本文整理汇总了C++中QgsSymbolV2::drawPreviewIcon方法的典型用法代码示例。如果您正苦于以下问题：C++ QgsSymbolV2::drawPreviewIcon方法的具体用法？C++ QgsSymbolV2::drawPreviewIcon怎么用？C++ QgsSymbolV2::drawPreviewIcon使用的例子？那么, 这里精选的方法代码示例或许可以为您提供帮助。您也可以进一步了解该方法所在类QgsSymbolV2的用法示例。
在下文中一共展示了QgsSymbolV2::drawPreviewIcon方法的1个代码示例，这些例子默认根据受欢迎程度排序。您可以为喜欢或者感觉有用的代码点赞，您的评价将有助于系统推荐出更棒的C++代码示例。
示例1: QSizeF
QSizeF QgsSymbolV2LegendNode::drawSymbol( const QgsLegendSettings& settings, ItemContext* ctx, double itemHeight ) const
{
QgsSymbolV2* s = mItem.symbol();
if ( !s )
{
return QSizeF();
}
// setup temporary render context
QgsRenderContext context;
context.setScaleFactor( settings.dpi() / 25.4 );
context.setRendererScale( settings.mapScale() );
context.setMapToPixel( QgsMapToPixel( 1 / ( settings.mmPerMapUnit() * context.scaleFactor() ) ) );
context.setForceVectorOutput( true );
context.setPainter( ctx ? ctx->painter : 0 );
//Consider symbol size for point markers
double height = settings.symbolSize().height();
double width = settings.symbolSize().width();
double size = 0;
//Center small marker symbols
double widthOffset = 0;
double heightOffset = 0;
if ( QgsMarkerSymbolV2* markerSymbol = dynamic_cast<QgsMarkerSymbolV2*>( s ) )
{
// allow marker symbol to occupy bigger area if necessary
size = markerSymbol->size() * QgsSymbolLayerV2Utils::lineWidthScaleFactor( context, s->outputUnit(), s->mapUnitScale() ) / context.scaleFactor();
height = size;
width = size;
if ( width < settings.symbolSize().width() )
{
widthOffset = ( settings.symbolSize().width() - width ) / 2.0;
}
if ( height < settings.symbolSize().height() )
{
heightOffset = ( settings.symbolSize().height() - height ) / 2.0;
}
}
if ( ctx )
{
double currentXPosition = ctx->point.x();
double currentYCoord = ctx->point.y() + ( itemHeight - settings.symbolSize().height() ) / 2;
QPainter* p = ctx->painter;
//setup painter scaling to dots so that raster symbology is drawn to scale
double dotsPerMM = context.scaleFactor();
int opacity = 255;
if ( QgsVectorLayer* vectorLayer = dynamic_cast<QgsVectorLayer*>( layerNode()->layer() ) )
opacity = 255 - ( 255 * vectorLayer->layerTransparency() / 100 );
p->save();
p->setRenderHint( QPainter::Antialiasing );
p->translate( currentXPosition + widthOffset, currentYCoord + heightOffset );
p->scale( 1.0 / dotsPerMM, 1.0 / dotsPerMM );
if ( opacity != 255 && settings.useAdvancedEffects() )
{
//semi transparent layer, so need to draw symbol to an image (to flatten it first)
//create image which is same size as legend rect, in case symbol bleeds outside its alloted space
QSize tempImageSize( width * dotsPerMM, height * dotsPerMM );
QImage tempImage = QImage( tempImageSize, QImage::Format_ARGB32 );
tempImage.fill( Qt::transparent );
QPainter imagePainter( &tempImage );
context.setPainter( &imagePainter );
s->drawPreviewIcon( &imagePainter, tempImageSize, &context );
context.setPainter( ctx->painter );
//reduce opacity of image
imagePainter.setCompositionMode( QPainter::CompositionMode_DestinationIn );
imagePainter.fillRect( tempImage.rect(), QColor( 0, 0, 0, opacity ) );
imagePainter.end();
//draw rendered symbol image
p->drawImage( 0, 0, tempImage );
}
else
{
s->drawPreviewIcon( p, QSize( width * dotsPerMM, height * dotsPerMM ), &context );
}
p->restore();
}
return QSizeF( qMax( width + 2 * widthOffset, ( double ) settings.symbolSize().width() ),
qMax( height + 2 * heightOffset, ( double ) settings.symbolSize().height() ) );
}