#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## $QT_BEGIN_LICENSE:BSD$
## You may use this file under the terms of the BSD license as follows:
##
## "Redistribution and use in source and binary forms, with or without
## modification, are permitted provided that the following conditions are
## met:
## * Redistributions of source code must retain the above copyright
## notice, this list of conditions and the following disclaimer.
## * Redistributions in binary form must reproduce the above copyright
## notice, this list of conditions and the following disclaimer in
## the documentation and/or other materials provided with the
## distribution.
## * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
## the names of its contributors may be used to endorse or promote
## products derived from this software without specific prior written
## permission.
##
## THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
## "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
## LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
## A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
## OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
## $QT_END_LICENSE$
##
#############################################################################
from PyQt5.QtCore import QDir, Qt
from PyQt5.QtGui import QImage, QPainter, QPalette, QPixmap
from PyQt5.QtWidgets import (QAction, QApplication, QFileDialog, QLabel,
QMainWindow, QMenu, QMessageBox, QScrollArea, QSizePolicy)
from PyQt5.QtPrintSupport import QPrintDialog, QPrinter
class ImageViewer(QMainWindow):
def __init__(self):
super(ImageViewer, self).__init__()
self.printer = QPrinter()
self.scaleFactor = 0.0
self.imageLabel = QLabel()
self.imageLabel.setBackgroundRole(QPalette.Base)
self.imageLabel.setSizePolicy(QSizePolicy.Ignored, QSizePolicy.Ignored)
self.imageLabel.setScaledContents(True)
self.scrollArea = QScrollArea()
self.scrollArea.setBackgroundRole(QPalette.Dark)
self.scrollArea.setWidget(self.imageLabel)
self.setCentralWidget(self.scrollArea)
self.createActions()
self.createMenus()
self.setWindowTitle("Image Viewer")
self.resize(500, 400)
def open(self):
fileName, _ = QFileDialog.getOpenFileName(self, "Open File",
QDir.currentPath())
if fileName:
image = QImage(fileName)
if image.isNull():
QMessageBox.information(self, "Image Viewer",
"Cannot load %s." % fileName)
return
self.imageLabel.setPixmap(QPixmap.fromImage(image))
self.scaleFactor = 1.0
self.printAct.setEnabled(True)
self.fitToWindowAct.setEnabled(True)
self.updateActions()
if not self.fitToWindowAct.isChecked():
self.imageLabel.adjustSize()
def print_(self):
dialog = QPrintDialog(self.printer, self)
if dialog.exec_():
painter = QPainter(self.printer)
rect = painter.viewport()
size = self.imageLabel.pixmap().size()
size.scale(rect.size(), Qt.KeepAspectRatio)
painter.setViewport(rect.x(), rect.y(), size.width(), size.height())
painter.setWindow(self.imageLabel.pixmap().rect())
painter.drawPixmap(0, 0, self.imageLabel.pixmap())
def zoomIn(self):
self.scaleImage(1.25)
def zoomOut(self):
self.scaleImage(0.8)
def normalSize(self):
self.imageLabel.adjustSize()
self.scaleFactor = 1.0
def fitToWindow(self):
fitToWindow = self.fitToWindowAct.isChecked()
self.scrollArea.setWidgetResizable(fitToWindow)
if not fitToWindow:
self.normalSize()
self.updateActions()
def about(self):
QMessageBox.about(self, "About Image Viewer",
"<p>The <b>Image Viewer</b> example shows how to combine "
"QLabel and QScrollArea to display an image. QLabel is "
"typically used for displaying text, but it can also display "
"an image. QScrollArea provides a scrolling view around "
"another widget. If the child widget exceeds the size of the "
"frame, QScrollArea automatically provides scroll bars.</p>"
"<p>The example demonstrates how QLabel's ability to scale "
"its contents (QLabel.scaledContents), and QScrollArea's "
"ability to automatically resize its contents "
"(QScrollArea.widgetResizable), can be used to implement "
"zooming and scaling features.</p>"
"<p>In addition the example shows how to use QPainter to "
"print an image.</p>")
def createActions(self):
self.openAct = QAction("&Open...", self, shortcut="Ctrl+O",
triggered=self.open)
self.printAct = QAction("&Print...", self, shortcut="Ctrl+P",
enabled=False, triggered=self.print_)
self.exitAct = QAction("E&xit", self, shortcut="Ctrl+Q",
triggered=self.close)
self.zoomInAct = QAction("Zoom &In (25%)", self, shortcut="Ctrl++",
enabled=False, triggered=self.zoomIn)
self.zoomOutAct = QAction("Zoom &Out (25%)", self, shortcut="Ctrl+-",
enabled=False, triggered=self.zoomOut)
self.normalSizeAct = QAction("&Normal Size", self, shortcut="Ctrl+S",
enabled=False, triggered=self.normalSize)
self.fitToWindowAct = QAction("&Fit to Window", self, enabled=False,
checkable=True, shortcut="Ctrl+F", triggered=self.fitToWindow)
self.aboutAct = QAction("&About", self, triggered=self.about)
self.aboutQtAct = QAction("About &Qt", self,
triggered=QApplication.instance().aboutQt)
def createMenus(self):
self.fileMenu = QMenu("&File", self)
self.fileMenu.addAction(self.openAct)
self.fileMenu.addAction(self.printAct)
self.fileMenu.addSeparator()
self.fileMenu.addAction(self.exitAct)
self.viewMenu = QMenu("&View", self)
self.viewMenu.addAction(self.zoomInAct)
self.viewMenu.addAction(self.zoomOutAct)
self.viewMenu.addAction(self.normalSizeAct)
self.viewMenu.addSeparator()
self.viewMenu.addAction(self.fitToWindowAct)
self.helpMenu = QMenu("&Help", self)
self.helpMenu.addAction(self.aboutAct)
self.helpMenu.addAction(self.aboutQtAct)
self.menuBar().addMenu(self.fileMenu)
self.menuBar().addMenu(self.viewMenu)
self.menuBar().addMenu(self.helpMenu)
def updateActions(self):
self.zoomInAct.setEnabled(not self.fitToWindowAct.isChecked())
self.zoomOutAct.setEnabled(not self.fitToWindowAct.isChecked())
self.normalSizeAct.setEnabled(not self.fitToWindowAct.isChecked())
def scaleImage(self, factor):
self.scaleFactor *= factor
self.imageLabel.resize(self.scaleFactor * self.imageLabel.pixmap().size())
self.adjustScrollBar(self.scrollArea.horizontalScrollBar(), factor)
self.adjustScrollBar(self.scrollArea.verticalScrollBar(), factor)
self.zoomInAct.setEnabled(self.scaleFactor < 3.0)
self.zoomOutAct.setEnabled(self.scaleFactor > 0.333)
def adjustScrollBar(self, scrollBar, factor):
scrollBar.setValue(int(factor * scrollBar.value()
+ ((factor - 1) * scrollBar.pageStep()/2)))
if __name__ == '__main__':
import sys
app = QApplication(sys.argv)
imageViewer = ImageViewer()
imageViewer.show()
sys.exit(app.exec_())
