Qt5开发学习之主窗体（六）

Qt5主窗体构成

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 QMainWindow是一个为用户提供主窗体程序的类，包含一个菜单栏（menu bar）、多个工具栏（tool bar）、多个锚接部件（dock widget）、以及一个中心部件（central widget）。是许多引用程序的基础，如文本编辑器和图片编辑器。  

菜单栏

Qt的菜单就是由一系列的QAction对象构成的列表，而菜单栏则是包容菜单的面板，它位于主窗口顶部标题栏的下面，一个主窗口最多只有一个菜单栏。

状态栏

状态栏通常用于显示 GUI程序的状态信息，位于主窗体的最底部，用户可在状态栏上添加、使用Qt窗口部件，一个主窗口最多只有一个状态栏。

工具栏

状态栏是由一系列类似于按钮的动作排列而成的面板，它通常由一些经常使用的动作组成。位于菜单栏的下面一个主窗口可以包含多个工具栏。

锚接部件

锚接部件作为一个容器使用，以包容其它窗口部件来实现某些功能。它位于工具栏内部，可以作为一个窗口自由的浮动在主窗口上面。

中心部件

位于主窗口的中心，锚接部件区的内部。

实例编写

完成一个文本编辑器的实例，针对QMainWindow创建流程和各种功能进行开发。
要完成的功能有：文件的操作功能、标准打印对话框的使用、画图实现图像打印、使用QMatrix实现图像的各种变换功能、最后是排版功能。
新建工程ImageProcessor，基类选择QMainWindow。imageprocessor.h文件用于创建工具栏、各种动作、创建菜单：

#include <QMainWindow>#include <QMenu>#include <QToolBar>#include <QTextCharFormat>#include <QApplication>#include <QImage>#include <QLabel>#include <QMenuBar>#include <QDialog>#include <QFileDialog>#include <QFile>#include <QTextStream>#include <QPainter>// Qt5将打印的这两个类归入到printsupport中，需要在pro文件中写入 QT += printsupport#include <QPrinter>#include <QPrintDialog>#include "showwidget.h"class ImageProcessor : public QMainWindow{    Q_OBJECTpublic:    ImageProcessor(QWidget *parent = 0);    ~ImageProcessor();    void createMenu(); // 创建菜单项    void createAction(); // 创建各种动作    void createToolBars(); // 创建工具栏    void loadFile(QString filename); // 加载文件    void mergeTextFormat(QTextCharFormat);private:    // 各种菜单栏    QMenu *fileMenu;    QMenu *zoomMenu;    QMenu *rotateMenu;    QMenu *mirrorMenu;    QImage img;    QString fileName;    ShowWidget *showWidget;    // 文件菜单项动作    QAction *openFileAction;    QAction *newFileAction;    QAction *printImgAction;    QAction *printTextAction;    QAction *exitAction;    // 编辑菜单项动作    QAction *copyAction;    QAction *cutAction;    QAction *pasteAction;    QAction *aboutAction;    QAction *zoomInAction;    QAction *zoomOutAction;    // 旋转菜单项动作    QAction *rotate90Action;    QAction *rotate180Action;    QAction *rotate270Action;    // 镜像菜单项动作    QAction *mirrorVerticalAction;    QAction *mirrorHorizontalAction;    QAction *undoAction;    QAction *redoAction;    // 工具栏    QToolBar *fileTool;    QToolBar *zoomTool;    QToolBar *rotateTool;    QToolBar *mirrorTool;    QToolBar *doTool;private slots:    // 打开窗口函数    void ShowOpenFile();    // 新建窗口函数    void ShowNewFile();    // 打印文本动作    void ShowPrintText();    // 打印图像动作    void ShowPrintImage();    // 图片放大    void ShowZoomIn();    // 图片缩小    void ShowZoomOut();    // 图片旋转    void ShowRotate90();    void ShowRotate180();    void ShowRotate270();    // 图片镜像    void ShowMirrorVertical();    void ShowMirrorHorizontal();};

