基于QMainWindow主窗体程序

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1.下面实现的是一个基本主窗口程序，包含一个菜单栏，一个工具栏，中央可编辑窗体以及状态栏

#ifndef MAINWINDOW_H#define MAINWINDOW_H#include <QMainWindow>class QAction;class QMenu;class QToolBar;class QTextEdit;class MainWindow : public QMainWindow{    Q_OBJECTpublic:    MainWindow();        void createMenus();//创建菜单    void createActions();//创建动作    void createToolBars();//创建工具栏    public slots:    void slotNewFile();    void slotOpenFile();    void slotSaveFile();    void slotCopy();    void slotCut();    void slotPaste();    void slotAbout();    private:        QTextCodec *codec;        QMenu *fileMenu;    QMenu *editMenu;    QMenu *aboutMenu;    QToolBar *fileTool;    QToolBar *editTool;    QAction *fileOpenAction;    QAction *fileNewAction;    QAction *fileSaveAction;    QAction *exitAction;    QAction *copyAction;    QAction *cutAction;    QAction *pasteAction;    QAction *aboutAction;     QTextEdit * text;};#endif // MAINWINDOW_H

构造函数

MainWindow::MainWindow(){    setWindowTitle(tr("Doc"));    text = new QTextEdit(this);    setCentralWidget(text);//把QTextEdit作为主窗口的中央窗体       createActions();/*QAction类为用户提供了一个统一的命令接口，无论是从菜单触发还是从工具栏触发，或者是快捷键触发都调用同样的操作接口，达到同样的目的。*/    createMenus();    createToolBars();}

void MainWindow::createActions(){    // file open action    fileOpenAction = new QAction(QIcon(":/images/open.png"),tr("Open"),this);// 打开文件/*指定动作所用的图标时，使用的是QIcon(":/images/open.png")，需要在程序所在的文件夹下面新增一个mainwindow.qrc文件用于说明程序中所用到的图标<!DOCTYPE RCC><RCC version="1.0"><qresource><file>images/copy.png</file><file>images/cut.png</file><file>images/new.png</file><file>images/open.png</file><file>images/paste.png</file><file>images/save.png</file></qresource></RCC>并且在.pro文件中加入一行:RESOURCES=mainwindow.qrc*/    fileOpenAction->setShortcut(tr("Ctrl+O"));//设置这个动作的快捷键    fileOpenAction->setStatusTip(tr("open a file"));//设定了状态条显示    connect(fileOpenAction,SIGNAL(triggered()),this,SLOT(slotOpenFile()));        // file new action    fileNewAction = new QAction(QIcon(":/images/new.png"),tr("New"),this);// 新建文件    fileNewAction->setShortcut(tr("Ctrl+N"));    fileNewAction->setStatusTip(tr("new file"));    connect(fileNewAction,SIGNAL(triggered()),this,SLOT(slotNewFile()));    // save file action    fileSaveAction = new QAction(QPixmap(":/images/save.png"),tr("Save"),this);// 保存文件     fileSaveAction->setShortcut(tr("Ctrl+S"));    fileSaveAction->setStatusTip(tr("save file"));    connect(fileSaveAction,SIGNAL(activated()),this,SLOT(slotSaveFile()));    // exit action    exitAction = new QAction(tr("Exit"), this);// 退出    exitAction->setShortcut(tr("Ctrl+Q"));    exitAction->setStatusTip(tr("exit"));    connect(exitAction, SIGNAL(triggered()), this, SLOT(close()));    cutAction = new QAction(QIcon(":/images/cut.png"), tr("Cut"), this);// 剪切    cutAction->setShortcut(tr("Ctrl+X"));    cutAction->setStatusTip(tr("cut to clipboard"));    connect(cutAction, SIGNAL(triggered()), text, SLOT(cut()));    copyAction = new QAction(QIcon(":/images/copy.png"), tr("Copy"), this);// 复制    copyAction->setShortcut(tr("Ctrl+C"));    copyAction->setStatusTip(tr("copy to clipboard"));    connect(copyAction, SIGNAL(triggered()), text, SLOT(copy()));    pasteAction = new QAction(QIcon(":/images/paste.png"), tr("Paste"), this);// 粘贴    pasteAction->setShortcut(tr("Ctrl+V"));    pasteAction->setStatusTip(tr("paste clipboard to selection"));    connect(pasteAction, SIGNAL(triggered()), text, SLOT(paste()));    aboutAction = new QAction(tr("About"), this);// 关于,可不指定图标，一般只在菜单栏中使用    connect(aboutAction, SIGNAL(triggered()), this, SLOT(slotAbout()));}

