svx: cache PNG export of graphic shapes

One scenario where this is useful is: manipulate a JPEG photo in
Online's Impress, e.g. resize it multiple times. Each time we generate
an SVG preview of the shape, which includes the PNG export of the bitmap
itself.

This helps with a desktop CPU:

debug:9976:9974: SVGFilter::filter finished in 3422 ms
debug:9976:9974: SVGFilter::filter finished in 176 ms

But it is meant to help on mobile, too, where writing such a bitmap as
PNG takes 16-17 seconds without this.

(This works because SVG writes the original bitmap, even if it's scaled.
If that invariant will be broken in the future, we still emit correct
output, but then the cache will be less useful.)

(cherry picked from commit 570be56b37e4ff105649e604ff4c8a6c368e2e79)

Change-Id: I7204b04efeeb42c6eec67f04dfdb8a4ed50443a9

2 files changed, 50 insertions, 10 deletions

diff --git a/filter/source/svg/svgwriter.cxx b/filter/source/svg/svgwriter.cxx
index 9253bbace5f3..dfb203360b4e 100644
--- a/filter/source/svg/svgwriter.cxx
+++ b/filter/source/svg/svgwriter.cxx
@@ -31,6 +31,8 @@
 #include <xmloff/unointerfacetouniqueidentifiermapper.hxx>
 #include <sax/tools/converter.hxx>
 #include <i18nlangtag/languagetag.hxx>
+#include <svx/unoshape.hxx>
+#include <svx/svdograf.hxx>
 
 #include <memory>
 
@@ -2673,10 +2675,29 @@ void SVGActionWriter::ImplWriteText( const Point& rPos, const OUString& rText,
     }
 }
 
+namespace
+{
+SdrGrafObj* GetSdrGrafObjFromXShape(const css::uno::Reference<css::drawing::XShape>* pShape)
+{
+    if (!pShape)
+    {
+        return nullptr;
+    }
+
+    auto pObject = dynamic_cast<SvxGraphicObject*>(pShape->get());
+    if (!pObject)
+    {
+        return nullptr;
+    }
+
+    return dynamic_cast<SdrGrafObj*>(pObject->GetSdrObject());
+}
+}
 
 void SVGActionWriter::ImplWriteBmp( const BitmapEx& rBmpEx,
                                     const Point& rPt, const Size& rSz,
-                                    const Point& rSrcPt, const Size& rSrcSz )
+                                    const Point& rSrcPt, const Size& rSrcSz,
+                                    const css::uno::Reference<css::drawing::XShape>* pShape )
 {
     if( !!rBmpEx )
     {
@@ -2691,8 +2712,27 @@ void SVGActionWriter::ImplWriteBmp( const BitmapEx& rBmpEx,
         {
             SvMemoryStream aOStm( 65535, 65535 );
 
-            if( GraphicConverter::Export( aOStm, rBmpEx, ConvertDataFormat::PNG ) == ERRCODE_NONE )
+            bool bCached = false;
+            SdrGrafObj* pGrafObj = nullptr;
+            if (pShape)
             {
+                pGrafObj = GetSdrGrafObjFromXShape(pShape);
+                if (pGrafObj && pGrafObj->GetPNGPreviewChecksum() == rBmpEx.GetChecksum())
+                {
+                    const std::vector<sal_Int8>& rPreviewData = pGrafObj->GetPNGPreviewData();
+                    aOStm.WriteBytes(rPreviewData.data(), rPreviewData.size());
+                    bCached = true;
+                }
+            }
+
+            if( bCached || GraphicConverter::Export( aOStm, rBmpEx, ConvertDataFormat::PNG ) == ERRCODE_NONE )
+            {
+                if (!bCached && pGrafObj)
+                {
+                    pGrafObj->SetPNGPreviewChecksum(rBmpEx.GetChecksum());
+                    pGrafObj->SetPNGPreviewData(aOStm);
+                }
+
                 Point                    aPt;
                 Size                     aSz;
                 Sequence< sal_Int8 >     aSeq( static_cast<sal_Int8 const *>(aOStm.GetData()), aOStm.Tell() );
@@ -3036,7 +3076,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
                             const MetaBmpScaleAction* pBmpScaleAction = static_cast<const MetaBmpScaleAction*>(pSubstAct);
                             ImplWriteBmp( BitmapEx(pBmpScaleAction->GetBitmap()),
                                           pA->GetPoint(), pA->GetSize(),
-                                          Point(), pBmpScaleAction->GetBitmap().GetSizePixel() );
+                                          Point(), pBmpScaleAction->GetBitmap().GetSizePixel(), pxShape );
                         }
                     }
                 }
@@ -3419,7 +3459,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
 
