/* -*- 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 <cstdlib>

#include <tuple>

#include <basegfx/matrix/b2dhommatrix.hxx>

#include <basegfx/numeric/ftools.hxx>

#include <basegfx/point/b2dpoint.hxx>

#include <basegfx/polygon/b2dpolygon.hxx>

#include <basegfx/polygon/b2dpolygontools.hxx>

#include <basegfx/range/b2drectangle.hxx>

#include <basegfx/utils/canvastools.hxx>

#include <basegfx/utils/keystoplerp.hxx>

#include <basegfx/utils/lerp.hxx>

#include <basegfx/utils/tools.hxx>

#include <com/sun/star/rendering/TexturingMode.hpp>

#include <rtl/math.hxx>

#include <comphelper/diagnose_ex.hxx>

#include <tools/poly.hxx>

#include <vcl/alpha.hxx>

#include <vcl/bitmap.hxx>

#include <vcl/canvastools.hxx>

#include <vcl/virdev.hxx>

#include <vcl/gradient.hxx>

#include <canvas/canvastools.hxx>

#include <parametricpolypolygon.hxx>

#include "canvashelper.hxx"

#include "impltools.hxx"

using namespace ::com::sun::star;

namespace vclcanvas

{

    namespace

    {

        bool textureFill( OutputDevice&         rOutDev,

                          const GraphicObject&  rGraphic,

                          const ::Point&        rPosPixel,

                          const ::Size&         rNextTileX,

                          const ::Size&         rNextTileY,

                          sal_Int32             nTilesX,

                          sal_Int32             nTilesY,

                          const ::Size&         rTileSize,

                          const GraphicAttr&    rAttr)

        {

            bool bRet( false );

            Point   aCurrPos;

            int     nX, nY;

            for( nY=0; nY < nTilesY; ++nY )

            {

                aCurrPos.setX( rPosPixel.X() + nY*rNextTileY.Width() );

                aCurrPos.setY( rPosPixel.Y() + nY*rNextTileY.Height() );

                for( nX=0; nX < nTilesX; ++nX )

                {

                    // update return value. This method should return true, if

                    // at least one of the looped Draws succeeded.

                    bRet |= rGraphic.Draw(rOutDev,

                                          aCurrPos,

                                          rTileSize,

                                          &rAttr);

                    aCurrPos.AdjustX(rNextTileX.Width() );

                    aCurrPos.AdjustY(rNextTileX.Height() );

                }

            }

            return bRet;

        }

        /** Fill linear or axial gradient

            Since most of the code for linear and axial gradients are

            the same, we've a unified method here

         */

        void fillLinearGradient( OutputDevice&                                  rOutDev,

                                 const ::basegfx::B2DHomMatrix&                 rTextureTransform,

                                 const ::tools::Rectangle&                             rBounds,

                                 unsigned int                                   nStepCount,

                                 const ::canvas::ParametricPolyPolygon::Values& rValues,

                                 const std::vector< ::Color >&                  rColors )

        {

            // determine general position of gradient in relation to

            // the bound rect

            // =====================================================

            ::basegfx::B2DPoint aLeftTop( 0.0, 0.0 );

            ::basegfx::B2DPoint aLeftBottom( 0.0, 1.0 );

            ::basegfx::B2DPoint aRightTop( 1.0, 0.0 );

            ::basegfx::B2DPoint aRightBottom( 1.0, 1.0 );

            aLeftTop    *= rTextureTransform;

            aLeftBottom *= rTextureTransform;

            aRightTop   *= rTextureTransform;

            aRightBottom*= rTextureTransform;

            // calc length of bound rect diagonal

            const ::basegfx::B2DVector aBoundRectDiagonal(

                vcl::unotools::b2DPointFromPoint( rBounds.TopLeft() ) -

                vcl::unotools::b2DPointFromPoint( rBounds.BottomRight() ) );

            const double nDiagonalLength( aBoundRectDiagonal.getLength() );

            // create direction of gradient:

            //     _______

            //     |  |  |

            // ->  |  |  | ...

            //     |  |  |

            //     -------

            ::basegfx::B2DVector aDirection( aRightTop - aLeftTop );

            aDirection.normalize();

            // now, we potentially have to enlarge our gradient area

            // atop and below the transformed [0,1]x[0,1] unit rect,

            // for the gradient to fill the complete bound rect.

            ::basegfx::utils::infiniteLineFromParallelogram( aLeftTop,

                                                             aLeftBottom,

                                                             aRightTop,

                                                             aRightBottom,

                                                             vcl::unotools::b2DRectangleFromRectangle(rBounds) );

            // render gradient

            // ===============

            // First try to use directly VCL's DrawGradient(), as that one is generally

            // a better choice than here decomposing to polygons. The VCL API allows

            // only 2 colors, but that should generally do.

            // Do not use nStepCount, it limits optimized implementations, and it's computed

            // by vclcanvas based on number of colors, so it's practically irrelevant.

