source/gdi/ctlayout.cxx

/**************************************************************
 *
 * 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
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 *
 *************************************************************/

//#include "salgdi.hxx"
#include "tools/debug.hxx"

#include "ctfonts.hxx"

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

class CTLayout
:	public SalLayout
{
public:
	explicit        CTLayout( const CTTextStyle* );
	virtual         ~CTLayout( void );

	virtual bool	LayoutText( ImplLayoutArgs& );
	virtual void	AdjustLayout( ImplLayoutArgs& );
	virtual void	DrawText( SalGraphics& ) const;

	virtual int     GetNextGlyphs( int nLen, sal_GlyphId* pOutGlyphIds, Point& rPos, int&,
						sal_Int32* pGlyphAdvances, int* pCharIndexes ) const;

	virtual long    GetTextWidth() const;
	virtual long    FillDXArray( sal_Int32* pDXArray ) const;
	virtual int     GetTextBreak( long nMaxWidth, long nCharExtra, int nFactor ) const;
	virtual void    GetCaretPositions( int nArraySize, sal_Int32* pCaretXArray ) const;
	virtual bool    GetGlyphOutlines( SalGraphics&, PolyPolyVector& ) const;
	virtual bool    GetBoundRect( SalGraphics&, Rectangle& ) const;

	const ImplFontData* GetFallbackFontData( sal_GlyphId ) const;

	virtual void	InitFont( void) const;
	virtual void	MoveGlyph( int nStart, long nNewXPos );
	virtual void	DropGlyph( int nStart );
	virtual void	Simplify( bool bIsBase );

private:
	const CTTextStyle* const	mpTextStyle;

	// CoreText specific objects
	CFAttributedStringRef mpAttrString;
	CTLineRef mpCTLine;

	int mnCharCount;		// ==mnEndCharPos-mnMinCharPos
	int mnTrailingSpaces;

	// to prevent overflows
	// font requests get size limited by downscaling huge fonts
	// in these cases the font scale becomes something bigger than 1.0
	float mfFontScale; // TODO: does CoreText have a font size limit?

	// cached details about the resulting layout
	// mutable members since these details are all lazy initialized
	mutable double	mfCachedWidth;			// cached value of resulting typographical width
	mutable double	mfTrailingSpaceWidth;   // in Pixels

	// x-offset relative to layout origin
	// currently only used in RTL-layouts
	mutable long	mnBaseAdv;
};

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

CTLayout::CTLayout( const CTTextStyle* pTextStyle )
:	mpTextStyle( pTextStyle )
,	mpAttrString( NULL )
,	mpCTLine( NULL )
,	mnCharCount( 0 )
,	mnTrailingSpaces( 0 )
,	mfFontScale( pTextStyle->mfFontScale )
,	mfCachedWidth( -1 )
,	mfTrailingSpaceWidth( 0 )
,	mnBaseAdv( 0 )
{
	CFRetain( mpTextStyle->GetStyleDict() );
}

// -----------------------------------------------------------------------

CTLayout::~CTLayout()
{
	if( mpCTLine )
		CFRelease( mpCTLine );
	if( mpAttrString )
		CFRelease( mpAttrString );
	CFRelease( mpTextStyle->GetStyleDict() );
}

// -----------------------------------------------------------------------

bool CTLayout::LayoutText( ImplLayoutArgs& rArgs )
{
	if( mpAttrString )
		CFRelease( mpAttrString );
	mpAttrString = NULL;
	if( mpCTLine )
		CFRelease( mpCTLine );
	mpCTLine = NULL;

	SalLayout::AdjustLayout( rArgs );
	mnCharCount = mnEndCharPos - mnMinCharPos;

	// short circuit if there is nothing to do
	if( mnCharCount <= 0 )
		return false;

	// create the CoreText line layout
	CFStringRef aCFText = CFStringCreateWithCharactersNoCopy( NULL, rArgs.mpStr + mnMinCharPos, mnCharCount, kCFAllocatorNull );
	mpAttrString = CFAttributedStringCreate( NULL, aCFText, mpTextStyle->GetStyleDict() );
	mpCTLine = CTLineCreateWithAttributedString( mpAttrString );
	CFRelease( aCFText);

	// get info about trailing whitespace to prepare for text justification in AdjustLayout()
	mnTrailingSpaces = 0;
	for( int i = mnEndCharPos; --i >= mnMinCharPos; ++mnTrailingSpaces )
		if( !IsSpacingGlyph( rArgs.mpStr[i] | GF_ISCHAR ))
			break;
	return true;
}

