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Calculate text wrapping in QgsTextDocumentMetrics
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Fixes incompatibility between text wrapping and HTML text formatting,
because currently the text wrapping is applied on the raw HTML
and does not consider text sizes calculated from the HTML. This
results in raw html content showing for layout item labels
when the item box is too narrow and forces wrapping.
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@nyalldawson
nyalldawson committed Oct 3, 2024
1 parent 91e9e06 commit bd3d972
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Showing 2 changed files with 169 additions and 41 deletions.
206 changes: 167 additions & 39 deletions src/core/textrenderer/qgstextdocumentmetrics.cpp
View file
Original file line number Diff line number Diff line change
Expand Up @@ -86,7 +86,7 @@ struct BlockMetrics
};


void QgsTextDocumentMetrics::finalizeBlock( QgsTextDocumentMetrics &res, const QgsTextFormat &format, DocumentMetrics &documentMetrics, QgsTextBlock outputBlock, BlockMetrics &metrics )
void QgsTextDocumentMetrics::finalizeBlock( QgsTextDocumentMetrics &res, const QgsTextFormat &format, DocumentMetrics &documentMetrics, QgsTextBlock &outputBlock, BlockMetrics &metrics )
{
if ( metrics.isFirstBlock )
{
Expand Down Expand Up @@ -173,6 +173,7 @@ void QgsTextDocumentMetrics::finalizeBlock( QgsTextDocumentMetrics &res, const Q
res.mFragmentHorizontalAdvance << metrics.fragmentHorizontalAdvance;

res.mDocument.append( outputBlock );
outputBlock.clear();

if ( !metrics.isFirstBlock )
documentMetrics.lastLineLeading = metrics.maxBlockLeading;
Expand All @@ -182,21 +183,27 @@ void QgsTextDocumentMetrics::finalizeBlock( QgsTextDocumentMetrics &res, const Q
};


void QgsTextDocumentMetrics::processFragment( const QgsRenderContext &context, double scaleFactor, const DocumentMetrics &documentMetrics, BlockMetrics &thisBlockMetrics, const QFont &font, const QgsTextFragment &fragment )
void QgsTextDocumentMetrics::processFragment( QgsTextDocumentMetrics &res, const QgsTextFormat &format, const QgsRenderContext &context, const QgsTextDocumentRenderContext &documentContext, double scaleFactor, DocumentMetrics &documentMetrics, BlockMetrics &thisBlockMetrics, const QFont &font, const QgsTextFragment &fragment, QgsTextBlock &currentOutputBlock )
{
if ( fragment.isTab() )
{
// special handling for tab characters
const double nextTabStop = ( std::floor( thisBlockMetrics.blockXMax / documentMetrics.tabStopDistancePainterUnits ) + 1 ) * documentMetrics.tabStopDistancePainterUnits;
const double fragmentWidth = nextTabStop - thisBlockMetrics.blockXMax;

// TODO!!
// first, calculate fragment width. We need this upfront to determine if we need to split this fragment up into a new block
// in order to respect text wrapping


thisBlockMetrics.blockWidth += fragmentWidth;
thisBlockMetrics.blockXMax += fragmentWidth;

thisBlockMetrics.fragmentVerticalOffsets << 0;
thisBlockMetrics.fragmentHorizontalAdvance << fragmentWidth;
thisBlockMetrics.fragmentFixedHeights << -1;
thisBlockMetrics.fragmentFonts << QFont();
currentOutputBlock.append( fragment );
}
else
{
Expand All @@ -210,6 +217,8 @@ void QgsTextDocumentMetrics::processFragment( const QgsRenderContext &context, d

QFontMetricsF fm( updatedFont );

// first, just do what we need to calculate the fragment width. We need this upfront to determine if we need to split this fragment up into a new block
// in order to respect text wrapping
if ( thisBlockMetrics.isFirstNonTabFragment )
thisBlockMetrics.previousNonSuperSubScriptFont = updatedFont;