            // 2 colors and 2 stops (at 0 and 1) is a linear gradient:

            if( rColors.size() == 2 && rValues.maStops.size() == 2 && rValues.maStops[0] == 0 && rValues.maStops[1] == 1)

            {

                // tdf#144073 and tdf#147645: use bounds and angle for gradient

                // Passing an expanded, rotated polygon noticeably modifies the

                // drawing of the gradient in a slideshow due to moving of the

                // starting and ending colors far off the edges of the drawing

                // surface. So try another way and set the angle of the

                // gradient and draw only the unadjusted bounds.

                Gradient vclGradient( css::awt::GradientStyle_LINEAR, rColors[ 0 ], rColors[ 1 ] );

                double fRotate = atan2( aDirection.getY(), aDirection.getX() );

                const double nAngleInTenthOfDegrees = 3600.0 - basegfx::rad2deg<10>( fRotate ) + 900.0;

                vclGradient.SetAngle( Degree10( ::basegfx::fround( nAngleInTenthOfDegrees ) ) );

                rOutDev.DrawGradient( rBounds, vclGradient );

                return;

            }

            // 3 colors with first and last being equal and 3 stops (at 0, 0.5 and 1) is an axial gradient:

            if( rColors.size() == 3 && rColors[ 0 ] == rColors[ 2 ]

                && rValues.maStops.size() == 3 && rValues.maStops[0] == 0

                && rValues.maStops[1] == 0.5 && rValues.maStops[2] == 1)

            {

                // tdf#144073 and tdf#147645: use bounds and angle for gradient

                // Passing an expanded, rotated polygon noticeably modifies the

                // drawing of the gradient in a slideshow due to moving of the

                // starting and ending colors far off the edges of the drawing

                // surface. So try another way and set the angle of the

                // gradient and draw only the unadjusted bounds.

                Gradient vclGradient( css::awt::GradientStyle_AXIAL, rColors[ 1 ], rColors[ 0 ] );

                double fRotate = atan2( aDirection.getY(), aDirection.getX() );

                const double nAngleInTenthOfDegrees = 3600.0 - basegfx::rad2deg<10>( fRotate ) + 900.0;

                vclGradient.SetAngle( Degree10( ::basegfx::fround( nAngleInTenthOfDegrees ) ) );

                rOutDev.DrawGradient( rBounds, vclGradient );

                return;

            }

            // for linear gradients, it's easy to render

            // non-overlapping polygons: just split the gradient into

            // nStepCount small strips. Prepare the strip now.

            // For performance reasons, we create a temporary VCL

            // polygon here, keep it all the way and only change the

            // vertex values in the loop below (as ::Polygon is a

            // pimpl class, creating one every loop turn would really

            // stress the mem allocator)

            ::tools::Polygon aTempPoly( static_cast<sal_uInt16>(5) );

            OSL_ENSURE( nStepCount >= 3,

                        "fillLinearGradient(): stepcount smaller than 3" );

            // fill initial strip (extending two times the bound rect's

            // diagonal to the 'left'

            // calculate left edge, by moving left edge of the

            // gradient rect two times the bound rect's diagonal to

            // the 'left'. Since we postpone actual rendering into the

            // loop below, we set the _right_ edge here, which will be

            // readily copied into the left edge in the loop below

            const ::basegfx::B2DPoint aPoint1( aLeftTop - 2.0*nDiagonalLength*aDirection );

            aTempPoly[1] = ::Point( ::basegfx::fround<::tools::Long>( aPoint1.getX() ),

                                    ::basegfx::fround<::tools::Long>( aPoint1.getY() ) );

            const ::basegfx::B2DPoint aPoint2( aLeftBottom - 2.0*nDiagonalLength*aDirection );

            aTempPoly[2] = ::Point( ::basegfx::fround<::tools::Long>( aPoint2.getX() ),

                                    ::basegfx::fround<::tools::Long>( aPoint2.getY() ) );

            // iteratively render all other strips

            // ensure that nStepCount matches color stop parity, to

            // have a well-defined middle color e.g. for axial

            // gradients.

            if( (rColors.size() % 2) != (nStepCount % 2) )

                ++nStepCount;

            rOutDev.SetLineColor();

            basegfx::utils::KeyStopLerp aLerper(rValues.maStops);

            // only iterate nStepCount-1 steps, as the last strip is

            // explicitly painted below

            for( unsigned int i=0; i<nStepCount-1; ++i )

            {

                std::ptrdiff_t nIndex;

                double fAlpha;

                std::tie(nIndex,fAlpha)=aLerper.lerp(double(i)/nStepCount);

                rOutDev.SetFillColor(

                    Color( static_cast<sal_uInt8>(basegfx::utils::lerp(rColors[nIndex].GetRed(),rColors[nIndex+1].GetRed(),fAlpha)),

                           static_cast<sal_uInt8>(basegfx::utils::lerp(rColors[nIndex].GetGreen(),rColors[nIndex+1].GetGreen(),fAlpha)),

                           static_cast<sal_uInt8>(basegfx::utils::lerp(rColors[nIndex].GetBlue(),rColors[nIndex+1].GetBlue(),fAlpha)) ));