// -----------------------------------------------------------------------

void CTLayout::AdjustLayout( ImplLayoutArgs& rArgs )
{
	if( !mpCTLine)
		return;

	const DynCoreTextSyms& rCT = DynCoreTextSyms::get();
	// CoreText fills trailing space during justification so we have to
	// take that into account when requesting CT to justify something
	mfTrailingSpaceWidth = rCT.LineGetTrailingWhitespaceWidth( mpCTLine );
	const int nTrailingSpaceWidth = rint( mfFontScale * mfTrailingSpaceWidth );

	int nOrigWidth = GetTextWidth();
	int nPixelWidth = rArgs.mnLayoutWidth;
	if( nPixelWidth )
	{
		nPixelWidth -= nTrailingSpaceWidth;
		if( nPixelWidth <= 0)
			return;
	}
	else if( rArgs.mpDXArray )
	{
		// for now we are only interested in the layout width
		// TODO: use all mpDXArray elements for layouting
		nPixelWidth = rArgs.mpDXArray[ mnCharCount - 1 - mnTrailingSpaces ];
	}

	// short-circuit when justifying an all-whitespace string
	if( mnTrailingSpaces >= mnCharCount)
	{
		mfCachedWidth = mfTrailingSpaceWidth = nPixelWidth / mfFontScale;
		return;
	}

	// in RTL-layouts trailing spaces are leftmost
	// TODO: use BiDi-algorithm to thoroughly check this assumption
	if( rArgs.mnFlags & SAL_LAYOUT_BIDI_RTL)
		mnBaseAdv = nTrailingSpaceWidth;

	// return early if there is nothing to do
	if( nPixelWidth <= 0 )
		return;

	// HACK: justification requests which change the width by just one pixel are probably
	// #i86038# introduced by lossy conversions between integer based coordinate system
	if( (nOrigWidth >= nPixelWidth-1) && (nOrigWidth <= nPixelWidth+1) )
		return;

	// if the text to be justified has whitespace in it then
	// - Writer goes crazy with its HalfSpace magic
	// - LayoutEngine handles spaces specially (in particular at the text start or end)
	if( mnTrailingSpaces ) {
		// adjust for Writer's SwFntObj::DrawText() Halfspace magic at the text end
		std::vector<sal_Int32> aOrigDXAry;
		aOrigDXAry.resize( mnCharCount);
		FillDXArray( &aOrigDXAry[0] );
		int nLastCharSpace = rArgs.mpDXArray[ mnCharCount-1-mnTrailingSpaces ]
			- aOrigDXAry[ mnCharCount-1-mnTrailingSpaces ];
		nPixelWidth -= nLastCharSpace;
		if( nPixelWidth < 0 )
			return;
		// recreate the CoreText line layout without trailing spaces
		CFRelease( mpCTLine );
		CFStringRef aCFText = CFStringCreateWithCharactersNoCopy( NULL, rArgs.mpStr + mnMinCharPos,
			mnCharCount - mnTrailingSpaces, kCFAllocatorNull );
		CFAttributedStringRef pAttrStr = CFAttributedStringCreate( NULL, aCFText, mpTextStyle->GetStyleDict() );
		mpCTLine = CTLineCreateWithAttributedString( pAttrStr );
		CFRelease( aCFText);
		CFRelease( pAttrStr );
	}

	CTLineRef pNewCTLine = rCT.LineCreateJustifiedLine( mpCTLine, 1.0, nPixelWidth / mfFontScale );
	if( !pNewCTLine ) { // CTLineCreateJustifiedLine can and does fail
		// handle failure by keeping the unjustified layout
		// TODO: a better solution such as
		// - forcing glyph overlap
		// - changing the font size
		// - changing the CTM matrix
		return;
	}
	CFRelease( mpCTLine );
	mpCTLine = pNewCTLine;
	mfCachedWidth = -1; // TODO: can we set it directly to target width we requested? For now we re-measure
	mfTrailingSpaceWidth = 0;
}

// -----------------------------------------------------------------------

void CTLayout::DrawText( SalGraphics& rGraphics ) const
{
	AquaSalGraphics& rAquaGraphics = static_cast<AquaSalGraphics&>(rGraphics);

	// short circuit if there is nothing to do
	if( (mnCharCount <= 0)
	||  !rAquaGraphics.CheckContext() )
		return;

