qt 6.5.1 original

examples/corelib/threads/mandelbrot/CMakeLists.txt

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+# Copyright (C) 2022 The Qt Company Ltd.
+# SPDX-License-Identifier: BSD-3-Clause
+
+cmake_minimum_required(VERSION 3.16)
+project(mandelbrot LANGUAGES CXX)
+
+if(NOT DEFINED INSTALL_EXAMPLESDIR)
+    set(INSTALL_EXAMPLESDIR "examples")
+endif()
+
+set(INSTALL_EXAMPLEDIR "${INSTALL_EXAMPLESDIR}/corelib/threads/mandelbrot")
+
+find_package(Qt6 REQUIRED COMPONENTS Core Gui Widgets)
+
+qt_standard_project_setup()
+
+qt_add_executable(mandelbrot
+    main.cpp
+    mandelbrotwidget.cpp mandelbrotwidget.h
+    renderthread.cpp renderthread.h
+)
+
+set_target_properties(mandelbrot PROPERTIES
+    WIN32_EXECUTABLE TRUE
+    MACOSX_BUNDLE TRUE
+)
+
+target_link_libraries(mandelbrot PRIVATE
+    Qt6::Core
+    Qt6::Gui
+    Qt6::Widgets
+)
+
+install(TARGETS mandelbrot
+    RUNTIME DESTINATION "${INSTALL_EXAMPLEDIR}"
+    BUNDLE DESTINATION "${INSTALL_EXAMPLEDIR}"
+    LIBRARY DESTINATION "${INSTALL_EXAMPLEDIR}"
+)

examples/corelib/threads/mandelbrot/main.cpp

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+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "mandelbrotwidget.h"
+
+#include <QApplication>
+
+#include <QScreen>
+
+#include <QCommandLineParser>
+#include <QCommandLineOption>
+#include <QDebug>
+#include <QRect>
+
+//! [0]
+int main(int argc, char *argv[])
+{
+    QApplication app(argc, argv);
+
+    QCommandLineParser parser;
+    parser.setApplicationDescription("Qt Mandelbrot Example");
+    parser.addHelpOption();
+    parser.addVersionOption();
+    QCommandLineOption passesOption("passes", "Number of passes (1-8)", "passes");
+    parser.addOption(passesOption);
+    parser.process(app);
+
+    if (parser.isSet(passesOption)) {
+        const auto passesStr = parser.value(passesOption);
+        bool ok;
+        const int passes = passesStr.toInt(&ok);
+        if (!ok || passes < 1 || passes > 8) {
+            qWarning() << "Invalid value:" << passesStr;
+            return -1;
+        }
+        RenderThread::setNumPasses(passes);
+    }
+
+    MandelbrotWidget widget;
+    widget.grabGesture(Qt::PinchGesture);
+    widget.show();
+    return app.exec();
+}
+//! [0]

examples/corelib/threads/mandelbrot/mandelbrot.pro

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+QT += widgets
+
+HEADERS       = mandelbrotwidget.h \
+                renderthread.h
+SOURCES       = main.cpp \
+                mandelbrotwidget.cpp \
+                renderthread.cpp
+
+# install
+target.path = $$[QT_INSTALL_EXAMPLES]/corelib/threads/mandelbrot
+INSTALLS += target

examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp

@@ -0,0 +1,248 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "mandelbrotwidget.h"
+
+#include <QGesture>
+#include <QKeyEvent>
+#include <QPainter>
+
+#include <math.h>
+
+//! [0]
+const double DefaultCenterX = -0.637011;
+const double DefaultCenterY = -0.0395159;
+const double DefaultScale = 0.00403897;
+
+const double ZoomInFactor = 0.8;
+const double ZoomOutFactor = 1 / ZoomInFactor;
+const int ScrollStep = 20;
+//! [0]
+
+//! [1]
+MandelbrotWidget::MandelbrotWidget(QWidget *parent) :
+    QWidget(parent),
+    centerX(DefaultCenterX),
+    centerY(DefaultCenterY),
+    pixmapScale(DefaultScale),
+    curScale(DefaultScale)
+{
+    help = tr("Zoom with mouse wheel, +/- keys or pinch.  Scroll with arrow keys or by dragging.");
+    connect(&thread, &RenderThread::renderedImage,
+            this, &MandelbrotWidget::updatePixmap);
+
+    setWindowTitle(tr("Mandelbrot"));
+#if QT_CONFIG(cursor)
+    setCursor(Qt::CrossCursor);
+#endif
+}
+//! [1]
+
+//! [2]
+void MandelbrotWidget::paintEvent(QPaintEvent * /* event */)
+{
+    QPainter painter(this);
+    painter.fillRect(rect(), Qt::black);
+
+    if (pixmap.isNull()) {
+        painter.setPen(Qt::white);
+        painter.drawText(rect(), Qt::AlignCenter|Qt::TextWordWrap, tr("Rendering initial image, please wait..."));
+//! [2] //! [3]
+        return;
+//! [3] //! [4]
+    }
+//! [4]
+
+//! [5]
+    if (qFuzzyCompare(curScale, pixmapScale)) {
+//! [5] //! [6]
+        painter.drawPixmap(pixmapOffset, pixmap);
+//! [6] //! [7]
+    } else {
+//! [7] //! [8]
+        auto previewPixmap = qFuzzyCompare(pixmap.devicePixelRatio(), qreal(1))
+            ? pixmap
+            : pixmap.scaled(pixmap.deviceIndependentSize().toSize(), Qt::KeepAspectRatio,
+                            Qt::SmoothTransformation);
+        double scaleFactor = pixmapScale / curScale;
+        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, previewPixmap, exposed);
+        painter.restore();
+    }
+//! [8] //! [9]
+
+    QFontMetrics metrics = painter.fontMetrics();
+    if (!info.isEmpty()){
+        int infoWidth = metrics.horizontalAdvance(info);
+        int infoHeight = metrics.height();
+
+        painter.setPen(Qt::NoPen);
+        painter.setBrush(QColor(0, 0, 0, 127));
+        infoHeight = (infoWidth/width()+1) * (infoHeight + 5);
+        painter.drawRect((width() - infoWidth) / 2 - 5, 0, infoWidth + 10, infoHeight);
+
+        painter.setPen(Qt::white);
+        painter.drawText(rect(), Qt::AlignHCenter|Qt::AlignTop|Qt::TextWordWrap, info);
+    }
+
+    int helpWidth = metrics.horizontalAdvance(help);
+    int helpHeight = metrics.height();
+
+    painter.setPen(Qt::NoPen);
+    painter.setBrush(QColor(0, 0, 0, 127));
+    helpHeight = (helpWidth/width()+1) * (helpHeight + 5);
+    painter.drawRect((width() - helpWidth) / 2 - 5, height()-helpHeight, helpWidth + 10, helpHeight);
+
+    painter.setPen(Qt::white);
+    painter.drawText(rect(), Qt::AlignHCenter|Qt::AlignBottom|Qt::TextWordWrap, help);
+
+}
+//! [9]
+
+//! [10]
+void MandelbrotWidget::resizeEvent(QResizeEvent * /* event */)
+{
+    thread.render(centerX, centerY, curScale, size(), devicePixelRatio());
+}
+//! [10]
+
+//! [11]
+void MandelbrotWidget::keyPressEvent(QKeyEvent *event)
+{
+    switch (event->key()) {
+    case Qt::Key_Plus:
+        zoom(ZoomInFactor);
+        break;
+    case Qt::Key_Minus:
+        zoom(ZoomOutFactor);
+        break;
+    case Qt::Key_Left:
+        scroll(-ScrollStep, 0);
+        break;
+    case Qt::Key_Right:
+        scroll(+ScrollStep, 0);
+        break;
+    case Qt::Key_Down:
+        scroll(0, -ScrollStep);
+        break;
+    case Qt::Key_Up:
+        scroll(0, +ScrollStep);
+        break;
+    case Qt::Key_Q:
+        close();
+        break;
+    default:
+        QWidget::keyPressEvent(event);
+    }
+}
+//! [11]
+
+#if QT_CONFIG(wheelevent)
+//! [12]
+void MandelbrotWidget::wheelEvent(QWheelEvent *event)
+{
+    const int numDegrees = event->angleDelta().y() / 8;
+    const double numSteps = numDegrees / double(15);
+    zoom(pow(ZoomInFactor, numSteps));
+}
+//! [12]
+#endif
+
+//! [13]
+void MandelbrotWidget::mousePressEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::LeftButton)
+        lastDragPos = event->position().toPoint();
+}
+//! [13]
+
+//! [14]
+void MandelbrotWidget::mouseMoveEvent(QMouseEvent *event)
+{
+    if (event->buttons() & Qt::LeftButton) {
+        pixmapOffset += event->position().toPoint() - lastDragPos;
+        lastDragPos = event->position().toPoint();
+        update();
+    }
+}
+//! [14]
+
+//! [15]
+void MandelbrotWidget::mouseReleaseEvent(QMouseEvent *event)
+{
+    if (event->button() == Qt::LeftButton) {
+        pixmapOffset += event->position().toPoint() - lastDragPos;
+        lastDragPos = QPoint();
+
+        const auto pixmapSize = pixmap.deviceIndependentSize().toSize();
+        int deltaX = (width() - pixmapSize.width()) / 2 - pixmapOffset.x();
+        int deltaY = (height() - pixmapSize.height()) / 2 - pixmapOffset.y();
+        scroll(deltaX, deltaY);
+    }
+}
+//! [15]
+
+//! [16]
+void MandelbrotWidget::updatePixmap(const QImage &image, double scaleFactor)
+{
+    if (!lastDragPos.isNull())
+        return;
+
+    info = image.text(RenderThread::infoKey());
+
+    pixmap = QPixmap::fromImage(image);
+    pixmapOffset = QPoint();
+    lastDragPos = QPoint();
+    pixmapScale = scaleFactor;
+    update();
+}
+//! [16]
+
+//! [17]
+void MandelbrotWidget::zoom(double zoomFactor)
+{
+    curScale *= zoomFactor;
+    update();
+    thread.render(centerX, centerY, curScale, size(), devicePixelRatio());
+}
+//! [17]
+
+//! [18]
+void MandelbrotWidget::scroll(int deltaX, int deltaY)
+{
+    centerX += deltaX * curScale;
+    centerY += deltaY * curScale;
+    update();
+    thread.render(centerX, centerY, curScale, size(), devicePixelRatio());
+}
+//! [18]
+
+//! [gesture1]
+#ifndef QT_NO_GESTURES
+bool MandelbrotWidget::gestureEvent(QGestureEvent *event)
+{
+    if (auto *pinch = static_cast<QPinchGesture *>(event->gesture(Qt::PinchGesture))) {
+        if (pinch->changeFlags().testFlag(QPinchGesture::ScaleFactorChanged))
+            zoom(1.0 / pinch->scaleFactor());
+        return true;
+    }
+    return false;
+}
+
+bool MandelbrotWidget::event(QEvent *event)
+{
+    if (event->type() == QEvent::Gesture)
+        return gestureEvent(static_cast<QGestureEvent*>(event));
+    return QWidget::event(event);
+}
+#endif
+//! [gesture1]

