PyQt實現圖片的縮放和旋轉

圖片的縮放和旋轉是圖片處理的常用功能，本實例通過QMatrix實現圖片的縮放和旋轉：

具體代碼實現如下：

# -*- coding: utf-8 -*-

from PyQt4.QtGui import *
from PyQt4.QtCore import *
import sys

QTextCodec.setCodecForTr(QTextCodec.codecForName("utf8"))

class MainWindow(QMainWindow):
    def __init__(self,parent=None):
        super(MainWindow,self).__init__(parent)
        f=QFont("ZYSong18030",12)
        self.setFont(f)

        self.setWindowTitle("Image Processor")
        self.imageLabel=QLabel()
        self.imageLabel.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Ignored)
        self.imageLabel.setScaledContents(True)

        self.setCentralWidget(self.imageLabel)
        self.image=QImage()
        if self.image.load("image/cc.png"):
                    self.imageLabel.setPixmap(QPixmap.fromImage(self.image))
                    self.resize(self.image.width(),self.image.height())

        self.createActions()
        self.createMenus()
        self.createToolBars()

    def createActions(self):
        self.zoominAction=QAction(QIcon("image/zoomin.png"),self.tr("放大"),self)
        self.zoominAction.setShortcut("Ctrl+P")
        self.zoominAction.setStatusTip(self.tr("放大"))
        self.connect(self.zoominAction,SIGNAL("triggered()"),self.slotZoomin)

        self.deflateAction=QAction(QIcon("image/deflate.png"),self.tr("縮小"),self)
        self.deflateAction.setShortcut("Ctrl+A")
        self.deflateAction.setStatusTip(self.tr("縮小"))
        self.connect(self.deflateAction,SIGNAL("triggered()"),self.slotDeflate)

        self.circumgyrate=QAction(QIcon("image/circumgyrate.png"),self.tr("旋轉"),self)
        self.circumgyrate.setShortcut("Ctrl+B")
        self.circumgyrate.setStatusTip(self.tr("旋轉"))
        self.connect(self.circumgyrate,SIGNAL("triggered()"),self.slotCircumgyrate)

    def createMenus(self):
        PrintMenu=self.menuBar().addMenu(self.tr("縮放"))
        PrintMenu.addAction(self.zoominAction)
        PrintMenu.addAction(self.deflateAction)
        circumgyrateMenu=self.menuBar().addMenu(self.tr("旋轉"))
        circumgyrateMenu.addAction(self.circumgyrate)

    def createToolBars(self):
        fileToolBar=self.addToolBar("Print")
        fileToolBar.addAction(self.zoominAction)
        fileToolBar.addAction(self.deflateAction)
        fileToolBar.addAction(self.circumgyrate)

    def slotZoomin(self):
        if self.image.isNull():
            return
        martix = QMatrix()
        martix.scale(2,2)
        self.image=self.image.transformed(martix);
        self.imageLabel.setPixmap(QPixmap.fromImage(self.image))
        self.resize(self.image.width(),self.image.height())

    def slotDeflate(self):
        if self.image.isNull():
            return
        martix = QMatrix()
        martix.scale(0.5,0.5)
        self.image=self.image.transformed(martix);
        self.imageLabel.setPixmap(QPixmap.fromImage(self.image))
        self.resize(self.image.width(),self.image.height())

    def slotCircumgyrate(self):
        if self.image.isNull():
            return
        martix = QMatrix()
        martix.rotate(90)
        self.image=self.image.transformed(martix);
        self.imageLabel.setPixmap(QPixmap.fromImage(self.image))
        self.resize(self.image.width(),self.image.height())

app=QApplication(sys.argv)
window=MainWindow()
window.show()
app.exec_()