                // copy right edge of polygon to left edge (and also

                // copy the closing point)

                aTempPoly[0] = aTempPoly[4] = aTempPoly[1];

                aTempPoly[3] = aTempPoly[2];

                // calculate new right edge, from interpolating

                // between start and end line. Note that i is

                // increased by one, to account for the fact that we

                // calculate the right border here (whereas the fill

                // color is governed by the left edge)

                const ::basegfx::B2DPoint aPoint3(

                    (nStepCount - i-1)/double(nStepCount)*aLeftTop +

                    (i+1)/double(nStepCount)*aRightTop );

                aTempPoly[1] = ::Point( ::basegfx::fround<::tools::Long>( aPoint3.getX() ),

                                        ::basegfx::fround<::tools::Long>( aPoint3.getY() ) );

                const ::basegfx::B2DPoint aPoint4(

                    (nStepCount - i-1)/double(nStepCount)*aLeftBottom +

                    (i+1)/double(nStepCount)*aRightBottom );

                aTempPoly[2] = ::Point( ::basegfx::fround<::tools::Long>( aPoint4.getX() ),

                                        ::basegfx::fround<::tools::Long>( aPoint4.getY() ) );

                rOutDev.DrawPolygon( aTempPoly );

            }

            // fill final strip (extending two times the bound rect's

            // diagonal to the 'right'

            // copy right edge of polygon to left edge (and also

            // copy the closing point)

            aTempPoly[0] = aTempPoly[4] = aTempPoly[1];

            aTempPoly[3] = aTempPoly[2];

            // calculate new right edge, by moving right edge of the

            // gradient rect two times the bound rect's diagonal to

            // the 'right'.

            const ::basegfx::B2DPoint aPoint3( aRightTop + 2.0*nDiagonalLength*aDirection );

            aTempPoly[0] = aTempPoly[4] = ::Point( ::basegfx::fround<::tools::Long>( aPoint3.getX() ),

                                                   ::basegfx::fround<::tools::Long>( aPoint3.getY() ) );

            const ::basegfx::B2DPoint aPoint4( aRightBottom + 2.0*nDiagonalLength*aDirection );

            aTempPoly[3] = ::Point( ::basegfx::fround<::tools::Long>( aPoint4.getX() ),

                                    ::basegfx::fround<::tools::Long>( aPoint4.getY() ) );

            rOutDev.SetFillColor( rColors.back() );

            rOutDev.DrawPolygon( aTempPoly );

        }

        void fillPolygonalGradient( OutputDevice&                                  rOutDev,

                                    const ::basegfx::B2DHomMatrix&                 rTextureTransform,

                                    const ::tools::Rectangle&                             rBounds,

                                    unsigned int                                   nStepCount,

                                    const ::canvas::ParametricPolyPolygon::Values& rValues,

                                    const std::vector< ::Color >&                  rColors )

        {

            const ::basegfx::B2DPolygon& rGradientPoly( rValues.maGradientPoly );

            ENSURE_OR_THROW( rGradientPoly.count() > 2,

                              "fillPolygonalGradient(): polygon without area given" );

            // For performance reasons, we create a temporary VCL polygon

            // here, keep it all the way and only change the vertex values

            // in the loop below (as ::Polygon is a pimpl class, creating

            // one every loop turn would really stress the mem allocator)

            ::basegfx::B2DPolygon   aOuterPoly( rGradientPoly );

            ::basegfx::B2DPolygon   aInnerPoly;

            // subdivide polygon _before_ rendering, would otherwise have

            // to be performed on every loop turn.

            if( aOuterPoly.areControlPointsUsed() )

                aOuterPoly = ::basegfx::utils::adaptiveSubdivideByAngle(aOuterPoly);

            aInnerPoly = aOuterPoly;

            // only transform outer polygon _after_ copying it into

            // aInnerPoly, because inner polygon has to be scaled before

            // the actual texture transformation takes place

            aOuterPoly.transform( rTextureTransform );

            // determine overall transformation for inner polygon (might

            // have to be prefixed by anisotrophic scaling)

            ::basegfx::B2DHomMatrix aInnerPolygonTransformMatrix;

            // apply scaling (possibly anisotrophic) to inner polygon

            // scale inner polygon according to aspect ratio: for

            // wider-than-tall bounds (nAspectRatio > 1.0), the inner

            // polygon, representing the gradient focus, must have

            // non-zero width. Specifically, a bound rect twice as wide as

            // tall has a focus polygon of half its width.

            const double nAspectRatio( rValues.mnAspectRatio );

            if( nAspectRatio > 1.0 )

            {

                // width > height case

                aInnerPolygonTransformMatrix.scale( 1.0 - 1.0/nAspectRatio,

                                                    0.0 );

            }

            else if( nAspectRatio < 1.0 )

            {

                // width < height case

                aInnerPolygonTransformMatrix.scale( 0.0,

                                                    1.0 - nAspectRatio );

            }

            else

            {

                // isotrophic case

                aInnerPolygonTransformMatrix.scale( 0.0, 0.0 );