examples/corelib/threads/mandelbrot/mandelbrotwidget.h

@@ -0,0 +1,59 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef MANDELBROTWIDGET_H
+#define MANDELBROTWIDGET_H
+
+#include <QGestureEvent>
+#include <QPixmap>
+#include <QWidget>
+#include "renderthread.h"
+
+
+//! [0]
+class MandelbrotWidget : public QWidget
+{
+    Q_OBJECT
+
+public:
+    MandelbrotWidget(QWidget *parent = nullptr);
+
+protected:
+    QSize sizeHint() const override { return {1024, 768}; };
+    void paintEvent(QPaintEvent *event) override;
+    void resizeEvent(QResizeEvent *event) override;
+    void keyPressEvent(QKeyEvent *event) override;
+#if QT_CONFIG(wheelevent)
+    void wheelEvent(QWheelEvent *event) override;
+#endif
+    void mousePressEvent(QMouseEvent *event) override;
+    void mouseMoveEvent(QMouseEvent *event) override;
+    void mouseReleaseEvent(QMouseEvent *event) override;
+#ifndef QT_NO_GESTURES
+    bool event(QEvent *event) override;
+#endif
+
+private slots:
+    void updatePixmap(const QImage &image, double scaleFactor);
+    void zoom(double zoomFactor);
+
+private:
+    void scroll(int deltaX, int deltaY);
+#ifndef QT_NO_GESTURES
+    bool gestureEvent(QGestureEvent *event);
+#endif
+
+    RenderThread thread;
+    QPixmap pixmap;
+    QPoint pixmapOffset;
+    QPoint lastDragPos;
+    QString help;
+    QString info;
+    double centerX;
+    double centerY;
+    double pixmapScale;
+    double curScale;
+};
+//! [0]
+
+#endif // MANDELBROTWIDGET_H

