limit bitmap size for glow/softedge effects to visible area (tdf#134237)

When zooming in the bitmap can become huge, requiring a lot
of processing, most of it not being used.

Change-Id: I0a4907f5cf23ab7316fed8568924fe76c744b81a
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/97872
Tested-by: Jenkins
Reviewed-by: Luboš Luňák <l.lunak@collabora.com>

1 files changed, 55 insertions, 32 deletions

diff --git a/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx b/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx
index b91bf57c360d..cec0ed29eaf6 100644
--- a/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx
+++ b/drawinglayer/source/processor2d/vclpixelprocessor2d.cxx
@@ -1002,26 +1002,38 @@ void VclPixelProcessor2D::processGlowPrimitive2D(const primitive2d::GlowPrimitiv
         mpOutputDevice->SetAntialiasing(AntialiasingFlags::NONE);
         mpOutputDevice->Erase();
         process(rCandidate);
-        const tools::Rectangle aRect(static_cast<long>(std::floor(aRange.getMinX())),
-                                     static_cast<long>(std::floor(aRange.getMinY())),
-                                     static_cast<long>(std::ceil(aRange.getMaxX())),
-                                     static_cast<long>(std::ceil(aRange.getMaxY())));
-        BitmapEx bmpEx = mpOutputDevice->GetBitmapEx(aRect.TopLeft(), aRect.GetSize());
-        mpOutputDevice->SetAntialiasing(aPrevAA);
-
-        AlphaMask mask
-            = ProcessAndBlurAlphaMask(bmpEx.GetAlpha(), fBlurRadius, fBlurRadius, nTransparency);
-
-        // The end result is the bitmap filled with glow color and blurred 8-bit alpha mask
-        const basegfx::BColor aGlowColor(
-            maBColorModifierStack.getModifiedColor(rCandidate.getGlowColor().getBColor()));
-        Bitmap bmp = bmpEx.GetBitmap();
-        bmp.Erase(Color(aGlowColor));
-        BitmapEx result(bmp, mask);
 
-        // back to old OutDev
-        mpOutputDevice = pLastOutputDevice;
-        mpOutputDevice->DrawBitmapEx(aRect.TopLeft(), result);
+        // Limit the bitmap size to the visible area.
+        basegfx::B2DRange viewRange(getViewInformation2D().getDiscreteViewport());
+        basegfx::B2DRange bitmapRange(aRange);
+        bitmapRange.intersect(viewRange);
+        if (!bitmapRange.isEmpty())
+        {
+            const tools::Rectangle aRect(static_cast<long>(std::floor(bitmapRange.getMinX())),
+                                         static_cast<long>(std::floor(bitmapRange.getMinY())),
+                                         static_cast<long>(std::ceil(bitmapRange.getMaxX())),
+                                         static_cast<long>(std::ceil(bitmapRange.getMaxY())));
+            BitmapEx bmpEx = mpOutputDevice->GetBitmapEx(aRect.TopLeft(), aRect.GetSize());
+            mpOutputDevice->SetAntialiasing(aPrevAA);
+
+            AlphaMask mask = ProcessAndBlurAlphaMask(bmpEx.GetAlpha(), fBlurRadius, fBlurRadius,
+                                                     nTransparency);
+
+            // The end result is the bitmap filled with glow color and blurred 8-bit alpha mask
+            const basegfx::BColor aGlowColor(
+                maBColorModifierStack.getModifiedColor(rCandidate.getGlowColor().getBColor()));
+            Bitmap bmp = bmpEx.GetBitmap();
+            bmp.Erase(Color(aGlowColor));
+            BitmapEx result(bmp, mask);
+
+            // back to old OutDev
+            mpOutputDevice = pLastOutputDevice;
+            mpOutputDevice->DrawBitmapEx(aRect.TopLeft(), result);
+        }
+        else
+        {
+            mpOutputDevice = pLastOutputDevice;
+        }
     }
     else
         SAL_WARN("drawinglayer", "Temporary buffered virtual device is not visible");
@@ -1053,23 +1065,34 @@ void VclPixelProcessor2D::processSoftEdgePrimitive2D(
         // because it would result in poor quality in areas not affected by the effect
         process(rCandidate);
 
-        const tools::Rectangle aRect(static_cast<long>(std::floor(aRange.getMinX())),
-                                     static_cast<long>(std::floor(aRange.getMinY())),
-                                     static_cast<long>(std::ceil(aRange.getMaxX())),
-                                     static_cast<long>(std::ceil(aRange.getMaxY())));
-        BitmapEx bitmap = mpOutputDevice->GetBitmapEx(aRect.TopLeft(), aRect.GetSize());
+        // Limit the bitmap size to the visible area.
+        basegfx::B2DRange viewRange(getViewInformation2D().getDiscreteViewport());
+        basegfx::B2DRange bitmapRange(aRange);
+        bitmapRange.intersect(viewRange);
+        if (!bitmapRange.isEmpty())
+        {
+            const tools::Rectangle aRect(static_cast<long>(std::floor(bitmapRange.getMinX())),
+                                         static_cast<long>(std::floor(bitmapRange.getMinY())),
+                                         static_cast<long>(std::ceil(bitmapRange.getMaxX())),
+                                         static_cast<long>(std::ceil(bitmapRange.getMaxY())));
+            BitmapEx bitmap = mpOutputDevice->GetBitmapEx(aRect.TopLeft(), aRect.GetSize());
 
-        AlphaMask aMask = bitmap.GetAlpha();
-        AlphaMask blurMask = ProcessAndBlurAlphaMask(aMask, -fBlurRadius, fBlurRadius, 0);
+            AlphaMask aMask = bitmap.GetAlpha();
+            AlphaMask blurMask = ProcessAndBlurAlphaMask(aMask, -fBlurRadius, fBlurRadius, 0);
 
-        aMask.BlendWith(blurMask);
+            aMask.BlendWith(blurMask);
 
-        // The end result is the original bitmap with blurred 8-bit alpha mask
-        BitmapEx result(bitmap.GetBitmap(), aMask);
+            // The end result is the original bitmap with blurred 8-bit alpha mask
+            BitmapEx result(bitmap.GetBitmap(), aMask);
 
-        // back to old OutDev
-        mpOutputDevice = pLastOutputDevice;
-        mpOutputDevice->DrawBitmapEx(aRect.TopLeft(), result);
+            // back to old OutDev
+            mpOutputDevice = pLastOutputDevice;
+            mpOutputDevice->DrawBitmapEx(aRect.TopLeft(), result);
+        }
+        else
+        {
+            mpOutputDevice = pLastOutputDevice;
+        }
     }
     else
         SAL_WARN("drawinglayer", "Temporary buffered virtual device is not visible");