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#!/usr/bin/env python
# -*- Mode: Python; py-indent-offset: 4 -*-
# vim: tabstop=4 shiftwidth=4 expandtab
#
# Copyright (C) 2010 Red Hat, Inc., John (J5) Palmieri <johnp@redhat.com>
#
# This library is free software; you can redistribute it and/or
# modify it under the terms of the GNU Lesser General Public
# License as published by the Free Software Foundation; either
# version 2.1 of the License, or (at your option) any later version.
#
# This library is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
# Lesser General Public License for more details.
#
# You should have received a copy of the GNU Lesser General Public
# License along with this library; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301
# USA
title = "Images"
description = """GtkImage is used to display an image; the image can be in a
number of formats. Typically, you load an image into a GdkPixbuf, then display
the pixbuf. This demo code shows some of the more obscure cases, in the simple
case a call to gtk_image_new_from_file() is all you need.
"""
import os
from os import path
from gi.repository import Gtk, Gdk, GdkPixbuf, GLib, Gio, GObject
class ImagesApp:
def __init__(self):
self.pixbuf_loader = None
self.image_stream = None
self.window = Gtk.Window(title="Images")
self.window.connect('destroy', self.cleanup_cb)
self.window.set_border_width(8)
vbox = Gtk.VBox(spacing=8)
vbox.set_border_width(8)
self.window.add(vbox)
label = Gtk.Label()
label.set_markup('<u>Image loaded from file</u>')
vbox.pack_start(label, False, False, 0)
frame = Gtk.Frame()
frame.set_shadow_type(Gtk.ShadowType.IN)
# The alignment keeps the frame from growing when users resize
# the window
align = Gtk.Alignment(xalign=0.5,
yalign=0.5,
xscale=0,
yscale=0)
align.add(frame)
vbox.pack_start(align, False, False, 0)
self.base_path = os.path.abspath(os.path.dirname(__file__))
self.base_path = os.path.join(self.base_path, 'data')
filename = os.path.join(self.base_path, 'gtk-logo-rgb.gif')
pixbuf = GdkPixbuf.Pixbuf.new_from_file(filename)
transparent = pixbuf.add_alpha(True, 0xff, 0xff, 0xff)
image = Gtk.Image.new_from_pixbuf(transparent)
frame.add(image)
# Animation
label = Gtk.Label()
label.set_markup('<u>Animation loaded from file</u>')
vbox.pack_start(label, False, False, 0)
frame = Gtk.Frame()
frame.set_shadow_type(Gtk.ShadowType.IN)
# The alignment keeps the frame from growing when users resize
# the window
align = Gtk.Alignment(xalign=0.5,
yalign=0.5,
xscale=0,
yscale=0)
align.add(frame)
vbox.pack_start(align, False, False, 0)
img_path = path.join(self.base_path, 'floppybuddy.gif')
image = Gtk.Image.new_from_file(img_path)
frame.add(image)
# Symbolic icon
label = Gtk.Label()
label.set_markup('<u>Symbolic themed icon</u>')
vbox.pack_start(label, False, False, 0)
frame = Gtk.Frame()
frame.set_shadow_type(Gtk.ShadowType.IN)
# The alignment keeps the frame from growing when users resize
# the window
align = Gtk.Alignment(xalign=0.5,
yalign=0.5,
xscale=0,
yscale=0)
align.add(frame)
vbox.pack_start(align, False, False, 0)
gicon = Gio.ThemedIcon.new_with_default_fallbacks('battery-caution-charging-symbolic')
image = Gtk.Image.new_from_gicon(gicon, Gtk.IconSize.DIALOG)
frame.add(image)
# progressive
label = Gtk.Label()
label.set_markup('<u>Progressive image loading</u>')
vbox.pack_start(label, False, False, 0)
frame = Gtk.Frame()
frame.set_shadow_type(Gtk.ShadowType.IN)
# The alignment keeps the frame from growing when users resize
# the window
align = Gtk.Alignment(xalign=0.5,
yalign=0.5,
xscale=0,
yscale=0)
align.add(frame)
vbox.pack_start(align, False, False, 0)
image = Gtk.Image.new_from_pixbuf(None)
frame.add(image)
self.start_progressive_loading(image)
# Sensistivity control
button = Gtk.ToggleButton.new_with_mnemonic('_Insensitive')
button.connect('toggled', self.toggle_sensitivity_cb, vbox)
vbox.pack_start(button, False, False, 0)
self.window.show_all()
def toggle_sensitivity_cb(self, button, container):
widget_list = container.get_children()
for w in widget_list:
if w != button:
w.set_sensitive(not button.get_active())
return True
def progressive_timeout(self, image):