imageprocessor.cpp：

#include "imageprocessor.h"ImageProcessor::ImageProcessor(QWidget *parent)    : QMainWindow(parent){    setWindowTitle(tr("MainWindow"));    // 设置showWidget为主窗体的中心部件    showWidget = new ShowWidget(this);    setCentralWidget(showWidget);    createAction();    createMenu();    createToolBars();    if (img.load("image.jpg"))    {        showWidget->imgLabel->setPixmap(QPixmap::fromImage(img.scaled(600, 600)));    }}ImageProcessor::~ImageProcessor(){}// 实现各种动作，通过菜单栏和工具栏提现出来void ImageProcessor::createMenu(){    // 调用QMainWindow的menuBar()函数即可得到主窗口的菜单指针，    // 在调用菜单条的addMenu()函数，即可完成在菜单中插入一个新菜单    fileMenu = menuBar()->addMenu(tr("file"));    fileMenu->addAction(openFileAction);    fileMenu->addAction(newFileAction);    fileMenu->addAction(printImgAction);    fileMenu->addAction(printTextAction);    // 在各种功能中间加横线分隔    fileMenu->addSeparator();    fileMenu->addAction(exitAction);    zoomMenu = menuBar()->addMenu(tr("zoom"));    zoomMenu->addAction(copyAction);    zoomMenu->addAction(cutAction);    zoomMenu->addAction(pasteAction);    zoomMenu->addAction(aboutAction);    zoomMenu->addSeparator();    zoomMenu->addAction(zoomInAction);    zoomMenu->addAction(zoomOutAction);    rotateMenu = menuBar()->addMenu(tr("rotate"));    rotateMenu->addAction(rotate90Action);    rotateMenu->addAction(rotate180Action);    rotateMenu->addAction(rotate270Action);    mirrorMenu = menuBar()->addMenu(tr("mirror"));    mirrorMenu->addAction(mirrorVerticalAction);    mirrorMenu->addAction(mirrorHorizontalAction    );}// 各种“动作”的实现void ImageProcessor::createAction(){    // 文件操作的实现    openFileAction = new QAction(tr("open"), this);    openFileAction->setShortcut(tr("Ctrl+O")); // 快捷键设置    openFileAction->setStatusTip("Open file"); // 鼠标放上时给出的提示    connect(openFileAction, &QAction::triggered, this, &ImageProcessor::ShowOpenFile);    newFileAction = new QAction(tr("new"), this);    newFileAction->setShortcut(tr("Ctrl+N"));    newFileAction->setStatusTip("New file");    connect(newFileAction, &QAction::triggered, this, &ImageProcessor::ShowNewFile);    exitAction = new QAction(tr("exit"), this);    exitAction->setShortcut(tr("Ctrl+Q"));    exitAction->setStatusTip("Exit");    connect(exitAction, &QAction::triggered, this, &ImageProcessor::close);    copyAction = new QAction(tr("copy"), this);    copyAction->setShortcut(tr("Ctrl+C"));    copyAction->setStatusTip("Copy");    connect(copyAction, &QAction::triggered, showWidget->text, &QTextEdit::copy);    cutAction = new QAction(tr("cut"), this);    cutAction->setShortcut(tr("Ctrl+X"));    cutAction->setStatusTip("Cut");    connect(cutAction, &QAction::triggered, showWidget->text, &QTextEdit::cut);    pasteAction = new QAction(tr("paste"), this);    pasteAction->setShortcut(tr("Ctrl+V"));    pasteAction->setStatusTip("Paste");    connect(pasteAction, &QAction::triggered, showWidget->text, &QTextEdit::paste);    aboutAction = new QAction(tr("about"), this);    connect(aboutAction, &QAction::triggered, this, &QApplication::aboutQt);    printImgAction = new QAction(tr("printImg"), this);    printImgAction->setStatusTip("print image");    connect(printImgAction, &QAction::triggered, this, &ImageProcessor::ShowPrintImage);    printTextAction = new QAction(tr("printText"), this);    printTextAction->setStatusTip("print text");    connect(printTextAction, &QAction::triggered, this, &ImageProcessor::ShowPrintText);    zoomInAction = new QAction(tr("zoomIn"), this);    zoomInAction->setStatusTip("zoom in");    connect(zoomInAction, &QAction::triggered, this, &ImageProcessor::ShowZoomIn);    zoomOutAction = new QAction(tr("zoomOut"), this);    zoomOutAction->setStatusTip("zoom out");    connect(zoomOutAction, &QAction::triggered, this, &ImageProcessor::ShowZoomOut);    rotate90Action = new QAction(tr("rotate90"), this);    rotate90Action->setStatusTip("rotat90");    connect(rotate90Action, &QAction::triggered, this, &ImageProcessor::ShowRotate90);    rotate180Action = new QAction(tr("rotate180"), this);    rotate180Action->setStatusTip("rotat180");    connect(rotate180Action, &QAction::triggered, this, &ImageProcessor::ShowRotate180);    rotate270Action = new QAction(tr("rotate270"), this);    rotate270Action->setStatusTip("rotat270");    connect(rotate270Action, &QAction::triggered, this, &ImageProcessor::ShowRotate270);    mirrorVerticalAction = new QAction(tr("mirrorVertical"), this);    mirrorVerticalAction->setStatusTip("mirrorVertical");    connect(mirrorVerticalAction, &QAction::triggered, this, &ImageProcessor::ShowMirrorVertical);    mirrorHorizontalAction = new QAction(tr("mirrorHorizontal"), this);    mirrorHorizontalAction->setStatusTip("mirrorHorizontal");    connect(mirrorHorizontalAction, &QAction::triggered, this, &ImageProcessor::ShowMirrorHorizontal);    undoAction = new QAction(tr("undo"), this);    undoAction->setStatusTip("undo");    