Expand Down Expand Up @@ -269,10 +278,33 @@ void QgsTextDocumentMetrics::processFragment( const QgsRenderContext &context, d
{
thisBlockMetrics.previousNonSuperSubScriptFont = updatedFont;
}
thisBlockMetrics.fragmentVerticalOffsets << fragmentVerticalOffset;

auto updateCommonBlockMetrics = [ &fragmentVerticalOffset,
&fragmentYMaxAdjust,
&fragmentHeightForVerticallyOffsetText,
&updatedFont,
&fm,
scaleFactor]( BlockMetrics & thisBlockMetrics, double fragmentWidth, const QgsTextFragment & fragment )
{
thisBlockMetrics.fragmentVerticalOffsets << fragmentVerticalOffset;
thisBlockMetrics.blockYMaxAdjustLabel = std::max( thisBlockMetrics.blockYMaxAdjustLabel, fragmentYMaxAdjust );
thisBlockMetrics.blockHeightUsingAscentAccountingForVerticalOffset = std::max( std::max( thisBlockMetrics.maxBlockAscent, fragmentHeightForVerticallyOffsetText ), thisBlockMetrics.blockHeightUsingAscentAccountingForVerticalOffset );

thisBlockMetrics.fragmentHorizontalAdvance << fragmentWidth;

thisBlockMetrics.blockWidth += fragmentWidth;
thisBlockMetrics.blockXMax += fragmentWidth;

thisBlockMetrics.fragmentFonts << updatedFont;

const double verticalOrientationFragmentHeight = thisBlockMetrics.isFirstNonTabFragment ? ( fm.ascent() / scaleFactor * fragment.text().size() + ( fragment.text().size() - 1 ) * updatedFont.letterSpacing() / scaleFactor )
: ( fragment.text().size() * ( fm.ascent() / scaleFactor + updatedFont.letterSpacing() / scaleFactor ) );
thisBlockMetrics.blockHeightVerticalOrientation += verticalOrientationFragmentHeight;

thisBlockMetrics.isFirstNonTabFragment = false;
};

// calculate width of fragment
double fragmentWidth = 0;
if ( fragment.isImage() )
{
double imageHeight = 0;
Expand Down Expand Up @@ -308,7 +340,15 @@ void QgsTextDocumentMetrics::processFragment( const QgsRenderContext &context, d
imageHeight = context.convertToPainterUnits( fragmentFormat.imageSize().height(), Qgis::RenderUnit::Points );
}

fragmentWidth = imageWidth;
// do we need to move this image fragment to a new block to respect wrapping?
if ( documentContext.flags() & Qgis::TextRendererFlag::WrapLines && documentContext.maximumWidth() > 0
&& ( thisBlockMetrics.blockXMax + imageWidth > documentContext.maximumWidth() ) )
{
// yep, need to wrap before the image

// TODO

}

// we consider the whole image as ascent, and descent as 0
thisBlockMetrics.blockHeightUsingAscentDescent = std::max( thisBlockMetrics.blockHeightUsingAscentDescent, imageHeight + fm.descent() / scaleFactor );
Expand All @@ -321,47 +361,138 @@ void QgsTextDocumentMetrics::processFragment( const QgsRenderContext &context, d
thisBlockMetrics.maxBlockMaxWidth = std::max( thisBlockMetrics.maxBlockMaxWidth, imageWidth );
thisBlockMetrics.maxBlockFixedItemHeight = std::max( thisBlockMetrics.maxBlockFixedItemHeight, imageHeight );
thisBlockMetrics.fragmentFixedHeights << imageHeight;
updateCommonBlockMetrics( thisBlockMetrics, imageWidth, fragment );
currentOutputBlock.append( fragment );
}
else
{
fragmentWidth = fm.horizontalAdvance( fragment.text() ) / scaleFactor;

const double fragmentHeightUsingAscentDescent = ( fm.ascent() + fm.descent() ) / scaleFactor;
const double fragmentHeightUsingLineSpacing = fm.lineSpacing() / scaleFactor;
thisBlockMetrics.blockHeightUsingAscentDescent = std::max( thisBlockMetrics.blockHeightUsingAscentDescent, fragmentHeightUsingAscentDescent );

