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https://gitee.com/drabel/LibQQt.git
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156 lines
2.6 KiB
C++
156 lines
2.6 KiB
C++
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#include "customshadoweffect.h"
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#include <QPainter>
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// #include <QGraphicsEffect>
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CustomShadowEffect::CustomShadowEffect ( QObject* parent ) :
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QGraphicsEffect ( parent ),
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_distance ( 4.0f ),
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_blurRadius ( 10.0f ),
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_color ( 0, 0, 0, 80 )
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{
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}
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QT_BEGIN_NAMESPACE
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extern Q_WIDGETS_EXPORT void qt_blurImage ( QPainter* p, QImage& blurImage, qreal radius, bool quality, bool alphaOnly, int transposed = 0 );
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QT_END_NAMESPACE
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void CustomShadowEffect::draw ( QPainter* painter )
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{
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// if nothing to show outside the item, just draw source
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if ( ( blurRadius() + distance() ) <= 0 )
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{
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drawSource ( painter );
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return;
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}
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PixmapPadMode mode = QGraphicsEffect::PadToEffectiveBoundingRect;
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QPoint offset;
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const QPixmap px = sourcePixmap ( Qt::DeviceCoordinates, &offset, mode );
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// return if no source
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if ( px.isNull() )
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return;
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// save world transform
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QTransform restoreTransform = painter->worldTransform();
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painter->setWorldTransform ( QTransform() );
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// Calculate size for the background image
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QSize szi ( px.size().width() + 2 * distance(), px.size().height() + 2 * distance() );
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QImage tmp ( szi, QImage::Format_ARGB32_Premultiplied );
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QPixmap scaled = px.scaled ( szi );
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tmp.fill ( 0 );
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QPainter tmpPainter ( &tmp );
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tmpPainter.setCompositionMode ( QPainter::CompositionMode_Source );
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tmpPainter.drawPixmap ( QPointF ( -distance(), -distance() ), scaled );
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tmpPainter.end();
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// blur the alpha channel
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QImage blurred ( tmp.size(), QImage::Format_ARGB32_Premultiplied );
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blurred.fill ( 0 );
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QPainter blurPainter ( &blurred );
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qt_blurImage ( &blurPainter, tmp, blurRadius(), false, true );
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blurPainter.end();
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tmp = blurred;
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// blacken the image...
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tmpPainter.begin ( &tmp );
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tmpPainter.setCompositionMode ( QPainter::CompositionMode_SourceIn );
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tmpPainter.fillRect ( tmp.rect(), color() );
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tmpPainter.end();
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// draw the blurred shadow...
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painter->drawImage ( offset, tmp );
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// draw the actual pixmap...
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painter->drawPixmap ( offset, px, QRectF() );
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// restore world transform
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painter->setWorldTransform ( restoreTransform );
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}
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QRectF CustomShadowEffect::boundingRectFor ( const QRectF& rect ) const
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{
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qreal delta = blurRadius() + distance();
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return rect.united ( rect.adjusted ( -delta, -delta, delta, delta ) );
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}
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