Rectangle size trimming

This Javascript makes a text field multiline and triple its height. (Doc Level Javascript)

var f = this.getField("myText");
var aRect = f.rect;// get bounding rectangle
f.multiline = true;// make it multiline
var height = aRect[1]-aRect[3];// calculate height
aRect[3] -= 2* height;// triple the height of the text field
f.rect = aRect;// and make it so

Here's another option:

If the text field is filled up by the user, allow additional text by setting the field to scroll.

if ( event.fieldFull )
{
app.alert("You've filled the given space with text,"
+ " and as a result, you've lost some text. I'll set the field to"
+ " scroll horizontally, and paste in the rest of your"
+ " missing text.");
this.resetForm([event.target.name]); // reset field to lose focus
event.target.doNotScroll = false;// make changes
if ( event.target.richText )
event.richChange = event.richChangeEx
else
event.change = event.changeEx;
}

Hope this helps.

Thanks Eugene for your answer.

I've wrote down your answers 'cause I've found them useful, however what I need is a little different.

What i need is a way to calculate the text length measured in pixels i order to define the rectangle dimensions.

Let me explain with more detail:
1) I create the PDF with iText.
2) The Pdf file already contains a text field since it is created, let's call it myField.
3) The Pdf file also has an injected javascript at "will print" which assigns the value to the field: "myField.value='...';"

So the variable content fieldText is refered to the user-agent who assigns the content.

From the javascript side the text field content appears as fixed length.

thanks again Eugene

Hi whatever,
The situation you've described is beyond my expertise. Please re-post this question here or on the user forum.

Sorry I couldn't help.