(转载)QPainter的用法
(转载)http://www.devdiv.com/home.php?mod=space&uid=1459&do=blog&id=1273
.h
#define MYIMGTEST_H_
#include <QWidget>
class MyImgTest : public QWidget
{
Q_OBJECT
public:
MyImgTest(QWidget* parent = 0);
~MyImgTest();
void paintEvent(QPaintEvent *);
};
#endif /* MYIMGTEST_H_ */
.cpp
#include "MyImgTest.h"
#include <QPainter>
#include <QRect>
#include <QPointF>
#include <QLineF>
MyImgTest::MyImgTest(QWidget* parent) : QWidget(parent)
{
setFixedSize(360,485); //固定大小
setWindowTitle("Hello DevDiv!");
}
MyImgTest::~MyImgTest()
{
}
void MyImgTest::paintEvent(QPaintEvent *)
{
// 画一条直线
QPainter painter(this); // 创建QPainter一个对象
QPen pen;
pen.setColor(Qt::yellow); // 设置画笔为黄色
painter.setPen(pen); // 设置画笔
painter.drawLine(rect().topLeft(), rect().bottomRight());
// 画一个空心矩形
pen.setColor(Qt::darkRed);
painter.setPen(pen);
painter.drawRect(QRect(1, 1, 100, 100));
// 画一个实心矩形
QBrush bruch(Qt::FDiagPattern); // 画刷
painter.setBrush(bruch); // 设置画刷
painter.drawRect(QRect(105, 1, 100, 100));
// 画一个多点线
pen.setColor(Qt::white);
painter.setPen(pen);
bruch.setStyle(Qt::NoBrush); // 将画刷设置成null
painter.setBrush(bruch);
static const QPointF points[4] = {QPointF(210.0, 1), QPointF(220.0, 50.3), QPointF(300, 100.4), QPointF(260.4, 120.0)};
painter.drawPolyline(points, 4);
// 画多个点
QPointF pointf[10];
for (int i=0; i<10; ++i)
{
pointf[i].setX(2.0+i*10.0);
pointf[i].setY(130.0);
}
painter.drawPoints(pointf, 10);
// 画多条线
QLineF linef[5];
for (int j=0; j<5; ++j)
{
linef[j].setP1(QPointF(110.9+j*10, 120.0));
linef[j].setP2(QPointF(120.8+j*12, 200.0));
}
painter.drawLines(linef, 5);
// 画一个多边形
QPolygonF polygon;
polygon << QPointF(200.0, 120.0) << QPointF(230.0, 130.0) << QPointF(260.0, 180.0) << QPointF(200.0, 200.0);
bruch.setStyle(Qt::CrossPattern);
painter.setBrush(bruch);
painter.drawPolygon(polygon, Qt::WindingFill);
// 画一个圆角矩形
QRectF rectangle(290.0, 110.0, 50, 50);
bruch.setStyle(Qt::SolidPattern);
painter.setBrush(bruch);
painter.drawRoundedRect(rectangle, 20.0, 15.0);
// 画一个QString
painter.drawText(50, 300, "Hello DevDiv!");
}
main.cpp
MyImgTest* widget = new MyImgTest();
widget->show();