void QgsSymbolLegendNode::exportSymbolToJson( const QgsLegendSettings &settings, const QgsRenderContext &context, QJsonObject &json ) const
{
const QgsSymbol *s = mItem.symbol();
if ( !s )
{
return;
}
QgsRenderContext ctx;
ctx.setScaleFactor( settings.dpi() / 25.4 );
ctx.setRendererScale( settings.mapScale() );
ctx.setMapToPixel( QgsMapToPixel( 1 / ( settings.mmPerMapUnit() * ctx.scaleFactor() ) ) );
ctx.setForceVectorOutput( true );
// ensure that a minimal expression context is available
QgsExpressionContext expContext = context.expressionContext();
expContext.appendScopes( QgsExpressionContextUtils::globalProjectLayerScopes( nullptr ) );
ctx.setExpressionContext( expContext );
const QPixmap pix = QgsSymbolLayerUtils::symbolPreviewPixmap( mItem.symbol(), minimumIconSize(), 0, &ctx );
QImage img( pix.toImage().convertToFormat( QImage::Format_ARGB32_Premultiplied ) );
int opacity = 255;
if ( QgsVectorLayer *vectorLayer = qobject_cast<QgsVectorLayer *>( layerNode()->layer() ) )
opacity = ( 255 * vectorLayer->opacity() );
if ( opacity != 255 )
{
QPainter painter;
painter.begin( &img );
painter.setCompositionMode( QPainter::CompositionMode_DestinationIn );
painter.fillRect( pix.rect(), QColor( 0, 0, 0, opacity ) );
painter.end();
}
QByteArray byteArray;
QBuffer buffer( &byteArray );
img.save( &buffer, "PNG" );
const QString base64 = QString::fromLatin1( byteArray.toBase64().data() );
json[ "icon" ] = base64;
}
QSize QgsSymbolLegendNode::minimumIconSize() const
{
std::unique_ptr<QgsRenderContext> context( createTemporaryRenderContext() );
return minimumIconSize( context.get() );
}
QSize QgsSymbolLegendNode::minimumIconSize() const
{
QScopedPointer<QgsRenderContext> context( createTemporaryRenderContext() );
return minimumIconSize( context.data() );
}
