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| author | Friedemann Kleint <Friedemann.Kleint@qt.io> | 2020-01-14 13:36:39 +0100 |
|---|---|---|
| committer | Friedemann Kleint <Friedemann.Kleint@qt.io> | 2020-03-12 08:24:09 +0100 |
| commit | a719c630f14e175902f6f82b753c3d5030724cc6 (patch) | |
| tree | 2d75408f01bdf0c77cf7963c73acaf58df1431bf /examples/corelib/threads/mandelbrot | |
| parent | 2c390e85cffbfa1eaeabaadfa823abcb61c1156a (diff) | |
Mandelbrot Example: Use High DPI scaling
Create the pixmap with a device pixel ratio set.
Change-Id: I7f7e90aec4d117304852f050be70e14a0c6bf69d
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>
Diffstat (limited to 'examples/corelib/threads/mandelbrot')
4 files changed, 28 insertions, 15 deletions
diff --git a/examples/corelib/threads/mandelbrot/main.cpp b/examples/corelib/threads/mandelbrot/main.cpp index 9832d55514..c5d4835192 100644 --- a/examples/corelib/threads/mandelbrot/main.cpp +++ b/examples/corelib/threads/mandelbrot/main.cpp @@ -55,6 +55,8 @@ //! [0] int main(int argc, char *argv[]) { + QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling); + QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps); QApplication app(argc, argv); MandelbrotWidget widget; widget.show(); diff --git a/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp b/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp index 420fd6186a..f47c9c8a8b 100644 --- a/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp +++ b/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp @@ -107,18 +107,22 @@ void MandelbrotWidget::paintEvent(QPaintEvent * /* event */) //! [6] //! [7] } else { //! [7] //! [8] + auto previewPixmap = qFuzzyCompare(pixmap.devicePixelRatioF(), qreal(1)) + ? pixmap + : pixmap.scaled(pixmap.size() / pixmap.devicePixelRatioF(), Qt::KeepAspectRatio, + Qt::SmoothTransformation); double scaleFactor = pixmapScale / curScale; - int newWidth = int(pixmap.width() * scaleFactor); - int newHeight = int(pixmap.height() * scaleFactor); - int newX = pixmapOffset.x() + (pixmap.width() - newWidth) / 2; - int newY = pixmapOffset.y() + (pixmap.height() - newHeight) / 2; + int newWidth = int(previewPixmap.width() * scaleFactor); + int newHeight = int(previewPixmap.height() * scaleFactor); + int newX = pixmapOffset.x() + (previewPixmap.width() - newWidth) / 2; + int newY = pixmapOffset.y() + (previewPixmap.height() - newHeight) / 2; painter.save(); painter.translate(newX, newY); painter.scale(scaleFactor, scaleFactor); QRectF exposed = painter.transform().inverted().mapRect(rect()).adjusted(-1, -1, 1, 1); - painter.drawPixmap(exposed, pixmap, exposed); + painter.drawPixmap(exposed, previewPixmap, exposed); painter.restore(); } //! [8] //! [9] @@ -139,7 +143,7 @@ void MandelbrotWidget::paintEvent(QPaintEvent * /* event */) //! [10] void MandelbrotWidget::resizeEvent(QResizeEvent * /* event */) { - thread.render(centerX, centerY, curScale, size()); + thread.render(centerX, centerY, curScale, size(), devicePixelRatioF()); } //! [10] @@ -208,8 +212,9 @@ void MandelbrotWidget::mouseReleaseEvent(QMouseEvent *event) pixmapOffset += event->pos() - lastDragPos; lastDragPos = QPoint(); - int deltaX = (width() - pixmap.width()) / 2 - pixmapOffset.x(); - int deltaY = (height() - pixmap.height()) / 2 - pixmapOffset.y(); + const auto pixmapSize = pixmap.size() / pixmap.devicePixelRatioF(); + int deltaX = (width() - pixmapSize.width()) / 2 - pixmapOffset.x(); + int deltaY = (height() - pixmapSize.height()) / 2 - pixmapOffset.y(); scroll(deltaX, deltaY); } } @@ -234,7 +239,7 @@ void MandelbrotWidget::zoom(double zoomFactor) { curScale *= zoomFactor; update(); - thread.render(centerX, centerY, curScale, size()); + thread.render(centerX, centerY, curScale, size(), devicePixelRatioF()); } //! [17] @@ -244,6 +249,6 @@ void MandelbrotWidget::scroll(int deltaX, int deltaY) centerX += deltaX * curScale; centerY += deltaY * curScale; update(); - thread.render(centerX, centerY, curScale, size()); + thread.render(centerX, centerY, curScale, size(), devicePixelRatioF()); } //! [18] diff --git a/examples/corelib/threads/mandelbrot/renderthread.cpp b/examples/corelib/threads/mandelbrot/renderthread.cpp index 22ce81c32d..4d2009471c 100644 --- a/examples/corelib/threads/mandelbrot/renderthread.cpp +++ b/examples/corelib/threads/mandelbrot/renderthread.cpp @@ -76,13 +76,14 @@ RenderThread::~RenderThread() //! [2] void RenderThread::render(double centerX, double centerY, double scaleFactor, - QSize resultSize) + QSize resultSize, double devicePixelRatio) { QMutexLocker locker(&mutex); this->centerX = centerX; this->centerY = centerY; this->scaleFactor = scaleFactor; + this->devicePixelRatio = devicePixelRatio; this->resultSize = resultSize; if (!isRunning()) { @@ -99,8 +100,10 @@ void RenderThread::run() { forever { mutex.lock(); - const QSize resultSize = this->resultSize; - const double scaleFactor = this->scaleFactor; + const double devicePixelRatio = this->devicePixelRatio; + const QSize resultSize = this->resultSize * devicePixelRatio; + const double requestedScaleFactor = this->scaleFactor; + const double scaleFactor = requestedScaleFactor / devicePixelRatio; const double centerX = this->centerX; const double centerY = this->centerY; mutex.unlock(); @@ -111,6 +114,7 @@ void RenderThread::run() //! [4] //! [5] int halfHeight = resultSize.height() / 2; QImage image(resultSize, QImage::Format_RGB32); + image.setDevicePixelRatio(devicePixelRatio); const int NumPasses = 8; int pass = 0; @@ -162,7 +166,7 @@ void RenderThread::run() pass = 4; } else { if (!restart) - emit renderedImage(image, scaleFactor); + emit renderedImage(image, requestedScaleFactor); //! [5] //! [6] ++pass; } diff --git a/examples/corelib/threads/mandelbrot/renderthread.h b/examples/corelib/threads/mandelbrot/renderthread.h index 934cc17d74..6174e0ed3d 100644 --- a/examples/corelib/threads/mandelbrot/renderthread.h +++ b/examples/corelib/threads/mandelbrot/renderthread.h @@ -69,7 +69,8 @@ public: RenderThread(QObject *parent = nullptr); ~RenderThread(); - void render(double centerX, double centerY, double scaleFactor, QSize resultSize); + void render(double centerX, double centerY, double scaleFactor, QSize resultSize, + double devicePixelRatio); signals: void renderedImage(const QImage &image, double scaleFactor); @@ -85,6 +86,7 @@ private: double centerX; double centerY; double scaleFactor; + double devicePixelRatio; QSize resultSize; bool restart = false; bool abort = false; |