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
|
# Test our C callback module
from callback import *
# -----------------------------------------------------
# Create a new widget and access a C callback function
# -----------------------------------------------------
# Create a new widget
w = new_widget()
# Attach a callback function written in C
widget_add_callback(w,FOO,"_0_void_p");
# Try using our callback function
widget_op(w,4.0)
# -----------------------------------------------------
# Create a new widget and attach a Python callback function
# -----------------------------------------------------
def callback(a):
print "Python callback function. Received : ",a
v = new_widget()
# Attach callback function
pywidget_add_callback(v,callback)
# Try calling our new function
widget_op(v,4.0)
# -----------------------------------------------------
# Now hammer on things a bit more
# -----------------------------------------------------
def print_array(a,nitems):
for i in range(0,nitems):
print "a[",i,"] = ", double_get(a,i)
def poly(a):
return 0.0025*a*a - 0.5*a + 4
t = new_widget()
pywidget_add_callback(t,poly)
# Create a C double array of 20 elements
a = double_array(20)
print "Using a Python function as a C callback"
# Call a C function for filling the array
fill_array(t,a,20)
# Print it out
print_array(a,20)
# Now attach an anonymous function
pywidget_add_callback(t,lambda x: 2*x)
print "Using a Python anonymous function as a C callback"
fill_array(t,a,20)
print_array(a,20)
# Now try to pass a class member in as a callback function
class Foo:
def __init__(self, nitems, func):
self.widget = new_widget()
self.data = double_array(nitems)
self.nitems = nitems
self.func = func
def __del__(self):
double_destroy(self.data)
def callback(self,value):
return self.func(value)
def fill(self):
pywidget_add_callback(self.widget,self.callback)
for i in range(0,self.nitems):
fill_array(self.widget,self.data,self.nitems)
def output(self):
for i in range(0,self.nitems):
print "data[",i,"] = ", double_get(self.data,i)
f = Foo(50,poly)
f.fill()
f.output()
|
