Warning, file /education/parley/src/practice/imagewidget.cpp was not indexed or was modified since last indexation (in which case cross-reference links may be missing, inaccurate or erroneous).

 /*
     SPDX-FileCopyrightText: 2009 Daniel Laidig <d.laidig@gmx.de>
     SPDX-License-Identifier: GPL-2.0-or-later
 */
 
 #include "imagewidget.h"
 #include <config-parley.h>
 
 #include <QPaintEngine>
 #include <QPainter>
 #include <QTimeLine>
 #include <QTimer>
 
 #include <QDebug>
 
 #if defined(Q_WS_X11)
 #include <QX11Info>
 #include <X11/Xlib.h>
 #include <X11/extensions/Xrender.h>
 #undef KeyPress
 #undef FocusOut
 #endif
 
 using namespace Practice;
 
 // The functions centerPixmaps() and transition() are copied from kdelibs/plasma/paintutils.cpp, revision 1133527
 // License: LGPLv2+
 // SPDX-FileCopyrightText: 2005 Aaron Seigo <aseigo@kde.org>
 // SPDX-FileCopyrightText: 2008 Andrew Lake <jamboarder@yahoo.com>
 // Don't just modify the code here, if there are issues they should probably also be fixed in libplasma.
 
 void centerPixmaps(QPixmap &from, QPixmap &to)
 {
     if (from.size() == to.size() && from.hasAlphaChannel() && to.hasAlphaChannel()) {
         return;
     }
     QRect fromRect(from.rect());
     QRect toRect(to.rect());
 
     QRect actualRect = QRect(QPoint(0, 0), fromRect.size().expandedTo(toRect.size()));
     fromRect.moveCenter(actualRect.center());
     toRect.moveCenter(actualRect.center());
 
     if (from.size() != actualRect.size() || !from.hasAlphaChannel()) {
         QPixmap result(actualRect.size());
         result.fill(Qt::transparent);
         QPainter p(&result);
         p.setCompositionMode(QPainter::CompositionMode_Source);
         p.drawPixmap(fromRect.topLeft(), from);
         p.end();
         from = result;
     }
 
     if (to.size() != actualRect.size() || !to.hasAlphaChannel()) {
         QPixmap result(actualRect.size());
         result.fill(Qt::transparent);
         QPainter p(&result);
         p.setCompositionMode(QPainter::CompositionMode_Source);
         p.drawPixmap(toRect.topLeft(), to);
         p.end();
         to = result;
     }
 }
 
 QPixmap transition(const QPixmap &from, const QPixmap &to, qreal amount)
 {
     if (from.isNull() && to.isNull()) {
         return from;
     }
 
     QPixmap startPixmap(from);
     QPixmap targetPixmap(to);
 
     if (from.size() != to.size() || !from.hasAlphaChannel() || !to.hasAlphaChannel()) {
         centerPixmaps(startPixmap, targetPixmap);
     }
 
     // paint to in the center of from
     QRect toRect = to.rect();
 
     QColor color;
     color.setAlphaF(amount);
 
     // If the native paint engine supports Porter/Duff compositing and CompositionMode_Plus
     QPaintEngine *paintEngine = from.paintEngine();
     if (paintEngine && paintEngine->hasFeature(QPaintEngine::PorterDuff) && paintEngine->hasFeature(QPaintEngine::BlendModes)) {
         QPainter p;
         p.begin(&targetPixmap);
         p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
         p.fillRect(targetPixmap.rect(), color);
         p.end();
 
         p.begin(&startPixmap);
         p.setCompositionMode(QPainter::CompositionMode_DestinationOut);
         p.fillRect(startPixmap.rect(), color);
         p.setCompositionMode(QPainter::CompositionMode_Plus);
         p.drawPixmap(toRect.topLeft(), targetPixmap);
         p.end();
 
         return startPixmap;
     }
 #if defined(Q_WS_X11)
     // We have Xrender support
     else if (paintEngine && paintEngine->hasFeature(QPaintEngine::PorterDuff)) {
         // QX11PaintEngine doesn't implement CompositionMode_Plus in Qt 4.3,
         // which we need to be able to do a transition from one pixmap to
         // another.
         //
         // In order to avoid the overhead of converting the pixmaps to images
         // and doing the operation entirely in software, this function has a
         // specialized path for X11 that uses Xrender directly to do the
         // transition. This operation can be fully accelerated in HW.
         //
         // This specialization can be removed when QX11PaintEngine supports
         // CompositionMode_Plus.
         QPixmap source(targetPixmap), destination(startPixmap);
 
         source.detach();
         destination.detach();
 
