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