Adding upstream version 1:7.0.4.upstream/1%7.0.4upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 520 insertions, 0 deletions

diff --git a/canvas/source/cairo/cairo_spritecanvashelper.cxx b/canvas/source/cairo/cairo_spritecanvashelper.cxx
new file mode 100644
index 000000000..47bde21e6
--- /dev/null
+++ b/canvas/source/cairo/cairo_spritecanvashelper.cxx
@@ -0,0 +1,520 @@
+/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/*
+ * This file is part of the LibreOffice project.
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * This file incorporates work covered by the following license notice:
+ *
+ *   Licensed to the Apache Software Foundation (ASF) under one or more
+ *   contributor license agreements. See the NOTICE file distributed
+ *   with this work for additional information regarding copyright
+ *   ownership. The ASF licenses this file to you under the Apache
+ *   License, Version 2.0 (the "License"); you may not use this file
+ *   except in compliance with the License. You may obtain a copy of
+ *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
+ */
+
+#include <sal/config.h>
+#include <sal/log.hxx>
+
+#include <boost/cast.hpp>
+
+#include <basegfx/range/b2irange.hxx>
+#include <tools/diagnose_ex.h>
+
+#include <canvas/canvastools.hxx>
+
+#include <cairo.h>
+
+#include "cairo_canvascustomsprite.hxx"
+#include "cairo_spritecanvashelper.hxx"
+
+using namespace ::cairo;
+using namespace ::com::sun::star;
+
+namespace cairocanvas
+{
+    namespace
+    {
+        /** Sprite redraw at original position
+
+            Used to repaint the whole canvas (background and all
+            sprites)
+         */
+        void spriteRedraw( const CairoSharedPtr& pCairo,
+                           const ::canvas::Sprite::Reference& rSprite )
+        {
+            // downcast to derived cairocanvas::Sprite interface, which
+            // provides the actual redraw methods.
+            ::boost::polymorphic_downcast< Sprite* >(rSprite.get())->redraw( pCairo, true);
+        }
+
+        void repaintBackground( const CairoSharedPtr&      pCairo,
+                                const SurfaceSharedPtr&    pBackgroundSurface,
+                                const ::basegfx::B2DRange& rArea )
+        {
+            cairo_save( pCairo.get() );
+            cairo_rectangle( pCairo.get(), ceil( rArea.getMinX() ), ceil( rArea.getMinY() ),
+                             floor( rArea.getWidth() ), floor( rArea.getHeight() ) );
+            cairo_clip( pCairo.get() );
+            cairo_set_source_surface( pCairo.get(), pBackgroundSurface->getCairoSurface().get(), 0, 0 );
+            cairo_set_operator( pCairo.get(), CAIRO_OPERATOR_SOURCE );
+            cairo_paint( pCairo.get() );
+            cairo_restore( pCairo.get() );
+        }
+
+        void opaqueUpdateSpriteArea( const ::canvas::Sprite::Reference& rSprite,
+                                     const CairoSharedPtr&              pCairo,
+                                     const ::basegfx::B2IRange&         rArea )
+        {
+            // clip output to actual update region (otherwise a)
+            // wouldn't save much render time, and b) will clutter
+            // scrolled sprite content outside this area)
+            cairo_save( pCairo.get() );
+            cairo_rectangle( pCairo.get(), rArea.getMinX(), rArea.getMinY(),
+                             sal::static_int_cast<sal_Int32>(rArea.getWidth()),
+                             sal::static_int_cast<sal_Int32>(rArea.getHeight()) );
+            cairo_clip( pCairo.get() );
+
+            // repaint affected sprite directly to output device (at
+            // the actual screen output position)
+            // rendering directly to device buffer
+            ::boost::polymorphic_downcast< Sprite* >( rSprite.get() )->redraw( pCairo, false );
+
+            cairo_restore( pCairo.get() );
+        }
+    }
+
+    SpriteCanvasHelper::SpriteCanvasHelper() :
+        mpRedrawManager( nullptr ),
+        mpOwningSpriteCanvas( nullptr ),
+        mpCompositingSurface(),
+        maCompositingSurfaceSize(),
+        mbCompositingSurfaceDirty(true)
+    {
+    }
+
+    void SpriteCanvasHelper::init( ::canvas::SpriteRedrawManager& rManager,
+                                   SpriteCanvas&                  rDevice,