	// the view is vertically flipped => flipped glyphs
	// so apply a temporary transformation that it flips back
	// also compensate if the font was size limited
	CGContextSaveGState( rAquaGraphics.mrContext );
	CGContextScaleCTM( rAquaGraphics.mrContext, +mfFontScale, -mfFontScale );
	CGContextSetShouldAntialias( rAquaGraphics.mrContext, !rAquaGraphics.mbNonAntialiasedText );

	// Draw the text
	const Point aVclPos = GetDrawPosition( Point(mnBaseAdv,0) );
	CGPoint aTextPos = { +aVclPos.X()/mfFontScale, -aVclPos.Y()/mfFontScale };

	if( mpTextStyle->mfFontRotation != 0.0 )
	{
		const CGFloat fRadians = mpTextStyle->mfFontRotation;
		CGContextRotateCTM( rAquaGraphics.mrContext, +fRadians );

		const CGAffineTransform aInvMatrix = CGAffineTransformMakeRotation( -fRadians );
		aTextPos = CGPointApplyAffineTransform( aTextPos, aInvMatrix );
	}

	CGContextSetTextPosition( rAquaGraphics.mrContext, aTextPos.x, aTextPos.y );
	CTLineDraw( mpCTLine, rAquaGraphics.mrContext );

	// request an update of the changed window area
	if( rAquaGraphics.IsWindowGraphics() )
	{
		const CGRect aInkRect = CTLineGetImageBounds( mpCTLine, rAquaGraphics.mrContext );
		const CGRect aRefreshRect = CGContextConvertRectToDeviceSpace( rAquaGraphics.mrContext, aInkRect );
		rAquaGraphics.RefreshRect( aRefreshRect );
	}

	// restore the original graphic context transformations
	CGContextRestoreGState( rAquaGraphics.mrContext );
}

// -----------------------------------------------------------------------

int CTLayout::GetNextGlyphs( int nLen, sal_GlyphId* pOutGlyphIds, Point& rPos, int& nStart,
	sal_Int32* pGlyphAdvances, int* pCharIndexes ) const
{
	if( !mpCTLine )
		return 0;

	if( nStart < 0 ) // first glyph requested?
		nStart = 0;
	nLen = 1; // TODO: handle nLen>1 below

	// prepare to iterate over the glyph runs
	int nCount = 0;
	int nSubIndex = nStart;

	const DynCoreTextSyms& rCT = DynCoreTextSyms::get();
	typedef std::vector<CGGlyph> CGGlyphVector;
	typedef std::vector<CGPoint> CGPointVector;
	typedef std::vector<CGSize>  CGSizeVector;
	typedef std::vector<CFIndex> CFIndexVector;
	CGGlyphVector aCGGlyphVec;
	CGPointVector aCGPointVec;
	CGSizeVector  aCGSizeVec;
	CFIndexVector aCFIndexVec;

	// TODO: iterate over cached layout
	CFArrayRef aGlyphRuns = rCT.LineGetGlyphRuns( mpCTLine );
	const int nRunCount = CFArrayGetCount( aGlyphRuns );
	for( int nRunIndex = 0; nRunIndex < nRunCount; ++nRunIndex ) {
		CTRunRef pGlyphRun = (CTRunRef)CFArrayGetValueAtIndex( aGlyphRuns, nRunIndex );
		const CFIndex nGlyphsInRun = rCT.RunGetGlyphCount( pGlyphRun );
		// skip to the first glyph run of interest
		if( nSubIndex >= nGlyphsInRun ) {
			nSubIndex -= nGlyphsInRun;
			continue;
		}
		const CFRange aFullRange = CFRangeMake( 0, nGlyphsInRun );

		// get glyph run details
		const CGGlyph* pCGGlyphIdx = rCT.RunGetGlyphsPtr( pGlyphRun );
		if( !pCGGlyphIdx ) {
			aCGGlyphVec.reserve( nGlyphsInRun );
			CTRunGetGlyphs( pGlyphRun, aFullRange, &aCGGlyphVec[0] );
			pCGGlyphIdx = &aCGGlyphVec[0];
		}
		const CGPoint* pCGGlyphPos = rCT.RunGetPositionsPtr( pGlyphRun );
		if( !pCGGlyphPos ) {
			aCGPointVec.reserve( nGlyphsInRun );
			CTRunGetPositions( pGlyphRun, aFullRange, &aCGPointVec[0] );
			pCGGlyphPos = &aCGPointVec[0];
		}

