绘图总结

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#ifndef RENDERAREA_H
#define RENDERAREA_H

#include <QWidget>

class RenderArea : public QWidget
{
    Q_OBJECT
public:
    explicit RenderArea(QWidget *parent = 0);
    void setDrawType(QString type);

protected:
    void paintEvent(QPaintEvent *);
private:
    QString drawType;

signals:

public slots:
};

#endif // RENDERAREA_H



#include "renderarea.h"
#include <QtWidgets>
#include <QPixmap>
#include <QPainter>


RenderArea::RenderArea(QWidget *parent) : QWidget(parent)
{

}

void RenderArea::setDrawType(QString type)
{
    drawType = type;
    update();
}

void RenderArea::paintEvent(QPaintEvent *)
{
    static const QPoint points[4] ={
      QPoint(10,8),
       QPoint(20,100),
        QPoint(80,30),
        QPoint(90,70)
    };

    QRect rect(10,20,80,60);

    QPainter painter(this);
    painter.setRenderHint(QPainter::Antialiasing,true);

    painter.fillRect(this->rect(),Qt::white); //设置背景

    painter.setBrush(Qt::red); //设置字体
    QFont font("Times",15,QFont::Bold);
    painter.setPen(Qt::blue); //设置画笔颜色
    painter.setFont(font);

    if(this->drawType == "Line")
    {
      //  painter.drawLine(10,10,100,10);
        painter.drawLine(rect.bottomLeft(),rect.topRight());
    }
    else if(drawType =="Points")
    {
        painter.drawPoints(points,4);

    }
    else if(drawType == "Polyline")
    {
        painter.drawPolyline(points,4);
    }
    else if(drawType == "Polygon")
    {
        painter.drawPolygon(points,4);
    }
    else if(drawType == "Rect")
    {
        painter.drawRect(30,40,120,80);
    }
    else if(drawType == "Ellipse")
    {
        painter.drawRect(30,40,120,80);
        painter.drawEllipse(30,40,120,80);
    }
    else if(drawType == "Arc")//圆弧
    {
        painter.drawArc(30,40,120,80,60*16,120*16);//坐标 长宽 起始角 圆弧角度
    }
    else if(drawType == "Chord")
    {
        painter.drawChord(30,40,120,80,60*16,120*16);
    }
    else if(drawType == "Pie")
    {
        painter.drawPie(30,40,120,80,60*16,120*16);
    }
    else if(drawType == "RoundedRect")
    {
        painter.drawRoundedRect(30,40,120,80,50,50,Qt::RelativeSize);//50 50 是弧形率大小
        painter.drawRoundedRect(160,40,120,80,100,100,Qt::RelativeSize);
       // painter.drawRoundedRect(160,40,120,80,100,100,Qt::AbsoluteSize);//相对
    }
    else if(drawType == "Text")
    {
        painter.drawText(30,40,120,80,Qt::AlignCenter,tr("Hello Qt!"));
    }
    else if(drawType == "Pixmap")
    {
        painter.drawPixmap(10,10,QPixmap(":/new/prefix1/8.png"));
    }
    else if(drawType == "Image")
    {
        QImage image("/mnt/Qt/test/untitled18/8.png");
        painter.drawImage(10,10,image);
    }
    else if(drawType == "Twoline")
    {
        QPainterPath path;
        path.moveTo(points[3]); //起点
        path.quadTo(points[2],points[1]);//一个控制点  终点

        painter.drawPath(path);
    }
    else if(drawType == "Threeline")
    {
        QPainterPath path;
        path.moveTo(points[0]);//起点
        path.cubicTo(points[1],points[2],points[3]); //两个控制点  终点

        painter.drawPath(path);

    }
    else if(drawType == "Path")
    {
        QPainterPath path;
        path.moveTo(20,80);
        path.lineTo(50,400);
        path.cubicTo(80,0,50,50,80,80);

        painter.drawPath(path);
    }
}

/*--------------------------------------------------------------------------------------*/


#ifndef WIDGET_H
#define WIDGET_H

#include <QWidget>
#include <QtWidgets>
#include "renderarea.h"


namespace Ui {
class Widget;
}

class Widget : public QWidget
{
    Q_OBJECT

public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();

private slots:
    void onRadioButtonClicked();

private:
    Ui::Widget *ui;

    QGroupBox *groupBox ;
    RenderArea *renderArea;
};

#endif // WIDGET_H


#include "widget.h"
#include "ui_widget.h"
#include <QObject>


static const QString drawType[16]={
  "Line" ,"Points","Polyline","Polygon",
    "Rect","Ellipse","Arc","Chord",
    "Pie","RoundedRect","Text","Pixmap",
    "Image","Twoline","Threeline","Path"
};

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);


    groupBox = new QGroupBox(this);

    QVBoxLayout *layout = new QVBoxLayout;
    for(int i=0;i<16;++i)
    {
        QRadioButton *radioButton = new QRadioButton(drawType[i]);
        connect(radioButton,SIGNAL(clicked(bool)),this,SLOT(onRadioButtonClicked()));
        layout->addWidget(radioButton);
    }
    groupBox->setLayout(layout);

    renderArea = new RenderArea(this);
    QGridLayout *gridLayout = new QGridLayout(this);
    gridLayout->setColumnStretch(0,3);
    gridLayout->setColumnStretch(1,1);
    gridLayout->addWidget(renderArea);
    gridLayout->addWidget(groupBox);
    setLayout(gridLayout);

    resize(500,500);
}


void Widget::onRadioButtonClicked()
{
    QRadioButton *sender = (QRadioButton*)QObject::sender();
    renderArea->setDrawType(sender->text());

}

Widget::~Widget()
{
    delete ui;
}


/*------------------------------------------------------------------------------------*/
#include "widget.h"
#include <QApplication>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();

    return a.exec();
}

 

转载于:https://my.oschina.net/osyunwei/blog/718327