cairo_textlayout.cxx

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#include <sal/config.h>
#include <sal/log.hxx>

#include <math.h>
#include <memory>

#include <com/sun/star/rendering/TextDirection.hpp>
#include <canvas/canvastools.hxx>
#include <basegfx/matrix/b2dhommatrix.hxx>
#include <basegfx/numeric/ftools.hxx>
#include <cppuhelper/supportsservice.hxx>
#include <tools/diagnose_ex.h>
#include <vcl/metric.hxx>
#include <vcl/sysdata.hxx>
#include <vcl/virdev.hxx>


#include "cairo_textlayout.hxx"

#include <cairo.h>

#if defined CAIRO_HAS_FT_FONT
# include <cairo-ft.h>
#else
# error Native API needed.
#endif

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

namespace cairocanvas
{
    namespace
    {
        void setupLayoutMode( OutputDevice& rOutDev,
                              sal_Int8      nTextDirection )
        {
            // TODO(P3): avoid if already correctly set
            ComplexTextLayoutFlags nLayoutMode = ComplexTextLayoutFlags::Default;
            switch( nTextDirection )
            {
                case rendering::TextDirection::WEAK_LEFT_TO_RIGHT:
                    break;
                case rendering::TextDirection::STRONG_LEFT_TO_RIGHT:
                    nLayoutMode = ComplexTextLayoutFlags::BiDiStrong;
                    break;
                case rendering::TextDirection::WEAK_RIGHT_TO_LEFT:
                    nLayoutMode = ComplexTextLayoutFlags::BiDiRtl;
                    break;
                case rendering::TextDirection::STRONG_RIGHT_TO_LEFT:
                    nLayoutMode = ComplexTextLayoutFlags::BiDiRtl | ComplexTextLayoutFlags::BiDiStrong;
                    break;
                default:
                    break;
            }

            // set calculated layout mode. Origin is always the left edge,
            // as required at the API spec
            rOutDev.SetLayoutMode( nLayoutMode | ComplexTextLayoutFlags::TextOriginLeft );
        }
    }

    TextLayout::TextLayout( const rendering::StringContext&     aText,
                            sal_Int8                            nDirection,
                            sal_Int64                           /*nRandomSeed*/,
                            const CanvasFont::Reference&        rFont,
                            const SurfaceProviderRef&           rRefDevice ) :
        TextLayout_Base( m_aMutex ),
        maText( aText ),
        maLogicalAdvancements(),
        mpFont( rFont ),
        mpRefDevice( rRefDevice ),
        mnTextDirection( nDirection )
    {
    }

    TextLayout::~TextLayout()
    {
    }

    void SAL_CALL TextLayout::disposing()
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        mpFont.clear();
        mpRefDevice.clear();
    }

    // XTextLayout
    uno::Sequence< uno::Reference< rendering::XPolyPolygon2D > > SAL_CALL TextLayout::queryTextShapes(  )
    {
        // TODO
        return uno::Sequence< uno::Reference< rendering::XPolyPolygon2D > >();
    }

    uno::Sequence< geometry::RealRectangle2D > SAL_CALL TextLayout::queryInkMeasures(  )
    {
        // TODO
        return uno::Sequence< geometry::RealRectangle2D >();
    }

    uno::Sequence< geometry::RealRectangle2D > SAL_CALL TextLayout::queryMeasures(  )
    {
        // TODO
        return uno::Sequence< geometry::RealRectangle2D >();
    }

    uno::Sequence< double > SAL_CALL TextLayout::queryLogicalAdvancements(  )
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        return maLogicalAdvancements;
    }

    void SAL_CALL TextLayout::applyLogicalAdvancements( const uno::Sequence< double >& aAdvancements )
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        if( aAdvancements.getLength() != maText.Length )
        {
            SAL_WARN("canvas.cairo", "TextLayout::applyLogicalAdvancements(): mismatching number of advancements" );
            throw lang::IllegalArgumentException();
        }

        maLogicalAdvancements = aAdvancements;
    }

    geometry::RealRectangle2D SAL_CALL TextLayout::queryTextBounds(  )
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        OutputDevice* pOutDev = mpRefDevice->getOutputDevice();
        if( !pOutDev )
            return geometry::RealRectangle2D();

        ScopedVclPtrInstance< VirtualDevice > pVDev( *pOutDev );
        pVDev->SetFont( mpFont->getVCLFont() );

        // need metrics for Y offset, the XCanvas always renders
        // relative to baseline
        const ::FontMetric& aMetric( pVDev->GetFontMetric() );

        setupLayoutMode( *pVDev, mnTextDirection );

        const sal_Int32 nAboveBaseline( -aMetric.GetAscent() );
        const sal_Int32 nBelowBaseline( aMetric.GetDescent() );

        if( maLogicalAdvancements.hasElements() )
        {
            return geometry::RealRectangle2D( 0, nAboveBaseline,
                                              maLogicalAdvancements[ maLogicalAdvancements.getLength()-1 ],
                                              nBelowBaseline );
        }
        else
        {
            return geometry::RealRectangle2D( 0, nAboveBaseline,
                                              pVDev->GetTextWidth(
                                                  maText.Text,
                                                  ::canvas::tools::numeric_cast<sal_uInt16>(maText.StartPosition),
                                                  ::canvas::tools::numeric_cast<sal_uInt16>(maText.Length) ),
                                              nBelowBaseline );
        }
    }

    double SAL_CALL TextLayout::justify( double /*nSize*/ )
    {
        // TODO
        return 0.0;
    }

