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
|
<?xml version="1.0" encoding="utf-8"?>
<page xmlns="http://projectmallard.org/1.0/" xmlns:its="http://www.w3.org/2005/11/its" xmlns:xi="http://www.w3.org/2001/XInclude" type="guide" style="task" id="widget_drawing.py" xml:lang="gl">
<info>
<title type="text">Xanela (Python)</title>
<link type="guide" xref="beginner.py#misc"/>
<revision version="0.1" date="2013-02-24" status="stub"/>
<credit type="author copyright">
<name>Marta Maria Casetti</name>
<email its:translate="no">mmcasetti@gmail.com</email>
<years>2013</years>
</credit>
<desc>A widget that uses the Cairo library to draw</desc>
<mal:credit xmlns:mal="http://projectmallard.org/1.0/" type="translator copyright">
<mal:name>Fran Dieguez</mal:name>
<mal:email>frandieguez@gnome.org</mal:email>
<mal:years>2012-2013.</mal:years>
</mal:credit>
</info>
<title>Widget</title>
<media type="image" mime="image/png" src="media/widget_drawing.png"/>
<p>Enter an angle, visualize it.</p>
<links type="section"/>
<section id="code">
<title>Código usado para xerar este exemplo</title>
<code mime="text/x-python" style="numbered">from gi.repository import Gtk
from gi.repository import cairo
import sys
import math
class MyWindow(Gtk.ApplicationWindow):
def __init__(self, app):
Gtk.Window.__init__(self, title="Choose an angle", application=app)
self.set_default_size(400, 400)
self.set_border_width(10)
# a default angle
self.angle = 360
grid = Gtk.Grid()
# a spinbutton that takes the value of an angle
ad = Gtk.Adjustment(360, 0, 360, 1, 0, 0)
self.spin = Gtk.SpinButton(adjustment=ad, climb_rate=1, digits=0)
self.spin.connect("value-changed", self.get_angle)
# a drawing area for drawing whatever we want
self.darea = Gtk.DrawingArea()
# that we describe in the method draw(), connected to the signal "draw"
self.darea.connect("draw", self.draw)
# we have to request a minimum size of the drawing area, or it will
# disappear
self.darea.set_size_request(300, 300)
grid.attach(self.spin, 0, 0, 1, 1)
grid.attach(self.darea, 0, 1, 1, 1)
self.add(grid)
# whenever we get a new angle in the spinbutton
def get_angle(self, event):
self.angle = self.spin.get_value_as_int()
# redraw what is in the drawing area
self.darea.queue_draw()
def draw(self, darea, cr):
# a 10-pixels-wide line
cr.set_line_width(10)
# red
cr.set_source_rgba(0.5, 0.0, 0.0, 1.0)
# get the width and height of the drawing area
w = self.darea.get_allocated_width()
h = self.darea.get_allocated_height()
# move to the center of the drawing area
# (translate from the top left corner to w/2, h/2)
cr.translate(w / 2, h / 2)
# draw a line to (55, 0)
cr.line_to(55, 0)
# and get back to (0, 0)
cr.line_to(0, 0)
# draw an arc centered in the origin, 50 pixels wide, from the angle 0
# (in radians) to the angle given by the spinbutton (in degrees)
cr.arc(0, 0, 50, 0, self.angle * (math.pi / 180))
# draw a line back to the origin
cr.line_to(0, 0)
# drawing the path, and keeping the path for future use
cr.stroke_preserve()
# set a colour
cr.set_source_rgba(0.0, 0.5, 0.5, 1.0)
# and use it to fill the path (that we had kept)
cr.fill()
class MyApplication(Gtk.Application):
def __init__(self):
Gtk.Application.__init__(self)
def do_activate(self):
win = MyWindow(self)
win.show_all()
def do_startup(self):
Gtk.Application.do_startup(self)
app = MyApplication()
exit_status = app.run(sys.argv)
sys.exit(exit_status)
</code>
</section>
<section id="references">
<title>API References</title>
<p>Neste exemplo empregaremos o seguinte:</p>
<list>
<item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkWidget.html">GtkWidget</link></p></item>
<item><p><link href="http://developer.gnome.org/gtk3/unstable/GtkDrawingArea.html">GtkDrawingArea</link></p></item>
<item><p><link href="http://www.tortall.net/mu/wiki/CairoTutorial">The Cairo Tutorial for Python Programmers</link></p></item>
</list>
</section>
</page>
|
