Qt第十八天
Graphics View绘图程序实例
**可以创建矩形,椭圆,圆,三角形,梯形,直线,文字等基本图形项
每个图形项可以被选择,拖动,放缩,旋转
图形项的前置和后置,组合和打散
双击,单击图形项会有不同的显示
键盘的按键也可以对图形项操作
mainwindow.h
#ifndef MAINWINDOW_H
#define MAINWINDOW_H
#include <QMainWindow>
#include<QGraphicsScene>
#include<QLabel>
#include<QGraphicsView>
#include<QTime>
#include<QPointF>
#include<QGraphicsItem>
#include<QFontDialog>
#include<QColorDialog>
#include<QGraphicsItemGroup>
#include<QGraphicsEllipseItem>
#include<QInputDialog>
#include<QGraphicsTextItem>
namespace Ui {
class MainWindow;
}
class MainWindow : public QMainWindow
{
Q_OBJECT
private:
static const int ItemId=1;//图形项自定义数据的Key
static const int ItemDesciption=2;//图形项自定义数据的Key
int seqNum=0;//用于图形项的编号,每个图形项有一个编号
int frontZ=0;//用于bring to front
//数值越大,越在前面显示
int backZ=0;//用于bring to back
//数值越小,越在后面显示
QGraphicsScene *scene;
QLabel *labViewCord;//用于记录View坐标
QLabel *labSceneCord;//用于记录Scene坐标
QLabel *labItemCord;//用于记录Item坐标
QLabel *labItemInfo;//用于距离Item信息
public:
explicit MainWindow(QWidget *parent = nullptr);
~MainWindow();
private slots:
void on_mouseMovePoint(QPoint point);//鼠标移动
void on_mouseClicked(QPoint point);//鼠标单击
void on_mouseDoubleClick(QPoint point);//鼠标双击
void on_keyPress(QKeyEvent *event);//按键事件
void on_actZoomIn_triggered();
void on_actZoomOut_triggered();
void on_actRotateLeft_triggered();
void on_actRotateRight_triggered();
void on_actRestore_triggered();
void on_actEdit_Front_triggered();
void on_actEdit_Back_triggered();
void on_actGroup_triggered();
void on_actGroupBreak_triggered();
void on_actEdit_Delete_triggered();
void on_actItem_Ellipse_triggered();
void on_actItem_Rect_triggered();
void on_actItem_Circle_triggered();
void on_actItem_Triangle_triggered();
void on_actItem_Polygon_triggered();
void on_actItem_Line_triggered();
void on_actItem_Text_triggered();
private:
Ui::MainWindow *ui;
};
#endif // MAINWINDOW_H
qwgraphicsview.h
#ifndef QWGRAPHICSVIEW_H
#define QWGRAPHICSVIEW_H
#include <QGraphicsView>
#include<QObject>
#include<QMouseEvent>
#include<QKeyEvent>
#include<QPoint>
class QWGraphicsView : public QGraphicsView
{
Q_OBJECT
public:
QWGraphicsView(QWidget *parent=nullptr);
protected:
void mouseMoveEvent(QMouseEvent *event);
void mousePressEvent(QMouseEvent *event);
void mouseDoubleClickEvent(QMouseEvent *event);
void keyPressEvent(QKeyEvent *event);
signals:
void mouseMovePoint(QPoint point);//鼠标移动
void mouseClicked(QPoint point);//鼠标单击
void mouseDoubleClicked(QPoint point);//鼠标双击
void keyPress(QKeyEvent *event);//按键事件
};
#endif // QWGRAPHICSVIEW_H
mainwindow.cpp
#include "mainwindow.h"
#include "ui_mainwindow.h"
MainWindow::MainWindow(QWidget *parent) :
QMainWindow(parent),
ui(new Ui::MainWindow)
{
ui->setupUi(this);
//创建状态栏标签
labViewCord=new QLabel("View 坐标:");
labViewCord->setMinimumWidth(150);
ui->statusBar->addWidget(labViewCord);
labSceneCord=new QLabel("Scene 坐标:");
labSceneCord->setMinimumWidth(150);
ui->statusBar->addWidget(labSceneCord);
labItemCord=new QLabel("Item 坐标:");
labItemCord->setMinimumWidth(150);
ui->statusBar->addWidget(labItemCord);
labItemInfo=new QLabel("ItemInfo: ");
labItemInfo->setMinimumWidth(200);
ui->statusBar->addWidget(labItemInfo);
//创建QGraphicsScene
scene=new QGraphicsScene(-300,-200,600,200);
ui->View->setScene(scene); //与view关联
ui->View->setDragMode(QGraphicsView::RubberBandDrag);//拖放模式,相当于视图选择
ui->View->setCursor(Qt::CrossCursor); //设置鼠标
ui->View->setMouseTracking(true); //窗口部件跟踪鼠标
this->setCentralWidget(ui->View);
//关联