thisBlockMetrics.blockHeightUsingLineSpacing = std::max( thisBlockMetrics.blockHeightUsingLineSpacing, fragmentHeightUsingLineSpacing );
thisBlockMetrics.maxBlockAscent = std::max( thisBlockMetrics.maxBlockAscent, fm.ascent() / scaleFactor );
thisBlockMetrics.maxBlockAscentForTextFragments = std::max( thisBlockMetrics.maxBlockAscentForTextFragments, fm.ascent() / scaleFactor );
auto finalizeTextFragment = [fragmentHeightUsingAscentDescent,
fragmentHeightUsingLineSpacing,
&fm,
scaleFactor,
&currentOutputBlock,
&updateCommonBlockMetrics
]( BlockMetrics & thisBlockMetrics, const QgsTextFragment & fragment, double fragmentWidth )
{
thisBlockMetrics.blockHeightUsingAscentDescent = std::max( thisBlockMetrics.blockHeightUsingAscentDescent, fragmentHeightUsingAscentDescent );

thisBlockMetrics.maxBlockCapHeight = std::max( thisBlockMetrics.maxBlockCapHeight, fm.capHeight() / scaleFactor );
thisBlockMetrics.blockHeightUsingLineSpacing = std::max( thisBlockMetrics.blockHeightUsingLineSpacing, fragmentHeightUsingLineSpacing );
thisBlockMetrics.maxBlockAscent = std::max( thisBlockMetrics.maxBlockAscent, fm.ascent() / scaleFactor );
thisBlockMetrics.maxBlockAscentForTextFragments = std::max( thisBlockMetrics.maxBlockAscentForTextFragments, fm.ascent() / scaleFactor );

thisBlockMetrics.maxBlockDescent = std::max( thisBlockMetrics.maxBlockDescent, fm.descent() / scaleFactor );
thisBlockMetrics.maxBlockMaxWidth = std::max( thisBlockMetrics.maxBlockMaxWidth, fm.maxWidth() / scaleFactor );
thisBlockMetrics.maxBlockCapHeight = std::max( thisBlockMetrics.maxBlockCapHeight, fm.capHeight() / scaleFactor );

if ( ( fm.lineSpacing() / scaleFactor ) > thisBlockMetrics.maxLineSpacing )
{
thisBlockMetrics.maxLineSpacing = fm.lineSpacing() / scaleFactor;
thisBlockMetrics.maxBlockLeading = fm.leading() / scaleFactor;
}
thisBlockMetrics.fragmentFixedHeights << -1;
}
thisBlockMetrics.maxBlockDescent = std::max( thisBlockMetrics.maxBlockDescent, fm.descent() / scaleFactor );
thisBlockMetrics.maxBlockMaxWidth = std::max( thisBlockMetrics.maxBlockMaxWidth, fm.maxWidth() / scaleFactor );

thisBlockMetrics.blockYMaxAdjustLabel = std::max( thisBlockMetrics.blockYMaxAdjustLabel, fragmentYMaxAdjust );
thisBlockMetrics.blockHeightUsingAscentAccountingForVerticalOffset = std::max( std::max( thisBlockMetrics.maxBlockAscent, fragmentHeightForVerticallyOffsetText ), thisBlockMetrics.blockHeightUsingAscentAccountingForVerticalOffset );
if ( ( fm.lineSpacing() / scaleFactor ) > thisBlockMetrics.maxLineSpacing )
{
thisBlockMetrics.maxLineSpacing = fm.lineSpacing() / scaleFactor;
thisBlockMetrics.maxBlockLeading = fm.leading() / scaleFactor;
}
thisBlockMetrics.fragmentFixedHeights << -1;
updateCommonBlockMetrics( thisBlockMetrics, fragmentWidth, fragment );
currentOutputBlock.append( fragment );
};

thisBlockMetrics.fragmentHorizontalAdvance << fragmentWidth;
double fragmentWidth = fm.horizontalAdvance( fragment.text() ) / scaleFactor;

thisBlockMetrics.blockWidth += fragmentWidth;
thisBlockMetrics.blockXMax += fragmentWidth;
// do we need to split this fragment to respect wrapping?
if ( documentContext.flags() & Qgis::TextRendererFlag::WrapLines && documentContext.maximumWidth() > 0
&& ( thisBlockMetrics.blockXMax + fragmentWidth > documentContext.maximumWidth() ) )
{
// yep, need to split the fragment!

