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
|
#
# animated wave demo (called by 'widget')
#
# based on Tcl/Tk8.5a2 widget demos
# destroy toplevel widget for this demo script
if defined?($aniwave_demo) && $aniwave_demo
$aniwave_demo.destroy
$aniwave_demo = nil
end
# create toplevel widget
$aniwave_demo = TkToplevel.new {|w|
title("Animated Wave Demonstration")
iconname("aniwave")
positionWindow(w)
}
base_frame = TkFrame.new($aniwave_demo).pack(:fill=>:both, :expand=>true)
# create label
msg = TkLabel.new(base_frame) {
font $font
wraplength '4i'
justify 'left'
text 'This demonstration contains a canvas widget with a line item inside it. The animation routines work by adjusting the coordinates list of the line.'
}
msg.pack('side'=>'top')
# create frame
TkFrame.new(base_frame) {|frame|
TkButton.new(frame) {
text 'Dismiss'
command proc{
tmppath = $aniwave_demo
$aniwave_demo = nil
tmppath.destroy
}
}.pack('side'=>'left', 'expand'=>'yes')
TkButton.new(frame) {
text 'See Code'
command proc{showCode 'aniwave'}
}.pack('side'=>'left', 'expand'=>'yes')
}.pack('side'=>'bottom', 'fill'=>'x', 'pady'=>'2m')
# animated wave
class AnimatedWaveDemo
def initialize(frame, dir=:left)
@direction = dir
# create canvas widget
@c = TkCanvas.new(frame, :width=>300, :height=>200,
:background=>'black')
@c.pack(:padx=>10, :pady=>10, :expand=>true)
# Creates a coordinates list of a wave.
@waveCoords = []
@backupCoords = []
n = 0
(-10..300).step(5){|n| @waveCoords << [n, 100]; @backupCoords << [n, 100] }
n = 305
@waveCoords << [n, 0]; @backupCoords << [n, 0]
@waveCoords << [n+5, 200]; @backupCoords << [n+5, 200]
@coordsLen = @waveCoords.length
# Create a smoothed line and arrange for its coordinates to be the
# contents of the variable waveCoords.
@line = TkcLine.new(@c, @waveCoords,
:width=>1, :fill=>'green', :smooth=>true)
# Main animation "loop".
# Theoretically 100 frames-per-second (==10ms between frames)
@timer = TkTimer.new(10){ basicMotion; reverser }
# Arrange for the animation loop to stop when the canvas is deleted
@c.bindtags_unshift(TkBindTag.new('Destroy'){ @timer.stop })
end
# Basic motion handler. Given what direction the wave is travelling
# in, it advances the y coordinates in the coordinate-list one step in
# that direction.
def basicMotion
@backupCoords, @waveCoords = @waveCoords, @backupCoords
(0...@coordsLen).each{|idx|
if @direction == :left
@waveCoords[idx][1] = @backupCoords[(idx+1 == @coordsLen)? 0: idx+1][1]
else
@waveCoords[idx][1] = @backupCoords[(idx == 0)? -1: idx-1][1]
end
}
@line.coords(@waveCoords)
end
# Oscillation handler. This detects whether to reverse the direction
# of the wave by checking to see if the peak of the wave has moved off
# the screen (whose size we know already.)
def reverser
if @waveCoords[0][1] < 10
@direction = :right
elsif @waveCoords[-1][1] < 10
@direction = :left
end
end
# animation control
def move
@timer.start
end
def stop
@timer.stop
end
end
# Start the animation processing
AnimatedWaveDemo.new(base_frame, :left).move
|