		const CGSize* pCGGlyphAdvs = NULL;
		if( pGlyphAdvances) {
			pCGGlyphAdvs = rCT.RunGetAdvancesPtr( pGlyphRun );
			if( !pCGGlyphAdvs) {
				aCGSizeVec.reserve( nGlyphsInRun );
				CTRunGetAdvances( pGlyphRun, aFullRange, &aCGSizeVec[0] );
				pCGGlyphAdvs = &aCGSizeVec[0];
			}
		}

		const CFIndex* pCGGlyphStrIdx = NULL;
		if( pCharIndexes) {
			pCGGlyphStrIdx = rCT.RunGetStringIndicesPtr( pGlyphRun );
			if( !pCGGlyphStrIdx) {
				aCFIndexVec.reserve( nGlyphsInRun );
				CTRunGetStringIndices( pGlyphRun, aFullRange, &aCFIndexVec[0] );
				pCGGlyphStrIdx = &aCFIndexVec[0];
			}
		}

		// get the details for each interesting glyph
		// TODO: handle nLen>1
		for(; (--nLen >= 0) && (nSubIndex < nGlyphsInRun); ++nSubIndex, ++nStart )
		{
			// convert glyph details for VCL
			*(pOutGlyphIds++) = pCGGlyphIdx[ nSubIndex ];
			if( pGlyphAdvances )
				*(pGlyphAdvances++) = pCGGlyphAdvs[ nSubIndex ].width;
			if( pCharIndexes )
				*(pCharIndexes++) = pCGGlyphStrIdx[ nSubIndex] + mnMinCharPos;
			if( !nCount++ ) {
				const CGPoint& rCurPos = pCGGlyphPos[ nSubIndex ];
				rPos = GetDrawPosition( Point( mfFontScale * rCurPos.x, mfFontScale * rCurPos.y) );
			}
		}
		nSubIndex = 0; // prepare for the next glyph run
		break; // TODO: handle nLen>1
	}

	return nCount;
}

// -----------------------------------------------------------------------

long CTLayout::GetTextWidth() const
{
	if( (mnCharCount <= 0) || !mpCTLine )
		return 0;

	if( mfCachedWidth < 0.0 )
		mfCachedWidth = CTLineGetTypographicBounds( mpCTLine, NULL, NULL, NULL );

	const long nScaledWidth = lrint( mfFontScale * mfCachedWidth );
	return nScaledWidth;
}

// -----------------------------------------------------------------------

long CTLayout::FillDXArray( sal_Int32* pDXArray ) const
{
	// short circuit requests which don't need full details
	if( !pDXArray )
		return GetTextWidth();

	long nPixWidth = GetTextWidth();
	if( pDXArray ) {
		// initialize the result array
		for( int i = 0; i < mnCharCount; ++i)
			pDXArray[i] = 0;
		// handle each glyph run
		CFArrayRef aGlyphRuns = CTLineGetGlyphRuns( mpCTLine );
		const int nRunCount = CFArrayGetCount( aGlyphRuns );
		typedef std::vector<CGSize> CGSizeVector;
		CGSizeVector aSizeVec;
		typedef std::vector<CFIndex> CFIndexVector;
		CFIndexVector aIndexVec;
		for( int nRunIndex = 0; nRunIndex < nRunCount; ++nRunIndex ) {
			CTRunRef pGlyphRun = (CTRunRef)CFArrayGetValueAtIndex( aGlyphRuns, nRunIndex );
			const CFIndex nGlyphCount = CTRunGetGlyphCount( pGlyphRun );
			const CFRange aFullRange = CFRangeMake( 0, nGlyphCount );
			aSizeVec.reserve( nGlyphCount );
			aIndexVec.reserve( nGlyphCount );
			CTRunGetAdvances( pGlyphRun, aFullRange, &aSizeVec[0] );
			CTRunGetStringIndices( pGlyphRun, aFullRange, &aIndexVec[0] );
			for( int i = 0; i != nGlyphCount; ++i ) {
				const int nRelIdx = aIndexVec[i];
				pDXArray[ nRelIdx ] += aSizeVec[i].width;
			}
		}
	}

	return nPixWidth;
}

// -----------------------------------------------------------------------

int CTLayout::GetTextBreak( long nMaxWidth, long nCharExtra, int nFactor ) const
{
	if( !mpCTLine )
		return STRING_LEN;