QObject::connect(ui->View,SIGNAL(mouseMovePoint(QPoint)),this, SLOT(on_mouseMovePoint(QPoint)));
QObject::connect(ui->View,SIGNAL(mouseClicked(QPoint)),this, SLOT(on_mouseClicked(QPoint)));
QObject::connect(ui->View,SIGNAL(mouseDoubleClick(QPoint)),this, SLOT(on_mouseDoubleClick(QPoint)));
QObject::connect(ui->View,SIGNAL(keyPress(QKeyEvent*)),this, SLOT(on_keyPress(QKeyEvent*)));
qsrand(QTime::currentTime().second());//随机数初始化
}
MainWindow::~MainWindow()
{
delete ui;
}
/*
* 这里用一个函数setBrushColor()为3种不同类的对象进行颜色填充
* setBrushColor()并不是使用了不同类型参数的同名重载函数,
* 而是在mainwindow.cpp中定义的一个独立模板函数
* 编译器会自动根据调用setBrushColor的参数的类型生成三个不同参数类型的函数
*/
template<class T> void setBrushColor(T *item)
{//函数模板
QColor color=item->brush().color();
color=QColorDialog::getColor(color,nullptr,"选择填充颜色");
if (color.isValid())
item->setBrush(QBrush(color));
}
/**
* @brief MainWindow::on_mouseMovePoint
* @param point
*/
void MainWindow::on_mouseMovePoint(QPoint point)
{//鼠标移动事件,point是 GraphicsView的坐标,物理坐标
labViewCord->setText(QString::asprintf("View 坐标:%d,%d",point.x(),point.y()));
QPointF pointScene=ui->View->mapToScene(point); //转换到Scene坐标
labSceneCord->setText(QString::asprintf("Scene 坐标:%.0f,%.0f",pointScene.x(),pointScene.y()));
}
/**
* @brief MainWindow::on_mouseClicked
* @param point
*/
void MainWindow::on_mouseClicked(QPoint point)
{//鼠标单击事件
QPointF pointScene=ui->View->mapToScene(point); //转换到Scene坐标
QGraphicsItem *item=nullptr;
item=scene->itemAt(pointScene,ui->View->transform()); //获取光标下的绘图项
if (item != nullptr) //有绘图项
{
QPointF pointItem=item->mapFromScene(pointScene); //转换为绘图项的局部坐标
labItemCord->setText(QString::asprintf("Item 坐标:%.0f,%.0f",pointItem.x(),pointItem.y()));
labItemInfo->setText(item->data(ItemDesciption).toString()+", ItemId="+
item->data(ItemId).toString());
}
}
/**
* @brief MainWindow::on_mouseDoubleClick
* @param point
*/
void MainWindow::on_mouseDoubleClick(QPoint point)
{//鼠标双击事件,调用相应的对话框,设置填充颜色、线条颜色或字体
QPointF pointScene=ui->View->mapToScene(point); //转换到Scene坐标
QGraphicsItem *item=nullptr;
item=scene->itemAt(pointScene,ui->View->transform()); //获取光标下的绘图项
if (item == nullptr) //没有绘图项
return;
switch (item->type()) //绘图项的类型
{ //
case QGraphicsRectItem::Type: //矩形框
{ //强制类型转换
QGraphicsRectItem *theItem=qgraphicsitem_cast<QGraphicsRectItem*>(item);
setBrushColor(theItem);
break;
}
case QGraphicsEllipseItem::Type: //椭圆和圆都是 QGraphicsEllipseItem
{
QGraphicsEllipseItem *theItem=qgraphicsitem_cast<QGraphicsEllipseItem*>(item);
setBrushColor(theItem);
break;
}
case QGraphicsPolygonItem::Type: //梯形和三角形
{
QGraphicsPolygonItem *theItem=qgraphicsitem_cast<QGraphicsPolygonItem*>(item);
setBrushColor(theItem);
break;
}
case QGraphicsLineItem::Type: //直线,设置线条颜色
{
QGraphicsLineItem *theItem=qgraphicsitem_cast<QGraphicsLineItem*>(item);
// setPenColor(theItem);
QPen pen=theItem->pen();
QColor color=theItem->pen().color();
color=QColorDialog::getColor(color,this,"选择线条颜色");
if (color.isValid())
{
pen.setColor(color);
theItem->setPen(pen);
}
break;
}
case QGraphicsTextItem::Type: //文字,设置字体
{
QGraphicsTextItem *theItem=qgraphicsitem_cast<QGraphicsTextItem*>(item);
QFont font=theItem->font();
bool ok=false;
font=QFontDialog::getFont(&ok,font,this,"设置字体");
if (ok)
theItem->setFont(font);
break;
}
}
}
void MainWindow::on_keyPress(QKeyEvent *event)
{ //按键事件
if (scene->selectedItems().count()!=1)
return; //没有选中的绘图项,或选中的多于1个
QGraphicsItem *item=scene->selectedItems().at(0);
if (event->key()==Qt::Key_Delete)//删除
scene->removeItem(item);
