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Diffstat (limited to 'examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp')
| -rw-r--r-- | examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp b/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp new file mode 100644 index 0000000000..633d4a1ec5 --- /dev/null +++ b/examples/corelib/threads/mandelbrot/mandelbrotwidget.cpp @@ -0,0 +1,239 @@ +/**************************************************************************** +** +** Copyright (C) 2013 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the examples of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** You may use this file under the terms of the BSD license as follows: +** +** "Redistribution and use in source and binary forms, with or without +** modification, are permitted provided that the following conditions are +** met: +** * Redistributions of source code must retain the above copyright +** notice, this list of conditions and the following disclaimer. +** * Redistributions in binary form must reproduce the above copyright +** notice, this list of conditions and the following disclaimer in +** the documentation and/or other materials provided with the +** distribution. +** * Neither the name of Digia Plc and its Subsidiary(-ies) nor the names +** of its contributors may be used to endorse or promote products derived +** from this software without specific prior written permission. +** +** +** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR +** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT +** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, +** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT +** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, +** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY +** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT +** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE +** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include <QPainter> +#include <QKeyEvent> + +#include <math.h> + +#include "mandelbrotwidget.h" + + +//! [0] +const double DefaultCenterX = -0.637011f; +const double DefaultCenterY = -0.0395159f; +const double DefaultScale = 0.00403897f; + +const double ZoomInFactor = 0.8f; +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; + + connect(&thread, SIGNAL(renderedImage(QImage,double)), this, SLOT(updatePixmap(QImage,double))); + + setWindowTitle(tr("Mandelbrot")); +#ifndef QT_NO_CURSOR + setCursor(Qt::CrossCursor); +#endif + resize(550, 400); + +} +//! [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, tr("Rendering initial image, please wait...")); +//! [2] //! [3] + return; +//! [3] //! [4] + } +//! [4] + +//! [5] + if (curScale == pixmapScale) { +//! [5] //! [6] + painter.drawPixmap(pixmapOffset, pixmap); +//! [6] //! [7] + } else { +//! [7] //! [8] + 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; + + painter.save(); + painter.translate(newX, newY); + painter.scale(scaleFactor, scaleFactor); + QRectF exposed = painter.matrix().inverted().mapRect(rect()).adjusted(-1, -1, 1, 1); + painter.drawPixmap(exposed, pixmap, exposed); + painter.restore(); + } +//! [8] //! [9] + + QString text = tr("Use mouse wheel or the '+' and '-' keys to zoom. " + "Press and hold left mouse button to scroll."); + QFontMetrics metrics = painter.fontMetrics(); + int textWidth = metrics.width(text); + + painter.setPen(Qt::NoPen); + painter.setBrush(QColor(0, 0, 0, 127)); + painter.drawRect((width() - textWidth) / 2 - 5, 0, textWidth + 10, metrics.lineSpacing() + 5); + painter.setPen(Qt::white); + painter.drawText((width() - textWidth) / 2, metrics.leading() + metrics.ascent(), text); +} +//! [9] + +//! [10] +void MandelbrotWidget::resizeEvent(QResizeEvent * /* event */) +{ + thread.render(centerX, centerY, curScale, size()); +} +//! [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; + default: + QWidget::keyPressEvent(event); + } +} +//! [11] + +#ifndef QT_NO_WHEELEVENT +//! [12] +void MandelbrotWidget::wheelEvent(QWheelEvent *event) +{ + int numDegrees = event->delta() / 8; + double numSteps = numDegrees / 15.0f; + zoom(pow(ZoomInFactor, numSteps)); +} +//! [12] +#endif + +//! [13] +void MandelbrotWidget::mousePressEvent(QMouseEvent *event) +{ + if (event->button() == Qt::LeftButton) + lastDragPos = event->pos(); +} +//! [13] + +//! [14] +void MandelbrotWidget::mouseMoveEvent(QMouseEvent *event) +{ + if (event->buttons() & Qt::LeftButton) { + pixmapOffset += event->pos() - lastDragPos; + lastDragPos = event->pos(); + update(); + } +} +//! [14] + +//! [15] +void MandelbrotWidget::mouseReleaseEvent(QMouseEvent *event) +{ + if (event->button() == Qt::LeftButton) { + pixmapOffset += event->pos() - lastDragPos; + lastDragPos = QPoint(); + + int deltaX = (width() - pixmap.width()) / 2 - pixmapOffset.x(); + int deltaY = (height() - pixmap.height()) / 2 - pixmapOffset.y(); + scroll(deltaX, deltaY); + } +} +//! [15] + +//! [16] +void MandelbrotWidget::updatePixmap(const QImage &image, double scaleFactor) +{ + if (!lastDragPos.isNull()) + return; + + 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()); +} +//! [17] + +//! [18] +void MandelbrotWidget::scroll(int deltaX, int deltaY) +{ + centerX += deltaX * curScale; + centerY += deltaY * curScale; + update(); + thread.render(centerX, centerY, curScale, size()); +} +//! [18] |