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| |
| #include "mandelbrotwidget.h" |
| |
| #include <QPainter> |
| #include <QKeyEvent> |
| |
| #include <math.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, &RenderThread::renderedImage, |
| this, &MandelbrotWidget::updatePixmap); |
| |
| 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.transform().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.horizontalAdvance(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] |
| |
| #if QT_CONFIG(wheelevent) |
| //! [12] |
| void MandelbrotWidget::wheelEvent(QWheelEvent *event) |
| { |
| int numDegrees = event->angleDelta().y() / 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] |