lok: render image preview with lower resolution

renderShapeSelection callback is used to render
image previews which are later used during
eg. rotation.

Do not render preview with original size which
slows down app a lot. Use 1280x720 max.

Change-Id: Ia8365a67d87cea869ef74cb70ce4830439a523b6
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129376
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/129497
Tested-by: Jenkins
Reviewed-by: Szymon Kłos <szymon.klos@collabora.com>

5 files changed, 39 insertions, 2 deletions

diff --git a/filter/source/svg/svgexport.cxx b/filter/source/svg/svgexport.cxx
index ef0c1ea37a80..c21b041b1bbc 100644
--- a/filter/source/svg/svgexport.cxx
+++ b/filter/source/svg/svgexport.cxx
@@ -796,7 +796,9 @@ bool SVGFilter::implExportWriterTextGraphic( const Reference< view::XSelectionSu
     const Graphic aOriginalGraphic(xOriginalGraphic);
 
     uno::Reference<graphic::XGraphic> xTransformedGraphic;
-    xPropertySet->getPropertyValue("TransformedGraphic") >>= xTransformedGraphic;
+    xPropertySet->getPropertyValue(
+        mbIsPreview ? OUString("GraphicPreview") : OUString("TransformedGraphic"))
+            >>= xTransformedGraphic;
 
     if (!xTransformedGraphic.is())
         return false;
@@ -971,6 +973,8 @@ bool SVGFilter::implExportDocument()
                 mpSVGWriter->SetEmbeddedBitmapRefs( &maBitmapActionMap );
                 implExportTiledBackground();
             }
+            if( mbIsPreview )
+                mpSVGWriter->SetPreviewMode();
 
             // #i124608# export a given object selection, so no MasterPage export at all
             if (!mbExportShapeSelection)
diff --git a/filter/source/svg/svgfilter.cxx b/filter/source/svg/svgfilter.cxx
index 4c3f033d02eb..c6677bf0c9dc 100644
--- a/filter/source/svg/svgfilter.cxx
+++ b/filter/source/svg/svgfilter.cxx
@@ -77,6 +77,7 @@ SVGFilter::SVGFilter( const Reference< XComponentContext >& rxCtx ) :
     mnVisiblePage( -1 ),
     mpObjects( nullptr ),
     mbExportShapeSelection(false),
+    mbIsPreview(false),
     mbWriterFilter(false),
     mbCalcFilter(false),
     mbImpressFilter(false),
@@ -108,6 +109,15 @@ sal_Bool SAL_CALL SVGFilter::filter( const Sequence< PropertyValue >& rDescripto
 
     for (const PropertyValue& rProp : rDescriptor)
     {
+        if (rProp.Name == "IsPreview")
+        {
+            rProp.Value >>= mbIsPreview;
+            break;
+        }
+    }
+
+    for (const PropertyValue& rProp : rDescriptor)
+    {
         if (rProp.Name == "FilterName")
         {
             OUString sFilterName;
diff --git a/filter/source/svg/svgfilter.hxx b/filter/source/svg/svgfilter.hxx
index eb889e81662e..93e14ec41671 100644
--- a/filter/source/svg/svgfilter.hxx
+++ b/filter/source/svg/svgfilter.hxx
@@ -209,6 +209,7 @@ private:
     Sequence< PropertyValue >           maFilterData;
     Reference< css::drawing::XDrawPage > mxDefaultPage;
     std::vector< Reference< css::drawing::XDrawPage > > mSelectedPages;
+    bool                                mbIsPreview;
 
     bool                                mbWriterFilter;
     bool                                mbCalcFilter;
diff --git a/filter/source/svg/svgwriter.cxx b/filter/source/svg/svgwriter.cxx
index 3d8183ebb2fd..f849315ce823 100644
--- a/filter/source/svg/svgwriter.cxx
+++ b/filter/source/svg/svgwriter.cxx
@@ -2942,7 +2942,27 @@ void SVGActionWriter::ImplWriteBmp( const BitmapEx& rBmpEx,
         }
     }
 
-    if( !(bCached || GraphicConverter::Export( aOStm, rBmpEx, ConvertDataFormat::PNG ) == ERRCODE_NONE) )
+    const BitmapEx* pBitmap = &rBmpEx;
+    std::unique_ptr<BitmapEx> pNewBitmap;
+
+    // for preview we generate downscaled images (1280x720 max)
+    if (mbIsPreview)
+    {
+        Size aSize = rBmpEx.GetSizePixel();
+        double fX = static_cast<double>(aSize.getWidth()) / 1280;
+        double fY = static_cast<double>(aSize.getHeight()) / 720;
+        double fFactor = fX > fY ? fX : fY;
+        if (fFactor > 1.0)
+        {
+            aSize.setWidth(aSize.getWidth() / fFactor);
+            aSize.setHeight(aSize.getHeight() / fFactor);
+            pNewBitmap = std::make_unique<BitmapEx>(rBmpEx);
+            pNewBitmap->Scale(aSize);
+            pBitmap = pNewBitmap.get();
+        }
+    }
+
+    if( !(bCached || GraphicConverter::Export( aOStm, *pBitmap, ConvertDataFormat::PNG ) == ERRCODE_NONE) )
         return;
 
     Point                    aPt;
diff --git a/filter/source/svg/svgwriter.hxx b/filter/source/svg/svgwriter.hxx
index fdfcd24d32b2..d48d68bdec72 100644
--- a/filter/source/svg/svgwriter.hxx
+++ b/filter/source/svg/svgwriter.hxx
@@ -318,6 +318,7 @@ private:
     bool                                        mbClipAttrChanged;
     bool                                        mbIsPlaceholderShape;
     const MetaBitmapActionMap*                  mpEmbeddedBitmapsMap;
+    bool                                        mbIsPreview;
 
 
     tools::Long                    ImplMap( sal_Int32 nVal ) const;
@@ -377,6 +378,7 @@ public:
     void                    SetEmbeddedBitmapRefs( const MetaBitmapActionMap* pEmbeddedBitmapsMap );
     void StartMask(const Point& rDestPt, const Size& rDestSize, const Gradient& rGradient,
                    sal_uInt32 nWriteFlags, OUString* pTextStyle = nullptr);
+    void                    SetPreviewMode(bool bState = true) { mbIsPreview = bState; }
 };