8.5. Example
The example program (rangewidgets.py) is a somewhat modified version of the "range controls" test from testgtk.py. It basically puts up a window with three range widgets all connected to the same adjustment, and a couple of controls for adjusting some of the parameters mentioned above and in the section on adjustments, so you can see how they affect the way these widgets work for the user. Figure 8.1 illustrates the result of running the program:
Figure 8.1 Range Widgets Example
1 #!/usr/bin/env python
2
3 # example rangewidgets.py
4
5 import gtk
6
7 # Convenience functions
8
9 def make_menu_item(name, callback, data=None):
10 item = gtk.GtkMenuItem(name)
11 item.connect("activate", callback, data)
12 item.show()
13 return item
14
15 def scale_set_default_values(scale):
16 scale.set_update_policy(gtk.UPDATE_CONTINUOUS)
17 scale.set_digits(1)
18 scale.set_value_pos(gtk.POS_TOP)
19 scale.set_draw_value(gtk.TRUE)
20
21 class RangeWidgets:
22 def cb_pos_menu_select(self, item, pos):
23 # Set the value position on both scale widgets
24 self.hscale.set_value_pos(pos)
25 self.vscale.set_value_pos(pos)
26
27 def cb_update_menu_select(self, item, policy):
28 # Set the update policy for both scale widgets
29 self.hscale.set_update_policy(policy)
30 self.vscale.set_update_policy(policy)
31
32 def cb_digits_scale(self, adj):
33 # Set the number of decimal places to which adj->value is rounded
34 self.hscale.set_digits(adj.value)
35 self.vscale.set_digits(adj.value)
36
37 def cb_page_size(self, get, set):
38 # Set the page size and page increment size of the sample
39 # adjustment to the value specified by the "Page Size" scale
40 set.set_all(set.value, set.lower, set.upper, set.step_increment,
41 get.value, get.value,)
42 # Now emit the "changed" signal to reconfigure all the widgets that
43 # are attached to this adjustment
44 set.emit("changed")
45
46 def cb_draw_value(self, button):
47 # Turn the value display on the scale widgets off or on depending
48 # on the state of the checkbutton
49 self.hscale.set_draw_value(button.active)
50 self.vscale.set_draw_value(button.active)
51
52 # makes the sample window
53
54 def __init__(self):
55 # Standard window-creating stuff
56 self.window = gtk.GtkWindow (gtk.WINDOW_TOPLEVEL)
57 self.window.connect("destroy", gtk.mainquit)
58 self.window.set_title("range controls")
59
60 box1 = gtk.GtkVBox(gtk.FALSE, 0)
61 self.window.add(box1)
62 box1.show()
63
64 box2 = gtk.GtkHBox(gtk.FALSE, 10)
65 box2.set_border_width(10)
66 box1.pack_start(box2, gtk.TRUE, gtk.TRUE, 0)
67 box2.show()
68
69 # value, lower, upper, step_increment, page_increment, page_size
70 # Note that the page_size value only makes a difference for
71 # scrollbar widgets, and the highest value you'll get is actually
72 # (upper - page_size).
73 adj1 = gtk.GtkAdjustment(0.0, 0.0, 101.0, 0.1, 1.0, 1.0)
74
75 self.vscale = gtk.GtkVScale(adj1)
76 scale_set_default_values(self.vscale)
77 box2.pack_start(self.vscale, gtk.TRUE, gtk.TRUE, 0)
78 self.vscale.show()
79
80 box3 = gtk.GtkVBox(gtk.FALSE, 10)
81 box2.pack_start(box3, gtk.TRUE, gtk.TRUE, 0)
82 box3.show()
83
84 # Reuse the same adjustment
85 self.hscale = gtk.GtkHScale(adj1)
86 self.hscale.set_usize(200, 30)
87 scale_set_default_values(self.hscale)
88 box3.pack_start(self.hscale, gtk.TRUE, gtk.TRUE, 0)
89 self.hscale.show()
90
91 # Reuse the same adjustment again
92 scrollbar = gtk.GtkHScrollbar(adj1)
93 # Notice how this causes the scales to always be updated
94 # continuously when the scrollbar is moved
95 scrollbar.set_update_policy(gtk.UPDATE_CONTINUOUS)
96 box3.pack_start(scrollbar, gtk.TRUE, gtk.TRUE, 0)
97 scrollbar.show()
98
99 box2 = gtk.GtkHBox(gtk.FALSE, 10)
100 box2.set_border_width(10)
101 box1.pack_start(box2, gtk.TRUE, gtk.TRUE, 0)
102 box2.show()
103
104 # A checkbutton to control whether the value is displayed or not
105 button = gtk.GtkCheckButton("Display value on scale widgets")
106 button.set_active(gtk.TRUE)
