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50
51#include "renderarea.h"
52
53#include <QPainter>
54#include <QPaintEvent>
55
56//! [0]
57RenderArea::RenderArea(QWidget *parent)
58 : QWidget(parent)
59{
60 QFont newFont = font();
61 newFont.setPixelSize(12);
62 setFont(newFont);
63
64 QFontMetrics fontMetrics(newFont);
65 xBoundingRect = fontMetrics.boundingRect(text: tr(s: "x"));
66 yBoundingRect = fontMetrics.boundingRect(text: tr(s: "y"));
67}
68//! [0]
69
70//! [1]
71void RenderArea::setOperations(const QList<Operation> &operations)
72{
73 this->operations = operations;
74 update();
75}
76//! [1]
77
78//! [2]
79void RenderArea::setShape(const QPainterPath &shape)
80{
81 this->shape = shape;
82 update();
83}
84//! [2]
85
86//! [3]
87QSize RenderArea::minimumSizeHint() const
88{
89 return QSize(182, 182);
90}
91//! [3]
92
93//! [4]
94QSize RenderArea::sizeHint() const
95{
96 return QSize(232, 232);
97}
98//! [4]
99
100//! [5]
101void RenderArea::paintEvent(QPaintEvent *event)
102{
103 QPainter painter(this);
104 painter.setRenderHint(hint: QPainter::Antialiasing);
105 painter.fillRect(event->rect(), QBrush(Qt::white));
106
107 painter.translate(dx: 66, dy: 66);
108//! [5]
109
110//! [6]
111 painter.save();
112 transformPainter(painter);
113 drawShape(painter);
114 painter.restore();
115//! [6]
116
117//! [7]
118 drawOutline(painter);
119//! [7]
120
121//! [8]
122 transformPainter(painter);
123 drawCoordinates(painter);
124}
125//! [8]
126
127//! [9]
128void RenderArea::drawCoordinates(QPainter &painter)
129{
130 painter.setPen(Qt::red);
131
132 painter.drawLine(x1: 0, y1: 0, x2: 50, y2: 0);
133 painter.drawLine(x1: 48, y1: -2, x2: 50, y2: 0);
134 painter.drawLine(x1: 48, y1: 2, x2: 50, y2: 0);
135 painter.drawText(x: 60 - xBoundingRect.width() / 2,
136 y: 0 + xBoundingRect.height() / 2, s: tr(s: "x"));
137
138 painter.drawLine(x1: 0, y1: 0, x2: 0, y2: 50);
139 painter.drawLine(x1: -2, y1: 48, x2: 0, y2: 50);
140 painter.drawLine(x1: 2, y1: 48, x2: 0, y2: 50);
141 painter.drawText(x: 0 - yBoundingRect.width() / 2,
142 y: 60 + yBoundingRect.height() / 2, s: tr(s: "y"));
143}
144//! [9]
145
146//! [10]
147void RenderArea::drawOutline(QPainter &painter)
148{
149 painter.setPen(Qt::darkGreen);
150 painter.setPen(Qt::DashLine);
151 painter.setBrush(Qt::NoBrush);
152 painter.drawRect(x: 0, y: 0, w: 100, h: 100);
153}
154//! [10]
155
156//! [11]
157void RenderArea::drawShape(QPainter &painter)
158{
159 painter.fillPath(path: shape, brush: Qt::blue);
160}
161//! [11]
162
163//! [12]
164void RenderArea::transformPainter(QPainter &painter)
165{
166 for (int i = 0; i < operations.size(); ++i) {
167 switch (operations[i]) {
168 case Translate:
169 painter.translate(dx: 50, dy: 50);
170 break;
171 case Scale:
172 painter.scale(sx: 0.75, sy: 0.75);
173 break;
174 case Rotate:
175 painter.rotate(a: 60);
176 break;
177 case NoTransformation:
178 default:
179 ;
180 }
181 }
182}
183//! [12]
184

source code of qtbase/examples/widgets/painting/transformations/renderarea.cpp