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/****************************************************************************
**
** Copyright (C) 2016 The Qt Company Ltd.
** Contact: https://www.qt.io/licensing/
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** Commercial License Usage
** Licensees holding valid commercial Qt licenses may use this file in
** accordance with the commercial license agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and The Qt Company. For licensing terms
** and conditions see https://www.qt.io/terms-conditions. For further
** information use the contact form at https://www.qt.io/contact-us.
**
** BSD License Usage
** Alternatively, 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 The Qt Company Ltd 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 "mandelbrotwidget.h"
#include "mandelbrotwidget.moc"
#include <QtGui/QPainter>
#include <QtGui/QKeyEvent>
#include <math.h>
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;
MandelbrotWidget::MandelbrotWidget(QWidget* parent)
: QWidget(parent)
, centerX(DefaultCenterX)
, centerY(DefaultCenterY)
, pixmapScale(DefaultScale)
, curScale(DefaultScale)
{
connect(&thread, &RenderThread::renderedImage, this, &MandelbrotWidget::updatePixmap);
setWindowTitle(tr("Mandelbrot"));
#if QT_CONFIG(cursor)
setCursor(Qt::CrossCursor);
#endif
resize(550, 400);
}
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..."));
return;
}
if (qFuzzyCompare(curScale, pixmapScale))
{
painter.drawPixmap(pixmapOffset, pixmap);
}
else
{
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(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();
}
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);
}
void MandelbrotWidget::resizeEvent(QResizeEvent* /* event */)
{
thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
}
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);
}
}
#if QT_CONFIG(wheelevent)
void MandelbrotWidget::wheelEvent(QWheelEvent* event)
{
const int numDegrees = event->angleDelta().y() / 8;
const double numSteps = numDegrees / double(15);
zoom(pow(ZoomInFactor, numSteps));
}
#endif
void MandelbrotWidget::mousePressEvent(QMouseEvent* event)
{
if (event->button() == Qt::LeftButton)
lastDragPos = event->pos();
}
void MandelbrotWidget::mouseMoveEvent(QMouseEvent* event)
{
if (event->buttons() & Qt::LeftButton)
{
pixmapOffset += event->pos() - lastDragPos;
lastDragPos = event->pos();
update();
}
}
void MandelbrotWidget::mouseReleaseEvent(QMouseEvent* event)
{
if (event->button() == Qt::LeftButton)
{
pixmapOffset += event->pos() - lastDragPos;
lastDragPos = QPoint();
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);
}
}
void MandelbrotWidget::updatePixmap(const QImage& image, double scaleFactor)
{
if (!lastDragPos.isNull())
return;
pixmap = QPixmap::fromImage(image);
pixmapOffset = QPoint();
lastDragPos = QPoint();
pixmapScale = scaleFactor;
update();
}
void MandelbrotWidget::zoom(double zoomFactor)
{
curScale *= zoomFactor;
update();
thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
}
void MandelbrotWidget::scroll(int deltaX, int deltaY)
{
centerX += deltaX * curScale;
centerY += deltaY * curScale;
update();
thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
}
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