+                                   const ::basegfx::B2ISize&      rSize )
+    {
+        mpRedrawManager = &rManager;
+        mpOwningSpriteCanvas = &rDevice;
+
+        CanvasHelper::init( rSize, rDevice, &rDevice );
+    }
+
+    void SpriteCanvasHelper::disposing()
+    {
+        mpCompositingSurface.reset();
+        mpOwningSpriteCanvas = nullptr;
+        mpRedrawManager = nullptr;
+
+        // forward to base
+        CanvasHelper::disposing();
+    }
+
+    uno::Reference< rendering::XAnimatedSprite > SpriteCanvasHelper::createSpriteFromAnimation(
+        const uno::Reference< rendering::XAnimation >& )
+    {
+        return uno::Reference< rendering::XAnimatedSprite >();
+    }
+
+    uno::Reference< rendering::XAnimatedSprite > SpriteCanvasHelper::createSpriteFromBitmaps(
+        const uno::Sequence< uno::Reference< rendering::XBitmap > >& /*animationBitmaps*/,
+        sal_Int8                                                     /*interpolationMode*/ )
+    {
+        return uno::Reference< rendering::XAnimatedSprite >();
+    }
+
+    uno::Reference< rendering::XCustomSprite > SpriteCanvasHelper::createCustomSprite( const geometry::RealSize2D& spriteSize )
+    {
+        if( !mpRedrawManager )
+            return uno::Reference< rendering::XCustomSprite >(); // we're disposed
+
+        return uno::Reference< rendering::XCustomSprite >(
+            new CanvasCustomSprite( spriteSize,
+                                    mpOwningSpriteCanvas ) );
+    }
+
+    uno::Reference< rendering::XSprite > SpriteCanvasHelper::createClonedSprite(
+        const uno::Reference< rendering::XSprite >& )
+    {
+        return uno::Reference< rendering::XSprite >();
+    }
+
+    bool SpriteCanvasHelper::updateScreen( const ::basegfx::B2IRange& /*rCurrArea*/,
+                                                 bool                   bUpdateAll,
+                                                 bool&                  io_bSurfaceDirty )
+    {
+        if( !mpRedrawManager ||
+            !mpOwningSpriteCanvas ||
+            !mpOwningSpriteCanvas->getWindowSurface() ||
+            !mpOwningSpriteCanvas->getBufferSurface() )
+        {
+            return false; // disposed, or otherwise dysfunctional
+        }
+
+        SAL_INFO("canvas.cairo", "SpriteCanvasHelper::updateScreen called");
+
+        const ::basegfx::B2ISize& rSize = mpOwningSpriteCanvas->getSizePixel();
+
+        // force compositing surface to be available before using it
+        // inside forEachSpriteArea
+        SurfaceSharedPtr pCompositingSurface = getCompositingSurface(rSize);
+        SurfaceSharedPtr pWindowSurface = mpOwningSpriteCanvas->getWindowSurface();
+        CairoSharedPtr pCompositingCairo = pCompositingSurface->getCairo();
+        CairoSharedPtr pWindowCairo = pWindowSurface->getCairo();
+
+        // TODO(P1): Might be worthwhile to track areas of background
+        // changes, too.
+        if( !bUpdateAll && !io_bSurfaceDirty && !mbCompositingSurfaceDirty )
+        {
+            // background has not changed, so we're free to optimize
+            // repaint to areas where a sprite has changed
+
+            // process each independent area of overlapping sprites
+            // separately.
+            mpRedrawManager->forEachSpriteArea( *this );
+        }
+        else
+        {
+            SAL_INFO("canvas.cairo", "SpriteCanvasHelper::updateScreen update ALL");
+
+            // background has changed, so we currently have no choice
+            // but repaint everything (or caller requested that)
+
+            cairo_rectangle( pCompositingCairo.get(), 0, 0, rSize.getX(), rSize.getY() );
+            cairo_clip( pCompositingCairo.get() );
+            cairo_save( pCompositingCairo.get() );
+            cairo_set_source_surface( pCompositingCairo.get(),
+                                      mpOwningSpriteCanvas->getBufferSurface()->getCairoSurface().get(),
+                                      0, 0 );
+            cairo_set_operator( pCompositingCairo.get(), CAIRO_OPERATOR_SOURCE );
+            cairo_paint( pCompositingCairo.get() );
+            cairo_restore( pCompositingCairo.get() );
+
+            // repaint all active sprites on top of background into
+            // VDev.