在实现了各个动作之后，需要把它通过菜单及工具栏快捷键的方式体现出来。

void MainWindow::createMenus(){//在菜单栏中添加新菜单    fileMenu = menuBar()->addMenu(tr("File"));    editMenu = menuBar()->addMenu(tr("Edit"));    aboutMenu = menuBar()->addMenu(tr("Help"));    //添加菜单条目到菜单    fileMenu->addAction(fileNewAction);    fileMenu->addAction(fileOpenAction);    fileMenu->addAction(fileSaveAction);    fileMenu->addAction(exitAction);        editMenu->addAction(copyAction);    editMenu->addAction(cutAction);    editMenu->addAction(pasteAction);        aboutMenu->addAction(aboutAction);         }

创建工具栏

void MainWindow::createToolBars(){//编辑两个工具栏,并排显示    fileTool = addToolBar("File");    fileTool->setMovable(false);//设置工具条的可移动性,此处为不可移动    editTool = addToolBar("Edit");        fileTool->addAction(fileNewAction);    fileTool->addAction(fileOpenAction);    fileTool->addAction(fileSaveAction);        editTool->addAction(copyAction);    editTool->addAction(cutAction);    editTool->addAction(pasteAction);   }

标准打印对话框QPrintDialog的使用

2.打印文本

#ifndef PRINTTEXT_H#define PRINTTEXT_H#include <QtGui>class PrintText : public QMainWindow{    Q_OBJECTpublic:    PrintText();    ~PrintText();    void createMenus();    void createActions();    void createToolBars();    private:    QTextEdit *contentTextEdit;        QMenu *printMenu;    QAction *printAction;    QToolBar *printTool;       protected slots:    void slotPrint();};#endif

#include "printtext.h"PrintText::PrintText()    : QMainWindow(){      QFont f("ZYSong18030",12);    setFont(f);          setWindowTitle(tr("Printer"));        contentTextEdit = new QTextEdit(this);setCentralWidget(contentTextEdit);//设置中央窗口部件    createActions();//创建动作    createMenus();//创建菜单    createToolBars();//创建工具栏               QFile file("QPrinter.txt");//创建一个file对象    if (file.open(QIODevice::ReadOnly|QIODevice::Text))//按行读取数据并显示在contentTextEdit中    {    QTextStream textStream(&file);    while(!textStream.atEnd())    {        contentTextEdit->append(textStream.readLine());    }    file.close();    }}PrintText::~PrintText(){}void PrintText::createActions(){    // print action    printAction = new QAction(QIcon(":/images/print.png"),tr("Print"),this);    printAction->setShortcut(tr("Ctrl+P"));    printAction->setStatusTip(tr("Print"));    connect(printAction,SIGNAL(triggered()),this,SLOT(slotPrint()));}void PrintText::createMenus(){    printMenu = menuBar()->addMenu(tr("Print"));    printMenu->addAction(printAction);}void PrintText::createToolBars(){    printTool = addToolBar("Print");    printTool->addAction(printAction);}void PrintText::slotPrint (){QPrinter printer; //创建一个QPrinter对象      QPrintDialog printDialog(&printer, this);/*参数为printer,QPrinterDialog是Qt提供的标准对话框，为打印机的使用提供了一种方便，规范的方法。*/    if (printDialog.exec()) //判断打印对话框显示后用户是否单击打印按钮    {QTextDocument *doc = contentTextEdit->document();//获得QTextEdit对象的文档doc->print(&printer);//打印}}

3.打印图像

打印图像实际上是在一个QPaintDevice中画图，与平常在QWidget,Qpixmap,Qimage中画图一样，都是在创建一个QPainter对象进行画图。

#ifndef PRINTIMAGE_H#define PRINTIMAGE_H#include <QtGui>class PrintImage : public QMainWindow{    Q_OBJECTpublic:    PrintImage();    ~PrintImage();    void createMenus();    void createActions();    void createToolBars();    private:    QImage image;    QLabel *imageLabel;        QMenu *printMenu;    QAction *printAction;    QToolBar *printTool;      protected slots:    void slotPrint();};#endif

