ACTIONSCRIPT 3 Developer’s Guide en

ACTIONSCRIPT 3.0 DEVELOPER’S GUIDE
Using the TextField class
public function getOptimalHeight(str:String):int
{
if (field.text == "" || field.text == null)
{
return this.preferredHeight;
}
else
{
this.linesPerCol = Math.ceil(field.numLines / this.numColumns);
}
}
var metrics:TextLineMetrics = field.getLineMetrics(0);
this.lineHeight = metrics.height;
var prefHeight:int = linesPerCol * this.lineHeight;
return prefHeight + 4;
First the getOptimalHeight() method calculates the width of each column. Then it sets the width and htmlText
property of the first TextField object in the array. The getOptimalHeight() method uses that first TextField object
to discover the total number of word-wrapped lines in the text, and from that it identifies how many lines should be
in each column. Next it calls the TextField.getLineMetrics() method to retrieve a TextLineMetrics object that
contains details about size of the text in the first line. The TextLineMetrics.height property represents the full
height of a line of text, in pixels, including the ascent, descent, and leading. The optimal height for the
MultiColumnTextField object is then the line height multiplied by the number of lines per column, plus 4 to account
for the two-pixel border at the top and the bottom of a TextField object.
Here is the code for the full layoutColumns() method:
public function layoutColumns():void
{
if (this._text == "" || this._text == null)
{
return;
}
var field:TextField = fieldArray[0] as TextField;
field.text = this._text;
field.setTextFormat(this.format);
this.preferredHeight = this.getOptimalHeight(field);
var remainder:String = this._text;
var fieldText:String = "";
var lastLineEndedPara:Boolean = true;
var indent:Number = this.format.indent as Number;
for (var i:int = 0; i < fieldArray.length; i++)
{
field = this.fieldArray[i] as TextField;
field.height = this.preferredHeight;
field.text = remainder;
field.setTextFormat(this.format);
Last updated 6/6/2012
394