         Display *dpy = QX11Info::display();
 
         XRenderPictFormat *format = XRenderFindStandardFormat(dpy, PictStandardA8);
         XRenderPictureAttributes pa;
         pa.repeat = 1; // RepeatNormal
 
         // Create a 1x1 8 bit repeating alpha picture
         Pixmap pixmap = XCreatePixmap(dpy, destination.handle(), 1, 1, 8);
         Picture alpha = XRenderCreatePicture(dpy, pixmap, format, CPRepeat, &pa);
         XFreePixmap(dpy, pixmap);
 
         // Fill the alpha picture with the opacity value
         XRenderColor xcolor;
         xcolor.alpha = quint16(0xffff * amount);
         XRenderFillRectangle(dpy, PictOpSrc, alpha, &xcolor, 0, 0, 1, 1);
 
         // Reduce the alpha of the destination with 1 - opacity
         XRenderComposite(dpy, PictOpOutReverse, alpha, None, destination.x11PictureHandle(), 0, 0, 0, 0, 0, 0, destination.width(), destination.height());
 
         // Add source * opacity to the destination
         XRenderComposite(dpy,
                          PictOpAdd,
                          source.x11PictureHandle(),
                          alpha,
                          destination.x11PictureHandle(),
                          toRect.x(),
                          toRect.y(),
                          0,
                          0,
                          0,
                          0,
                          destination.width(),
                          destination.height());
 
         XRenderFreePicture(dpy, alpha);
         return destination;
     }
 #endif
     else {
         // Fall back to using QRasterPaintEngine to do the transition.
         QImage under = startPixmap.toImage();
         QImage over = targetPixmap.toImage();
 
         QPainter p;
         p.begin(&over);
         p.setCompositionMode(QPainter::CompositionMode_DestinationIn);
         p.fillRect(over.rect(), color);
         p.end();
 
         p.begin(&under);
         p.setCompositionMode(QPainter::CompositionMode_DestinationOut);
         p.fillRect(under.rect(), color);
         p.setCompositionMode(QPainter::CompositionMode_Plus);
         p.drawImage(toRect.topLeft(), over);
         p.end();
 
         return QPixmap::fromImage(under);
     }
 }
 
 ImageWidget::ImageWidget(QWidget *parent)
     : QWidget(parent)
 {
     m_scaleTimer = new QTimer(this);
     m_scaleTimer->setSingleShot(true);
     m_scaleTimer->setInterval(500);
 
     m_animation = new QTimeLine(300, this);
 
     m_scaledPixmapOutOfDate = false;
     connect(m_scaleTimer, SIGNAL(timeout()), this, SLOT(scalePixmap()));
     connect(m_animation, SIGNAL(valueChanged(qreal)), this, SLOT(update()));
     connect(m_animation, &QTimeLine::finished, this, &ImageWidget::animationFinished);
 }
 
 void ImageWidget::setPixmap(const QPixmap &pixmap)
 {
     // qDebug() << "set new pixmap, size:" << pixmap.size();
     if (m_animation->state() == QTimeLine::Running) {
         m_scaledPixmap = transition(m_animationPixmap, m_scaledPixmap, m_animation->currentValue());
         m_animation->stop();
         animationFinished();
     }
 
     m_animationPixmap = m_scaledPixmap;
     m_originalPixmap = pixmap;
     m_scaledPixmap = QPixmap();
     m_scaledBackupPixmap = QPixmap();
     m_scaledPixmapOutOfDate = true;
     if (!m_scaling) {
         m_scaledPixmap = pixmap;
     }
     scalePixmap(true);
     if (m_fading) {
         m_animation->start();
     }
     update();
 }
 
 void ImageWidget::setScalingEnabled(bool scaling, bool onlyDownscaling)
 {
     m_scaling = scaling;
     m_onlyDownscaling = onlyDownscaling;
 }
 
