自学qt之QPainter

drawPoint() drawArc()
drawLine() drawChord()
drawPolyline()drawPie()
drawPoints()drawText()
drawLines()drawPixmap()
drawPolygon()drawPath()
drawRect()
drawRoundRect()
drawEllipse()

protected:
void painEvent(QPainEvent *);//继承下来的函数
void painEvent(QPointEvent *)
{
QPainter painter(this);//在哪里画
painter.drawRect(100,100,200,200);//左上角，宽度和高度
painter.drawLine(50,50,500,50);//起点和终点
painter.drawLine(QPoint(20,30),QPoint(20,400));
painter.setBrush(QBrush:(Qt::blue));//设置画刷
painter.setBrush(QBrush(Qt::white));
painter.drawRect(this->rect());//画背景
painter.setBrush(QBrush:(Qt::red));
painter.drawEllipse(Qpoint(200,400),100,70);//画椭圆
QPixmap pix(“dog.jpg”);
painter.drawPixmap(400,100,pix);
painter.drawText(400,420,”软件开发”);
QFont font；
font.setFamily(“黑体”)；
font.setPointSize(22);
painter.setFont(font);
painter.drawText(400,420,”软件开发”)；
painter.setPen(QPen(Qt::green));//一开始设置不是最后
}

enum shape{Line,Ellipse,Pie};shape drawShape;//枚举变量this->drawShape=Widget::line;painter.setRenderHint(Qpainter::Antialiasing,true);//反走样painter.setPen(QPen(Qt::red,20,QT::SolidLine));//实心线  默认方帽子painter.setPen(QPen(Qt::red,20,Qt::SolidLine,Qt::RoundCap));//加上圆帽子painter.setPen(QPen(Qt::red,20,Qt::SolidLine,Qt::SquareCap));//加上方帽子update();//切记这个函数  槽函数里面这个Qt::DashDotLine;//点划线painter.drawPie(80,80,400,240,60*16,270*16);//最后两个是角度，画饼  一定要乘16  MiterJoin     尖的连接的地方Qt::RoundJoin,//圆的连接地方 Qt::BevelJoin;//平的

painter.setBrush(QBrush(Qt::green,Qt::VerPattern));//垂直线做画刷                                  Qt::HorPattern;//横线                                  Qt::BDiagPattern;//后斜线                                  Qt::FDiagPattern;//前斜线                                  Qt::Den//各种线性渐变 QLinearGradient辐射渐变 QredialGradient锥形渐变 QConicalGradient纹理画刷

#ifndef RENDERLABEL_H#define RENDERLABEL_H#include <QLabel>clasee RenderLabel:public QLabel{  Q_OBJECT    enum BrudhPattern{LinearGradient,RadialGradient,ConicalGradient,TexturePattern};  public:    RenderLabel(QWidget *parent=0);    void setBrushPattern(BrushPattern brushPattern );  protected:    void painEvent(QPaintEvent *);  protected:    BrushPattern brushPattern;}RenderLabel::RenderLabel(QWidget *parent):QLabel(parent){}this->renderLabel=new RenderLabel(this);this->renderLabel->setGeometry(0,0,500,500);//定位在哪void RenderLabel::setBrushPattern(BrushPattern brushPattern){  this->brushPattern=brushPattern;}void RenderLabel::paintEvent(QPaintEvent *){    QLinearGradient linearGradient(10,10,400,200);//大小和范围 左上角 宽度和高度    linearGradient.setColorAt(0,Qt::red);    linearGradient.setColorAt(0.3,Qt::blue);    linearGradient.setColorAt(1,Qt::yellow);    painter.setBrush(linearGradient);}painter.setBrush(QBrush(QPixmap(":/images/tt.jpg")));painter.drawEllipse(10,10,500,500);//图片当画刷

QPainter painter(this);painter.fillRect(rect(),Qt::white);//画背景