基于qt draw的输入坐标轴显示图像的demo

Posted 2021-10-22 狗蛋儿l

ui把外框放到最大

然后添加这些元素
头文件：

#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QTimeLine>
#include <QPainter>
#include <QDateTime>
#include <string>
#include<QTextEdit>
#include <QMainWindow>
#include <QWidget>
#include <QPaintEvent>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
    Q_OBJECT

public:
    MainWindow(QWidget *parent = nullptr);
    ~MainWindow();

private slots:
    void on_pushButton_rectangle_clicked();

    void on_pushButton_circle_clicked();

    void on_pushButton_triangle_clicked();

    void on_pushButton_line_clicked();

protected:
    void paintEvent(QPaintEvent *);
private:
    Ui::MainWindow *ui;
       int w=100,h=100;
       int x=20,y=20;
       bool crcle=0;//标志是否点击按钮
       bool squer=0;
       bool Polygon=0;
       bool line=0;
     };
#endif // MAINWINDOW_H

窗口实现：

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QPainter>
#include <QTime>
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}

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

void MainWindow::paintEvent(QPaintEvent *)
{
    QPainter painter(this);
    if(squer==1)
    {
        painter.drawRect(x,y,w,h);
        squer=0;
    }
    if(crcle==1)
    {
        painter.drawEllipse(x,y,w,h);
        crcle=0;
    }
    if(Polygon==1)
    {
        QPointF points[4] = {QPointF(x, y+h), QPointF((x+w)/2, y),QPointF(x+w, y+h)};
        painter.drawPolygon(points,3);
        Polygon=0;
    }
    if(line==1)
    {
        // 反走样 防止绘制出来的线条出现锯齿
            painter.setRenderHint(QPainter::Antialiasing, true);
            // 绘制直线
            painter.drawLine(QPointF(x, y), QPointF(x+w, y+w));
            line=0;
    }
}


void MainWindow::on_pushButton_rectangle_clicked()
{
    x=(ui->lineEdit_x->text()).toInt();
    y=(ui->lineEdit_y->text()).toInt();
    w=(ui->lineEdit_w->text()).toInt();
    h=(ui->lineEdit_h->text()).toInt();
    squer=1;

    QWidget::update();
}

void MainWindow::on_pushButton_circle_clicked()
{
    x=(ui->lineEdit_x->text()).toInt();
    y=(ui->lineEdit_y->text()).toInt();
    w=(ui->lineEdit_w->text()).toInt();
    h=(ui->lineEdit_h->text()).toInt();
    crcle=1;
    QWidget::update();
}



void MainWindow::on_pushButton_triangle_clicked()
{
    x=(ui->lineEdit_x->text()).toInt();
    y=(ui->lineEdit_y->text()).toInt();
    w=(ui->lineEdit_w->text()).toInt();
    h=(ui->lineEdit_h->text()).toInt();
    Polygon=1;
    QWidget::update();
}



void MainWindow::on_pushButton_line_clicked()
{
    x=(ui->lineEdit_x->text()).toInt();
    y=(ui->lineEdit_y->text()).toInt();
    w=(ui->lineEdit_w->text()).toInt();
    h=(ui->lineEdit_h->text()).toInt();
    line=1;
    QWidget::update();
}

main主文件不变
最后成品：

码云代码