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
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
|
# 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 logging
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._in_zoomtouch = False
self._zoomtouch_scale = 1
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):
if zoom < ZOOM_MIN or zoom > ZOOM_MAX:
return
self._zoom = zoom
self.queue_draw()
def get_zoom(self):
return self._zoom
def can_zoom_in(self):
return self._zoom + ZOOM_STEP < ZOOM_MAX
def can_zoom_out(self):
return self._zoom - ZOOM_STEP > ZOOM_MIN
def zoom_in(self):
if not self.can_zoom_in():
return
self._zoom += ZOOM_STEP
self.queue_draw()
def zoom_out(self):
if not self.can_zoom_out():
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
alloc = self.get_allocation()
surface_width = self._surface.get_width()
surface_height = self._surface.get_height()
if alloc.width < surface_width or alloc.height < surface_height:
# Image is larger than allocated size
self._zoom = min(alloc.width * 1.0 / surface_width,
alloc.height * 1.0 / surface_height)
else:
self._zoom = 1.0
self.queue_draw()
def zoom_original(self):
self._zoom = 1
self.queue_draw()
def start_zoomtouch(self, center):
logging.debug("start_zoomtouch %r", center)
self._in_zoomtouch = True
self._zoomtouch_scale = 1
self.queue_draw()
def update_zoomtouch(self, center, scale):
logging.debug("update_zoomtouch %r", (center, scale))
self._zoomtouch_scale = scale
self.queue_draw()
def finish_zoomtouch(self):
logging.debug("finish_zoomtouch")
# apply zoom
self._zoom = self._zoom * self._zoomtouch_scale
self._in_zoomtouch = False
self._zoomtouch_scale = 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.
zoom_absolute = self._zoom * self._zoomtouch_scale
scaled_width = int(self._surface.get_width() * zoom_absolute)
scaled_height = int(self._surface.get_height() * zoom_absolute)
alloc = self.get_allocation()
x_offset = (alloc.width * 1.0 - scaled_width) / 2
y_offset = (alloc.height * 1.0 - scaled_height) / 2
ctx.translate(x_offset, y_offset)
ctx.scale(zoom_absolute, zoom_absolute)
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()
|