connect(undoAction, &QAction::triggered, showWidget->text, &QTextEdit::undo);    redoAction = new QAction(tr("redo"), this);    redoAction->setStatusTip("redo");    connect(redoAction, &QAction::triggered, showWidget->text, &QTextEdit::redo);}// 一个菜单对应一个工具条void ImageProcessor::createToolBars(){    // 调用QMainWindow的addToolBar()函数获得窗口的工具条对象    fileTool = addToolBar(tr("File"));    fileTool->addAction(openFileAction);    fileTool->addAction(newFileAction);    fileTool->addAction(printImgAction);    fileTool->addAction(printTextAction);    fileTool->addAction(exitAction);    zoomTool = addToolBar(tr("zoom"));    zoomTool->addAction(copyAction);    zoomTool->addAction(cutAction);    zoomTool->addAction(pasteAction);    zoomTool->addSeparator();    zoomTool->addAction(zoomInAction);    zoomTool->addAction(zoomOutAction);    rotateTool = addToolBar(tr("rotate"));    rotateTool->addAction(rotate90Action);    rotateTool->addAction(rotate180Action);    rotateTool->addAction(rotate270Action);    mirrorTool = addToolBar(tr("mirror"));    mirrorTool->addAction(mirrorVerticalAction);    mirrorTool->addAction(mirrorHorizontalAction);    doTool = addToolBar(tr("do"));    doTool->addAction(undoAction);    doTool->addAction(redoAction);    // 工具条默认是一个可移动的窗口，停靠的区域由QToolBar的allowAreas决定    fileTool->setAllowedAreas(Qt::TopToolBarArea | Qt::LeftToolBarArea);    // 使用setMovable()函数设定可移动性    fileTool->setMovable(false);}void ImageProcessor::loadFile(QString filename){    // 利用QFile和QTextStream完成读取文件操作    QFile file(filename);    if (file.open(QIODevice::ReadOnly | QIODevice::Text))    {        QTextStream textStream(&file);        while (!textStream.atEnd())        {            showWidget->text->append(textStream.readLine());        }    }}void ImageProcessor::ShowOpenFile(){    fileName = QFileDialog::getOpenFileName(this);    if (!fileName.isEmpty())    {        if (showWidget->text->document()->isEmpty())        {            loadFile(fileName);        }        else        {            ImageProcessor *newImgProcessor = new ImageProcessor;            newImgProcessor->show();            newImgProcessor->loadFile(fileName);        }    }}void ImageProcessor::ShowNewFile(){    ImageProcessor *newImgProcessor = new ImageProcessor;    newImgProcessor->show();}void ImageProcessor::ShowPrintText(){    // Qt的QPrintDialog提供了标准打印对话框    // 新建一个QPrinter对象    QPrinter printer;    // 新建一个QPrintDialog对象，参数为QPrinter对象    QPrintDialog printDialog(&printer, this);    // 判断用户是否点击了“打印”按钮    if (printDialog.exec())    {        // 获取QTextEdit对象的文档        QTextDocument *doc = showWidget->text->document();        doc->print(&printer);    }}void ImageProcessor::ShowPrintImage(){    QPrinter printer;    QPrintDialog printDialog(&printer, this);    if (printDialog.exec())    {        // 创建一个QPainter对象，指定绘图设备为printer        QPainter painter(&printer);        // 获得QPainter对象的视口矩形区域        QRect rect = painter.viewport();        // 获得图像大小        QSize size = img.size();        // 按照图片的大小重新设置对象矩形区域        size.scale(rect.size(), Qt::KeepAspectRatio);        painter.setViewport(rect.x(), rect.y(), size.width(), size.height());        painter.setWindow(img.rect());        painter.drawImage(0, 0, img);    }}void ImageProcessor::ShowZoomIn(){    if (img.isNull())        return;    // 声明一个Matrix对象    QMatrix matrix;    // 按照两倍的比例对水平和垂直方向进行放大    matrix.scale(2, 2);    // 将当前显示的图形按照该坐标矩阵进行转换    img = img.transformed(matrix);    // 重新设置图形    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img));}void ImageProcessor::ShowZoomOut(){    if (img.isNull())        return;    // 声明一个Matrix对象    QMatrix matrix;    // 按照两倍的比例对水平和垂直方向进行放大    matrix.scale(0.5    , 0.5);    // 将当前显示的图形按照该坐标矩阵进行转换    img = img.transformed(matrix);    // 重新设置图形    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img));}void ImageProcessor::ShowRotate90(){    if (img.isNull())        return;    QMatrix matrix;    matrix.rotate(90);    img = img.transformed(matrix);    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img.scaled(600, 600)));}void ImageProcessor::ShowRotate180(){    if (img.isNull())        return;    QMatrix matrix;    matrix.rotate(180);    img = img.transformed(matrix);    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img.scaled(600, 600)));}void ImageProcessor::ShowRotate270(){    if (img.isNull())        return;    QMatrix matrix;    matrix.rotate(270);    img = img.transformed(matrix);    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img.scaled(600, 600)));}void ImageProcessor::ShowMirrorVertical(){    if (img.isNull())        return;    img.mirrored(false, true);    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img.scaled(600, 600)));}void ImageProcessor::ShowMirrorHorizontal(){    if (img.isNull())        return;    img.mirrored(true, false);    showWidget->imgLabel->setPixmap(QPixmap::fromImage(img.scaled(600, 600)));}