justhomework/SoftwareDesign/Lab5/lab5_1_painter/mainwindow.cpp

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <QColorDialog>
#include <QDebug>
#include <QDialog>
#include <QFileDialog>
#include <QFontDialog>
#include <QInputDialog>
#include <QMessageBox>
#include <QMouseEvent>
#include <QPainter>
#include <QProgressDialog>
bool enable = false;
bool drawing = false;
MainWindow::MainWindow(QWidget *parent)
    : QMainWindow(parent), ui(new Ui::MainWindow) {
  ui->setupUi(this);
  this->setProperty("canMove", false);
  resize(600, 500); //窗口大小设置为600*500
  pix = QPixmap(600, 500);
  pix.fill(Qt::white);
}

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

void MainWindow::on_styCor_triggered() //边框颜色
{
  QPainter pp(&pix); // 根据鼠标指针前后两个位置就行绘制直线
  pp.drawLine(
      lastPoint,
      endPoint); // 让前一个坐标值等于后一个坐标值，这样就能实现画出连续的线
  lastPoint = endPoint;
  QPainter painter(this);
  painter.drawPixmap(0, 0, pix);
}
void MainWindow::paintEvent(QPaintEvent *event) {
  QPainter painter(this);
  painter.drawLine(QPoint(100, 100), QPoint(200, 200));

  QPen pen(Qt::green, 5, Qt::DotLine, Qt::RoundCap, Qt::RoundJoin);
  painter.setPen(pen);
  QRectF rect(170.0, 140.0, 180.0, 60.0);
  int startAngle = 30 * 16;
  int spanAngle = 120 * 16;
  painter.drawArc(rect, startAngle, spanAngle);

  pen.setWidth(1);
  pen.setStyle(Qt::SolidLine);
  painter.setPen(pen);
  painter.drawRect(260, 220, 250, 240);
  QBrush brush(QColor(0, 0, 255), Qt::Dense4Pattern);
  painter.setBrush(brush);
  painter.drawEllipse(220, 220, 250, 150);

  static const QPointF points[4] = {
      QPointF(270.0, 180.0), QPointF(290.0, 110.0), QPointF(350.0, 130.0),
      QPointF(390.0, 170.0)};
  painter.drawPolygon(points, 4);

  painter.fillRect(QRect(10, 100, 150, 20), QBrush(Qt::darkYellow));
  painter.eraseRect(QRect(50, 0, 50, 120));
}
// void MainWindow::paintEvent(QPaintEvent *event) {
//   if (enable)
//     switch (drawStatus) {
//     case line:
//       QPainter pp(&pix); // 根据鼠标指针前后两个位置就行绘制直线
//       pp.drawLine(
//           lastPoint,
//           endPoint); //
//           让前一个坐标值等于后一个坐标值，这样就能实现画出连续的线
//       enable = false;
//     }
//   QPainter painter(this);
//   painter.drawPixmap(0, 0, pix);

//  drawStatus = idle;
//}
void MainWindow::drawLineTriger() { drawStatus = line; }

void MainWindow::on_drawLine_triggered() {
  enable = true;
  drawStatus = line;
}

void MainWindow::mousePressEvent(QMouseEvent *event) {

  if (event->button() == Qt::LeftButton) //鼠标左键按下
    if (drawing) {
      endPoint = event->pos();
      drawing = false;
      enable = true;
      update();
    } else {
      drawing = true;
      lastPoint = event->pos();
    }
}