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Python Tkinter Scrollable Text
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# Copyright 2019 Tal Einat | |
# | |
# Redistribution and use in source and binary forms, with or without | |
# modification, are permitted provided that the following conditions are met: | |
# | |
# 1. Redistributions of source code must retain the above copyright notice, | |
# this list of conditions and the following disclaimer. | |
# | |
# 2. 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. | |
# | |
# 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 HOLDER 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 functools import update_wrapper | |
from tkinter import Frame, Scrollbar, Text, NONE,\ | |
HORIZONTAL, VERTICAL, EW, NS, NSEW, TclError | |
__all__ = ['AutoHiddenScrollbar', 'add_config_callback', 'ScrollableTextFrame'] | |
class AutoHiddenScrollbar(Scrollbar): | |
"""A scrollbar that is automatically hidden when not needed. | |
Only the grid geometry manager is supported. | |
""" | |
def set(self, lo, hi): | |
if float(lo) > 0.0 or float(hi) < 1.0: | |
self.grid() | |
else: | |
self.grid_remove() | |
super().set(lo, hi) | |
def pack(self, **kwargs): | |
raise TclError(f'{self.__class__.__name__} does not support "pack"') | |
def place(self, **kwargs): | |
raise TclError(f'{self.__class__.__name__} does not support "place"') | |
def add_config_callback(config_callback): | |
"""Class decorator adding a configuration callback for Tk widgets. | |
The supplied callback will be called whenever a configuration change | |
is made to an instance of the decorated class, except if changes are | |
made directly at the Tk level, i.e. not via the Tkinter interface. | |
The callback will be called with a single dict parameter, containing | |
the new configuration info. | |
The callback is called before the configuration change is made to | |
the underlying widget, so that the previous configuration values may | |
be inspected by calling the widget's .configure() method. | |
""" | |
def decorator(cls): | |
class WidgetWithConfigHook(cls): | |
def __setitem__(self, key, value): | |
config_callback({key: value}) | |
super().__setitem__(key, value) | |
def configure(self, cnf=None, **kw): | |
if cnf is not None: | |
config_callback(cnf) | |
if kw: | |
config_callback(kw) | |
super().configure(cnf=cnf, **kw) | |
config = configure | |
update_wrapper(WidgetWithConfigHook, cls, updated=[]) | |
return WidgetWithConfigHook | |
return decorator | |
class ScrollableTextFrame(Frame): | |
"""Frame with a Text widget and scroll bars. | |
Scrollbars are dynamically shown and hidden according to the | |
contents of the text widget, so that they are shown only when | |
needed. | |
""" | |
def __init__(self, master, **kwargs): | |
"""Initialize the frame, scroll bars and text widget. | |
master - master widget for this frame | |
The Text widget is accessible via the 'text' attribute. | |
Its 'wrap' setting is initially set to 'none'; it can be | |
changed be calling e.g. `text.configure(wrap=tkinter.WORD)`. | |
""" | |
super().__init__(master, **kwargs) | |
@add_config_callback(self._handle_wrap) | |
class TextWithConfigHook(Text): | |
pass | |
self.text = TextWithConfigHook(self, wrap=NONE) | |
self.text.grid(row=0, column=0, sticky=NSEW) | |
self.grid_rowconfigure(0, weight=1) | |
self.grid_columnconfigure(0, weight=1) | |
# vertical scrollbar | |
self.yscroll = AutoHiddenScrollbar(self, orient=VERTICAL, | |
takefocus=False, | |
command=self.text.yview) | |
self.yscroll.grid(row=0, column=1, sticky=NS) | |
self.text['yscrollcommand'] = self.yscroll.set | |
# horizontal scrollbar | |
self.xscroll = AutoHiddenScrollbar(self, orient=HORIZONTAL, | |
takefocus=False, | |
command=self.text.xview) | |
self.xscroll.grid(row=1, column=0, sticky=EW) | |
self.text['xscrollcommand'] = self.xscroll.set | |
self.has_horiz_scroll = True | |
def _handle_wrap(self, cnf): | |
if 'wrap' in cnf: | |
self._set_xscroll(cnf['wrap']) | |
def _set_xscroll(self, wrap): | |
"""show/hide the horizontal scrollbar as per the 'wrap' setting""" | |
# show the scrollbar only when wrap is set to NONE | |
if wrap != NONE and self.has_horiz_scroll: | |
self.xscroll.grid_remove() | |
self.text['xscrollcommand'] = '' | |
self.has_horiz_scroll = False | |
elif wrap == NONE and not self.has_horiz_scroll: | |
self.xscroll.grid() | |
self.text['xscrollcommand'] = self.xscroll.set | |
self.has_horiz_scroll = True |
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# Copyright 2019 Tal Einat | |
# | |
# Redistribution and use in source and binary forms, with or without | |
# modification, are permitted provided that the following conditions are met: | |
# | |
# 1. Redistributions of source code must retain the above copyright notice, | |
# this list of conditions and the following disclaimer. | |
# | |
# 2. 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. | |
# | |
# 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 HOLDER 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. | |
import unittest | |
from tkinter import Tk, CHAR, NONE, WORD | |
from scrollable_text import ScrollableTextFrame | |
class ScrollableTextFrameTest(unittest.TestCase): | |
@classmethod | |
def setUpClass(cls): | |
cls.root = root = Tk() | |
root.withdraw() | |
@classmethod | |
def tearDownClass(cls): | |
cls.root.update_idletasks() | |
cls.root.destroy() | |
del cls.root | |
def make_frame(self, **kwargs): | |
frame = ScrollableTextFrame(self.root, **kwargs) | |
def cleanup_frame(): | |
frame.update_idletasks() | |
frame.destroy() | |
self.addCleanup(cleanup_frame) | |
return frame | |
def test_line1(self): | |
frame = self.make_frame() | |
text = frame.text | |
text.insert('1.0', 'lorem ipsum') | |
self.assertEqual(text.get('1.0', '1.end'), 'lorem ipsum') | |
def test_horiz_scrollbar(self): | |
# The horizontal scrollbar should be shown/hidden according to | |
# the 'wrap' setting: It should only be shown when 'wrap' is | |
# set to NONE. | |
frame = self.make_frame() | |
text = frame.text | |
# Check with default wrapping setting. | |
self.assertEqual(frame.has_horiz_scroll, text.cget('wrap') == NONE) | |
# Check after updating the 'wrap' setting in various ways. | |
text.config(wrap=NONE) | |
self.assertTrue(frame.has_horiz_scroll) | |
text.configure(wrap=CHAR) | |
self.assertFalse(frame.has_horiz_scroll) | |
text['wrap'] = NONE | |
self.assertTrue(frame.has_horiz_scroll) | |
text['wrap'] = WORD | |
self.assertFalse(frame.has_horiz_scroll) | |
if __name__ == '__main__': | |
unittest.main(verbosity=2) |
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