Qt之鼠标随手画及画多边形

首先介绍下项目结构，其中

class Figure

是

class FreeHand

和

class Polygon

的父类。

class ViewWidget

是画图区，继承自

QWidget

下面介绍具体代码：main.cpp

#include "Widgets/mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])

{

_CrtSetDbgFlag(_CrtSetDbgFlag(_CRTDBG_REPORT_FLAG) | _CRTDBG_LEAK_CHECK_DF);//内存检漏

QApplication a(argc, argv);

MainWindow main;

main.show();

return a.exec();

}

mainwindow.h

#ifndef MAINWINDOW_H

#define MAINWINDOW_H

#include "Widgets/viewwidget.h"

#include<QMainWindow>

#include<QAction>

#include<QWidget>

namespace Ui {

class MainWindow;

}

class MainWindow : public QMainWindow

{

Q_OBJECT

public:

explicit MainWindow(QWidget *parent = 0);

void Init();

void CreateButtons();

~MainWindow();

private:

QAction *hello_world_action_;

QToolBar *main_toolbar_;

QMenu *main_menu_;

ViewWidget* view_widget_;   //声明ViewWidget指针

Ui::MainWindow *ui;

};

#endif // MAINWINDOW_H

mainwindow.cpp

#include "Widgets/mainwindow.h"

#include "ui_mainwindow.h"

#include "Widgets/viewwidget.h"

#include<QAction>

#include<QWidget>

#include<QToolBar>

using namespace std;

MainWindow::MainWindow(QWidget *parent) :

QMainWindow(parent),ui(new Ui::MainWindow)

{

ui->setupUi(this);

Init();

}

void  MainWindow::Init()

{

view_widget_ = new ViewWidget();

setCentralWidget(view_widget_);

CreateButtons();

}

void MainWindow::CreateButtons()

{

hello_world_action_ = new QAction(QIcon(":/Mainwindow/picture/Polygon"), tr("&Polygon"), this);  //增加Polygon工具栏

connect(hello_world_action_, &QAction::triggered, view_widget_, &ViewWidget::set_figure_type_to_Polygon); //响应画多边形

main_menu_->addAction(hello_world_action_);

main_toolbar_->addSeparator();

main_toolbar_->addAction(hello_world_action_);

hello_world_action_ = new QAction(QIcon(":/Mainwindow/picture/FreeHand"), tr("&FreeHand"), this);  //增加FreeHand工具栏

connect(hello_world_action_, &QAction::triggered, view_widget_, &ViewWidget::set_figure_type_to_FreeHand); //响应画自由曲线

main_menu_->addAction(hello_world_action_);

main_toolbar_->addSeparator();

main_toolbar_->addAction(hello_world_action_);

hello_world_action_ = new QAction(QIcon(":/Mainwindow/picture/Delete"), tr("&Delete"), this);  //增加Delete工具栏

connect(hello_world_action_, &QAction::triggered, view_widget_, &ViewWidget::delete_last_action);

main_menu_->addAction(hello_world_action_);

main_toolbar_->addSeparator();

main_toolbar_->addAction(hello_world_action_);

hello_world_action_ = new QAction(tr("&About MiniDraw"), this);

connect(hello_world_action_, &QAction::triggered, view_widget_, &ViewWidget::set_figure_type_to_Rectangle);

}

MainWindow::~MainWindow()

{

delete ui;

}

viewwidget.h

#ifndef VIEWWIDGET_H

#define VIEWWIDGET_H

#include <QWidget>

#include <vector>

#include <QPainterPath>

#include <QAction>

#include "Resource/figure.h"

#include "Resource/polygon.h"

#include "Resource/freehand.h"

using namespace std;

enum FigureType;

class ViewWidget : public QWidget

{

Q_OBJECT

public:

enum FigureType

{

kDefault = 0, kLine = 1, kRectangle = 2, kEllipse = 3, kPolygon = 4, kFreeHand = 5,

};

FigureType figure_type_;

vector<Figure*> figure_array_;

vector<Line*>  line_array_;

explicit ViewWidget(QWidget *parent = 0);

void mousePressEvent(QMouseEvent *event);

void mouseMoveEvent(QMouseEvent *event);

void mouseReleaseEvent(QMouseEvent *event);

void paintEvent(QPaintEvent*);

void set_figure_type_to_Polygon();

void set_figure_type_to_FreeHand();

void delete_last_action();

~ViewWidget();

signals:

public slots:

private:

bool  draw_status_;  //绘制状态，true为绘制当前鼠标拖动的图元，false为不绘制

QPoint start_point_;  //当前图元的起始点

  QPoint end_point_;//当前图元的终点

QPoint current_point_;

vector<QPoint> points;

QPainterPath  *path;

};

#endif // VIEWWIDGET_H

viewwidget.cpp

#include "Widgets/viewwidget.h"

#include <QPainter>

#include <vector>

#include <QAction>

#include "Widgets/mainwindow.h"

#include <QMessageBox>

#include <QMouseEvent>

ViewWidget::ViewWidget(QWidget *parent) : QWidget(parent)