//first step is to identify words which must be on their own line (too long to fit)
const QStringList words = fragment.text().split( ' ' );
QStringList linesToProcess;
QString wordsInCurrentLine;
double remainingWidthInCurrentLine = documentContext.maximumWidth() - thisBlockMetrics.blockXMax;
for ( const QString &word : words )
{
const double wordWidth = fm.horizontalAdvance( word ) / scaleFactor;
if ( wordWidth > remainingWidthInCurrentLine )
{
//too long to fit
if ( !wordsInCurrentLine.isEmpty() )
linesToProcess << wordsInCurrentLine;
wordsInCurrentLine.clear();
linesToProcess << word;
remainingWidthInCurrentLine = documentContext.maximumWidth();
}
else
{
if ( !wordsInCurrentLine.isEmpty() )
wordsInCurrentLine.append( ' ' );
wordsInCurrentLine.append( word );
}
}
if ( !wordsInCurrentLine.isEmpty() )
linesToProcess << wordsInCurrentLine;

remainingWidthInCurrentLine = documentContext.maximumWidth() - thisBlockMetrics.blockXMax;
for ( int lineIndex = 0; lineIndex < linesToProcess.size(); ++lineIndex )
{
QString remainingText = linesToProcess.at( lineIndex );
int lastPos = remainingText.lastIndexOf( ' ' );
while ( lastPos > -1 )
{
//check if remaining text is short enough to go in one line
if ( ( fm.horizontalAdvance( remainingText ) / scaleFactor ) <= remainingWidthInCurrentLine )
{
break;
}

const double widthTextToLastPos = fm.horizontalAdvance( remainingText.left( lastPos ) ) / scaleFactor;
if ( widthTextToLastPos <= remainingWidthInCurrentLine )
{
QgsTextFragment thisLineFragment;
thisLineFragment.setCharacterFormat( fragment.characterFormat() );
thisLineFragment.setText( remainingText.left( lastPos ) );
finalizeTextFragment( thisBlockMetrics, thisLineFragment, widthTextToLastPos );
// move to new block
finalizeBlock( res, format, documentMetrics, currentOutputBlock, thisBlockMetrics );
thisBlockMetrics.isFirstBlock = false;
remainingWidthInCurrentLine = documentContext.maximumWidth();
remainingText = remainingText.mid( lastPos + 1 );
lastPos = 0;
}
lastPos = remainingText.lastIndexOf( ' ', lastPos - 1 );
}

thisBlockMetrics.fragmentFonts << updatedFont;
// if too big, and block is not empty, then flush current block first
if ( ( fm.horizontalAdvance( remainingText ) / scaleFactor ) > remainingWidthInCurrentLine && !currentOutputBlock.empty() )
{
finalizeBlock( res, format, documentMetrics, currentOutputBlock, thisBlockMetrics );
thisBlockMetrics.isFirstBlock = false;
remainingWidthInCurrentLine = documentContext.maximumWidth();
}

const double verticalOrientationFragmentHeight = thisBlockMetrics.isFirstNonTabFragment ? ( fm.ascent() / scaleFactor * fragment.text().size() + ( fragment.text().size() - 1 ) * updatedFont.letterSpacing() / scaleFactor )
: ( fragment.text().size() * ( fm.ascent() / scaleFactor + updatedFont.letterSpacing() / scaleFactor ) );
thisBlockMetrics.blockHeightVerticalOrientation += verticalOrientationFragmentHeight;
QgsTextFragment thisLineFragment;
thisLineFragment.setCharacterFormat( fragment.characterFormat() );
thisLineFragment.setText( remainingText );
finalizeTextFragment( thisBlockMetrics, thisLineFragment, fm.horizontalAdvance( remainingText ) / scaleFactor );

