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50
51 #include "mandelbrotwidget.h"
52 #include "mandelbrotwidget.moc"
53
54 #include <QtGui/QPainter>
55 #include <QtGui/QKeyEvent>
56
57 #include <math.h>
58
59 const double DefaultCenterX = -0.637011;
60 const double DefaultCenterY = -0.0395159;
61 const double DefaultScale = 0.00403897;
62
63 const double ZoomInFactor = 0.8;
64 const double ZoomOutFactor = 1 / ZoomInFactor;
65 const int ScrollStep = 20;
66
MandelbrotWidget(QWidget * parent)67 MandelbrotWidget::MandelbrotWidget(QWidget* parent)
68 : QWidget(parent)
69 , centerX(DefaultCenterX)
70 , centerY(DefaultCenterY)
71 , pixmapScale(DefaultScale)
72 , curScale(DefaultScale)
73 {
74 connect(&thread, &RenderThread::renderedImage, this, &MandelbrotWidget::updatePixmap);
75
76 setWindowTitle(tr("Mandelbrot"));
77 #if QT_CONFIG(cursor)
78 setCursor(Qt::CrossCursor);
79 #endif
80 resize(550, 400);
81 }
82
paintEvent(QPaintEvent *)83 void MandelbrotWidget::paintEvent(QPaintEvent* /* event */)
84 {
85 QPainter painter(this);
86 painter.fillRect(rect(), Qt::black);
87
88 if (pixmap.isNull())
89 {
90 painter.setPen(Qt::white);
91 painter.drawText(rect(), Qt::AlignCenter, tr("Rendering initial image, please wait..."));
92 return;
93 }
94
95 if (qFuzzyCompare(curScale, pixmapScale))
96 {
97 painter.drawPixmap(pixmapOffset, pixmap);
98 }
99 else
100 {
101 auto previewPixmap = qFuzzyCompare(pixmap.devicePixelRatioF(), qreal(1))
102 ? pixmap
103 : pixmap.scaled(pixmap.size() / pixmap.devicePixelRatioF(),
104 Qt::KeepAspectRatio, Qt::SmoothTransformation);
105 double scaleFactor = pixmapScale / curScale;
106 int newWidth = int(previewPixmap.width() * scaleFactor);
107 int newHeight = int(previewPixmap.height() * scaleFactor);
108 int newX = pixmapOffset.x() + (previewPixmap.width() - newWidth) / 2;
109 int newY = pixmapOffset.y() + (previewPixmap.height() - newHeight) / 2;
110
111 painter.save();
112 painter.translate(newX, newY);
113 painter.scale(scaleFactor, scaleFactor);
114
115 QRectF exposed = painter.transform().inverted().mapRect(rect()).adjusted(-1, -1, 1, 1);
116 painter.drawPixmap(exposed, previewPixmap, exposed);
117 painter.restore();
118 }
119
120 QString text = tr("Use mouse wheel or the '+' and '-' keys to zoom. "
121 "Press and hold left mouse button to scroll.");
122 QFontMetrics metrics = painter.fontMetrics();
123 int textWidth = metrics.horizontalAdvance(text);
124
125 painter.setPen(Qt::NoPen);
126 painter.setBrush(QColor(0, 0, 0, 127));
127 painter.drawRect((width() - textWidth) / 2 - 5, 0, textWidth + 10, metrics.lineSpacing() + 5);
128 painter.setPen(Qt::white);
129 painter.drawText((width() - textWidth) / 2, metrics.leading() + metrics.ascent(), text);
130 }
131
resizeEvent(QResizeEvent *)132 void MandelbrotWidget::resizeEvent(QResizeEvent* /* event */)
133 {
134 thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
135 }
136
keyPressEvent(QKeyEvent * event)137 void MandelbrotWidget::keyPressEvent(QKeyEvent* event)
138 {
139 switch (event->key())
140 {
141 case Qt::Key_Plus:
142 zoom(ZoomInFactor);
143 break;
144 case Qt::Key_Minus:
145 zoom(ZoomOutFactor);
146 break;
147 case Qt::Key_Left:
148 scroll(-ScrollStep, 0);
149 break;
150 case Qt::Key_Right:
151 scroll(+ScrollStep, 0);
152 break;
153 case Qt::Key_Down:
154 scroll(0, -ScrollStep);
155 break;
156 case Qt::Key_Up:
157 scroll(0, +ScrollStep);
158 break;
159 default:
160 QWidget::keyPressEvent(event);
161 }
162 }
163
164 #if QT_CONFIG(wheelevent)
wheelEvent(QWheelEvent * event)165 void MandelbrotWidget::wheelEvent(QWheelEvent* event)
166 {
167 const int numDegrees = event->angleDelta().y() / 8;
168 const double numSteps = numDegrees / double(15);
169 zoom(pow(ZoomInFactor, numSteps));
170 }
171 #endif
172
mousePressEvent(QMouseEvent * event)173 void MandelbrotWidget::mousePressEvent(QMouseEvent* event)
174 {
175 if (event->button() == Qt::LeftButton)
176 lastDragPos = event->pos();
177 }
178
mouseMoveEvent(QMouseEvent * event)179 void MandelbrotWidget::mouseMoveEvent(QMouseEvent* event)
180 {
181 if (event->buttons() & Qt::LeftButton)
182 {
183 pixmapOffset += event->pos() - lastDragPos;
184 lastDragPos = event->pos();
185 update();
186 }
187 }
188
mouseReleaseEvent(QMouseEvent * event)189 void MandelbrotWidget::mouseReleaseEvent(QMouseEvent* event)
190 {
191 if (event->button() == Qt::LeftButton)
192 {
193 pixmapOffset += event->pos() - lastDragPos;
194 lastDragPos = QPoint();
195
196 const auto pixmapSize = pixmap.size() / pixmap.devicePixelRatioF();
197 int deltaX = (width() - pixmapSize.width()) / 2 - pixmapOffset.x();
198 int deltaY = (height() - pixmapSize.height()) / 2 - pixmapOffset.y();
199 scroll(deltaX, deltaY);
200 }
201 }
202
updatePixmap(const QImage & image,double scaleFactor)203 void MandelbrotWidget::updatePixmap(const QImage& image, double scaleFactor)
204 {
205 if (!lastDragPos.isNull())
206 return;
207
208 pixmap = QPixmap::fromImage(image);
209 pixmapOffset = QPoint();
210 lastDragPos = QPoint();
211 pixmapScale = scaleFactor;
212 update();
213 }
214
zoom(double zoomFactor)215 void MandelbrotWidget::zoom(double zoomFactor)
216 {
217 curScale *= zoomFactor;
218 update();
219 thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
220 }
221
scroll(int deltaX,int deltaY)222 void MandelbrotWidget::scroll(int deltaX, int deltaY)
223 {
224 centerX += deltaX * curScale;
225 centerY += deltaY * curScale;
226 update();
227 thread.render(centerX, centerY, curScale, size(), devicePixelRatioF());
228 }
229