	CTTypesetterRef aCTTypeSetter = CTTypesetterCreateWithAttributedString( mpAttrString );
	const double fCTMaxWidth = (double)nMaxWidth / (nFactor * mfFontScale);
	CFIndex nIndex = CTTypesetterSuggestClusterBreak( aCTTypeSetter, 0, fCTMaxWidth );
	if( nIndex >= mnCharCount )
		return STRING_LEN;

	nIndex += mnMinCharPos;
	return (int)nIndex;
}

// -----------------------------------------------------------------------

void CTLayout::GetCaretPositions( int nMaxIndex, sal_Int32* pCaretXArray ) const
{
	DBG_ASSERT( ((nMaxIndex>0)&&!(nMaxIndex&1)),
		"CTLayout::GetCaretPositions() : invalid number of caret pairs requested");

	// initialize the caret positions
	for( int i = 0; i < nMaxIndex; ++i )
		pCaretXArray[ i ] = -1;

	const DynCoreTextSyms& rCT = DynCoreTextSyms::get();
	for( int n = 0; n <= mnCharCount; ++n )
	{
		// measure the characters cursor position
		CGFloat fPos2 = -1;
		const CGFloat fPos1 = rCT.LineGetOffsetForStringIndex( mpCTLine, n, &fPos2 );
		(void)fPos2; // TODO: split cursor at line direction change
		// update previous trailing position
		if( n > 0 )
			pCaretXArray[ 2*n-1 ] = lrint( fPos1 * mfFontScale );
		// update current leading position
		if( 2*n >= nMaxIndex )
			break;
		pCaretXArray[ 2*n+0 ] = lrint( fPos1 * mfFontScale );
	}
}

// -----------------------------------------------------------------------

bool CTLayout::GetBoundRect( SalGraphics& rGraphics, Rectangle& rVCLRect ) const
{
	AquaSalGraphics& rAquaGraphics = static_cast<AquaSalGraphics&>(rGraphics);
	CGRect aMacRect = CTLineGetImageBounds( mpCTLine, rAquaGraphics.mrContext );
	CGPoint aMacPos = CGContextGetTextPosition( rAquaGraphics.mrContext );
	aMacRect.origin.x -= aMacPos.x;
	aMacRect.origin.y -= aMacPos.y;

	const Point aPos = GetDrawPosition( Point(mnBaseAdv, 0) );

	// CoreText top-bottom are vertically flipped from a VCL aspect
	rVCLRect.Left()   = aPos.X() + mfFontScale * aMacRect.origin.x;
	rVCLRect.Right()  = aPos.X() + mfFontScale * (aMacRect.origin.x + aMacRect.size.width);
	rVCLRect.Bottom() = aPos.Y() - mfFontScale * aMacRect.origin.y;
	rVCLRect.Top()    = aPos.Y() - mfFontScale * (aMacRect.origin.y + aMacRect.size.height);
	return true;
}

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

// glyph fallback is supported directly by Aqua
// so methods used only by MultiSalLayout can be dummy implementated
bool CTLayout::GetGlyphOutlines( SalGraphics&, PolyPolyVector& ) const { return false; }
void CTLayout::InitFont() const {}
void CTLayout::MoveGlyph( int /*nStart*/, long /*nNewXPos*/ ) {}
void CTLayout::DropGlyph( int /*nStart*/ ) {}
void CTLayout::Simplify( bool /*bIsBase*/ ) {}

// get the ImplFontData for a glyph fallback font
// for a glyphid that was returned by CTLayout::GetNextGlyphs()
const ImplFontData* CTLayout::GetFallbackFontData( sal_GlyphId /*aGlyphId*/ ) const
{
#if 0
	// check if any fallback fonts were needed
	if( !mpFallbackInfo )
		return NULL;
	// check if the current glyph needs a fallback font
	int nFallbackLevel = (aGlyphId & GF_FONTMASK) >> GF_FONTSHIFT;
	if( !nFallbackLevel )
		return NULL;
	pFallbackFont = mpFallbackInfo->GetFallbackFontData( nFallbackLevel );
#else
	// let CoreText's font cascading handle glyph fallback
	const ImplFontData* pFallbackFont = NULL;
#endif
	return pFallbackFont;
}

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

SalLayout* CTTextStyle::GetTextLayout( void ) const
{
	return new CTLayout( this);
}

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