            }

            // and finally, add texture transform to it.

            aInnerPolygonTransformMatrix *= rTextureTransform;

            // apply final matrix to polygon

            aInnerPoly.transform( aInnerPolygonTransformMatrix );

            const sal_uInt32 nNumPoints( aOuterPoly.count() );

            ::tools::Polygon aTempPoly( static_cast<sal_uInt16>(nNumPoints+1) );

            // increase number of steps by one: polygonal gradients have

            // the outermost polygon rendered in rColor2, and the

            // innermost in rColor1. The innermost polygon will never

            // have zero area, thus, we must divide the interval into

            // nStepCount+1 steps. For example, to create 3 steps:

            // |                       |

            // |-------|-------|-------|

            // |                       |

            // 3       2       1       0

            // This yields 4 tick marks, where 0 is never attained (since

            // zero-area polygons typically don't display perceivable

            // color).

            ++nStepCount;

            rOutDev.SetLineColor();

            basegfx::utils::KeyStopLerp aLerper(rValues.maStops);

            // fill background

            rOutDev.SetFillColor( rColors.front() );

            rOutDev.DrawRect( rBounds );

            // render polygon

            // ==============

            for( unsigned int i=1,p; i<nStepCount; ++i )

            {

                const double fT( i/double(nStepCount) );

                std::ptrdiff_t nIndex;

                double fAlpha;

                std::tie(nIndex,fAlpha)=aLerper.lerp(fT);

                // lerp color

                rOutDev.SetFillColor(

                    Color( static_cast<sal_uInt8>(basegfx::utils::lerp(rColors[nIndex].GetRed(),rColors[nIndex+1].GetRed(),fAlpha)),

                           static_cast<sal_uInt8>(basegfx::utils::lerp(rColors[nIndex].GetGreen(),rColors[nIndex+1].GetGreen(),fAlpha)),

                           static_cast<sal_uInt8>(basegfx::utils::lerp(rColors[nIndex].GetBlue(),rColors[nIndex+1].GetBlue(),fAlpha)) ));

                // scale and render polygon, by interpolating between

                // outer and inner polygon.

                for( p=0; p<nNumPoints; ++p )

                {

                    const ::basegfx::B2DPoint& rOuterPoint( aOuterPoly.getB2DPoint(p) );

                    const ::basegfx::B2DPoint& rInnerPoint( aInnerPoly.getB2DPoint(p) );

                    aTempPoly[static_cast<sal_uInt16>(p)] = ::Point(

                        basegfx::fround<::tools::Long>( fT*rInnerPoint.getX() + (1-fT)*rOuterPoint.getX() ),

                        basegfx::fround<::tools::Long>( fT*rInnerPoint.getY() + (1-fT)*rOuterPoint.getY() ) );

                }

                // close polygon explicitly

                aTempPoly[static_cast<sal_uInt16>(p)] = aTempPoly[0];

                // TODO(P1): compare with vcl/source/gdi/outdev4.cxx,

                // OutputDevice::ImplDrawComplexGradient(), there's a note

                // that on some VDev's, rendering disjunct poly-polygons

                // is faster!

                rOutDev.DrawPolygon( aTempPoly );

            }

        }

        void doGradientFill( OutputDevice&                                  rOutDev,

                             const ::canvas::ParametricPolyPolygon::Values& rValues,

                             const std::vector< ::Color >&                  rColors,

                             const ::basegfx::B2DHomMatrix&                 rTextureTransform,

                             const ::tools::Rectangle&                      rBounds,

                             unsigned int                                   nStepCount )

        {

            switch( rValues.meType )

            {

                case ::canvas::ParametricPolyPolygon::GradientType::Linear:

                    fillLinearGradient( rOutDev,

                                        rTextureTransform,

                                        rBounds,

                                        nStepCount,

                                        rValues,

                                        rColors );

                    break;

                case ::canvas::ParametricPolyPolygon::GradientType::Elliptical:

                case ::canvas::ParametricPolyPolygon::GradientType::Rectangular:

                    fillPolygonalGradient( rOutDev,

                                           rTextureTransform,

                                           rBounds,

                                           nStepCount,

                                           rValues,

                                           rColors );

                    break;

                default:

                    ENSURE_OR_THROW( false,

                                      "CanvasHelper::doGradientFill(): Unexpected case" );

            }

        }

        int numColorSteps( const ::Color& rColor1, const ::Color& rColor2 )

        {

            return std::max(

                std::abs( rColor1.GetRed() - rColor2.GetRed() ),

                std::max(

                    std::abs( rColor1.GetGreen() - rColor2.GetGreen() ),

                    std::abs( rColor1.GetBlue()  - rColor2.GetBlue() ) ) );

        }

        bool gradientFill( OutputDevice&                                   rOutDev,

                           OutputDevice*                                   p2ndOutDev,

                           const ::canvas::ParametricPolyPolygon::Values&  rValues,

                           const std::vector< ::Color >&                   rColors,

                           const ::tools::PolyPolygon&                     rPoly,

                           const rendering::ViewState&                     viewState,

                           const rendering::RenderState&                   renderState,

                           const rendering::Texture&                       texture,

                           int                                             nTransparency )

        {

            // TODO(T2): It is maybe necessary to lock here, should

            // maGradientPoly someday cease to be const. But then, beware of

            // deadlocks, canvashelper calls this method with locked own

            // mutex.

