ActionScript 2.0 Language Reference - Adobe Help and Support

myformat.font = "Courier";
mytext.text = "this is my first test field object text";
mytext.setTextFormat(myformat);
getTextExtent (TextFormat.getTextExtent method)
public getTextExtent(text:String, [width:Number]) : Object
Returns text measurement information for the text string text in the format specified by
my_fmt. The text string is treated as plain text (not HTML).
The method returns an object with six properties: ascent, descent, width, height,
textFieldHeight, and textFieldWidth. All measurements are in pixels.
If a width parameter is specified, word wrapping is applied to the specified text. This lets you
determine the height at which a text box shows all of the specified text.
The ascent and descent measurements provide, respectively, the distance above and below
the baseline for a line of text. The baseline for the first line of text is positioned at the text
field's origin plus its ascent measurement.
The width and height measurements provide the width and height of the text string. The
textFieldHeight and textFieldWidth measurements provide the height and width
required for a text field object to display the entire text string. Text fields have a 2-pixel-wide
gutter around them, so the value of textFieldHeight is equal the value of height + 4;
likewise, the value of textFieldWidth is always equal to the value of width + 4.
If you are creating a text field based on the text metrics, use textFieldHeight rather than
height and textFieldWidth rather than width.
TextFormat 1255