107 button.connect("toggled", self.cb_draw_value)
108 box2.pack_start(button, gtk.TRUE, gtk.TRUE, 0)
109 button.show()
110
111 box2 = gtk.GtkHBox(gtk.FALSE, 10)
112 box2.set_border_width(10)
113
114 # An option menu to change the position of the value
115 label = gtk.GtkLabel("Scale Value Position:")
116 box2.pack_start(label, gtk.FALSE, gtk.FALSE, 0)
117 label.show()
118
119 opt = gtk.GtkOptionMenu()
120 menu = gtk.GtkMenu()
121
122 item = make_menu_item ("Top", self.cb_pos_menu_select, gtk.POS_TOP)
123 menu.append(item)
124
125 item = make_menu_item ("Bottom", self.cb_pos_menu_select,
126 gtk.POS_BOTTOM)
127 menu.append(item)
128
129 item = make_menu_item ("Left", self.cb_pos_menu_select, gtk.POS_LEFT)
130 menu.append(item)
131
132 item = make_menu_item ("Right", self.cb_pos_menu_select, gtk.POS_RIGHT)
133 menu.append(item)
134
135 opt.set_menu(menu)
136 box2.pack_start(opt, gtk.TRUE, gtk.TRUE, 0)
137 opt.show()
138
139 box1.pack_start(box2, gtk.TRUE, gtk.TRUE, 0)
140 box2.show()
141
142 box2 = gtk.GtkHBox(gtk.FALSE, 10)
143 box2.set_border_width(10)
144
145 # Yet another option menu, this time for the update policy of the
146 # scale widgets
147 label = gtk.GtkLabel("Scale Update Policy:")
148 box2.pack_start(label, gtk.FALSE, gtk.FALSE, 0)
149 label.show()
150
151 opt = gtk.GtkOptionMenu()
152 menu = gtk.GtkMenu()
153
154 item = make_menu_item("Continuous", self.cb_update_menu_select,
155 gtk.UPDATE_CONTINUOUS)
156 menu.append(item)
157
158 item = make_menu_item ("Discontinuous", self.cb_update_menu_select,
159 gtk.UPDATE_DISCONTINUOUS)
160 menu.append(item)
161
162 item = make_menu_item ("Delayed", self.cb_update_menu_select,
163 gtk.UPDATE_DELAYED)
164 menu.append(item)
165
166 opt.set_menu(menu)
167 box2.pack_start(opt, gtk.TRUE, gtk.TRUE, 0)
168 opt.show()
169
170 box1.pack_start(box2, gtk.TRUE, gtk.TRUE, 0)
171 box2.show()
172
173 box2 = gtk.GtkHBox(gtk.FALSE, 10)
174 box2.set_border_width(10)
175
176 # An HScale widget for adjusting the number of digits on the
177 # sample scales.
178 label = gtk.GtkLabel("Scale Digits:")
179 box2.pack_start(label, gtk.FALSE, gtk.FALSE, 0)
180 label.show()
181
182 adj2 = gtk.GtkAdjustment(1.0, 0.0, 5.0, 1.0, 1.0, 0.0)
183 adj2.connect("value_changed", self.cb_digits_scale)
184 scale = gtk.GtkHScale(adj2)
185 scale.set_digits(0)
186 box2.pack_start(scale, gtk.TRUE, gtk.TRUE, 0)
187 scale.show()
188
189 box1.pack_start(box2, gtk.TRUE, gtk.TRUE, 0)
190 box2.show()
191
192 box2 = gtk.GtkHBox(gtk.FALSE, 10)
193 box2.set_border_width(10)
194
195 # And, one last HScale widget for adjusting the page size of the
196 # scrollbar.
197 label = gtk.GtkLabel("Scrollbar Page Size:")
198 box2.pack_start(label, gtk.FALSE, gtk.FALSE, 0)
199 label.show()
200
201 adj2 = gtk.GtkAdjustment(1.0, 1.0, 101.0, 1.0, 1.0, 0.0)
202 adj2.connect("value_changed", self.cb_page_size, adj1)
203 scale = gtk.GtkHScale(adj2)
204 scale.set_digits(0)
205 box2.pack_start(scale, gtk.TRUE, gtk.TRUE, 0)
206 scale.show()
207
208 box1.pack_start(box2, gtk.TRUE, gtk.TRUE, 0)
209 box2.show()
210
211 separator = gtk.GtkHSeparator()
212 box1.pack_start(separator, gtk.FALSE, gtk.TRUE, 0)
213 separator.show()
214
215 box2 = gtk.GtkVBox(gtk.FALSE, 10)
216 box2.set_border_width(10)
217 box1.pack_start(box2, gtk.FALSE, gtk.TRUE, 0)
218 box2.show()
219
220 button = gtk.GtkButton("Quit")
221 button.connect_object("clicked", gtk.mainquit, self.window)
222 box2.pack_start(button, gtk.TRUE, gtk.TRUE, 0)
223 button.set_flags(gtk.CAN_DEFAULT)
224 button.grab_default()
225 button.show()
226 self.window.show()
227
228 def main():
229 gtk.mainloop()
230 return 0
231
232 if __name__ == "__main__":
233 RangeWidgets()
234 main()
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You will notice that the program does not call the connect() method for the "delete_event", but only for the "destroy" signal. This will still perform the desired operation, because an unhandled "delete_event" will result in a "destroy" signal being given to the window.