# This shows off fully-paranoid error handling, so looks scary.
# You could factor out the error handling code into a nice separate
# function to make things nicer.
if self.image_stream:
try:
buf = self.image_stream.read(256)
except IOError as e:
dialog = Gtk.MessageDialog(self.window,
Gtk.DialogFlags.DESTROY_WITH_PARENT,
Gtk.MessageType.ERROR,
Gtk.ButtonsType.CLOSE,
"Failure reading image file 'alphatest.png': %s" % (str(e), ))
self.image_stream.close()
self.image_stream = None
self.load_timeout = 0
dialog.show()
dialog.connect('response', lambda x, y: dialog.destroy())
return False # uninstall the timeout
try:
self.pixbuf_loader.write(buf)
except GObject.GError as e:
dialog = Gtk.MessageDialog(self.window,
Gtk.DialogFlags.DESTROY_WITH_PARENT,
Gtk.MessageType.ERROR,
Gtk.ButtonsType.CLOSE,
e.message)
self.image_stream.close()
self.image_stream = None
self.load_timeout = 0
dialog.show()
dialog.connect('response', lambda x, y: dialog.destroy())
return False # uninstall the timeout
if len(buf) < 256: # eof
self.image_stream.close()
self.image_stream = None
# Errors can happen on close, e.g. if the image
# file was truncated we'll know on close that
# it was incomplete.
try:
self.pixbuf_loader.close()
except GObject.GError as e:
dialog = Gtk.MessageDialog(self.window,
Gtk.DialogFlags.DESTROY_WITH_PARENT,
Gtk.MessageType.ERROR,
Gtk.ButtonsType.CLOSE,
'Failed to load image: %s' % e.message)
self.load_timeout = 0
dialog.show()
dialog.connect('response', lambda x, y: dialog.destroy())
return False # uninstall the timeout
else:
img_path = path.join(self.base_path, 'alphatest.png')
try:
self.image_stream = open(img_path, 'rb')
except IOError as e:
dialog = Gtk.MessageDialog(self.window,
Gtk.DialogFlags.DESTROY_WITH_PARENT,
Gtk.MessageType.ERROR,
Gtk.ButtonsType.CLOSE,
str(e))
self.load_timeout = 0
dialog.show()
dialog.connect('response', lambda x, y: dialog.destroy())
return False # uninstall the timeout
if self.pixbuf_loader:
try:
self.pixbuf_loader.close()
except GObject.GError:
pass
self.pixbuf_loader = None
self.pixbuf_loader = GdkPixbuf.PixbufLoader()
self.pixbuf_loader.connect('area-prepared',
self.progressive_prepared_callback,
image)
self.pixbuf_loader.connect('area-updated',
self.progressive_updated_callback,
image)
# leave timeout installed
return True
def progressive_prepared_callback(self, loader, image):
pixbuf = loader.get_pixbuf()
# Avoid displaying random memory contents, since the pixbuf
# isn't filled in yet.
pixbuf.fill(0xaaaaaaff)
image.set_from_pixbuf(pixbuf)
def progressive_updated_callback(self, loader, x, y, width, height, image):
# We know the pixbuf inside the GtkImage has changed, but the image
# itself doesn't know this; so queue a redraw. If we wanted to be
# really efficient, we could use a drawing area or something
# instead of a GtkImage, so we could control the exact position of
# the pixbuf on the display, then we could queue a draw for only
# the updated area of the image.
image.queue_draw()
def start_progressive_loading(self, image):
# This is obviously totally contrived (we slow down loading
# on purpose to show how incremental loading works).
# The real purpose of incremental loading is the case where
# you are reading data from a slow source such as the network.
# The timeout simply simulates a slow data source by inserting
# pauses in the reading process.
self.load_timeout = Gdk.threads_add_timeout(150,
GLib.PRIORITY_DEFAULT_IDLE,
self.progressive_timeout,
image)
def cleanup_cb(self, widget):
if self.load_timeout:
GLib.source_remove(self.load_timeout)
if self.pixbuf_loader:
try:
self.pixbuf_loader.close()
except GObject.GError:
pass
if self.image_stream:
self.image_stream.close()
Gtk.main_quit()
def main(demoapp=None):
ImagesApp()
Gtk.main()
if __name__ == '__main__':
main()
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