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50
51
52#include "paintarea.h"
53#include "interfaces.h"
54
55#include <QMouseEvent>
56#include <QPainter>
57
58PaintArea::PaintArea(QWidget *parent) : QWidget(parent)
59{
60 setAttribute(Qt::WA_StaticContents);
61 setAttribute(Qt::WA_OpaquePaintEvent);
62
63 theImage.fill(pixel: qRgb(r: 255, g: 255, b: 255));
64}
65
66bool PaintArea::openImage(const QString &fileName)
67{
68 QImage image;
69 if (!image.load(fileName))
70 return false;
71
72 setImage(image);
73 return true;
74}
75
76bool PaintArea::saveImage(const QString &fileName, const char *fileFormat)
77{
78 return theImage.save(fileName, format: fileFormat);
79}
80
81void PaintArea::setImage(const QImage &image)
82{
83 theImage = image.convertToFormat(f: QImage::Format_RGB32);
84 update();
85 updateGeometry();
86}
87
88void PaintArea::insertShape(const QPainterPath &path)
89{
90 pendingPath = path;
91#ifndef QT_NO_CURSOR
92 setCursor(Qt::CrossCursor);
93#endif
94}
95
96void PaintArea::setBrushColor(const QColor &color)
97{
98 this->color = color;
99}
100
101void PaintArea::setBrushWidth(int width)
102{
103 thickness = width;
104}
105
106//! [0]
107void PaintArea::setBrush(BrushInterface *brushInterface, const QString &brush)
108{
109 this->brushInterface = brushInterface;
110 this->brush = brush;
111}
112//! [0]
113
114QSize PaintArea::sizeHint() const
115{
116 return theImage.size();
117}
118
119void PaintArea::paintEvent(QPaintEvent * /* event */)
120{
121 QPainter painter(this);
122 painter.drawImage(p: QPoint(0, 0), image: theImage);
123}
124
125void PaintArea::mousePressEvent(QMouseEvent *event)
126{
127 if (event->button() == Qt::LeftButton) {
128 if (!pendingPath.isEmpty()) {
129 QPainter painter(&theImage);
130 setupPainter(painter);
131
132 const QRectF boundingRect = pendingPath.boundingRect();
133 QLinearGradient gradient(boundingRect.topRight(),
134 boundingRect.bottomLeft());
135 gradient.setColorAt(pos: 0.0, color: QColor(color.red(), color.green(),
136 color.blue(), 63));
137 gradient.setColorAt(pos: 1.0, color: QColor(color.red(), color.green(),
138 color.blue(), 191));
139 painter.setBrush(gradient);
140 painter.translate(offset: event->pos() - boundingRect.center());
141 painter.drawPath(path: pendingPath);
142
143 pendingPath = QPainterPath();
144#ifndef QT_NO_CURSOR
145 unsetCursor();
146#endif
147 update();
148 } else {
149 if (brushInterface) {
150 QPainter painter(&theImage);
151 setupPainter(painter);
152 const QRect rect = brushInterface->mousePress(brush, painter,
153 pos: event->pos());
154 update(rect);
155 }
156
157 lastPos = event->pos();
158 }
159 }
160}
161
162//! [1]
163void PaintArea::mouseMoveEvent(QMouseEvent *event)
164{
165 if ((event->buttons() & Qt::LeftButton) && lastPos != QPoint(-1, -1)) {
166 if (brushInterface) {
167 QPainter painter(&theImage);
168 setupPainter(painter);
169 const QRect rect = brushInterface->mouseMove(brush, painter, oldPos: lastPos,
170 newPos: event->pos());
171 update(rect);
172 }
173
174 lastPos = event->pos();
175 }
176}
177//! [1]
178
179void PaintArea::mouseReleaseEvent(QMouseEvent *event)
180{
181 if (event->button() == Qt::LeftButton && lastPos != QPoint(-1, -1)) {
182 if (brushInterface) {
183 QPainter painter(&theImage);
184 setupPainter(painter);
185 QRect rect = brushInterface->mouseRelease(brush, painter,
186 pos: event->pos());
187 update(rect);
188 }
189
190 lastPos = QPoint(-1, -1);
191 }
192}
193
194void PaintArea::setupPainter(QPainter &painter)
195{
196 painter.setRenderHint(hint: QPainter::Antialiasing, on: true);
197 painter.setPen(QPen(color, thickness, Qt::SolidLine, Qt::RoundCap,
198 Qt::RoundJoin));
199}
200

source code of qtbase/examples/widgets/tools/plugandpaint/app/paintarea.cpp