                     ImplWriteBmp( BitmapEx(pA->GetBitmap()),
                                   pA->GetPoint(), mpVDev->PixelToLogic( pA->GetBitmap().GetSizePixel() ),
-                                  Point(), pA->GetBitmap().GetSizePixel() );
+                                  Point(), pA->GetBitmap().GetSizePixel(), pxShape );
                 }
             }
             break;
@@ -3439,7 +3479,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
                     {
                         ImplWriteBmp( BitmapEx(pA->GetBitmap()),
                                       pA->GetPoint(), pA->GetSize(),
-                                      Point(), pA->GetBitmap().GetSizePixel() );
+                                      Point(), pA->GetBitmap().GetSizePixel(), pxShape );
                     }
                 }
             }
@@ -3453,7 +3493,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
 
                     ImplWriteBmp( BitmapEx(pA->GetBitmap()),
                                   pA->GetDestPoint(), pA->GetDestSize(),
-                                  pA->GetSrcPoint(), pA->GetSrcSize() );
+                                  pA->GetSrcPoint(), pA->GetSrcSize(), pxShape );
                 }
             }
             break;
@@ -3466,7 +3506,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
 
                     ImplWriteBmp( pA->GetBitmapEx(),
                                   pA->GetPoint(), mpVDev->PixelToLogic( pA->GetBitmapEx().GetSizePixel() ),
-                                  Point(), pA->GetBitmapEx().GetSizePixel() );
+                                  Point(), pA->GetBitmapEx().GetSizePixel(), pxShape );
                 }
             }
             break;
@@ -3486,7 +3526,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
                     {
                         ImplWriteBmp( pA->GetBitmapEx(),
                                       pA->GetPoint(), pA->GetSize(),
-                                      Point(), pA->GetBitmapEx().GetSizePixel() );
+                                      Point(), pA->GetBitmapEx().GetSizePixel(), pxShape );
                     }
                 }
             }
@@ -3500,7 +3540,7 @@ void SVGActionWriter::ImplWriteActions( const GDIMetaFile& rMtf,
 
                     ImplWriteBmp( pA->GetBitmapEx(),
                                   pA->GetDestPoint(), pA->GetDestSize(),
-                                  pA->GetSrcPoint(), pA->GetSrcSize() );
+                                  pA->GetSrcPoint(), pA->GetSrcSize(), pxShape );
                 }
             }
             break;
diff --git a/filter/source/svg/svgwriter.hxx b/filter/source/svg/svgwriter.hxx
index f0271ed4090b..1418818b0c16 100644
--- a/filter/source/svg/svgwriter.hxx
+++ b/filter/source/svg/svgwriter.hxx
@@ -360,7 +360,7 @@ private:
     void                    ImplWriteMask( GDIMetaFile& rMtf, const Point& rDestPt, const Size& rDestSize, const Gradient& rGradient, sal_uInt32 nWriteFlags );
     void                    ImplWriteText( const Point& rPos, const OUString& rText, const long* pDXArray, long nWidth );
     void                    ImplWriteText( const Point& rPos, const OUString& rText, const long* pDXArray, long nWidth, Color aTextColor );
-    void                    ImplWriteBmp( const BitmapEx& rBmpEx, const Point& rPt, const Size& rSz, const Point& rSrcPt, const Size& rSrcSz );
+    void                    ImplWriteBmp( const BitmapEx& rBmpEx, const Point& rPt, const Size& rSz, const Point& rSrcPt, const Size& rSrcSz, const css::uno::Reference<css::drawing::XShape>* pShape);
 
     void                    ImplWriteActions( const GDIMetaFile& rMtf,
                                               sal_uInt32 nWriteFlags,