+            mpRedrawManager->forEachSprite(
+                    [&pCompositingCairo]( const Sprite::Reference rSprite )
+                    { spriteRedraw( pCompositingCairo, rSprite ); }
+                    );
+
+            // flush to screen
+            cairo_rectangle( pWindowCairo.get(), 0, 0, rSize.getX(), rSize.getY() );
+            cairo_clip( pWindowCairo.get() );
+            cairo_set_source_surface( pWindowCairo.get(),
+                                      pCompositingSurface->getCairoSurface().get(),
+                                      0, 0 );
+            cairo_set_operator( pWindowCairo.get(), CAIRO_OPERATOR_SOURCE );
+            cairo_paint( pWindowCairo.get() );
+        }
+
+        // change record vector must be cleared, for the next turn of
+        // rendering and sprite changing
+        mpRedrawManager->clearChangeRecords();
+
+        mbCompositingSurfaceDirty = false;
+        io_bSurfaceDirty = false;
+
+        // commit to screen
+        mpOwningSpriteCanvas->flush();
+
+        return true;
+    }
+
+    void SpriteCanvasHelper::backgroundPaint( const ::basegfx::B2DRange& rUpdateRect )
+    {
+        if( mpOwningSpriteCanvas && mpCompositingSurface )
+            repaintBackground( mpCompositingSurface->getCairo(),
+                               mpOwningSpriteCanvas->getBufferSurface(),
+                               rUpdateRect );
+    }
+
+    void SpriteCanvasHelper::scrollUpdate( const ::basegfx::B2DRange&                       rMoveStart,
+                                           const ::basegfx::B2DRange&                       rMoveEnd,
+                                           const ::canvas::SpriteRedrawManager::UpdateArea& rUpdateArea )
+    {
+        ENSURE_OR_THROW( mpOwningSpriteCanvas &&
+                          mpOwningSpriteCanvas->getBufferSurface(),
+                          "SpriteCanvasHelper::scrollUpdate(): NULL device pointer " );
+
+        SAL_INFO("canvas.cairo", "SpriteCanvasHelper::scrollUpdate called");
+
+        const ::basegfx::B2ISize& rSize = mpOwningSpriteCanvas->getSizePixel();
+        const ::basegfx::B2IRange  aOutputBounds( 0,0,
+                                                  rSize.getX(),
+                                                  rSize.getY() );
+
+        SurfaceSharedPtr pCompositingSurface = getCompositingSurface(rSize);
+        SurfaceSharedPtr pWindowSurface = mpOwningSpriteCanvas->getWindowSurface();
+        CairoSharedPtr pCompositingCairo = pCompositingSurface->getCairo();
+        CairoSharedPtr pWindowCairo = pWindowSurface->getCairo();
+
+        // round rectangles to integer pixel. Note: have to be
+        // extremely careful here, to avoid off-by-one errors for
+        // the destination area: otherwise, the next scroll update
+        // would copy pixel that are not supposed to be part of
+        // the sprite.
+        ::basegfx::B2IRange aSourceRect(
+            ::canvas::tools::spritePixelAreaFromB2DRange( rMoveStart ) );
+        const ::basegfx::B2IRange& rDestRect(
+            ::canvas::tools::spritePixelAreaFromB2DRange( rMoveEnd ) );
+        ::basegfx::B2IPoint aDestPos( rDestRect.getMinimum() );
+
+        std::vector< ::basegfx::B2IRange > aUnscrollableAreas;
+
+        // TODO(E3): This is plain buggy (but copies the behaviour of
+        // the old Impress slideshow) - the scrolled area might
+        // actually lie _below_ another window!
