Qt之QGraphicsEffect阴影、模糊效果

Qt之QGraphicsEffect阴影、模糊效果

 

• • Qt之QGraphicsEffect阴影模糊效果
    • 效果图
      • 阴影和模糊效果
      • 正常效果
    • 代码
      • customshadoweffecth
      • customshadoweffectcpp
      • QGraphicsBlurEffect 模糊度setBlurRadius参考文献
      • Applying It
    • 结尾
    • 参考地址

 

效果图

阴影和模糊效果

正常效果

代码

customshadoweffect.h

#ifndef CUSTOMSHADOWEFFECT_H #define CUSTOMSHADOWEFFECT_H #include <QGraphicsDropShadowEffect> #include <QGraphicsEffect> class CustomShadowEffect : public QGraphicsEffect { Q_OBJECT public: explicit CustomShadowEffect(QObject *parent = 0); void draw(QPainter* painter); QRectF boundingRectFor(const QRectF& rect) const; inline void setDistance(qreal distance) { _distance = distance; updateBoundingRect(); } inline qreal distance() const { return _distance; } inline void setBlurRadius(qreal blurRadius) { _blurRadius = blurRadius; updateBoundingRect(); } inline qreal blurRadius() const { return _blurRadius; } inline void setColor(const QColor& color) { _color = color; } inline QColor color() const { return _color; } private: qreal _distance; qreal _blurRadius; QColor _color; }; #endif // CUSTOMSHADOWEFFECT_H

customshadoweffect.cpp

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

QGraphicsBlurEffect 模糊度setBlurRadius参考文献

Applying It

CustomShadow::CustomShadow(QWidget *parent) : QWidget(parent) { ui.setupUi(this); ui.pushButton->installEventFilter(this); ui.widget->installEventFilter(this); //模糊效果 auto blurEffect = new QGraphicsBlurEffect(ui.lineEdit); blurEffect->setBlurRadius(2); ui.lineEdit->setGraphicsEffect(blurEffect); } bool CustomShadow::eventFilter(QObject *obj, QEvent *event) { if (obj == ui.pushButton) { if (event->type() == QEvent::Enter) { Shadow* bodyShadow = new Shadow(ui.pushButton); ui.pushButton->setGraphicsEffect(bodyShadow); return true; } else if (event->type() == QEvent::Leave) { ui.pushButton->setGraphicsEffect(nullptr); return true; } else { return false; } } else if (obj == ui.widget) { if (event->type() == QEvent::Enter) { Shadow* bodyShadow = new Shadow(ui.widget); ui.widget->setGraphicsEffect(bodyShadow); return true; } else if (event->type() == QEvent::Leave) { ui.widget->setGraphicsEffect(nullptr); return true; } else { return false; } } else { // pass the event on to the parent class return __super::eventFilter(obj, event); } }

结尾

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参考地址

Qt: shadow around window 

http://blog.csdn.net/ly305750665/article/details/79209774