1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
|
#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2005-2005 Trolltech AS. All rights reserved.
##
## This file is part of the example classes of the Qt Toolkit.
##
## This file may be used under the terms of the GNU General Public
## License version 2.0 as published by the Free Software Foundation
## and appearing in the file LICENSE.GPL included in the packaging of
## this file. Please review the following information to ensure GNU
## General Public Licensing requirements will be met:
## http://www.trolltech.com/products/qt/opensource.html
##
## If you are unsure which license is appropriate for your use, please
## review the following information:
## http://www.trolltech.com/products/qt/licensing.html or contact the
## sales department at sales@trolltech.com.
##
## This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
## WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
##
#############################################################################
from PyQt4 import QtCore, QtGui
class ImageViewer(QtGui.QMainWindow):
def __init__(self):
super(ImageViewer, self).__init__()
self.printer = QtGui.QPrinter()
self.scaleFactor = 0.0
self.imageLabel = QtGui.QLabel()
self.imageLabel.setBackgroundRole(QtGui.QPalette.Base)
self.imageLabel.setSizePolicy(QtGui.QSizePolicy.Ignored,
QtGui.QSizePolicy.Ignored)
self.imageLabel.setScaledContents(True)
self.scrollArea = QtGui.QScrollArea()
self.scrollArea.setBackgroundRole(QtGui.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 = QtGui.QFileDialog.getOpenFileName(self, "Open File",
QtCore.QDir.currentPath())
if fileName:
image = QtGui.QImage(fileName)
if image.isNull():
QtGui.QMessageBox.information(self, "Image Viewer",
"Cannot load %s." % fileName)
return
self.imageLabel.setPixmap(QtGui.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 = QtGui.QPrintDialog(self.printer, self)
if dialog.exec_():
painter = QtGui.QPainter(self.printer)
rect = painter.viewport()
size = self.imageLabel.pixmap().size()
size.scale(rect.size(), QtCore.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):
QtGui.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 = QtGui.QAction("&Open...", self, shortcut="Ctrl+O",
triggered=self.open)
self.printAct = QtGui.QAction("&Print...", self, shortcut="Ctrl+P",
enabled=False, triggered=self.print_)
self.exitAct = QtGui.QAction("E&xit", self, shortcut="Ctrl+Q",
triggered=self.close)
self.zoomInAct = QtGui.QAction("Zoom &In (25%)", self,
shortcut="Ctrl++", enabled=False, triggered=self.zoomIn)
self.zoomOutAct = QtGui.QAction("Zoom &Out (25%)", self,
shortcut="Ctrl+-", enabled=False, triggered=self.zoomOut)
self.normalSizeAct = QtGui.QAction("&Normal Size", self,
shortcut="Ctrl+S", enabled=False, triggered=self.normalSize)
self.fitToWindowAct = QtGui.QAction("&Fit to Window", self,
enabled=False, checkable=True, shortcut="Ctrl+F",
triggered=self.fitToWindow)
self.aboutAct = QtGui.QAction("&About", self, triggered=self.about)
self.aboutQtAct = QtGui.QAction("About &Qt", self,
triggered=QtGui.qApp.aboutQt)
def createMenus(self):
self.fileMenu = QtGui.QMenu("&File", self)
self.fileMenu.addAction(self.openAct)
self.fileMenu.addAction(self.printAct)
self.fileMenu.addSeparator()
self.fileMenu.addAction(self.exitAct)
self.viewMenu = QtGui.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 = QtGui.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 = QtGui.QApplication(sys.argv)
imageViewer = ImageViewer()
imageViewer.show()
sys.exit(app.exec_())
|