+
+        // clip to output bounds (cannot properly scroll stuff
+        // _outside_ our screen area)
+        if( !::canvas::tools::clipScrollArea( aSourceRect,
+                                              aDestPos,
+                                              aUnscrollableAreas,
+                                              aOutputBounds ) )
+        {
+            // fully clipped scroll area: cannot simply scroll
+            // then. Perform normal opaque update (can use that, since
+            // one of the preconditions for scrollable update is
+            // opaque sprite content)
+
+            // repaint all affected sprites directly to output device
+            for( const auto& rComponent : rUpdateArea.maComponentList )
+            {
+                const ::canvas::Sprite::Reference& rSprite( rComponent.second.getSprite() );
+                if( rSprite.is() )
+                    ::boost::polymorphic_downcast< Sprite* >( rSprite.get() )->redraw(
+                        pCompositingCairo, true );
+            }
+        }
+        else
+        {
+            const ::basegfx::B2IVector aSourceUpperLeftPos( aSourceRect.getMinimum() );
+
+            // clip dest area (which must be inside rDestBounds)
+            ::basegfx::B2IRange aDestRect( rDestRect );
+            aDestRect.intersect( aOutputBounds );
+
+            ::basegfx::B2ISize aScrollSize( aDestRect.getWidth(), aDestRect.getHeight() );
+            SurfaceSharedPtr pScrollSurface( getTemporarySurface() );
+            CairoSharedPtr pScrollCairo( pScrollSurface->getCairo() );
+
+            cairo_save( pScrollCairo.get() );
+            // scroll the current content of the compositing surface (and,
+            // thus, of the window) in temp. surface
+            cairo_set_source_surface( pScrollCairo.get(),
+                                      pCompositingSurface->getCairoSurface().get(),
+                                      aDestPos.getX() - aSourceUpperLeftPos.getX(),
+                                      aDestPos.getY() - aSourceUpperLeftPos.getY() );
+            cairo_rectangle( pScrollCairo.get(),
+                    aDestPos.getX(), aDestPos.getY(),
+                    aScrollSize.getX(), aScrollSize.getY() );
+            cairo_clip( pScrollCairo.get() );
+            cairo_set_operator( pScrollCairo.get(), CAIRO_OPERATOR_SOURCE );
+            cairo_paint( pScrollCairo.get() );
+            cairo_restore( pScrollCairo.get() );
+
+            cairo_save( pCompositingCairo.get() );
+            // copy the scrolled area back onto the compositing surface
+            cairo_set_source_surface( pCompositingCairo.get(),
+                                      pScrollSurface->getCairoSurface().get(),
+                                      0, 0 );
+            cairo_rectangle( pCompositingCairo.get(),
+                             aDestPos.getX(), aDestPos.getY(),
+                             aScrollSize.getX(), aScrollSize.getY() );
+            cairo_clip( pCompositingCairo.get() );
+            cairo_set_operator( pCompositingCairo.get(), CAIRO_OPERATOR_SOURCE );
+            cairo_paint( pCompositingCairo.get() );
+            cairo_restore( pCompositingCairo.get() );
+
+            const ::canvas::SpriteRedrawManager::SpriteConnectedRanges::ComponentListType::const_iterator
+                aFirst( rUpdateArea.maComponentList.begin() );
+            ::canvas::SpriteRedrawManager::SpriteConnectedRanges::ComponentListType::const_iterator
+                  aSecond( aFirst );
+            ++aSecond;
+
+            ENSURE_OR_THROW( aFirst->second.getSprite().is(),
+                             "VCLCanvas::scrollUpdate(): no sprite" );
+
+            // repaint uncovered areas from sprite. Need to actually
+            // clip here, since we're only repainting _parts_ of the
+            // sprite
+            for( const auto& rArea : aUnscrollableAreas )
+                opaqueUpdateSpriteArea( aFirst->second.getSprite(),
+                                        pCompositingCairo, rArea );
+        }
+
+        // repaint uncovered areas from backbuffer - take the
+        // _rounded_ rectangles from above, to have the update
+        // consistent with the scroll above.
