lib/dijit/form/_ExpandingTextAreaMixin.js.uncompressed.js

   1 define("dijit/form/_ExpandingTextAreaMixin", [
   2         "dojo/_base/declare", // declare
   3         "dojo/dom-construct", // domConstruct.create
   4         "dojo/_base/lang", // lang.hitch
   5         "dojo/_base/window" // win.body
   6 ], function(declare, domConstruct, lang, win){
   7
   8         // module:
   9         //              dijit/form/_ExpandingTextAreaMixin
  10         // summary:
  11         //              Mixin for textarea widgets to add auto-expanding capability
  12
  13         // feature detection
  14         var needsHelpShrinking;
  15
  16         return declare("dijit.form._ExpandingTextAreaMixin", null, {
  17                 // summary:
  18                 //              Mixin for textarea widgets to add auto-expanding capability
  19
  20                 _setValueAttr: function(){
  21                         this.inherited(arguments);
  22                         this.resize();
  23                 },
  24
  25                 postCreate: function(){
  26                         this.inherited(arguments);
  27                         var textarea = this.textbox;
  28
  29                         if(needsHelpShrinking == undefined){
  30                                 var te = domConstruct.create('textarea', {rows:"5", cols:"20", value: ' ', style: {zoom:1, overflow:'hidden', visibility:'hidden', position:'absolute', border:"0px solid black", padding:"0px"}}, win.body(), "last");
  31                                 needsHelpShrinking = te.scrollHeight >= te.clientHeight;
  32                                 win.body().removeChild(te);
  33                         }
  34                         this.connect(textarea, "onscroll", "_resizeLater");
  35                         this.connect(textarea, "onresize", "_resizeLater");
  36                         this.connect(textarea, "onfocus", "_resizeLater");
  37                         textarea.style.overflowY = "hidden";
  38                         this._estimateHeight();
  39                         this._resizeLater();
  40                 },
  41
  42                 _onInput: function(e){
  43                         this.inherited(arguments);
  44                         this.resize();
  45                 },
  46
  47                 _estimateHeight: function(){
  48                         // summary:
  49                         //              Approximate the height when the textarea is invisible with the number of lines in the text.
  50                         //              Fails when someone calls setValue with a long wrapping line, but the layout fixes itself when the user clicks inside so . . .
  51                         //              In IE, the resize event is supposed to fire when the textarea becomes visible again and that will correct the size automatically.
  52                         //
  53                         var textarea = this.textbox;
  54                         textarea.style.height = "auto";
  55                         // #rows = #newlines+1
  56                         // Note: on Moz, the following #rows appears to be 1 too many.
  57                         // Actually, Moz is reserving room for the scrollbar.
  58                         // If you increase the font size, this behavior becomes readily apparent as the last line gets cut off without the +1.
  59                         textarea.rows = (textarea.value.match(/\n/g) || []).length + 2;
  60                 },
  61
  62                 _resizeLater: function(){
  63                         this.defer("resize");
  64                 },
  65
  66                 resize: function(){
  67                         // summary:
  68                         //              Resizes the textarea vertically (should be called after a style/value change)
  69                         function textareaScrollHeight(){
  70                                 var empty = false;
  71                                 if(textarea.value === ''){
  72                                         textarea.value = ' ';
  73                                         empty = true;
  74                                 }
  75                                 var sh = textarea.scrollHeight;
  76                                 if(empty){ textarea.value = ''; }
  77                                 return sh;
  78                         }
  79
  80                         var textarea = this.textbox;
  81                         if(textarea.style.overflowY == "hidden"){ textarea.scrollTop = 0; }
  82                         if(this.busyResizing){ return; }
  83                         this.busyResizing = true;
  84                         if(textareaScrollHeight() || textarea.offsetHeight){
  85                                 var currentHeight = textarea.style.height;
  86                                 if(!(/px/.test(currentHeight))){
  87                                         currentHeight = textareaScrollHeight();
  88                                         textarea.rows = 1;
  89                                         textarea.style.height = currentHeight + "px";
  90                                 }
  91                                 var newH = Math.max(Math.max(textarea.offsetHeight, parseInt(currentHeight)) - textarea.clientHeight, 0) + textareaScrollHeight();
  92                                 var newHpx = newH + "px";
  93                                 if(newHpx != textarea.style.height){
  94                                         textarea.rows = 1;
  95                                         textarea.style.height = newHpx;
  96                                 }
  97                                 if(needsHelpShrinking){
  98                                         var     origScrollHeight = textareaScrollHeight(),
  99                                                 newScrollHeight = origScrollHeight,
 100                                                 origMinHeight = textarea.style.minHeight,
 101                                                 decrement = 4, // not too fast, not too slow
 102                                                 thisScrollHeight;
 103                                         textarea.style.minHeight = newHpx; // maintain current height
 104                                         textarea.style.height = "auto"; // allow scrollHeight to change
 105                                         while(newH > 0){
 106                                                 textarea.style.minHeight = Math.max(newH - decrement, 4) + "px";
 107                                                 thisScrollHeight = textareaScrollHeight();
 108                                                 var change = newScrollHeight - thisScrollHeight;
 109                                                 newH -= change;
 110                                                 if(change < decrement){
 111                                                         break; // scrollHeight didn't shrink
 112                                                 }
 113                                                 newScrollHeight = thisScrollHeight;
 114                                                 decrement <<= 1;
 115                                         }
 116                                         textarea.style.height = newH + "px";
 117                                         textarea.style.minHeight = origMinHeight;
 118                                 }
 119                                 textarea.style.overflowY = textareaScrollHeight() > textarea.clientHeight ? "auto" : "hidden";
 120                         }else{
 121                                 // hidden content of unknown size
 122                                 this._estimateHeight();
 123                         }
 124                         this.busyResizing = false;
 125                 }
 126         });
 127 });