            // calc step size

            int nColorSteps = 0;

            for( size_t i=0; i<rColors.size()-1; ++i )

                nColorSteps += numColorSteps(rColors[i],rColors[i+1]);

            ::basegfx::B2DHomMatrix aTotalTransform;

            const int nStepCount=

                ::canvastools::calcGradientStepCount(aTotalTransform,

                                                       viewState,

                                                       renderState,

                                                       texture,

                                                       nColorSteps);

            rOutDev.SetLineColor();

            // determine maximal bound rect of texture-filled

            // polygon

            const ::tools::Rectangle aPolygonDeviceRectOrig(

                rPoly.GetBoundRect() );

            if( vclcanvastools::isRectangle( rPoly ) )

            {

                // use optimized output path

                // this distinction really looks like a

                // micro-optimization, but in fact greatly speeds up

                // especially complex gradients. That's because when using

                // clipping, we can output polygons instead of

                // poly-polygons, and don't have to output the gradient

                // twice for XOR

                rOutDev.Push( vcl::PushFlags::CLIPREGION );

                rOutDev.IntersectClipRegion( aPolygonDeviceRectOrig );

                doGradientFill( rOutDev,

                                rValues,

                                rColors,

                                aTotalTransform,

                                aPolygonDeviceRectOrig,

                                nStepCount );

                rOutDev.Pop();

                if( p2ndOutDev && nTransparency < 253 )

                {

                    // HACK. Normally, CanvasHelper does not care about

                    // actually what mp2ndOutDev is...  well, here we do &

                    // assume a 1bpp target - everything beyond 97%

                    // transparency is fully transparent

                    p2ndOutDev->SetFillColor( COL_BLACK );

                    p2ndOutDev->DrawRect( aPolygonDeviceRectOrig );

                }

            }

            else

            {

                const vcl::Region aPolyClipRegion( rPoly );

                rOutDev.Push( vcl::PushFlags::CLIPREGION );

                rOutDev.IntersectClipRegion( aPolyClipRegion );

                doGradientFill( rOutDev,

                                rValues,

                                rColors,

                                aTotalTransform,

                                aPolygonDeviceRectOrig,

                                nStepCount );

                rOutDev.Pop();

                if( p2ndOutDev && nTransparency < 253 )

                {

                    // HACK. Normally, CanvasHelper does not care about

                    // actually what mp2ndOutDev is...  well, here we do &

                    // assume a 1bpp target - everything beyond 97%

                    // transparency is fully transparent

                    p2ndOutDev->SetFillColor( COL_BLACK );

                    p2ndOutDev->DrawPolyPolygon( rPoly );

                }

            }

#ifdef DEBUG_CANVAS_CANVASHELPER_TEXTUREFILL

            // extra-verbosity

            {

                ::basegfx::B2DRectangle aRect(0.0, 0.0, 1.0, 1.0);

                ::basegfx::B2DHomMatrix aTextureTransform;

                ::basegfx::B2DRectangle aTextureDeviceRect = ::canvastools::calcTransformedRectBounds(

                                                            aRect,

                                                            aTextureTransform );

                rOutDev.SetLineColor( COL_RED );

                rOutDev.SetFillColor();

                rOutDev.DrawRect( vcl::unotools::rectangleFromB2DRectangle( aTextureDeviceRect ) );

                rOutDev.SetLineColor( COL_BLUE );

                ::tools::Polygon aPoly1(

                    vcl::unotools::rectangleFromB2DRectangle( aRect ));

                ::basegfx::B2DPolygon aPoly2( aPoly1.getB2DPolygon() );

                aPoly2.transform( aTextureTransform );

                ::tools::Polygon aPoly3( aPoly2 );

                rOutDev.DrawPolygon( aPoly3 );

            }

#endif

            return true;

        }

    }

    uno::Reference< rendering::XCachedPrimitive > CanvasHelper::fillTexturedPolyPolygon( const rendering::XCanvas*                          pCanvas,

                                                                                         const uno::Reference< rendering::XPolyPolygon2D >& xPolyPolygon,

                                                                                         const rendering::ViewState&                        viewState,

                                                                                         const rendering::RenderState&                      renderState,

                                                                                         const uno::Sequence< rendering::Texture >&         textures )

    {

        ENSURE_ARG_OR_THROW( xPolyPolygon.is(),

                         "CanvasHelper::fillPolyPolygon(): polygon is NULL");

        ENSURE_ARG_OR_THROW( textures.hasElements(),

                         "CanvasHelper::fillTexturedPolyPolygon: empty texture sequence");

        if( mpOutDevProvider )

        {

            vclcanvastools::OutDevStateKeeper aStateKeeper( mpProtectedOutDevProvider );

            const int nTransparency( setupOutDevState( viewState, renderState, IGNORE_COLOR ) );

            ::tools::PolyPolygon aPolyPoly( vclcanvastools::mapPolyPolygon(

                                       ::basegfx::unotools::b2DPolyPolygonFromXPolyPolygon2D(xPolyPolygon),

                                       viewState, renderState ) );

            // TODO(F1): Multi-texturing

            if( textures[0].Gradient.is() )

            {

                // try to cast XParametricPolyPolygon2D reference to

                // our implementation class.