thisBlockMetrics.isFirstNonTabFragment = false;
if ( lineIndex < linesToProcess.size() - 1 )
{
// start new block if we aren't at the last line
finalizeBlock( res, format, documentMetrics, currentOutputBlock, thisBlockMetrics );
thisBlockMetrics.isFirstBlock = false;
remainingWidthInCurrentLine = documentContext.maximumWidth();
}

thisBlockMetrics.isFirstBlock = false;
}
}
else
{
// simple case, no wrapping
finalizeTextFragment( thisBlockMetrics, fragment, fragmentWidth );
}
}
}
}

Expand All @@ -386,8 +517,6 @@ QgsTextDocumentMetrics QgsTextDocumentMetrics::calculateMetrics( const QgsTextDo
res.mDocument.reserve( documentMetrics.blockSize );
res.mFragmentFonts.reserve( documentMetrics.blockSize );

BlockMetrics thisBlockMetrics;

for ( int blockIndex = 0; blockIndex < documentMetrics.blockSize; blockIndex++ )
{
const QgsTextBlock &block = document.at( blockIndex );
Expand All @@ -397,22 +526,21 @@ QgsTextDocumentMetrics QgsTextDocumentMetrics::calculateMetrics( const QgsTextDo

const int fragmentSize = block.size();

BlockMetrics thisBlockMetrics;
thisBlockMetrics.fragmentVerticalOffsets.reserve( fragmentSize );
thisBlockMetrics.fragmentFonts.reserve( fragmentSize );
thisBlockMetrics.fragmentHorizontalAdvance.reserve( fragmentSize );
thisBlockMetrics.fragmentFixedHeights.reserve( fragmentSize );

thisBlockMetrics.isFirstBlock = blockIndex == 0;
thisBlockMetrics.isLastBlock = blockIndex == documentMetrics.blockSize - 1;

for ( int fragmentIndex = 0; fragmentIndex < fragmentSize; ++fragmentIndex )
{
const QgsTextFragment &fragment = block.at( fragmentIndex );


processFragment( context, scaleFactor, documentMetrics, thisBlockMetrics, font, fragment );
outputBlock.append( fragment );
processFragment( res, format, context, documentContext, scaleFactor, documentMetrics, thisBlockMetrics, font, fragment, outputBlock );
}

thisBlockMetrics.isFirstBlock = blockIndex == 0;
thisBlockMetrics.isLastBlock = blockIndex == documentMetrics.blockSize - 1;
finalizeBlock( res, format, documentMetrics, outputBlock, thisBlockMetrics );
}

Expand Down
4 changes: 2 additions & 2 deletions src/core/textrenderer/qgstextdocumentmetrics.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -251,8 +251,8 @@ class CORE_EXPORT QgsTextDocumentMetrics
double mLastLineAscentOffset = 0;
double mFirstLineCapHeight = 0;

static void finalizeBlock( QgsTextDocumentMetrics &res, const QgsTextFormat &format, DocumentMetrics &documentMetrics, QgsTextBlock outputBlock, BlockMetrics &metrics );
static void processFragment( const QgsRenderContext &context, double scaleFactor, const DocumentMetrics &documentMetrics, BlockMetrics &thisBlockMetrics, const QFont &font, const QgsTextFragment &fragment );
static void finalizeBlock( QgsTextDocumentMetrics &res, const QgsTextFormat &format, DocumentMetrics &documentMetrics, QgsTextBlock &outputBlock, BlockMetrics &metrics );
static void processFragment( QgsTextDocumentMetrics &res, const QgsTextFormat &format, const QgsRenderContext &context, const QgsTextDocumentRenderContext &documentContext, double scaleFactor, DocumentMetrics &documentMetrics, BlockMetrics &thisBlockMetrics, const QFont &font, const QgsTextFragment &fragment, QgsTextBlock &currentOutputBlock );
};

#endif // QGSTEXTDOCUMENTMETRICS_H

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