# coding: utf-8

import sys
from PyQt5.QtCore import Qt
from PyQt5.QtGui import QImage, QIcon, QPixmap, QPainter
from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QSizePolicy, QAction
from PyQt5.QtPrintSupport import QPrinter, QPrintDialog

class MainWindow(QMainWindow):
    def __init__(self, parent=None):
        super(MainWindow, self).__init__(parent)
        self.setWindowTitle(self.tr("打印图片"))
        # 创建一个放置图像的QLabel对象imageLabel，并将该QLabel对象设置为中心窗体
        self.imageLabel = QLabel()
        self.imageLabel.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Ignored)
        self.setCentralWidget(self.imageLabel)

        self.image = QImage()

        # 创建菜单，工具条等部件
        self.createActions()
        self.createMenus()
        self.createToolBars()

        # 在imageLabel对象中放置图像
        if self.image.load("./images/screen.png"):
            self.imageLabel.setPixmap(QPixmap.fromImage(self.image))
            self.resize(self.image.width(), self.image.height())

    def createActions(self):
        self.PrintAction = QAction(QIcon("./images/printer.png"), self.tr("打印"), self)
        self.PrintAction.setShortcut("Ctrl+P")
        self.PrintAction.setStatusTip(self.tr("打印"))
        self.PrintAction.triggered.connect(self.slotPrint)

    def createMenus(self):
        PrintMenu = self.menuBar().addMenu(self.tr("打印"))
        PrintMenu.addAction(self.PrintAction)

    def createToolBars(self):
        fileToolBar = self.addToolBar("Print")
        fileToolBar.addAction(self.PrintAction)

    def slotPrint(self):
        # 新建一个QPrinter对象
        printer = QPrinter()
        # 创建一个QPrintDialog对象，参数为QPrinter对象
        printDialog = QPrintDialog(printer, self)
        '''
        判断打印对话框显示后用户是否单击“打印”按钮，若单击“打印”按钮，
        则相关打印属性可以通过创建QPrintDialog对象时使用的QPrinter对象获得，
        若用户单击“取消”按钮，则不执行后续的打印操作。 
        '''
        if printDialog.exec_():
            # 创建一个QPainter对象，并指定绘图设备为一个QPrinter对象
            painter = QPainter(printer)
            # 获得QPainter对象的视口矩形
            rect = painter.viewport()
            # 获得图像的大小
            size = self.image.size()
            # 按照图形的比例大小重新设置视口矩形
            size.scale(rect.size(), Qt.KeepAspectRatio)
            painter.setViewport(rect.x(), rect.y(), size.width(), size.height())
            # 设置QPainter窗口大小为图像的大小
            painter.setWindow(self.image.rect())
            # 打印
            painter.drawImage(0, 0, self.image)

if __name__ == "__main__":
    app = QApplication(sys.argv)    
    main = MainWindow()
    main.show()
    sys.exit(app.exec_())
