lib/tk8.4/demos/ctext.tcl

   1 # ctext.tcl --
   2 #
   3 # This demonstration script creates a canvas widget with a text
   4 # item that can be edited and reconfigured in various ways.
   5 #
   6 # RCS: @(#) $Id: ctext.tcl,v 1.3 2001/06/14 10:56:58 dkf Exp $
   7
   8 if {![info exists widgetDemo]} {
   9     error "This script should be run from the \"widget\" demo."
  10 }
  11
  12 set w .ctext
  13 catch {destroy $w}
  14 toplevel $w
  15 wm title $w "Canvas Text Demonstration"
  16 wm iconname $w "Text"
  17 positionWindow $w
  18 set c $w.c
  19
  20 label $w.msg -font $font -wraplength 5i -justify left -text "This window displays a string of text to demonstrate the text facilities of canvas widgets.  You can click in the boxes to adjust the position of the text relative to its positioning point or change its justification.  The text also supports the following simple bindings for editing:
  21   1. You can point, click, and type.
  22   2. You can also select with button 1.
  23   3. You can copy the selection to the mouse position with button 2.
  24   4. Backspace and Control+h delete the selection if there is one;
  25      otherwise they delete the character just before the insertion cursor.
  26   5. Delete deletes the selection if there is one; otherwise it deletes
  27      the character just after the insertion cursor."
  28 pack $w.msg -side top
  29
  30 frame $w.buttons
  31 pack $w.buttons -side bottom -fill x -pady 2m
  32 button $w.buttons.dismiss -text Dismiss -command "destroy $w"
  33 button $w.buttons.code -text "See Code" -command "showCode $w"
  34 pack $w.buttons.dismiss $w.buttons.code -side left -expand 1
  35
  36 canvas $c -relief flat -borderwidth 0 -width 500 -height 350
  37 pack $w.c -side top -expand yes -fill both
  38
  39 set textFont {Helvetica 24}
  40
  41 $c create rectangle 245 195 255 205 -outline black -fill red
  42
  43 # First, create the text item and give it bindings so it can be edited.
  44
  45 $c addtag text withtag [$c create text 250 200 -text "This is just a string of text to demonstrate the text facilities of canvas widgets. Bindings have been been defined to support editing (see above)." -width 440 -anchor n -font {Helvetica 24} -justify left]
  46 $c bind text <1> "textB1Press $c %x %y"
  47 $c bind text <B1-Motion> "textB1Move $c %x %y"
  48 $c bind text <Shift-1> "$c select adjust current @%x,%y"
  49 $c bind text <Shift-B1-Motion> "textB1Move $c %x %y"
  50 $c bind text <KeyPress> "textInsert $c %A"
  51 $c bind text <Return> "textInsert $c \\n"
  52 $c bind text <Control-h> "textBs $c"
  53 $c bind text <BackSpace> "textBs $c"
  54 $c bind text <Delete> "textDel $c"
  55 $c bind text <2> "textPaste $c @%x,%y"
  56
  57 # Next, create some items that allow the text's anchor position
  58 # to be edited.
  59
  60 proc mkTextConfig {w x y option value color} {
  61     set item [$w create rect $x $y [expr {$x+30}] [expr {$y+30}] \
  62             -outline black -fill $color -width 1]
  63     $w bind $item <1> "$w itemconf text $option $value"
  64     $w addtag config withtag $item
  65 }
  66
  67 set x 50
  68 set y 50
  69 set color LightSkyBlue1
  70 mkTextConfig $c $x $y -anchor se $color
  71 mkTextConfig $c [expr {$x+30}] [expr {$y   }] -anchor s      $color
  72 mkTextConfig $c [expr {$x+60}] [expr {$y   }] -anchor sw     $color
  73 mkTextConfig $c [expr {$x   }] [expr {$y+30}] -anchor e      $color
  74 mkTextConfig $c [expr {$x+30}] [expr {$y+30}] -anchor center $color
  75 mkTextConfig $c [expr {$x+60}] [expr {$y+30}] -anchor w      $color
  76 mkTextConfig $c [expr {$x   }] [expr {$y+60}] -anchor ne     $color
  77 mkTextConfig $c [expr {$x+30}] [expr {$y+60}] -anchor n      $color
  78 mkTextConfig $c [expr {$x+60}] [expr {$y+60}] -anchor nw     $color
  79 set item [$c create rect \
  80         [expr {$x+40}] [expr {$y+40}] [expr {$x+50}] [expr {$y+50}] \
  81         -outline black -fill red]
  82 $c bind $item <1> "$c itemconf text -anchor center"
  83 $c create text [expr {$x+45}] [expr {$y-5}] \
  84         -text {Text Position}  -anchor s  -font {Times 24}  -fill brown
  85
  86 # Lastly, create some items that allow the text's justification to be
  87 # changed.
  88
  89 set x 350
  90 set y 50
  91 set color SeaGreen2
  92 mkTextConfig $c $x $y -justify left $color
  93 mkTextConfig $c [expr {$x+30}] $y -justify center $color
  94 mkTextConfig $c [expr {$x+60}] $y -justify right $color
  95 $c create text [expr {$x+45}] [expr {$y-5}] \
  96         -text {Justification}  -anchor s  -font {Times 24}  -fill brown
  97
  98 $c bind config <Enter> "textEnter $c"
  99 $c bind config <Leave> "$c itemconf current -fill \$textConfigFill"
 100
 101 set textConfigFill {}
 102
 103 proc textEnter {w} {
 104     global textConfigFill
 105     set textConfigFill [lindex [$w itemconfig current -fill] 4]
 106     $w itemconfig current -fill black
 107 }
 108
 109 proc textInsert {w string} {
 110     if {$string == ""} {
 111         return
 112     }
 113     catch {$w dchars text sel.first sel.last}
 114     $w insert text insert $string
 115 }
 116
 117 proc textPaste {w pos} {
 118     catch {
 119         $w insert text $pos [selection get]
 120     }
 121 }
 122
 123 proc textB1Press {w x y} {
 124     $w icursor current @$x,$y
 125     $w focus current
 126     focus $w
 127     $w select from current @$x,$y
 128 }
 129
 130 proc textB1Move {w x y} {
 131     $w select to current @$x,$y
 132 }
 133
 134 proc textBs {w} {
 135     if {![catch {$w dchars text sel.first sel.last}]} {
 136         return
 137     }
 138     set char [expr {[$w index text insert] - 1}]
 139     if {$char >= 0} {$w dchar text $char}
 140 }
 141
 142 proc textDel {w} {
 143     if {![catch {$w dchars text sel.first sel.last}]} {
 144         return
 145     }
 146     $w dchars text insert
 147 }