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#!/usr/bin/env python
#############################################################################
##
## Copyright (C) 2013 Riverbank Computing Limited.
## All rights reserved.
##
## This file is part of the examples of PyQt.
##
## 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 Riverbank Computing Limited 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,
## SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
## LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
## DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
## THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
## (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
## OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
##
#############################################################################
from PyQt5.QtCore import pyqtProperty, pyqtSignal, pyqtSlot
from PyQt5.QtWidgets import QApplication, QTextEdit
# The purpose of this class is to show that Designer's property editor shows
# all Python classes in the hierarchy that define properties.
class PyTextViewer(QTextEdit):
# Initialise the instance.
def __init__(self, parent=None):
super(PyTextViewer, self).__init__(parent)
self.setReadOnly(True)
# Initialise the author property by calling it's reset function.
self.resetAuthor()
# The getter for the author property. Note that we cannot follow the Qt
# naming convention (ie. by using the naming the getter "author") because
# it would conflict with the property name.
def getAuthor(self):
return self._author
# The setter for the author property.
def setAuthor(self, name):
self._author = name
# The resetter for the author property. Only Qt Designer uses this. Qt
# Designer does not use the deleter function of the property.
def resetAuthor(self):
self._author = "David Boddie"
# Define the author property. This will look like a C++ property to Qt
# Designer and a Python property to Python.
author = pyqtProperty(str, getAuthor, setAuthor, resetAuthor)
# This is the class that implements the custom widget.
class PyDemo(PyTextViewer):
# Define the Qt signals as a sequence of C++ function signatures excluding
# the return type. These may be connected to other signals or slots in Qt
# Designer.
zoomChanged = pyqtSignal(int)
# Initialise the instance.
def __init__(self, parent=None):
super(PyDemo, self).__init__(parent)
self.setWindowTitle("PyQt Demonstration Widget")
self.setText(_demo_text)
# Initialise the zoom property. We don't just call the resetter
# because it assumes that this has already been initialised.
self._zoom = 0
# The getter for the zoom property.
def getZoom(self):
return self._zoom
# The setter for the zoom property. We also make define this as a Qt slot
# which can be connected to Qt signals in Qt Designer.
@pyqtSlot(int)
def setZoom(self, zoom):
# Don't do anything if nothing has changed.
if self._zoom == zoom:
return
# Zoom in or out according to the relative zoom levels.
if self._zoom < zoom:
self.zoomIn(zoom - self._zoom)
elif self._zoom > zoom:
self.zoomOut(self._zoom - zoom)
# Remember the new zoom level.
self._zoom = zoom
# Emit the Qt signal to say that the zoom level has changed.
self.zoomChanged.emit(zoom)
# The resetter for the zoom property.
def resetZoom(self):
self.setZoom(0)
# Define the zoom property. Changing the value of this in Qt Designer's
# property editor causes the zoom level to change dynamically.
zoom = pyqtProperty(int, getZoom, setZoom, resetZoom)
# The text displayed in the custom widget.
_demo_text = """<h3>PyQt Demonstration Widget</h3>
<p>This simple example demonstrates the following features.</p>
<ul>
<li>The definition of properties that behave as C++ properties to Qt and
Python properties to Python.</li>
<li>The definition of new Qt signals that can be connected to other signals
and Qt slots in Designer.</li>
<li>The definition of new Qt slots that can be connected to signals in
Designer.</li>
</ul>
"""
# Display the custom widget if the script is being run directly from the
# command line.
if __name__ == "__main__":
import sys
app = QApplication(sys.argv)
demo = PyDemo()
demo.show()
sys.exit(app.exec_())
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