else if (event->key()==Qt::Key_Space) //顺时针旋转90度
item->setRotation(90+item->rotation());
else if (event->key()==Qt::Key_PageUp)//放大
item->setScale(0.1+item->scale());
else if (event->key()==Qt::Key_PageDown) //缩小
item->setScale(-0.1+item->scale());
else if (event->key()==Qt::Key_Left) //左移
item->setX(-1+item->x());
else if (event->key()==Qt::Key_Right) //右移
item->setX(1+item->x());
else if (event->key()==Qt::Key_Up) //上移
item->setY(-1+item->y());
else if (event->key()==Qt::Key_Down) //下移
item->setY(1+item->y());
}
void MainWindow::on_actZoomIn_triggered()//放大
{
int cnt=scene->selectedItems().count();
if(cnt==1)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->setScale(0.1+item->scale());
}
else//对View放大
{
ui->View->scale(1.1,1.1);
}
}
void MainWindow::on_actZoomOut_triggered()//缩小
{
int cnt=scene->selectedItems().count();
if(cnt==1)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->setScale(item->scale()-0.1);
}
else//对View缩小
{
ui->View->scale(0.9,0.9);
}
}
void MainWindow::on_actRotateLeft_triggered()//左旋转
{
int cnt=scene->selectedItems().count();
if(cnt==1)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->setRotation(-30+item->rotation());
}
else
{
ui->View->rotate(-30);
}
}
void MainWindow::on_actRotateRight_triggered()//右旋转
{
int cnt=scene->selectedItems().count();
if(cnt==1)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->setRotation(30+item->rotation());
}
else
{
ui->View->rotate(30);
}
}
void MainWindow::on_actRestore_triggered()//恢复
{
int cnt=scene->selectedItems().count();
if(cnt==1)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->resetTransform();
}
else
{
ui->View->resetTransform();
}
}
void MainWindow::on_actEdit_Front_triggered()//前置
{
int cnt=scene->selectedItems().count();
if(cnt>0)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->setZValue(++frontZ);
}
}
void MainWindow::on_actEdit_Back_triggered()//后置
{
int cnt=scene->selectedItems().count();
if(cnt>0)
{
QGraphicsItem *item=scene->selectedItems().at(0);
item->setZValue(--backZ);
}
}
void MainWindow::on_actGroup_triggered()//组合
{
int cnt=scene->selectedItems().count();
if(cnt>1)
{
QGraphicsItemGroup *group=new QGraphicsItemGroup;//创建组合
scene->addItem(group);//添加到场景
for(int i=0;i<cnt;i++)
{
QGraphicsItem *item=scene->selectedItems().at(i);
item->setSelected(false);//清除选择框
item->clearFocus();//清除焦点
group->addToGroup(item);//添加到组合中
}
group->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
group->setZValue(++frontZ);
scene->clearSelection();
group->setSelected(true);
}
}
void MainWindow::on_actGroupBreak_triggered()//打散
{
int cnt=scene->selectedItems().count();
if(cnt>0)
{
QGraphicsItemGroup *group;
group=(QGraphicsItemGroup*)scene->selectedItems().at(0);//这里假设在单击打散按钮时,选中的是一个组合对象,并没有做类型判断
scene->destroyItemGroup(group);
}
}
void MainWindow::on_actEdit_Delete_triggered()//删除
{
int cnt=scene->selectedItems().count();
if(cnt>0)
{
for(int i=0;i<cnt;i++)
{
QGraphicsItem *item=scene->selectedItems().at(0);
scene->removeItem(item);
}
}
}
void MainWindow::on_actItem_Ellipse_triggered()//画椭圆
{
QGraphicsEllipseItem *item=new QGraphicsEllipseItem(-50,-30,100,60);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
item->setBrush(Qt::black);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"椭圆");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
void MainWindow::on_actItem_Rect_triggered()//画矩形
{
QGraphicsRectItem *item=new QGraphicsRectItem(-50,-30,100,60);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