{

draw_status_ = false;  //初始状态为不绘制

this->path = NULL;

}

void ViewWidget::mousePressEvent(QMouseEvent* event)  //鼠标击发响应函数主体

{

if(Qt::LeftButton == event->button()) //判断鼠标是否左击

{

draw_status_ = true;   //设置绘制状态为——绘制

start_point_ = end_point_ = event->pos();  //将图元初始点设置为当前鼠标击发点

if(figure_type_ == kPolygon)

{

points.push_back(start_point_);

}

if(figure_type_ == kFreeHand)

{

path = new QPainterPath;

path->moveTo(event->pos());

}

}

}

void ViewWidget::mouseMoveEvent(QMouseEvent *event)  //鼠标移动响应函数主体

{

if(draw_status_)  //判断当前绘制状态

{

end_point_ = event->pos();  //若为真，则设置图元终止点为当前鼠标位置

}

if(figure_type_ == kFreeHand)

{

path->lineTo(event->pos());

}

}

void ViewWidget::mouseReleaseEvent(QMouseEvent *event) //鼠标释放响应函数主体

{

Figure* current_figure_ = NULL;

switch(figure_type_)

{

case kDefault:

break;

case kPolygon:

points.push_back(end_point_);

if(Qt::RightButton == event->button())

{

current_figure_ = new Polygon(points);

figure_array_.push_back(current_figure_);

points.clear();

}

break;

case kFreeHand:

current_figure_ = new FreeHand(*path);

figure_array_.push_back(current_figure_);

draw_status_ = false;

delete path;

path = NULL;

break;

default:

break;

}

current_figure_ = NULL;

}

void ViewWidget::paintEvent(QPaintEvent *)

{

QPainter painter(this); //定义painter

for(size_t i = 0; i < figure_array_.size(); i++)

{

if(figure_array_[i] != NULL)

figure_array_[i]->Draw(painter);

}

if(draw_status_)

{

switch(figure_type_)

{

case kDefault:

break;

case kFreeHand:

   std::cout<<"4"<<std::endl;

if(path != NULL)

painter.drawPath(*path);

break;

case kPolygon:

if(points.size()==0)

{

break;

}

QPoint pre = points[0];

for(int i=1;i < points.size();i++)

{

painter.drawLine(pre,points[i]);

pre = points[i];

}

break;

}

}

update();

}

void ViewWidget::set_figure_type_to_Polygon()

{

figure_type_ = kPolygon;

}

void ViewWidget::set_figure_type_to_FreeHand()

{

figure_type_ = kFreeHand;

}

void ViewWidget::delete_last_action()

{

if(!figure_array_.empty())

{

delete figure_array_.back();

figure_array_.pop_back();

}

}

ViewWidget::~ViewWidget()

{

for(size_t i = 0; i < figure_array_.size(); i++)

{

if(figure_array_[i])

{

delete figure_array_[i];

}

}

figure_array_.clear();

}

figure.h

#ifndef FIGURE_H

#define FIGURE_H

#include <QPainter>

class Figure

{

public:

 Figure();

virtual void Draw(QPainter &);

virtual ~Figure();

};

#endif // FIGURE_H

figure.cpp

#include "Resource/figure.h"

#include<QPainter>

Figure::Figure()

{

}

Figure::~Figure()

{

}

void Figure::Draw(QPainter &)

{

}

freehand.h

#ifndef FREEHAND_H

#define FREEHAND_H

#include"Resource/figure.h"

#include<QPainter>

#include<QPainterPath>

class FreeHand : public Figure

{

public:

FreeHand();

FreeHand( QPainterPath paths);

void Draw(QPainter &paint);

//void addPoint(QPoint point);

~FreeHand();

private:

QPainterPath path;

//  QVector<QPoint> points;

};

#endif // FREEHAND_H

freehand.cpp

#include "Resource/freehand.h"

#include <QPainter>

#include <QPainterPath>

#include <iostream>

FreeHand::FreeHand(QPainterPath paths)

{

path = paths;

}

void FreeHand::Draw(QPainter& paint)

{

paint.drawPath(path);

}

FreeHand::~FreeHand()

{

}

polygon.h

#ifndef POLYGON_H

#define POLYGON_H

#include "Resource/figure.h"

#include<vector>

using namespace std;

class Polygon : public Figure

{

public:

Polygon();

Polygon(const vector<QPoint> points);

void Draw(QPainter& paint);

~Polygon();

private:

vector<QPoint> point;

};

#endif // POLYGON_H

polygon.cpp

#include "Resource/polygon.h"

#include <QPainter>

#include <vector>

using namespace std;

Polygon::Polygon()

{

}

Polygon::Polygon(const vector<QPoint> points)

{

point = points;

}

void Polygon::Draw(QPainter &paint)

{

paint.drawPolygon(&point.at(0),point.size());

}

Polygon::~Polygon()

{

}

好了，以上是这个程序的代码，我是第一次写博客，也不知道怎么说，就直接贴代码了。