+        std::vector< ::basegfx::B2DRange > aUncoveredAreas;
+        ::basegfx::computeSetDifference( aUncoveredAreas,
+                                         rUpdateArea.maTotalBounds,
+                                         ::basegfx::B2DRange( rDestRect ) );
+        for( const auto& rArea : aUncoveredAreas )
+            repaintBackground( pCompositingCairo,
+                               mpOwningSpriteCanvas->getBufferSurface(), rArea );
+
+        cairo_rectangle( pWindowCairo.get(), 0, 0, rSize.getX(), rSize.getY() );
+        cairo_clip( pWindowCairo.get() );
+        cairo_set_source_surface( pWindowCairo.get(),
+                                  pCompositingSurface->getCairoSurface().get(),
+                                  0, 0 );
+        cairo_set_operator( pWindowCairo.get(), CAIRO_OPERATOR_SOURCE );
+        cairo_paint( pWindowCairo.get() );
+    }
+
+    void SpriteCanvasHelper::opaqueUpdate( const ::basegfx::B2DRange&                          rTotalArea,
+                                           const std::vector< ::canvas::Sprite::Reference >& rSortedUpdateSprites )
+    {
+        ENSURE_OR_THROW( mpOwningSpriteCanvas &&
+                          mpOwningSpriteCanvas->getBufferSurface(),
+                          "SpriteCanvasHelper::opaqueUpdate(): NULL device pointer " );
+
+        SAL_INFO("canvas.cairo", "SpriteCanvasHelper::opaqueUpdate called");
+
+        const ::basegfx::B2ISize& rDeviceSize = mpOwningSpriteCanvas->getSizePixel();
+
+        SurfaceSharedPtr pCompositingSurface = getCompositingSurface(rDeviceSize);
+        SurfaceSharedPtr pWindowSurface = mpOwningSpriteCanvas->getWindowSurface();
+        CairoSharedPtr pCompositingCairo = pCompositingSurface->getCairo();
+        CairoSharedPtr pWindowCairo = pWindowSurface->getCairo();
+
+        cairo_rectangle( pCompositingCairo.get(), 0, 0, rDeviceSize.getX(), rDeviceSize.getY() );
+        cairo_clip( pCompositingCairo.get() );
+
+        ::basegfx::B2DVector aPos( ceil( rTotalArea.getMinX() ), ceil( rTotalArea.getMinY() ) );
+        ::basegfx::B2DVector aSize( floor( rTotalArea.getMaxX() - aPos.getX() ), floor( rTotalArea.getMaxY() - aPos.getY() ) );
+
+        cairo_rectangle( pCompositingCairo.get(), aPos.getX(), aPos.getY(), aSize.getX(), aSize.getY() );
+        cairo_clip( pCompositingCairo.get() );
+
+        // repaint all affected sprites directly to output device
+        for( const auto& rSprite : rSortedUpdateSprites )
+        {
+            if( rSprite.is() )
+                ::boost::polymorphic_downcast< Sprite* >( rSprite.get() )->redraw(
+                    pCompositingCairo, false );
+        }
+
+        // flush to screen
+        cairo_rectangle( pWindowCairo.get(), 0, 0, rDeviceSize.getX(), rDeviceSize.getY() );
+        cairo_clip( pWindowCairo.get() );
+        cairo_rectangle( pWindowCairo.get(), aPos.getX(), aPos.getY(), aSize.getX(), aSize.getY() );
+        cairo_clip( pWindowCairo.get() );
+        cairo_set_source_surface( pWindowCairo.get(),
+                                  pCompositingSurface->getCairoSurface().get(),
+                                  0, 0 );
+        cairo_set_operator( pWindowCairo.get(), CAIRO_OPERATOR_SOURCE );
+        cairo_paint( pWindowCairo.get() );
+    }
+
+    void SpriteCanvasHelper::genericUpdate( const ::basegfx::B2DRange&                          rRequestedArea,
+                                            const std::vector< ::canvas::Sprite::Reference >& rSortedUpdateSprites )
+    {
+        // TODO
+        SAL_INFO("canvas.cairo", "SpriteCanvasHelper::genericUpdate called");
+
+        ENSURE_OR_THROW( mpOwningSpriteCanvas &&
+                         mpOwningSpriteCanvas->getBufferSurface(),
+                         "SpriteCanvasHelper::genericUpdate(): NULL device pointer " );
+
+        // limit size of update VDev to target outdev's size
+        const ::basegfx::B2ISize& rSize = mpOwningSpriteCanvas->getSizePixel();
+
+        SurfaceSharedPtr pCompositingSurface = getCompositingSurface(rSize);
+        SurfaceSharedPtr pWindowSurface = mpOwningSpriteCanvas->getWindowSurface();
+        CairoSharedPtr pCompositingCairo = pCompositingSurface->getCairo();
+        CairoSharedPtr pWindowCairo = pWindowSurface->getCairo();
+
+        // round output position towards zero. Don't want to truncate
+        // a fraction of a sprite pixel...  Clip position at origin,
+        // otherwise, truncation of size below might leave visible
+        // areas uncovered by VDev.
