tdf#150610 fix broken rendering of text meta actions

Even when drawing to a VirtualDevice where antialiasing
is disabled, text will still be drawn with some
antialiased pixels on HiDPI displays. So, expand the
size of the VirtualDevice slightly to capture any of
the pixles drawn past the edges of the destination
bounds.

Change-Id: Ibcba8234708d8784c12f984289ec0a8fcad6694e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/156098
Tested-by: Jenkins
Reviewed-by: Mike Kaganski <mike.kaganski@collabora.com>
Reviewed-by: Patrick Luby <plubius@neooffice.org>

1 files changed, 58 insertions, 9 deletions

diff --git a/cppcanvas/source/mtfrenderer/transparencygroupaction.cxx b/cppcanvas/source/mtfrenderer/transparencygroupaction.cxx
index b8350a8f3944..e0caeaa7cf2a 100644
--- a/cppcanvas/source/mtfrenderer/transparencygroupaction.cxx
+++ b/cppcanvas/source/mtfrenderer/transparencygroupaction.cxx
@@ -205,6 +205,8 @@ namespace cppcanvas::internal
                     return false;
                 }
 
+                ::Point aMtfOffsetPoint;
+
                 // if there's no buffer bitmap, or as soon as the
                 // total transformation changes, we've got to
                 // re-render the bitmap
@@ -215,15 +217,59 @@ namespace cppcanvas::internal
                 {
                     DBG_TESTSOLARMUTEX();
 
+                    // tdf#150610 fix broken rendering of text meta actions
+                    // Even when drawing to a VirtualDevice where antialiasing
+                    // is disabled, text will still be drawn with some
+                    // antialiased pixels on HiDPI displays. So, expand the
+                    // size of the VirtualDevice slightly to capture any of
+                    // the pixles drawn past the edges of the destination
+                    // bounds.
+                    bool        bHasTextActions = false;
+                    MetaAction* pCurrAct;
+                    int         nCurrActionIndex;
+                    for( nCurrActionIndex=0, pCurrAct=mpGroupMtf->FirstAction();
+                         pCurrAct && !bHasTextActions;
+                         ++nCurrActionIndex, pCurrAct = mpGroupMtf->NextAction() )
+                    {
+                        switch( pCurrAct->GetType() )
+                        {
+                            case MetaActionType::TEXT:
+                            case MetaActionType::TEXTARRAY:
+                            case MetaActionType::STRETCHTEXT:
+                            case MetaActionType::TEXTRECT:
+                                if( ( rSubset.mnSubsetBegin == 0 && rSubset.mnSubsetEnd == -1 ) || ( rSubset.mnSubsetBegin <= nCurrActionIndex && rSubset.mnSubsetEnd > nCurrActionIndex ) )
+                                    bHasTextActions = true;
+                                break;
+                            default:
+                                break;
+                        }
+                    }
+
                     // output size of metafile
                     ::Size aOutputSizePixel( ::basegfx::fround( aScale.getX() * maDstSize.getWidth() ),
                                              ::basegfx::fround( aScale.getY() * maDstSize.getHeight() ) );
 
-                    // pixel size of cache bitmap: round up to nearest int
-                    ::Size aBitmapSizePixel( static_cast<sal_Int32>( aScale.getX() * maDstSize.getWidth() )+1,
-                                             static_cast<sal_Int32>( aScale.getY() * maDstSize.getHeight() )+1 );
+                    sal_Int32 nBitmapExtra;
+                    if ( bHasTextActions )
+                    {
+                        nBitmapExtra = 10;
+                        aMtfOffsetPoint = ::Point( nBitmapExtra / 2, nBitmapExtra / 2 );
+                    }
+                    else
+                    {
+                        // Related tdf#150610 assume antialiasing is enabled
+                        // Although antialiasing is normally disabled in the
+                        // VirtualDevice, lines in tdf#150610 will draw past
+                        // the edge of the VirtualDevice when running a
+                        // slideshow so always add an extra pixel on the
+                        // right and bottom edges.
+                        nBitmapExtra = 1;
+                    }
 
-                    ::Point aEmptyPoint;
+                    // pixel size of cache bitmap: round up to nearest int
+                    ::Point aBitmapPoint;
+                    ::Size aBitmapSizePixel( static_cast<sal_Int32>( aScale.getX() * maDstSize.getWidth() ) + nBitmapExtra,
+                                             static_cast<sal_Int32>( aScale.getY() * maDstSize.getHeight() ) + nBitmapExtra );
 
                     // render our content into an appropriately sized
                     // VirtualDevice with alpha channel
@@ -238,8 +284,6 @@ namespace cppcanvas::internal
                         // true subset - extract referenced
                         // metaactions from mpGroupMtf
                         GDIMetaFile aMtf;
-                        MetaAction* pCurrAct;
-                        int         nCurrActionIndex;
 
                         // extract subset actions
                         for( nCurrActionIndex=0,
@@ -320,7 +364,9 @@ namespace cppcanvas::internal
                         }
 
                         aVDev->DrawTransparent( aMtf,
-                                               aEmptyPoint,
+                                               aBitmapPoint,
+                                               aBitmapSizePixel,
+                                               aMtfOffsetPoint,
                                                aOutputSizePixel,
                                                *mpAlphaGradient );
                     }
@@ -328,7 +374,9 @@ namespace cppcanvas::internal
                     {
                         // no subsetting - render whole mtf
                         aVDev->DrawTransparent( *mpGroupMtf,
-                                               aEmptyPoint,
+                                               aBitmapPoint,
+                                               aBitmapSizePixel,
+                                               aMtfOffsetPoint,
                                                aOutputSizePixel,
                                                *mpAlphaGradient );
                     }
@@ -338,7 +386,7 @@ namespace cppcanvas::internal
                     BitmapSharedPtr aBmp( VCLFactory::createBitmap(
                                               mpCanvas,
                                               aVDev->GetBitmapEx(
-                                                  aEmptyPoint,
+                                                  aBitmapPoint,
                                                   aBitmapSizePixel ) ) );
                     mxBufferBitmap = aBmp->getUNOBitmap();
                     maLastTransformation = aTotalTransform;
@@ -362,6 +410,7 @@ namespace cppcanvas::internal
                 // the contained scaling, we've got to right-multiply with
                 // the inverse.
                 ::basegfx::B2DHomMatrix aScaleCorrection;
+                aScaleCorrection.translate( -aMtfOffsetPoint.X(), -aMtfOffsetPoint.Y() );
                 aScaleCorrection.scale( 1/aScale.getX(), 1/aScale.getY() );
                 aTransform = aTransform * aScaleCorrection;