examples/corelib/threads/mandelbrot/renderthread.cpp

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+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#include "renderthread.h"
+
+#include <QImage>
+
+#include <QElapsedTimer>
+#include <QTextStream>
+
+#include <cmath>
+
+int RenderThread::numPasses = 8;
+
+//! [0]
+RenderThread::RenderThread(QObject *parent)
+    : QThread(parent)
+{
+    for (int i = 0; i < ColormapSize; ++i)
+        colormap[i] = rgbFromWaveLength(380.0 + (i * 400.0 / ColormapSize));
+}
+//! [0]
+
+//! [1]
+RenderThread::~RenderThread()
+{
+    mutex.lock();
+    abort = true;
+    condition.wakeOne();
+    mutex.unlock();
+
+    wait();
+}
+//! [1]
+
+//! [2]
+void RenderThread::render(double centerX, double centerY, double scaleFactor,
+                          QSize resultSize, double devicePixelRatio)
+{
+    QMutexLocker locker(&mutex);
+
+    this->centerX = centerX;
+    this->centerY = centerY;
+    this->scaleFactor = scaleFactor;
+    this->devicePixelRatio = devicePixelRatio;
+    this->resultSize = resultSize;
+
+    if (!isRunning()) {
+        start(LowPriority);
+    } else {
+        restart = true;
+        condition.wakeOne();
+    }
+}
+//! [2]
+
+//! [3]
+void RenderThread::run()
+{
+    QElapsedTimer timer;
+    forever {
+        mutex.lock();
+        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();
+//! [3]
+
+//! [4]
+        int halfWidth = resultSize.width() / 2;
+//! [4] //! [5]
+        int halfHeight = resultSize.height() / 2;
+        QImage image(resultSize, QImage::Format_RGB32);
+        image.setDevicePixelRatio(devicePixelRatio);
+
+        int pass = 0;
+        while (pass < numPasses) {
+            const int MaxIterations = (1 << (2 * pass + 6)) + 32;
+            const int Limit = 4;
+            bool allBlack = true;
+
+            timer.restart();
+
+            for (int y = -halfHeight; y < halfHeight; ++y) {
+                if (restart)
+                    break;
+                if (abort)
+                    return;
+
+                auto scanLine =
+                        reinterpret_cast<uint *>(image.scanLine(y + halfHeight));
+                const double ay = centerY + (y * scaleFactor);
+
+                for (int x = -halfWidth; x < halfWidth; ++x) {
+                    const double ax = centerX + (x * scaleFactor);
+                    double a1 = ax;
+                    double b1 = ay;
+                    int numIterations = 0;
+
+                    do {
+                        ++numIterations;
+                        const double a2 = (a1 * a1) - (b1 * b1) + ax;
+                        const double b2 = (2 * a1 * b1) + ay;
+                        if ((a2 * a2) + (b2 * b2) > Limit)
+                            break;
+
+                        ++numIterations;
+                        a1 = (a2 * a2) - (b2 * b2) + ax;
+                        b1 = (2 * a2 * b2) + ay;
+                        if ((a1 * a1) + (b1 * b1) > Limit)
+                            break;
+                    } while (numIterations < MaxIterations);
+
+                    if (numIterations < MaxIterations) {
+                        *scanLine++ = colormap[numIterations % ColormapSize];
+                        allBlack = false;
+                    } else {
+                        *scanLine++ = qRgb(0, 0, 0);
+                    }
+                }
+            }
+
+            if (allBlack && pass == 0) {
+                pass = 4;
+            } else {
+                if (!restart) {
+                    QString message;
+                    QTextStream str(&message);
+                    str << " Pass " << (pass + 1) << '/' << numPasses
+                        << ", max iterations: " << MaxIterations << ", time: ";
+                    const auto elapsed = timer.elapsed();
+                    if (elapsed > 2000)
+                        str << (elapsed / 1000) << 's';
+                    else
+                        str << elapsed << "ms";
+                    image.setText(infoKey(), message);
+
+                    emit renderedImage(image, requestedScaleFactor);
+                }
+//! [5] //! [6]
+                ++pass;
+            }
+//! [6] //! [7]
+        }
+//! [7]
+
+//! [8]
+        mutex.lock();
+//! [8] //! [9]
+        if (!restart)
+            condition.wait(&mutex);
+        restart = false;
+        mutex.unlock();
+    }
+}
+//! [9]
+
+//! [10]
+uint RenderThread::rgbFromWaveLength(double wave)
+{
+    double r = 0;
+    double g = 0;
+    double b = 0;
+
+    if (wave >= 380.0 && wave <= 440.0) {
+        r = -1.0 * (wave - 440.0) / (440.0 - 380.0);
+        b = 1.0;
+    } else if (wave >= 440.0 && wave <= 490.0) {
+        g = (wave - 440.0) / (490.0 - 440.0);
+        b = 1.0;
+    } else if (wave >= 490.0 && wave <= 510.0) {
+        g = 1.0;
+        b = -1.0 * (wave - 510.0) / (510.0 - 490.0);
+    } else if (wave >= 510.0 && wave <= 580.0) {
+        r = (wave - 510.0) / (580.0 - 510.0);
+        g = 1.0;
+    } else if (wave >= 580.0 && wave <= 645.0) {
+        r = 1.0;
+        g = -1.0 * (wave - 645.0) / (645.0 - 580.0);
+    } else if (wave >= 645.0 && wave <= 780.0) {
+        r = 1.0;
+    }
+
+    double s = 1.0;
+    if (wave > 700.0)
+        s = 0.3 + 0.7 * (780.0 - wave) / (780.0 - 700.0);
+    else if (wave <  420.0)
+        s = 0.3 + 0.7 * (wave - 380.0) / (420.0 - 380.0);
+
+    r = std::pow(r * s, 0.8);
+    g = std::pow(g * s, 0.8);
+    b = std::pow(b * s, 0.8);
+    return qRgb(int(r * 255), int(g * 255), int(b * 255));
+}
+//! [10]