 void ImageWidget::setKeepAspectRatio(Qt::AspectRatioMode mode)
 {
     m_keepAspectRatio = mode;
 }
 
 void ImageWidget::setFadingEnabled(bool fading)
 {
     m_fading = fading;
 }
 
 void ImageWidget::setAlignment(Qt::Alignment alignment)
 {
     m_alignment = alignment;
 }
 
 void ImageWidget::paintEvent(QPaintEvent *e)
 {
     QWidget::paintEvent(e);
     QPainter painter(this);
     if (m_scaling && m_scaledPixmapOutOfDate) {
         m_scaleTimer->start();
         scalePixmap(false);
     }
     QPixmap pm = m_scaledPixmap;
     if (m_animation->state() == QTimeLine::Running) {
         pm = transition(m_animationPixmap, m_scaledPixmap, m_animation->currentValue());
     }
 
     int x = (size().width() - pm.width()) / 2;
     if (m_alignment.testFlag(Qt::AlignLeft)) {
         x = 0;
     } else if (m_alignment.testFlag(Qt::AlignRight)) {
         x = size().width() - pm.width();
     }
     int y = (size().height() - pm.height()) / 2;
     if (m_alignment.testFlag(Qt::AlignTop)) {
         y = 0;
     } else if (m_alignment.testFlag(Qt::AlignBottom)) {
         y = size().height() - pm.height();
     }
     painter.drawPixmap(x, y, pm);
 }
 
 void ImageWidget::resizeEvent(QResizeEvent *e)
 {
     if (!m_scaledPixmapOutOfDate) {
         m_scaledBackupPixmap = m_scaledPixmap;
     }
     // stop animations when resizing
     if (m_animation->state() == QTimeLine::Running) {
         m_animation->stop();
         animationFinished();
     }
     m_scaledPixmapOutOfDate = true;
     QWidget::resizeEvent(e);
     Q_EMIT sizeChanged();
 }
 
 void ImageWidget::scalePixmap(bool smooth)
 {
     bool scaleUp = m_originalPixmap.width() <= size().width() && m_originalPixmap.height() <= size().height();
     if ((m_onlyDownscaling && scaleUp) || m_originalPixmap.size() == size()) {
         // qDebug() << "no need to scale pixmap";
         m_scaledPixmapOutOfDate = false;
         m_scaledPixmap = m_originalPixmap;
         m_scaledBackupPixmap = QPixmap();
     } else if (smooth) {
         // qDebug() << "smooth scaling to" << size();
         if (m_originalPixmap.isNull() || size().isEmpty()) {
             m_scaledPixmapOutOfDate = false;
             m_scaledPixmap = QPixmap();
             update();
             return;
         }
         m_scaledPixmap = m_originalPixmap.scaled(size(), m_keepAspectRatio, Qt::SmoothTransformation);
         m_scaledBackupPixmap = QPixmap();
         m_scaledPixmapOutOfDate = false;
         update();
     } else {
         // qDebug() << "fast scaling to" << size();
         // Try to find out if it makes sense to use the scaled backup pixmap.
         // If the scaled backup gets too small, we use the original image.
         float ratio = 0;
         if (!size().isEmpty()) {
             ratio = qMin(float(m_scaledBackupPixmap.width()) / size().width(), float(m_scaledBackupPixmap.height()) / size().height());
         }
         if (ratio > 0.4 && !m_scaledBackupPixmap.isNull()) {
             m_scaledPixmap = m_scaledBackupPixmap.scaled(size(), m_keepAspectRatio, Qt::FastTransformation);
         } else {
             if (m_originalPixmap.isNull() || size().isEmpty()) {
                 m_scaledPixmap = QPixmap();
                 return;
             }
             // use the original pixmap
             m_scaledPixmap = m_originalPixmap.scaled(size(), m_keepAspectRatio, Qt::FastTransformation);
             m_scaledBackupPixmap = m_scaledPixmap;
         }
         m_scaledPixmapOutOfDate = true;
     }
 }
 
 void ImageWidget::animationFinished()
 {
     m_animationPixmap = QPixmap();
 }