75163, mentioned at
-    // ImplGetDeviceTransformation declaration
-    basegfx::B2DHomMatrix aFullTransform(ImplGetDeviceTransformation() * rTransformation);
 
     if(!bMetafile)
     {