                ::canvas::ParametricPolyPolygon* pGradient =

                      dynamic_cast< ::canvas::ParametricPolyPolygon* >( textures[0].Gradient.get() );

                if( pGradient && pGradient->getValues().maColors.hasElements() )

                {

                    // copy state from Gradient polypoly locally

                    // (given object might change!)

                    const ::canvas::ParametricPolyPolygon::Values aValues(

                        pGradient->getValues() );

                    if( aValues.maColors.getLength() < 2 )

                    {

                        rendering::RenderState aTempState=renderState;

                        aTempState.DeviceColor = aValues.maColors[0];

                        fillPolyPolygon(pCanvas, xPolyPolygon, viewState, aTempState);

                    }

                    else

                    {

                        std::vector< ::Color > aColors(aValues.maColors.getLength());

                        std::transform(&aValues.maColors[0],

                                       &aValues.maColors[0]+aValues.maColors.getLength(),

                                       aColors.begin(),

                                       [](const uno::Sequence< double >& aColor) {

                                           return vcl::unotools::stdColorSpaceSequenceToColor( aColor );

                                       } );

                        // TODO(E1): Return value

                        // TODO(F1): FillRule

                        gradientFill( mpOutDevProvider->getOutDev(),

                                      mp2ndOutDevProvider ? &mp2ndOutDevProvider->getOutDev() : nullptr,

                                      aValues,

                                      aColors,

                                      aPolyPoly,

                                      viewState,

                                      renderState,

                                      textures[0],

                                      nTransparency );

                    }

                }

                else

                {

                    // TODO(F1): The generic case is missing here

                    ENSURE_OR_THROW( false,

                                      "CanvasHelper::fillTexturedPolyPolygon(): unknown parametric polygon encountered" );

                }

            }

            else if( textures[0].Bitmap.is() )

            {

                geometry::IntegerSize2D aBmpSize( textures[0].Bitmap->getSize() );

                ENSURE_ARG_OR_THROW( aBmpSize.Width != 0 &&

                                 aBmpSize.Height != 0,

                                 "CanvasHelper::fillTexturedPolyPolygon(): zero-sized texture bitmap" );

                // determine maximal bound rect of texture-filled

                // polygon

                const ::tools::Rectangle aPolygonDeviceRect(

                    aPolyPoly.GetBoundRect() );

                // first of all, determine whether we have a

                // drawBitmap() in disguise

                // =========================================

                const bool bRectangularPolygon( vclcanvastools::isRectangle( aPolyPoly ) );

                ::basegfx::B2DHomMatrix aTotalTransform;

                ::canvastools::mergeViewAndRenderTransform(aTotalTransform,

                                                             viewState,

                                                             renderState);

                ::basegfx::B2DHomMatrix aTextureTransform;

                ::basegfx::unotools::homMatrixFromAffineMatrix( aTextureTransform,

                                                                textures[0].AffineTransform );

                aTotalTransform *= aTextureTransform;

                const ::basegfx::B2DRectangle aRect(0.0, 0.0, 1.0, 1.0);

                ::basegfx::B2DRectangle aTextureDeviceRect = ::canvastools::calcTransformedRectBounds(

                                                            aRect,

                                                            aTotalTransform );

                const ::tools::Rectangle aIntegerTextureDeviceRect(

                    vcl::unotools::rectangleFromB2DRectangle( aTextureDeviceRect ) );

                if( bRectangularPolygon &&

                    aIntegerTextureDeviceRect == aPolygonDeviceRect )

                {

                    rendering::RenderState aLocalState( renderState );

                    ::canvastools::appendToRenderState(aLocalState,

                                                         aTextureTransform);

                    ::basegfx::B2DHomMatrix aScaleCorrection;

                    aScaleCorrection.scale( 1.0/aBmpSize.Width,

                                            1.0/aBmpSize.Height );

                    ::canvastools::appendToRenderState(aLocalState,

                                                         aScaleCorrection);

                    // need alpha modulation?

                    if( !::rtl::math::approxEqual( textures[0].Alpha,

                                                   1.0 ) )

                    {

                        // setup alpha modulation values

                        aLocalState.DeviceColor.realloc(4);

                        double* pColor = aLocalState.DeviceColor.getArray();

                        pColor[0] =

                        pColor[1] =

                        pColor[2] = 0.0;

                        pColor[3] = textures[0].Alpha;

                        return drawBitmapModulated( pCanvas,

                                                    textures[0].Bitmap,

                                                    viewState,

                                                    aLocalState );

                    }

                    else

                    {

                        return drawBitmap( pCanvas,

                                           textures[0].Bitmap,

                                           viewState,

                                           aLocalState );

                    }

                }

                else

                {

                    // No easy mapping to drawBitmap() - calculate

                    // texturing parameters

                    // ===========================================

                    ::Bitmap aBmp( vclcanvastools::bitmapFromXBitmap( textures[0].Bitmap ) );

                    // scale down bitmap to [0,1]x[0,1] rect, as required

                    // from the XCanvas interface.

