[4512] | 1 | # -*- mode: tcl; indent-tabs-mode: nil -*- |
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| 2 | # ---------------------------------------------------------------------- |
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| 3 | # COMPONENT: tweener - used for animating smooth movements |
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| 4 | # |
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| 5 | # Each Tweener executes a command repeatedly through a series of |
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| 6 | # values from one extreme to another. For example, the command may |
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| 7 | # change the size of a rectangle, and the values may go from 10 to |
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| 8 | # 200. The Tweener will make that happen over a specified interval |
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| 9 | # of time. The animation can be stopped or changed at any point, |
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| 10 | # and if the Tweener is destroyed, the action is cancelled. |
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| 11 | # ====================================================================== |
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| 12 | # AUTHOR: Michael McLennan, Purdue University |
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| 13 | # Copyright (c) 2004-2012 HUBzero Foundation, LLC |
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| 14 | # |
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| 15 | # See the file "license.terms" for information on usage and |
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| 16 | # redistribution of this file, and for a DISCLAIMER OF ALL WARRANTIES. |
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| 17 | # ====================================================================== |
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| 18 | package require Itcl |
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| 19 | |
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| 20 | itcl::class Rappture::Tweener { |
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| 21 | public variable from 0 ;# value goes from this... |
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| 22 | public variable to 1 ;# ...to this |
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| 23 | public variable duration 500 ;# during this time interval |
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| 24 | public variable steps 10 ;# with this many steps |
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| 25 | public variable command "" ;# gets executed with %v for value |
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| 26 | public variable finalize "" ;# gets executed at the end to finish up |
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| 27 | |
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| 28 | constructor {args} { eval configure $args } |
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| 29 | destructor { # defined below } |
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| 30 | |
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| 31 | public method go {{how "-resume"}} |
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| 32 | public method stop {} |
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| 33 | |
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| 34 | private method _next {} |
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| 35 | |
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| 36 | private variable _nstep 0 ;# current step number |
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| 37 | private variable _afterid "" ;# pending after event |
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| 38 | } |
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| 39 | |
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| 40 | # ---------------------------------------------------------------------- |
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| 41 | # DESTRUCTOR |
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| 42 | # ---------------------------------------------------------------------- |
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| 43 | itcl::body Rappture::Tweener::destructor {} { |
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| 44 | stop |
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| 45 | } |
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| 46 | |
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| 47 | # ---------------------------------------------------------------------- |
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| 48 | # USAGE: go ?-resume|-restart? |
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| 49 | # |
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| 50 | # Causes the current animation to start running, either where it |
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| 51 | # left off (-resume) or fromt the beginning (-restart). |
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| 52 | # ---------------------------------------------------------------------- |
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| 53 | itcl::body Rappture::Tweener::go {{how -resume}} { |
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| 54 | switch -- $how { |
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| 55 | -resume { |
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| 56 | # leave _nstep alone |
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| 57 | } |
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| 58 | -restart { |
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| 59 | set _nstep 0 |
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| 60 | } |
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| 61 | default { |
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| 62 | error "bad option \"$how\": should be -restart or -resume" |
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| 63 | } |
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| 64 | } |
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| 65 | stop |
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| 66 | set _afterid [after idle [itcl::code $this _next]] |
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| 67 | } |
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| 68 | |
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| 69 | # ---------------------------------------------------------------------- |
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| 70 | # USAGE: stop |
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| 71 | # |
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| 72 | # Causes the animation to stop by cancelling any pending after event. |
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| 73 | # ---------------------------------------------------------------------- |
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| 74 | itcl::body Rappture::Tweener::stop {} { |
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| 75 | if {"" != $_afterid} { |
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| 76 | after cancel $_afterid |
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| 77 | set _afterid "" |
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| 78 | } |
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| 79 | } |
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| 80 | |
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| 81 | # ---------------------------------------------------------------------- |
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| 82 | # USAGE: _next |
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| 83 | # |
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| 84 | # Used internally to advance the animation. Executes the -command |
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| 85 | # option with the current value substituted in place of any %v values. |
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| 86 | # ---------------------------------------------------------------------- |
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| 87 | itcl::body Rappture::Tweener::_next {} { |
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| 88 | set value [expr {($to-$from)/double($steps)*$_nstep + $from}] |
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| 89 | set cmd $command |
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| 90 | regsub -all %v $cmd $value cmd |
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| 91 | if {[catch {uplevel #0 $cmd} result]} { |
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| 92 | bgerror "$result\n (while managing tweener $this)" |
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| 93 | } |
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| 94 | |
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| 95 | if {[incr _nstep] <= $steps} { |
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| 96 | set delay [expr {round($duration/double($steps))}] |
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| 97 | set _afterid [after $delay [itcl::code $this _next]] |
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| 98 | } elseif {[string length $finalize] > 0} { |
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| 99 | set cmd $finalize |
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| 100 | regsub -all %v $cmd $value cmd |
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| 101 | if {[catch {uplevel #0 $cmd} result]} { |
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| 102 | bgerror "$result\n (while finalizing tweener $this)" |
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| 103 | } |
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| 104 | } |
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| 105 | } |
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| 106 | |
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| 107 | # ---------------------------------------------------------------------- |
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| 108 | # CONFIGURATION OPTION: -command |
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| 109 | # ---------------------------------------------------------------------- |
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| 110 | itcl::configbody Rappture::Tweener::command { |
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| 111 | if {[string length $command] == 0} { |
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| 112 | stop |
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| 113 | } |
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| 114 | } |
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