#include "printimage.h"PrintImage::PrintImage()    : QMainWindow(){      QFont f("ZYSong18030",12);    setFont(f);          setWindowTitle(tr("PrintImage"));        imageLabel = new QLabel(this);      imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);    imageLabel->setScaledContents(true);setCentralWidget(imageLabel); //设置中央窗口部件    createActions();    createMenus();    createToolBars();          if(image.load("tux.png"));//载入图片    {    imageLabel->setPixmap (QPixmap::fromImage(image));//在imageLabel中显示图片    resize(image.width(), image.height());    }}PrintImage::~PrintImage(){}void PrintImage::createActions(){    // print action    printAction = new QAction(QIcon(":/images/print.png"),tr("Print"),this);    printAction->setShortcut(tr("Ctrl+P"));    printAction->setStatusTip(tr("Print"));    connect(printAction,SIGNAL(triggered()),this,SLOT(slotPrint()));}void PrintImage::createMenus(){    printMenu = menuBar()->addMenu(tr("Print"));    printMenu->addAction(printAction);}void PrintImage::createToolBars(){    printTool = addToolBar("Print");    printTool->addAction(printAction);}void PrintImage::slotPrint (){QPrinter printer;       QPrintDialog printDialog(&printer, this);    if (printDialog.exec()) //若用户单击打印按钮    {        QPainter painter(&printer);//指定绘图设备为QPrinter对象        QRect rect = painter.viewport();//获得QPainter对象的视口矩形        qWarning("rect.x()=%d,rect.y()=%d",rect.x(),rect.y());        qWarning("rect.width()=%d,rect.height()=%d",rect.width(),rect.height());        QSize size = image.size();//获得图像大小        qWarning("size.width()=%d,size.height()=%d",size.width(),size.height());        size.scale(rect.size(), Qt::KeepAspectRatio);//按照图形的比例大小重新设置视口矩形        qWarning("size.width()=%d,size.height()=%d",size.width(),size.height());        painter.setViewport(rect.x(), rect.y(),size.width(), size.height());        painter.setWindow(image.rect());//设置QPainter窗口大小为图像大小        painter.drawImage(0, 0, image);//打印    }}

4.图片的旋转与缩放

使用QMatrix实现坐标变换

QMatrix类提供了世界坐标系统的2D转换功能，可以使窗体转换变形，可实现坐标系统的移动，缩放，变形以及旋转的功能

下面是其构造函数

ImgProcessor::ImgProcessor()    : QMainWindow(){      QFont f("ZYSong18030",12);    setFont(f);          setWindowTitle(tr("Image Processor"));        imageLabel = new QLabel(this);        imageLabel->setSizePolicy(QSizePolicy::Ignored, QSizePolicy::Ignored);    imageLabel->setScaledContents(true);//是否会根据其大小自动调节内容大小，默认为false.       setCentralWidget(imageLabel);//设置中央窗口部件        createActions();    createMenus();    createToolBars();}

载入图形文件函数

void ImgProcessor::slotOpenFile (){    QString s = QFileDialog::getOpenFileName(               this, "open image file",        ".",        "Image files (*.bmp *.jpg *.pbm *.pgm *.png *.ppm *.xbm *.xpm);;All files (*.*)");                    if(s != "")    {    if(img.load(s));    {    imageLabel->setPixmap (QPixmap::fromImage(img));    resize(img.width(), img.height());    }    }}

图像的放大与缩小函数

void ImgProcessor::slotZoomIn ()//实现图形的放大功能{if(img.isNull())//行为的有效性判断{return;}QMatrix martix;//QMatrix类的实例martix.scale (2,2); // 按照两倍的比例对水平和垂直方向进行放大img=img.transformed(martix);//并将当前显示的图形按照该坐标矩阵进行转换imageLabel->setPixmap (QPixmap::fromImage(img));//重新设置显示图形resize(img.width(),img.height()); //调整大小 }void ImgProcessor::slotZoomOut (){if(img.isNull()){return;}QMatrix martix;martix.scale(0.5,0.5);  img=img.transformed(martix);imageLabel->setPixmap (QPixmap::fromImage(img));resize(img.width(),img.height());}

实现旋转函数

void ImgProcessor::slotRotate90 (){if(img.isNull()){return;}QMatrix martix;martix.rotate(90); //实现坐标的逆时针旋转img=img.transformed(martix);imageLabel->setPixmap (QPixmap::fromImage(img));resize(img.width(),img.height());}

垂直与水平镜像函数

void ImgProcessor::slotMirrorVertical ()//实现图形的垂直镜像{if(img.isNull()){return;}img=img.mirrored(false,true);//第一个参数表示水平，第二个参数表示垂直imageLabel->setPixmap (QPixmap::fromImage(img));resize(img.width(),img.height()); }void ImgProcessor::slotMirrorHorizontal (){if(img.isNull()){return;} img=img.mirrored(true,false);imageLabel->setPixmap (QPixmap::fromImage(img));resize(img.width(),img.height()); }

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