    double SAL_CALL TextLayout::combinedJustify( const uno::Sequence< uno::Reference< rendering::XTextLayout > >& /*aNextLayouts*/,
                                                 double /*nSize*/ )
    {
        // TODO
        return 0.0;
    }

    rendering::TextHit SAL_CALL TextLayout::getTextHit( const geometry::RealPoint2D& /*aHitPoint*/ )
    {
        // TODO
        return rendering::TextHit();
    }

    rendering::Caret SAL_CALL TextLayout::getCaret( sal_Int32 /*nInsertionIndex*/,
                                                    sal_Bool /*bExcludeLigatures*/ )
    {
        // TODO
        return rendering::Caret();
    }

    sal_Int32 SAL_CALL TextLayout::getNextInsertionIndex( sal_Int32 /*nStartIndex*/,
                                                          sal_Int32 /*nCaretAdvancement*/,
                                                          sal_Bool /*bExcludeLigatures*/ )
    {
        // TODO
        return 0;
    }

    uno::Reference< rendering::XPolyPolygon2D > SAL_CALL TextLayout::queryVisualHighlighting( sal_Int32 /*nStartIndex*/,
                                                                                              sal_Int32 /*nEndIndex*/ )
    {
        // TODO
        return uno::Reference< rendering::XPolyPolygon2D >();
    }

    uno::Reference< rendering::XPolyPolygon2D > SAL_CALL TextLayout::queryLogicalHighlighting( sal_Int32 /*nStartIndex*/,
                                                                                               sal_Int32 /*nEndIndex*/ )
    {
        // TODO
        return uno::Reference< rendering::XPolyPolygon2D >();
    }

    double SAL_CALL TextLayout::getBaselineOffset(  )
    {
        // TODO
        return 0.0;
    }

    sal_Int8 SAL_CALL TextLayout::getMainTextDirection(  )
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        return mnTextDirection;
    }

    uno::Reference< rendering::XCanvasFont > SAL_CALL TextLayout::getFont(  )
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        return mpFont.get();
    }

    rendering::StringContext SAL_CALL TextLayout::getText(  )
    {
        ::osl::MutexGuard aGuard( m_aMutex );

        return maText;
    }

    void TextLayout::draw( OutputDevice&                 rOutDev,
                           const Point&                  rOutpos,
                           const rendering::ViewState&   viewState,
                           const rendering::RenderState& renderState ) const
    {
        ::osl::MutexGuard aGuard( m_aMutex );
        setupLayoutMode( rOutDev, mnTextDirection );

        std::unique_ptr< long []> aOffsets(new long[maLogicalAdvancements.getLength()]);

        if( maLogicalAdvancements.hasElements() )
            setupTextOffsets( aOffsets.get(), maLogicalAdvancements, viewState, renderState );

        if (maLogicalAdvancements.hasElements())
        {
            rOutDev.DrawTextArray( rOutpos, maText.Text, aOffsets.get(),
                                   ::canvas::tools::numeric_cast<sal_uInt16>(maText.StartPosition),
                                   ::canvas::tools::numeric_cast<sal_uInt16>(maText.Length) );
        }
        else
        {
            rOutDev.DrawText( rOutpos, maText.Text,
                              ::canvas::tools::numeric_cast<sal_uInt16>(maText.StartPosition),
                              ::canvas::tools::numeric_cast<sal_uInt16>(maText.Length) );
        }
    }

    namespace
    {
        class OffsetTransformer
        {
        public:
            explicit OffsetTransformer( const ::basegfx::B2DHomMatrix& rMat ) :
                maMatrix( rMat )
            {
            }

            sal_Int32 operator()( const double& rOffset )
            {
                // This is an optimization of the normal rMat*[x,0]
                // transformation of the advancement vector (in x
                // direction), followed by a length calculation of the
                // resulting vector: advancement' =
                // ||rMat*[x,0]||. Since advancements are vectors, we
                // can ignore translational components, thus if [x,0],
                // it follows that rMat*[x,0]=[x',0] holds. Thus, we
                // just have to calc the transformation of the x
                // component.

                // TODO(F2): Handle non-horizontal advancements!
                return ::basegfx::fround( hypot(maMatrix.get(0,0)*rOffset,
                                                maMatrix.get(1,0)*rOffset) );
            }

        private:
            ::basegfx::B2DHomMatrix maMatrix;
        };
    }

    void TextLayout::setupTextOffsets( long*                       outputOffsets,
                                       const uno::Sequence< double >&   inputOffsets,
                                       const rendering::ViewState&      viewState,
                                       const rendering::RenderState&    renderState     ) const
    {
        ENSURE_OR_THROW( outputOffsets!=nullptr,
                          "TextLayout::setupTextOffsets offsets NULL" );

        ::basegfx::B2DHomMatrix aMatrix;

        ::canvas::tools::mergeViewAndRenderTransform(aMatrix,
                                                     viewState,
                                                     renderState);

        // fill integer offsets
        std::transform( inputOffsets.begin(),
                          inputOffsets.end(),
                          outputOffsets,
                          OffsetTransformer( aMatrix ) );
    }

    OUString SAL_CALL TextLayout::getImplementationName()
    {
        return "CairoCanvas::TextLayout";
    }

    sal_Bool SAL_CALL TextLayout::supportsService( const OUString& ServiceName )
    {
        return cppu::supportsService( this, ServiceName );
    }

    uno::Sequence< OUString > SAL_CALL TextLayout::getSupportedServiceNames()
    {
        return { "com.sun.star.rendering.TextLayout" };
    }
}

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