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
|
# Copyright (C) 2008, One Laptop per Child
# Author: Sayamindu Dasgupta <sayamindu@laptop.org>
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# This program 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 General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
import cairo
from gi.repository import Gtk
from gi.repository import Gdk
from gi.repository import GdkPixbuf
from gi.repository import GObject
ZOOM_STEP = 0.05
ZOOM_MAX = 4
ZOOM_MIN = 0.05
def _surface_from_file(file_location, ctx):
pixbuf = GdkPixbuf.Pixbuf.new_from_file(file_location)
surface = ctx.get_target().create_similar(
cairo.CONTENT_COLOR_ALPHA, pixbuf.get_width(),
pixbuf.get_height())
ctx_surface = cairo.Context(surface)
Gdk.cairo_set_source_pixbuf(ctx_surface, pixbuf, 0, 0)
ctx_surface.paint()
return surface
class ImageViewer(Gtk.DrawingArea):
def __init__(self):
Gtk.DrawingArea.__init__(self)
self._file_location = None
self._surface = None
self._zoom = None
self.connect('draw', self.__draw_cb)
def set_file_location(self, file_location):
self._file_location = file_location
self.queue_draw()
def set_zoom(self, zoom):
self._zoom = zoom
self.queue_draw()
def get_zoom(self):
return self._zoom
def zoom_in(self):
if self._zoom + ZOOM_STEP > ZOOM_MAX:
return
self._zoom += ZOOM_STEP
self.queue_draw()
def zoom_out(self):
if self._zoom - ZOOM_STEP < ZOOM_MIN:
return
self._zoom -= ZOOM_MIN
self.queue_draw()
def zoom_to_fit(self):
# This tries to figure out a best fit model
# If the image can fit in, we show it in 1:1,
# in any other case we show it in a fit to screen way
parent_allocation = self.get_parent().get_allocation()
parent_width = parent_allocation.width
parent_height = parent_allocation.height
surface_width = self._surface.get_width()
surface_height = self._surface.get_height()
if parent_width < surface_width or parent_height < surface_height:
# Image is larger than allocated size
self._zoom = min(parent_width * 1.0 / surface_width,
parent_height * 1.0 / surface_height)
else:
self._zoom = 1.0
self.queue_draw()
def zoom_equal(self):
self._zoom = 1
self.queue_draw()
def __draw_cb(self, widget, ctx):
# If the image surface is not set, it reads it from the file
# location. If the file location is not set yet, it just
# returns.
if self._surface is None:
if self._file_location is None:
return
self._surface = _surface_from_file(self._file_location, ctx)
if self._zoom is None:
self.zoom_to_fit()
# FIXME investigate
ctx.set_antialias(cairo.ANTIALIAS_NONE)
# Scale and center the image according to the current zoom.
scaled_width = int(self._surface.get_width() * self._zoom)
scaled_height = int(self._surface.get_height() * self._zoom)
parent_allocation = self.get_parent().get_allocation()
parent_width = parent_allocation.width
parent_height = parent_allocation.height
x_offset = (parent_width * 1.0 - scaled_width) / 2
y_offset = (parent_height * 1.0 - scaled_height) / 2
ctx.translate(x_offset, y_offset)
ctx.scale(self._zoom, self._zoom)
ctx.set_source_surface(self._surface, 0, 0)
# FIXME investigate
ctx.get_source().set_filter(cairo.FILTER_NEAREST)
ctx.paint()
if __name__ == '__main__':
import sys
window = Gtk.Window()
window.connect("destroy", Gtk.main_quit)
view = ImageViewer()
view.set_file_location(sys.argv[1])
window.add(view)
view.show()
window.set_size_request(800, 600)
window.show()
Gtk.main()
|