图片缩放与旋转

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图片缩放与旋转

图片的缩放与旋转是图像处理的常用功能。QMatrix类提供了坐标系统的2D转化功能，可以使窗体转化变形，经常在绘图程序中使用，QMatrix可以实现坐标系统的移动、缩放、变形以及旋转功能。

1、创建imgprocessor.h

#ifndef IMGPROCESSOR_H#define IMGPROCESSOR_H#include <QtGui>class ImgProcessor : public QMainWindow{    Q_OBJECTpublic :    ImgProcessor();    void createMenus();    void createActions();    void createToolBars();private:    QImage img;    QLabel *imageLabel;    QMenu *fileMenu;    QMenu *zoomMenu;    QMenu *rotateMenu;    QMenu *mirrorMenu;    QAction *openFileAction;    QAction *zoomInAction;    QAction *zoomOutAction;    QAction *rotate90Action;    QAction *rotate180Action;    QAction *rotate270Action;    QAction *mirrorVerticalAction;    QAction *mirrorHorizontalAction;    QToolBar *fileTool;    QToolBar *zoomTool;    QToolBar *rotateTool;    QToolBar *mirrorTool;protected slots:    void slotOpenFile();    void slotZoomIn();    void slotZoomOut();    void slotRotate90();    void slotRotate180();    void slotRotate270();    void slotMirrorVertical();    void slotMirrorHorizontal();};#endif // IMGPROCESSOR_H

