利用QT中Qpainter画点，直线，弧线等简单图形

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MyImgTest.h:

#ifndef MYIMGTEST_H#define MYIMGTEST_H

#include

class MyImgTest : public QWidget{

//Q_OBJECTpublic:

MyImgTest(QWidget* parent = 0); ~MyImgTest();

void paintEvent(QPaintEvent *);};

#endif

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. 50. 51. 52. 53. . 55. 56. 57. 58. 59. 60. MyImgTest.cpp:

#include \"MyImgTest.h\"#include //#include //#include //#include

MyImgTest::MyImgTest(QWidget* parent) : QWidget(parent){

setFixedSize(360,360); //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.setStyle(Qt::DashLine);

pen.setColor(Qt::red); // 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(1, 1, 100, 100); //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::black); painter.setPen(pen);

bruch.setStyle(Qt::NoBrush); // 将画刷设置成null//fow what 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);

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// 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!\");}

1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. main.cpp：

#include #include \"MyImgTest.h\"

int main(int argc,char *argv[]){

QApplication app(argc,argv);

MyImgTest* widget = new MyImgTest(); widget->show();return app.exec();}

操作步骤：

1.qmake-qt4 -project2.qmake-qt43.make