item->setBrush(Qt::red);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"矩形");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
void MainWindow::on_actItem_Circle_triggered()//画圆形
{
QGraphicsEllipseItem *item=new QGraphicsEllipseItem(-30,-30,60,60);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
item->setBrush(Qt::green);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"圆形");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
void MainWindow::on_actItem_Triangle_triggered()//画三角形
{
QGraphicsPolygonItem *item=new QGraphicsPolygonItem;
QPolygonF points;
points.append(QPointF(0,-40));
points.append(QPointF(60,40));
points.append(QPointF(-60,40));
item->setPolygon(points);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
item->setBrush(Qt::yellow);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"三角形");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
void MainWindow::on_actItem_Polygon_triggered()//画梯形
{
QGraphicsPolygonItem *item=new QGraphicsPolygonItem;
QPolygonF points;
points.append(QPointF(30,-40));
points.append(QPointF(60,40));
points.append(QPointF(-60,40));
points.append(QPointF(-30,-40));
item->setPolygon(points);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
item->setBrush(Qt::blue);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"梯形");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
void MainWindow::on_actItem_Line_triggered()//画直线
{
QGraphicsLineItem *item=new QGraphicsLineItem(-30,40,30,40);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
QPen pen(Qt::gray);
item->setPen(pen);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"直线");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
void MainWindow::on_actItem_Text_triggered()//添加文字
{
QString str=QInputDialog::getText(this,"输入文字","请输入文字");
QGraphicsTextItem *item=new QGraphicsTextItem(str);
item->setFlags(QGraphicsItem::ItemIsMovable
|QGraphicsItem::ItemIsFocusable
|QGraphicsItem::ItemIsSelectable);
QFont font;
font.setBold(true);
font.setWeight(2);
item->setFont(font);
item->setZValue(++frontZ);
item->setPos(-50+(qrand()%100),-50+(qrand()%100));
item->setData(ItemId,++seqNum);
item->setData(ItemDesciption,"文字");
scene->addItem(item);
scene->clearSelection();
item->setSelected(true);
}
qwgraphicsview.cpp
#include "qwgraphicsview.h"
#include<QEvent>
#include<QGraphicsView>
/**
* @brief QWGraphicsView::mouseMoveEvent
* @param event
*/
void QWGraphicsView::mouseMoveEvent(QMouseEvent *event)//鼠标移动
{
QPoint point=event->pos();
emit mouseMovePoint(point);
QGraphicsView::mouseMoveEvent(event);
}
/**
* @brief QWGraphicsView::mousePressEvent
* @param event
*/
void QWGraphicsView::mousePressEvent(QMouseEvent *event)//鼠标单击
{
if(event->button()==Qt::LeftButton)
{
QPoint point=event->pos();
emit mouseClicked(point);
}
QGraphicsView::mousePressEvent(event);
}
/**
* @brief QWGraphicsView::mouseDoubleClickEvent
* @param event
*/
void QWGraphicsView::mouseDoubleClickEvent(QMouseEvent *event)//鼠标双击
{
if(event->button()==Qt::LeftButton)
{
QPoint point=event->pos();
emit mouseDoubleClicked(point);
}
QGraphicsView::mouseDoubleClickEvent(event);
}
/**
* @brief QWGraphicsView::keyPressEvent
* @param event
*/
void QWGraphicsView::keyPressEvent(QKeyEvent *event)//按键事件
{
emit keyPress(event);
QGraphicsView::keyPressEvent(event);
}
/**
* @brief QWGraphicsView::QWGraphicsView
* @param parent
*/
QWGraphicsView::QWGraphicsView(QWidget *parent):QGraphicsView(parent)
{
}
mainwindow.ui
运行结果