+        const Point aOutputPosition(
+            std::max( sal_Int32( 0 ),
+                        static_cast< sal_Int32 >(rRequestedArea.getMinX()) ),
+            std::max( sal_Int32( 0 ),
+                        static_cast< sal_Int32 >(rRequestedArea.getMinY()) ) );
+        // round output size towards +infty. Don't want to truncate a
+        // fraction of a sprite pixel... Limit size of VDev to output
+        // device's area.
+        const Size  aOutputSize(
+            std::min( rSize.getX(),
+                        ::canvas::tools::roundUp( rRequestedArea.getMaxX() - aOutputPosition.X()) ),
+            std::min( rSize.getY(),
+                        ::canvas::tools::roundUp( rRequestedArea.getMaxY() - aOutputPosition.Y()) ) );
+
+        cairo_rectangle( pCompositingCairo.get(), aOutputPosition.X(), aOutputPosition.Y(), aOutputSize.Width(), aOutputSize.Height() );
+        cairo_clip( pCompositingCairo.get() );
+
+        // paint background
+        cairo_save( pCompositingCairo.get() );
+        cairo_set_source_surface( pCompositingCairo.get(),
+                                  mpOwningSpriteCanvas->getBufferSurface()->getCairoSurface().get(),
+                                  0, 0 );
+        cairo_set_operator( pCompositingCairo.get(), CAIRO_OPERATOR_SOURCE );
+        cairo_paint( pCompositingCairo.get() );
+        cairo_restore( pCompositingCairo.get() );
+
+        // repaint all affected sprites on top of background into
+        // VDev.
+        for( const auto& rSprite : rSortedUpdateSprites )
+        {
+            if( rSprite.is() )
+                ::boost::polymorphic_downcast< Sprite* >( rSprite.get() )->redraw(
+                    pCompositingCairo, true );
+        }
+
+        // flush to screen
+        cairo_rectangle( pWindowCairo.get(), aOutputPosition.X(), aOutputPosition.Y(), aOutputSize.Width(), aOutputSize.Height() );
+        cairo_clip( pWindowCairo.get() );
+        cairo_set_source_surface( pWindowCairo.get(),
+                                  pCompositingSurface->getCairoSurface().get(),
+                                  0, 0 );
+        cairo_set_operator( pWindowCairo.get(), CAIRO_OPERATOR_SOURCE );
+        cairo_paint( pWindowCairo.get() );
+    }
+
+    ::cairo::SurfaceSharedPtr const & SpriteCanvasHelper::getCompositingSurface( const ::basegfx::B2ISize& rNeededSize )
+    {
+        if( rNeededSize.getX() > maCompositingSurfaceSize.getX() ||
+            rNeededSize.getY() > maCompositingSurfaceSize.getY() )
+        {
+            // need to give buffer more size
+            mpCompositingSurface.reset();
+        }
+
+        if( !mpCompositingSurface )
+        {
+            mpCompositingSurface = createSurface( rNeededSize );
+            maCompositingSurfaceSize = rNeededSize;
+            mbCompositingSurfaceDirty = true;
+            mpTemporarySurface.reset();
+        }
+
+        return mpCompositingSurface;
+    }
+
+    ::cairo::SurfaceSharedPtr const & SpriteCanvasHelper::getTemporarySurface()
+    {
+        if ( !mpTemporarySurface )
+            mpTemporarySurface = createSurface( maCompositingSurfaceSize );
+        return mpTemporarySurface;
+    }
+
+    ::cairo::SurfaceSharedPtr SpriteCanvasHelper::createSurface( const ::basegfx::B2ISize& rNeededSize ) const
+    {
+        return mpOwningSpriteCanvas->getWindowSurface()->getSimilar(
+                    CAIRO_CONTENT_COLOR,
+                    rNeededSize.getX(), rNeededSize.getY() );
+    }
+}
+
+/* vim:set shiftwidth=4 softtabstop=4 expandtab: */