                    ::basegfx::B2DHomMatrix aScaling;

                    ::basegfx::B2DHomMatrix aPureTotalTransform; // pure view*render*texture transform

                    aScaling.scale( 1.0/aBmpSize.Width,

                                    1.0/aBmpSize.Height );

                    aTotalTransform = aTextureTransform * aScaling;

                    aPureTotalTransform = aTextureTransform;

                    // combine with view and render transform

                    ::basegfx::B2DHomMatrix aMatrix;

                    ::canvastools::mergeViewAndRenderTransform(aMatrix, viewState, renderState);

                    // combine all three transformations into one

                    // global texture-to-device-space transformation

                    aTotalTransform *= aMatrix;

                    aPureTotalTransform *= aMatrix;

                    // analyze transformation, and setup an

                    // appropriate GraphicObject

                    ::basegfx::B2DVector aScale;

                    ::basegfx::B2DPoint  aOutputPos;

                    double               nRotate;

                    double               nShearX;

                    aTotalTransform.decompose( aScale, aOutputPos, nRotate, nShearX );

                    GraphicAttr             aGrfAttr;

                    GraphicObjectSharedPtr  pGrfObj;

                    if( ::basegfx::fTools::equalZero( nShearX ) )

                    {

                        // no shear, GraphicObject is enough (the

                        // GraphicObject only supports scaling, rotation

                        // and translation)

                        // #i75339# don't apply mirror flags, having

                        // negative size values is enough to make

                        // GraphicObject flip the bitmap

                        // The angle has to be mapped from radian to tenths of

                        // degrees with the orientation reversed: [0,2Pi) ->

                        // (3600,0].  Note that the original angle may have

                        // values outside the [0,2Pi) interval.

                        const double nAngleInTenthOfDegrees (3600.0 - basegfx::rad2deg<10>(nRotate));

                        aGrfAttr.SetRotation( Degree10(::basegfx::fround(nAngleInTenthOfDegrees)) );

                        pGrfObj = std::make_shared<GraphicObject>( aBmp );

                    }

                    else

                    {

                        // modify output position, to account for the fact

                        // that transformBitmap() always normalizes its output

                        // bitmap into the smallest enclosing box.

                        ::basegfx::B2DRectangle aDestRect = ::canvastools::calcTransformedRectBounds(

                                                                    ::basegfx::B2DRectangle(0,

                                                                                            0,

                                                                                            aBmpSize.Width,

                                                                                            aBmpSize.Height),

                                                                    aMatrix );

                        aOutputPos.setX( aDestRect.getMinX() );

                        aOutputPos.setY( aDestRect.getMinY() );

                        // complex transformation, use generic affine bitmap

                        // transformation

                        aBmp = vclcanvastools::transformBitmap( aBmp, aTotalTransform);

                        pGrfObj = std::make_shared<GraphicObject>( aBmp );

                        // clear scale values, generated bitmap already

                        // contains scaling

                        aScale.setX( 1.0 ); aScale.setY( 1.0 );

                        // update bitmap size, bitmap has changed above.

                        aBmpSize = vcl::unotools::integerSize2DFromSize(aBmp.GetSizePixel());

                    }

                    // render texture tiled into polygon

                    // =================================

                    // calc device space direction vectors. We employ

                    // the following approach for tiled output: the

                    // texture bitmap is output in texture space

                    // x-major order, i.e. tile neighbors in texture

                    // space x direction are rendered back-to-back in

                    // device coordinate space (after the full device

                    // transformation). Thus, the aNextTile* vectors

                    // denote the output position updates in device

                    // space, to get from one tile to the next.

                    ::basegfx::B2DVector aNextTileX( 1.0, 0.0 );

                    ::basegfx::B2DVector aNextTileY( 0.0, 1.0 );

                    aNextTileX *= aPureTotalTransform;

                    aNextTileY *= aPureTotalTransform;

                    ::basegfx::B2DHomMatrix aInverseTextureTransform( aPureTotalTransform );

                    ENSURE_ARG_OR_THROW( aInverseTextureTransform.isInvertible(),

                                     "CanvasHelper::fillTexturedPolyPolygon(): singular texture matrix" );

                    aInverseTextureTransform.invert();

                    // calc bound rect of extended texture area in

                    // device coordinates. Therefore, we first calc

                    // the area of the polygon bound rect in texture

                    // space. To maintain texture phase, this bound

                    // rect is then extended to integer coordinates

                    // (extended, because shrinking might leave some

                    // inner polygon areas unfilled).

