MS Rounded Text is very useful for creating full/half circle rounded text. you may even set the font, color, size and underline. Note: If you are using font you need to have an embedded font in your library.

By Using Component on Stage.

componentInstance.createHalfCircleText(textString:String, Radius:Number, [rotationType:String (Clockwise, AntiClockwise)], iTextColor:Number, fontID:String, iFontSize:Number, isUnderline:Boolean);

componentInstance.createFullCircleText(textString:String, Radius:Number, [rotationType:String (Clockwise, AntiClockwise)], iTextColor:Number, fontID:String, iFontSize:Number, isUnderline:Boolean); 

How to craete on runtime?

just drag this component into the library.

this.createEmptyMovieClip("textHolder_mc", this.getNextHighestDepth()); 
textHolder_mc._x = 100; 
textHolder_mc._y = 100; 
var myText:MSRoundedText = new MSRoundedText(textHolder_mc) 
myText.createFullCircleText("Marghoob Suleman", 150, "Clockwise", 0xD10000, "Arial", 20, false); 
//myText.createHalfCircleText("Marghoob Suleman", 150, "Clockwise", 0xD10000, "Arial", 20, false);

Example

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