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#!/usr/bin/env python
'''Pixbufs
A GdkPixbuf represents an image, normally in RGB or RGBA format.
Pixbufs are normally used to load files from disk and perform image scaling.
This demo is not all that educational, but looks cool. It was written by
Extreme Pixbuf Hacker Federico Mena Quintero. It also shows off how to use
GtkDrawingArea to do a simple animation.
Look at the Image demo for additional pixbuf usage examples.'''
# pygtk version: Maik Hertha <maik.hertha@berlin.de>
import os
import math
import gobject
import gtk
FRAME_DELAY = 50
CYCLE_LEN = 60
IMAGE_DIR = os.path.join(os.path.dirname(__file__), 'images')
BACKGROUND_NAME = "background.jpg"
image_names = [
"apple-red.png",
"gnome-applets.png",
"gnome-calendar.png",
"gnome-foot.png",
"gnome-gmush.png",
"gnome-gimp.png",
"gnome-gsame.png",
"gnu-keys.png"
]
class PixbufsDemo(gtk.Window):
frame = None # frame of the background image
background = None # background-pixbuf
images = [] # list of pixbufs
back_width = 0 # width of background image
back_height = 0 # height of background image
timeout_id = 0 # timeout id
frame_num = 0 # number of the current frame
timeout_id = None
def __init__(self, parent=None):
gtk.Window.__init__(self)
try:
self.set_screen(parent.get_screen())
except AttributeError:
self.connect("destroy", lambda *w: gtk.main_quit())
self.connect("destroy", self.cleanup_callback)
self.set_title(self.__class__.__name__)
self.set_resizable(False)
if not self.load_pixbufs():
dialog = gtk.MessageDialog(self,
gtk.DIALOG_DESTROY_WITH_PARENT,
gtk.MESSAGE_ERROR,
gtk.BUTTONS_CLOSE,
"Failed to load an image")
dialog.connect("response", lambda d, r: d.destroy())
dialog.show()
else:
self.set_size_request(self.back_width, self.back_height)
self.frame = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, False, 8,
self.back_width, self.back_height)
da = gtk.DrawingArea()
da.connect("expose_event", self.expose_cb)
self.add(da)
self.timeout_id = gtk.timeout_add(FRAME_DELAY, self.timeout)
self.show_all()
def load_pixbufs(self):
''' Loads the images for the demo and returns whether the
operation succeeded.
'''
if self.background is not None:
return True # already loaded earlier
# look in the the current directory where the file is installed
try:
self.background = gtk.gdk.pixbuf_new_from_file(
os.path.join(IMAGE_DIR, BACKGROUND_NAME))
except gobject.GError, error:
return False
self.back_width = self.background.get_width()
self.back_height = self.background.get_height()
for filename in image_names:
try:
self.images.append(gtk.gdk.pixbuf_new_from_file(
os.path.join(IMAGE_DIR, filename)))
except gobject.GError, error:
return False
return True
def expose_cb(self, draw_area, event):
''' Expose callback for the drawing area. '''
rowstride = self.frame.get_rowstride()
# FIXME: what should be the result, string guchar an integer result?
#pixels = frame.get_pixels() + rowstride * event.area.y + event.area.x * 3
#pixels = frame.get_pixels()[len(frame.get_pixels()) + rowstride * event.area.y + event.area.x * 3]
pixels = self.frame.get_pixels()
draw_area.window.draw_rgb_image(
draw_area.style.black_gc,
event.area.x, event.area.y,
event.area.width, event.area.height,
'normal',
pixels, rowstride,
event.area.x, event.area.y)
return True
def cleanup_callback(self, win):
if self.timeout_id is not None:
gtk.timeout_remove(self.timeout_id)
self.timeout_id = None
def timeout(self):
''' Timeout handler to regenerate the frame. '''
self.background.copy_area(0, 0, self.back_width, self.back_height,
self.frame, 0, 0)
f = float(self.frame_num % CYCLE_LEN) / float(CYCLE_LEN)
xmid = self.back_width / 2.0
ymid = self.back_height / 2.0
radius = min(xmid, ymid) / 2.0
N_IMAGES = len(image_names)
for i_name in image_names:
i = image_names.index(i_name)
ang = 2.0 * math.pi * i / N_IMAGES - f * 2.0 * math.pi
iw = self.images[i].get_width()
ih = self.images[i].get_height()
r = radius +(radius / 3.0) * math.sin(f * 2.0 * math.pi)
xpos = math.floor(xmid + r * math.cos(ang) - iw / 2.0 + 0.5)
ypos = math.floor(ymid + r * math.sin(ang) - ih / 2.0 + 0.5)
if i % 2 == 0:
k = math.cos(f * 2.0 * math.pi)
else:
k = math.sin(f * 2.0 * math.pi)
k = 2.0 * k * k
k = max(0.25, k)
# satisfy the c-source
r1 = gtk.gdk.Rectangle()
r1.x = int(xpos)
r1.y = int(ypos)
r1.width = iw * k
r1.height = ih * k
r2 = gtk.gdk.Rectangle()
r2.x = 0
r2.y = 0
r2.width = self.back_width
r2.height = self.back_height
dest = r1.intersect(r2)
if dest is not None:
if i % 2 == 0:
alpha = int(
max(127, math.fabs(255 * math.cos(f * 2.0 * math.pi))))
else:
alpha = int(
max(127, math.fabs(255 * math.sin(f * 2.0 * math.pi))))
self.images[i].composite(
self.frame,
dest.x, dest.y,
dest.width, dest.height,
xpos, ypos,
k, k,
gtk.gdk.INTERP_NEAREST,
alpha)
if self is not None:
self.queue_draw()
self.frame_num += 1
return True
def main():
PixbufsDemo()
gtk.main()
if __name__ == '__main__':
main()
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