| ingenious |
2015-11-07 22:21 |
Qt5实现类似cad画图功能
[attachment=14496][attachment=14497][attachment=14498]包含三个文件Draw.pro MyWidget .h MyWidget.cpp
Draw.pro:
QT += core widgets gui
HEADERS += \ MyWidget.h
SOURCES += \ MyWidget.cpp
MyWidget .h :
#ifndef MYWIDGET_H#define MYWIDGET_H
#include <QWidget>
typedef struct MyLine{ QPoint startPnt; QPoint endPnt;}myLine;
class MyWidget : public QWidget{ Q_OBJECTpublic: explicit MyWidget(QWidget *parent = 0);
void paintEvent(QPaintEvent *);
void mouseMoveEvent(QMouseEvent *); void mousePressEvent(QMouseEvent *); void mouseReleaseEvent(QMouseEvent *);
signals:
public slots:
public: //QVector< QVector<QPoint> > lines;
QPoint startPnt; QPoint endPnt;
QVector<myLine*> lines; bool isPressed;
};
#endif // MYWIDGET_H
MyWidget.cpp
#include "MyWidget.h"#include <QPainter>#include <QPixmap>#include <QMouseEvent>#include <QDebug>
MyWidget::MyWidget(QWidget *parent) : QWidget(parent){
}
void MyWidget::paintEvent(QPaintEvent *) //执行过程painting-pressed-moved-painting-released{
QPainter painter(this); if(startPnt != endPnt) painter.drawLine(startPnt, endPnt);
for(int i = 0;i<lines.size();i++) { //重绘时需要画出所有线 myLine* pLine = lines; painter.drawLine(pLine->startPnt,pLine->endPnt); }}
void MyWidget::mouseMoveEvent(QMouseEvent *ev){
if(isPressed==false)//鼠标移动，但是鼠标是松开的 { endPnt = ev->pos(); update(); qDebug()<<ev->pos(); } else { setMouseTracking(false); }}void MyWidget::mousePressEvent(QMouseEvent *ev){ isPressed=true; if (hasMouseTracking()) { myLine* line = new myLine; line->startPnt = startPnt; line->endPnt = endPnt; this->lines.push_back(line);
setMouseTracking(false); } else { startPnt = endPnt = ev->pos(); setMouseTracking(true);//默认情况下mouse tracking是false的，由于左键被按下之后，被设为了true，所以在上面要被设为false update(); }}
void MyWidget::mouseReleaseEvent(QMouseEvent *ev){
isPressed = false; update(); qDebug()<<lines.size();}
#include <QApplication>int main(int argc, char** argv){ QApplication app(argc, argv);
MyWidget w; w.show();
return app.exec();}
上面的代码，实现了鼠标点击两点画直线，但我想对上面实现改进：
如何才能实现画多条折线，每画完一条折线后，用滚轮键结束命令，总之一句话就是类似于cad画直线的操作，最好也要像cad一样，弹出一个LineEdit，在里面输入点的位置画直线。希望各路大神，积极发表意见，感激不尽，这样每个人都能学到知识！
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