From 6371d623d2ae1945e26feabf16fecf68fb899a70 Mon Sep 17 00:00:00 2001 From: Friedemann Kleint Date: Wed, 7 Apr 2021 22:14:23 +0200 Subject: [PATCH] Brush up the mandelbrot example The example refines the image by running a number of passes with increasing number of iterations, which is not really visible to the user. Set an informational text string on the generated image which provides this information along with the elapsed time. The idea is to do the same to the corresponding Qt for Python example to have some sort of speed comparison for number crunching. Add a command line option for the number of passes. Make the window a bit larger to accommodate the information. Change-Id: I2afc1009ab53b580123d82a6aa645d9ffaa63ea2 Reviewed-by: Paul Wicking (cherry picked from commit 0e69349f6f8e9445877ea5b2105973115ad79cf7) --- examples/corelib/threads/mandelbrot/main.cpp | 34 ++++++++++++++++++- .../threads/mandelbrot/mandelbrotwidget.cpp | 16 ++++++--- .../threads/mandelbrot/mandelbrotwidget.h | 4 ++- .../threads/mandelbrot/renderthread.cpp | 28 ++++++++++++--- .../corelib/threads/mandelbrot/renderthread.h | 7 +++- 5 files changed, 77 insertions(+), 12 deletions(-) diff --git a/examples/corelib/threads/mandelbrot/main.cpp b/examples/corelib/threads/mandelbrot/main.cpp index 9832d55514e..19ea8cf417a 100644 --- a/examples/corelib/threads/mandelbrot/main.cpp +++ b/examples/corelib/threads/mandelbrot/main.cpp @@ -1,6 +1,6 @@ /**************************************************************************** ** -** Copyright (C) 2016 The Qt Company Ltd. +** Copyright (C) 2021 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. @@ -52,11 +52,43 @@ #include +#include + +#include +#include +#include +#include + //! [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; + const auto geometry = widget.screen()->availableGeometry(); + widget.resize((2 * geometry.size()) / 3); + const auto pos = (geometry.size() - widget.size()) / 2; + widget.move(geometry.topLeft() + QPoint(pos.width(), pos.height())); + widget.show(); return app.exec(); } diff --git a/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp b/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp index b0c3733b221..bb1f83482b0 100644 --- a/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp +++ b/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp @@ -1,6 +1,6 @@ /**************************************************************************** ** -** Copyright (C) 2016 The Qt Company Ltd. +** Copyright (C) 2021 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. @@ -73,6 +73,8 @@ MandelbrotWidget::MandelbrotWidget(QWidget *parent) : pixmapScale(DefaultScale), curScale(DefaultScale) { + help = tr("Use mouse wheel or the '+' and '-' keys to zoom. " + "Press and hold left mouse button to scroll."); connect(&thread, &RenderThread::renderedImage, this, &MandelbrotWidget::updatePixmap); @@ -80,8 +82,6 @@ MandelbrotWidget::MandelbrotWidget(QWidget *parent) : #if QT_CONFIG(cursor) setCursor(Qt::CrossCursor); #endif - resize(550, 400); - } //! [1] @@ -127,8 +127,9 @@ void MandelbrotWidget::paintEvent(QPaintEvent * /* event */) } //! [8] //! [9] - QString text = tr("Use mouse wheel or the '+' and '-' keys to zoom. " - "Press and hold left mouse button to scroll."); + QString text = help; + if (!info.isEmpty()) + text += ' ' + info; QFontMetrics metrics = painter.fontMetrics(); int textWidth = metrics.horizontalAdvance(text); @@ -169,6 +170,9 @@ void MandelbrotWidget::keyPressEvent(QKeyEvent *event) case Qt::Key_Up: scroll(0, +ScrollStep); break; + case Qt::Key_Q: + close(); + break; default: QWidget::keyPressEvent(event); } @@ -226,6 +230,8 @@ 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(); diff --git a/examples/corelib/threads/mandelbrot/mandelbrotwidget.h b/examples/corelib/threads/mandelbrot/mandelbrotwidget.h index cb409625355..956ffc10a8d 100644 --- a/examples/corelib/threads/mandelbrot/mandelbrotwidget.h +++ b/examples/corelib/threads/mandelbrot/mandelbrotwidget.h @@ -1,6 +1,6 @@ /**************************************************************************** ** -** Copyright (C) 2016 The Qt Company Ltd. +** Copyright (C) 2021 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. @@ -86,6 +86,8 @@ private: QPixmap pixmap; QPoint pixmapOffset; QPoint lastDragPos; + QString help; + QString info; double centerX; double centerY; double pixmapScale; diff --git a/examples/corelib/threads/mandelbrot/renderthread.cpp b/examples/corelib/threads/mandelbrot/renderthread.cpp index 4d2009471ca..1f2af3b999b 100644 --- a/examples/corelib/threads/mandelbrot/renderthread.cpp +++ b/examples/corelib/threads/mandelbrot/renderthread.cpp @@ -1,6 +1,6 @@ /**************************************************************************** ** -** Copyright (C) 2016 The Qt Company Ltd. +** Copyright (C) 2021 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. @@ -51,8 +51,14 @@ #include "renderthread.h" #include + +#include +#include + #include +int RenderThread::numPasses = 8; + //! [0] RenderThread::RenderThread(QObject *parent) : QThread(parent) @@ -98,6 +104,7 @@ void RenderThread::render(double centerX, double centerY, double scaleFactor, //! [3] void RenderThread::run() { + QElapsedTimer timer; forever { mutex.lock(); const double devicePixelRatio = this->devicePixelRatio; @@ -116,13 +123,14 @@ void RenderThread::run() QImage image(resultSize, QImage::Format_RGB32); image.setDevicePixelRatio(devicePixelRatio); - const int NumPasses = 8; int pass = 0; - while (pass < NumPasses) { + 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; @@ -165,8 +173,20 @@ void RenderThread::run() if (allBlack && pass == 0) { pass = 4; } else { - if (!restart) + 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; } diff --git a/examples/corelib/threads/mandelbrot/renderthread.h b/examples/corelib/threads/mandelbrot/renderthread.h index 6174e0ed3d5..7bbd9ae0566 100644 --- a/examples/corelib/threads/mandelbrot/renderthread.h +++ b/examples/corelib/threads/mandelbrot/renderthread.h @@ -1,6 +1,6 @@ /**************************************************************************** ** -** Copyright (C) 2016 The Qt Company Ltd. +** Copyright (C) 2021 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. @@ -72,6 +72,10 @@ public: 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); @@ -88,6 +92,7 @@ private: double scaleFactor; double devicePixelRatio; QSize resultSize; + static int numPasses; bool restart = false; bool abort = false;