The fontName property of the FontDescription object can be a single name or a comma-separated list of names. For example, in a list such as “Arial, Helvetica, _sans”, Flash Player or AIR looks for “Arial” first, then “Helvetica”, and finally “_sans”, if it can’t find either of the first two fonts. The set of font names include three generic device font names: “_sans”, “_serif”, and “_typewriter”. They map to specific device fonts, depending on the playback system. It is good practice to specify default names such as these in all font descriptions that use device fonts. If no fontName is specified, “_serif” is used as the default.

The fontPosture property can either be set to the default ( FontPosture.NORMAL ) or to italics ( FontPosture.ITALIC ). The fontWeight property can be set to the default ( FontWeight.NORMAL ) or to bold ( FontWeight.BOLD ).

var fd1:FontDescription = new FontDescription(); 
fd1.fontName = "Arial, Helvetica, _sans"; 
fd1.fontPosture = FontPosture.NORMAL; 
fd1.fontWeight = FontWeight.BOLD;

The fontLookup property of the FontDescription object specifies whether Flash Player and AIR look for a device font or embedded font to render text. If a device font ( FontLookup.DEVICE ) is specified, the runtime looks for the font on the playback system. Specifying an embedded font ( FontLookup.EMBEDDED_CFF ) causes the runtime to look for an embedded font with the specified name in the SWF file. Only embedded CFF (Compact Font Format) fonts work with this setting. If the specified font is not found, a fallback device font is used.

Device fonts result in a smaller SW file size. Embedded fonts give you greater fidelity across platforms.

var fd1:FontDescription = new FontDescription(); 
fd1.fontLookup = FontLookup.EMBEDDED_CFF; 
fd1.fontName = "Garamond, _serif";

CFF (Compact Font Format) rendering is available starting with Flash Player 10 and Adobe AIR 1.5. This type of font rendering makes text more legible, and permits higher-quality display of fonts at small sizes. This setting only applies to embedded fonts. FontDescription defaults to this setting ( RenderingMode.CFF ) for the renderingMode property. You can set this property to RenderingMode.NORMAL to match the type of rendering used by Flash Player 7 or earlier versions.

When CFF rendering is selected, a second property, cffHinting , controls how a font’s horizontal stems are fit to the subpixel grid. The default value, CFFHinting.HORIZONTAL_STEM , uses CFF hinting. Setting this property to CFFHinting.NONE removes hinting, which is appropriate for animation or for large font sizes.

var fd1:FontDescription = new FontDescription(); 
fd1.renderingMode = RenderingMode.CFF; 
fd1.cffHinting = CFFHinting.HORIZONTAL_STEM;

When a FontDescription object is assigned to an ElementFormat , its locked property is automatically set to true . Attempting to modify a locked FontDescription object throws an IllegalOperationError . The best practice is to fully define such an object before assigning it to a ElementFormat .

If you want to modify an existing FontDescription , first check its locked property. If it’s true , use the clone() method to create an unlocked copy of the object. The properties of this unlocked object can be changed, and it can then be assigned to the ElementFormat . Any new lines created from this TextElement have the new formatting. Previous lines created from this same object are unchanged.

package 
{ 
    import flash.display.Sprite; 
    import flash.text.*; 
 
    public class FontDescriptionCloneExample extends Sprite 
    { 
        private var tb:TextBlock = new TextBlock(); 
        private var te:TextElement; 
        private var ef1:ElementFormat; 
        private var ef2:ElementFormat; 
         private var fd1:FontDescription = new FontDescription(); 
        private var fd2:FontDescription; 
 
        public function FontDescriptionCloneExample() 
        { 
            fd1.fontName = "Garamond"; 
            ef1 = new ElementFormat(fd); 
            var str:String = "This is flash text"; 
            te = new TextElement(str, ef); 
            tb.content = te; 
            var tx1:TextLine = tb.createTextLine(null,600); 
            addChild(tx1); 
             
            fd2 = (fd1.locked) ? fd1.clone() : fd1; 
            fd2.fontName = "Arial"; 
            ef2 = (ef1.locked) ? ef1.clone() : ef1; 
            ef2.fontDescription = fd2; 
            tb.content.elementFormat = ef2; 
            var tx2:TextLine = tb.createTextLine(null,600); 
            addChild(tx2); 
        } 
    } 
}