2、创建imgprocessor.cpp

#include "imgprocessor.h"ImgProcessor::ImgProcessor() : QMainWindow(){    setWindowTitle(tr("Image Processor"));    imageLabel = new QLabel(this);    imageLabel->setSizePolicy(QSizePolicy::Ignored,QSizePolicy::Ignored);    imageLabel->setScaledContents(true);    setCentralWidget(imageLabel);    createActions();    createMenus();    createToolBars();}void ImgProcessor::createActions(){    openFileAction = new    QAction(QIcon(":/images/openfile.png"),tr("Open"),this);    openFileAction->setShortcut(tr("Ctrl+O"));    openFileAction->setStatusTip(tr("Open File"));    connect(openFileAction,SIGNAL(triggered()),this,SLOT(slotOpenFile()));    // zoom in action    zoomInAction = new QAction(QIcon(":/images/zoomin.png"),tr("ZoomIn"),this);    zoomInAction->setShortcut(tr("PgUp"));    zoomInAction->setStatusTip(tr("Zoom In"));    connect(zoomInAction,SIGNAL(triggered()),this,SLOT(slotZoomIn()));    // zoom out action    zoomOutAction = new QAction(QIcon(":/images/zoomout.png"),tr("ZoomOut"),this);    zoomOutAction->setShortcut(tr("PgDown"));    zoomOutAction->setStatusTip(tr("Zoom Out"));    connect(zoomOutAction,SIGNAL(triggered()),this,SLOT(slotZoomOut()));    // rotate 90 action    rotate90Action = new QAction(QIcon(":/images/rotate90.png"),tr("Rotate90"), this);    rotate90Action->setShortcut(tr("Ctrl+Right"));    rotate90Action->setStatusTip(tr("Rotate 90"));    connect(rotate90Action, SIGNAL(triggered()), this, SLOT(slotRotate90()));    // rotate 180 action    rotate180Action = new QAction(QIcon(":/images/rotate180.png"),tr("Rotate180"), this);    rotate180Action->setShortcut(tr("Ctrl+Down"));    rotate180Action->setStatusTip(tr("Rotate 180"));    connect(rotate180Action, SIGNAL(triggered()), this, SLOT(slotRotate180()));    // rotate 270 action    rotate270Action = new QAction(QIcon(":/images/rotate270.png"),tr("Rotate270"), this);    rotate270Action->setShortcut(tr("Ctrl+Left"));    rotate270Action->setStatusTip(tr("Rotate 270"));    connect(rotate270Action, SIGNAL(triggered()), this, SLOT(slotRotate270()));    // mirror vertical action    mirrorVerticalAction = new QAction(QIcon(":/images/mirrorvertical.png"),tr("MirrorVertical"), this);    mirrorVerticalAction->setShortcut(tr("Ctrl+V"));    mirrorVerticalAction->setStatusTip(tr("Mirror Vertical"));    connect(mirrorVerticalAction, SIGNAL(triggered()), this, SLOT(slotMirrorVertical()));    // mirror horizontal action    mirrorHorizontalAction = new QAction(QIcon(":/images/mirrorhorizontal.png"),tr("MirrorHorizontal"), this);    mirrorHorizontalAction->setShortcut(tr("Ctrl+H"));    mirrorHorizontalAction->setStatusTip(tr("Mirror Horizontal"));    connect(mirrorHorizontalAction, SIGNAL(triggered()), this, SLOT(slotMirrorHorizontal()));}void ImgProcessor::createMenus(){    fileMenu = menuBar()->addMenu(tr("File"));    zoomMenu = menuBar()->addMenu(tr("zoom"));    rotateMenu = menuBar()->addMenu(tr("rotate"));    mirrorMenu = menuBar()->addMenu(tr("mirror"));    fileMenu->addAction(openFileAction);    zoomMenu->addAction(zoomInAction);    zoomMenu->addAction(zoomOutAction);    rotateMenu->addAction(rotate90Action);    rotateMenu->addAction(rotate180Action);    rotateMenu->addAction(rotate270Action);    mirrorMenu->addAction(mirrorVerticalAction);    mirrorMenu->addAction(mirrorHorizontalAction);}void ImgProcessor::createToolBars(){    fileTool = addToolBar("File");    zoomTool = addToolBar("Zoom");    rotateTool = addToolBar("Rotate");    mirrorTool = addToolBar("Mirror");    fileTool->addAction(openFileAction);    zoomTool->addAction(zoomInAction);    zoomTool->addAction(zoomOutAction);    rotateTool->addAction(rotate90Action);    rotateTool->addAction(rotate180Action);    rotateTool->addAction(rotate270Action);    mirrorTool->addAction(mirrorVerticalAction);    mirrorTool->addAction(mirrorHorizontalAction);}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());        }    }}void ImgProcessor::slotZoomIn(){    if(img.isNull())    {        return;    }    else    {        QMatrix matrix;        matrix.scale(2,2);        img = img.transformed(matrix);        imageLabel->setPixmap(QPixmap::fromImage(img));        resize(img.width(),img.height());    }}void ImgProcessor::slotZoomOut(){    if(img.isNull())    {        return;    }    QMatrix matrix;    matrix.scale(0.5,0.5);    img = img.transformed(matrix);    imageLabel->setPixmap(QPixmap::fromImage(img));    resize(img.width(),img.height());}void ImgProcessor::slotRotate90 (){    if(img.isNull())    {        return;    }    QMatrix matrix;    matrix.rotate(90);    img = img.transformed(matrix);    imageLabel->setPixmap(QPixmap::fromImage(img));    resize(img.width(),img.height());}void ImgProcessor::slotRotate180 (){    if(img.isNull())    {        return;    }    QMatrix matrix;    matrix.rotate(180);    img = img.transformed(matrix);    imageLabel->setPixmap(QPixmap::fromImage(img));    resize(img.width(),img.height());}void ImgProcessor::slotRotate270 (){    if(img.isNull())    {        return;    }    QMatrix matrix;    matrix.rotate(270);    img = img.transformed(matrix);    imageLabel->setPixmap(QPixmap::fromImage(img));    resize(img.width(),img.height());}void ImgProcessor::slotMirrorVertical (){    if(img.isNull())    {        return;    }    img = img.mirrored(false,true);    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());}

3、创建main.cpp

#include <QApplication>#include "imgprocessor.h"int main(int argc,char *argv[]){    QApplication app(argc,argv);    ImgProcessor *img = new ImgProcessor;    img->show();    return app.exec();}

4、创建资源文件imgprocessor.qrc

5、运行程序，读取一张图片，可以试一下放大，缩小等功能。
这里写图片描述

6、资源代码

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