                    // Finally, the bound rect is transformed back to

                    // device coordinate space, were we determine the

                    // start point from it.

                    ::basegfx::B2DRectangle aTextureSpacePolygonRect = ::canvastools::calcTransformedRectBounds(

                                                                vcl::unotools::b2DRectangleFromRectangle(aPolygonDeviceRect),

                                                                aInverseTextureTransform );

                    // calc left, top of extended polygon rect in

                    // texture space, create one-texture instance rect

                    // from it (i.e. rect from start point extending

                    // 1.0 units to the right and 1.0 units to the

                    // bottom). Note that the rounding employed here

                    // is a bit subtle, since we need to round up/down

                    // as _soon_ as any fractional amount is

                    // encountered. This is to ensure that the full

                    // polygon area is filled with texture tiles.

                    const sal_Int32 nX1( ::canvastools::roundDown( aTextureSpacePolygonRect.getMinX() ) );

                    const sal_Int32 nY1( ::canvastools::roundDown( aTextureSpacePolygonRect.getMinY() ) );

                    const sal_Int32 nX2( ::canvastools::roundUp( aTextureSpacePolygonRect.getMaxX() ) );

                    const sal_Int32 nY2( ::canvastools::roundUp( aTextureSpacePolygonRect.getMaxY() ) );

                    const ::basegfx::B2DRectangle aSingleTextureRect(

                        nX1, nY1,

                        nX1 + 1.0,

                        nY1 + 1.0 );

                    // and convert back to device space

                    ::basegfx::B2DRectangle aSingleDeviceTextureRect = ::canvastools::calcTransformedRectBounds(

                                                                aSingleTextureRect,

                                                                aPureTotalTransform );

                    const ::Point aPtRepeat( vcl::unotools::pointFromB2DPoint(

                                                 aSingleDeviceTextureRect.getMinimum() ) );

                    const ::Size  aSz( ::basegfx::fround<::tools::Long>( aScale.getX() * aBmpSize.Width ),

                                       ::basegfx::fround<::tools::Long>( aScale.getY() * aBmpSize.Height ) );

                    const ::Size  aIntegerNextTileX( vcl::unotools::sizeFromB2DSize(aNextTileX) );

                    const ::Size  aIntegerNextTileY( vcl::unotools::sizeFromB2DSize(aNextTileY) );

                    const ::Point aPt( textures[0].RepeatModeX == rendering::TexturingMode::NONE ?

                                       ::basegfx::fround<::tools::Long>( aOutputPos.getX() ) : aPtRepeat.X(),

                                       textures[0].RepeatModeY == rendering::TexturingMode::NONE ?

                                       ::basegfx::fround<::tools::Long>( aOutputPos.getY() ) : aPtRepeat.Y() );

                    const sal_Int32 nTilesX( textures[0].RepeatModeX == rendering::TexturingMode::NONE ?

                                             1 : nX2 - nX1 );

                    const sal_Int32 nTilesY( textures[0].RepeatModeX == rendering::TexturingMode::NONE ?

                                             1 : nY2 - nY1 );

                    OutputDevice& rOutDev( mpOutDevProvider->getOutDev() );

                    if( bRectangularPolygon )

                    {

                        // use optimized output path

                        // this distinction really looks like a

                        // micro-optimization, but in fact greatly speeds up

                        // especially complex fills. That's because when using

                        // clipping, we can output polygons instead of

                        // poly-polygons, and don't have to output the gradient

                        // twice for XOR

                        // setup alpha modulation

                        if( !::rtl::math::approxEqual( textures[0].Alpha,

                                                       1.0 ) )

                        {

                            // TODO(F1): Note that the GraphicManager has

                            // a subtle difference in how it calculates

                            // the resulting alpha value: it's using the

                            // inverse alpha values (i.e. 'transparency'),

                            // and calculates transOrig + transModulate,

                            // instead of transOrig + transModulate -

                            // transOrig*transModulate (which would be

                            // equivalent to the origAlpha*modulateAlpha

                            // the DX canvas performs)

                            aGrfAttr.SetAlpha(

                                static_cast< sal_uInt8 >(

                                    ::basegfx::fround( 255.0 * textures[0].Alpha ) ) );

                        }

                        rOutDev.IntersectClipRegion( aPolygonDeviceRect );

                        textureFill( rOutDev,

                                     *pGrfObj,

                                     aPt,

                                     aIntegerNextTileX,

                                     aIntegerNextTileY,

                                     nTilesX,

                                     nTilesY,

                                     aSz,

                                     aGrfAttr );

                        if( mp2ndOutDevProvider )

                        {

                            OutputDevice& r2ndOutDev( mp2ndOutDevProvider->getOutDev() );

                            r2ndOutDev.IntersectClipRegion( aPolygonDeviceRect );

                            textureFill( r2ndOutDev,

                                         *pGrfObj,

                                         aPt,

                                         aIntegerNextTileX,

                                         aIntegerNextTileY,

                                         nTilesX,

                                         nTilesY,

                                         aSz,