void ImageView::paintEvent(QPaintEvent* event) {
// if the image is scaled and we have a high quality cached image
if(imageItem_ && scaleFactor_ != 1.0 && !cachedPixmap_.isNull()) {
// rectangle of the whole image in viewport coordinate
QRect viewportImageRect = sceneToViewport(imageItem_->rect());
// the visible part of the image.
QRect desiredCachedRect = viewportToScene(viewportImageRect.intersected(viewport()->rect()));
// check if the cached area is what we need and if the cache is out of date
if(cachedSceneRect_ == desiredCachedRect) {
// rect of the image area that needs repaint, in viewport coordinate
QRect repaintImageRect = viewportImageRect.intersected(event->rect());
// see if the part asking for repaint is contained by our cache.
if(cachedRect_.contains(repaintImageRect)) {
QPainter painter(viewport());
painter.fillRect(event->rect(), backgroundBrush());
painter.drawPixmap(repaintImageRect, cachedPixmap_);
return;
}
}
}
if(!image_.isNull()) { // we don't have a cache yet or it's out of date already, generate one
queueGenerateCache();
}
QGraphicsView::paintEvent(event);
}
void ImageView::setImage(QImage image, bool show) {
if(show && (gifMovie_ || isSVG)) { // a gif animation or SVG file was shown before
scene_->clear();
isSVG = false;
if(gifMovie_) { // should be deleted explicitly
delete gifMovie_;
gifMovie_ = nullptr;
}
// recreate the rect item
imageItem_ = new QGraphicsRectItem();
imageItem_->hide();
imageItem_->setPen(QPen(Qt::NoPen));
scene_->addItem(imageItem_);
}
image_ = image;
if(image.isNull()) {
imageItem_->hide();
imageItem_->setBrush(QBrush());
scene_->setSceneRect(0, 0, 0, 0);
}
else {
if(show) {
imageItem_->setRect(0, 0, image_.width(), image_.height());
imageItem_->setBrush(image_);
imageItem_->show();
}
scene_->setSceneRect(0, 0, image_.width(), image_.height());
}
if(autoZoomFit_)
zoomFit();
queueGenerateCache();
}
void ImageView::setScaleFactor(double factor) {
if(factor != scaleFactor_) {
scaleFactor_ = factor;
resetTransform();
scale(factor, factor);
queueGenerateCache();
}
}
void ImageView::zoomOut() {
autoZoomFit_ = false;
if(!image_.isNull()) {
resetTransform();
scaleFactor_ /= 1.1;
scale(scaleFactor_, scaleFactor_);
queueGenerateCache();
}
}
void ImageView::zoomFit()
{
if (!m_image.isNull() && m_image.width() <= width() && m_image.height() <= height()) {
zoomOriginal();
return;
}
fitInView(m_scene->sceneRect(), Qt::KeepAspectRatio);
m_scaleFactor = transform().m11();
queueGenerateCache();
}
void ImageView::zoomFit() {
if(!image_.isNull()) {
// if the image is smaller than our view, use its original size
// instead of scaling it up.
if(image_.width() <= width() && image_.height() <= height()) {
zoomOriginal();
return;
}
}
fitInView(scene_->sceneRect(), Qt::KeepAspectRatio);
scaleFactor_ = transform().m11();
queueGenerateCache();
}
void ImageView::zoom(double scale)
{
if (m_scaleFactor == scale)
return;
m_autoZoomFit = false;
resetTransform();
m_scaleFactor = scale;
this->scale(scale, scale);
queueGenerateCache();
}
void ImageView::setSVG(QString fileName) {
image_ = QImage(fileName); // for tracking position and dimensions
if(image_.isNull()) {
if(imageItem_) {
imageItem_->hide();
imageItem_->setBrush(QBrush());
}
scene_->setSceneRect(0, 0, 0, 0);
}
else {
scene_->clear();
imageItem_ = nullptr;
isSVG = true;
QGraphicsSvgItem *svgItem = new QGraphicsSvgItem(fileName);
scene_->addItem(svgItem);
scene_->setSceneRect(svgItem->boundingRect());
}
if(autoZoomFit_)
zoomFit();
queueGenerateCache(); // deletes the cache timer in this case
}
void ImageView::setImage(const QImage &image)
{
reset();
if (image.format() == QImage::Format_Indexed8)
m_image = image.convertToFormat(QImage::Format_ARGB32_Premultiplied);
else
m_image = image;
m_item = new QGraphicsRectItem();
m_item->setRect(0, 0, m_image.width(), m_image.height());
m_item->setBrush(m_image);
m_item->setPen(Qt::NoPen);
m_scene->addItem(m_item);
m_scene->setSceneRect(0, 0, m_image.width(), m_image.height());
if (m_autoZoomFit)
zoomFit();
queueGenerateCache();
}
void ImageView::paintEvent(QPaintEvent* event)
{
if (m_item && m_scaleFactor != 1.0 && !m_cachedPixmap.isNull()) {
const QRect viewportImageRect = sceneToViewport(m_item->rect());
const QRect desiredCachedRect = viewportToScene(viewportImageRect.intersected(viewport()->rect()));
if (m_cachedSceneRect == desiredCachedRect) {
const QRect repaintImageRect = viewportImageRect.intersected(event->rect());
if (m_cachedRect.contains(repaintImageRect)) {
QPainter painter(viewport());
painter.fillRect(event->rect(), backgroundBrush());
painter.drawPixmap(repaintImageRect, m_cachedPixmap);
return;
}
}
}
if (!m_image.isNull())
queueGenerateCache();
QGraphicsView::paintEvent(event);
}
void ImageView::setGifAnimation(QString fileName) {
/* the built-in gif reader gives the first frame, which won't
be shown but is used for tracking position and dimensions */
image_ = QImage(fileName);
if(image_.isNull()) {
if(imageItem_) {
imageItem_->hide();
imageItem_->setBrush(QBrush());
}
scene_->setSceneRect(0, 0, 0, 0);
}
else {
scene_->clear();
imageItem_ = nullptr; // it's deleted by clear();
if(gifMovie_) {
delete gifMovie_;
gifMovie_ = nullptr;
}
QPixmap pix(image_.size());
pix.fill(Qt::transparent);
QGraphicsItem *gifItem = new QGraphicsPixmapItem(pix);
QLabel *gifLabel = new QLabel();
gifMovie_ = new QMovie(fileName);
QGraphicsProxyWidget* gifWidget = new QGraphicsProxyWidget(gifItem);
gifLabel->setAttribute(Qt::WA_NoSystemBackground);
gifLabel->setMovie(gifMovie_);
gifWidget->setWidget(gifLabel);
gifMovie_->start();
scene_->addItem(gifItem);
scene_->setSceneRect(gifItem->boundingRect());
}
if(autoZoomFit_)
zoomFit();
queueGenerateCache(); // deletes the cache timer in this case
}
void ImageView::zoomOriginal() {
resetTransform();
scaleFactor_ = 1.0;
autoZoomFit_ = false;
queueGenerateCache();
}