examples/corelib/threads/mandelbrot/renderthread.h

@@ -0,0 +1,57 @@
+// Copyright (C) 2021 The Qt Company Ltd.
+// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+
+#ifndef RENDERTHREAD_H
+#define RENDERTHREAD_H
+
+#include <QMutex>
+#include <QSize>
+#include <QThread>
+#include <QWaitCondition>
+
+QT_BEGIN_NAMESPACE
+class QImage;
+QT_END_NAMESPACE
+
+//! [0]
+class RenderThread : public QThread
+{
+    Q_OBJECT
+
+public:
+    RenderThread(QObject *parent = nullptr);
+    ~RenderThread();
+
+    void render(double centerX, double centerY, double scaleFactor, QSize resultSize,
+                double devicePixelRatio);
+
+    static void setNumPasses(int n) { numPasses = n; }
+
+    static QString infoKey() { return QStringLiteral("info"); }
+
+signals:
+    void renderedImage(const QImage &image, double scaleFactor);
+
+protected:
+    void run() override;
+
+private:
+    static uint rgbFromWaveLength(double wave);
+
+    QMutex mutex;
+    QWaitCondition condition;
+    double centerX;
+    double centerY;
+    double scaleFactor;
+    double devicePixelRatio;
+    QSize resultSize;
+    static int numPasses;
+    bool restart = false;
+    bool abort = false;
+
+    enum { ColormapSize = 512 };
+    uint colormap[ColormapSize];
+};
+//! [0]
+
+#endif // RENDERTHREAD_H