Loading Fonts at Runtime

Tue Jan 5 09:53:51 2010

One of the painstaking things about creating swf files is embedding large font files which often end up bloating your flash movies and causing long wait times for your users. But what if I told you that there is a way to load fonts at runtime? Well, there is and it just so happens that I have prepared an example to guide you through it, allowing you the peace of mind that you can easily import the fonts you need when you need them and create subsets of them when every character in a font set is not necessary, and thus giving you a lot of power indeed.

Creating a SWF Contained Font

First off, you need to create a swf file containing the font that you wish to load into your movies. The big advantage to this is that you can have a library of preprepared swf files containing all your favourite fonts to load when and where you want. To understand how this is done, take a look at the following code.

package
{	
   import flash.display.Sprite;
   import flash.text.Font;
	
   public class FontEmbed extends Sprite{
      [Embed(systemFont='OCR A Std', fontName="OCR", 
      mimeType="application/x-font", unicodeRange="U+0041-U+005A")]

      public var ocr:Class;

      public function FontEmbed(){
         Font.registerFont(ocr);
      }
   }
}

On lines 7-8, we simply embed whatever font we want to be contained inside the swf file that is to be output on compilation of this class. In this example, I have chosen the font OCR A Std because it is a rather unusual font and will stand out against default fonts when testing to see if the font was actually embedded correctly. To embed your own font, simply change the systemFont string to the name of a font on your system if you don't have OCR A Std, which is highly likely if you are not on a Machintosh. The fontName can be any name you choose to remember this font by. This is important because we will be using this name to load in the font later. In my example, I have chosen the name "OCR" for simplicity. The mimeType is not something to worry about as it simply tells the Flex SDK what type of file to expect. Finally, the real power comes with the use of unicodeRange, which allows you to determine a range of characters you wish to embed. In this case, I have chosen the range U+0041-U+005A which is simply Unicode for A-Z.

There is a great little list of Unicode values to be found here at Wikipedia. Also, if you are running a mac, you could simply open a program such as TextEdit and go to Edit > Special Characters and roll over the characters to display their Unicode values. I'm sure Windows has something similar but don't quote me on that.

Continuing on, any font embedded must be datatyped to a Class, which is what the code on line 10 does. Finally, inside the constructor function on line 13, we register the font using Font.registerFont. Don't forget that to access any method of the Font class, you must import flash.text.Font (see line 4).

Once all that is done, simply compile the class to create the swf file containing your prefered font. As nothing has been added to the display list, nothing will be visible if you choose to view the swf file at this point.

Loading the Contained Font

Loading fonts is pretty simple. Take a look at the following code.

package
{	
   import flash.display.*;
   import flash.events.Event;
   import flash.text.TextField;
   import flash.text.TextFormat;
   import flash.text.TextFieldAutoSize;
   import flash.net.URLRequest;
	
   public class FontLoading extends MovieClip{
      private var ldr:Loader = new Loader();
      private var txt:TextField = new TextField();

      public function FontLoading()
      {
         ldr.contentLoaderInfo.addEventListener(Event.INIT, loaded)	
         ldr.load(new URLRequest("FontEmbed.swf"));
      }
		
      private function loaded(event:Event):void{
	 addChild(txt);
	 txt.autoSize = TextFieldAutoSize.LEFT;
	 txt.embedFonts = true;
	 txt.defaultTextFormat = new TextFormat("OCR", 22, 0x333333);
	 txt.text = "THIS FONT WAS LOADED AT RUNTIME";
      }

   }
}

On line 11 I have instantiated a Loader called "ldr", which will be used to load the font. The TextField on line 12 will only be used to display the results and is not necessary to load the font itself. On line 16, we add an EventListener to listen for the INIT event which basically means it will be waiting for the load to begin. Once it does, it will call the loaded function on line 20. The loaded function will add the TextField txt to the display list and auto-size it to fit the text on line 22. On line 23, we tell flash to use Embed fonts if it finds any (it should find our font) using txt.embedFonts = true. On line 24, we set the defaultTextFormat font on the TextField "txt" to "OCR". This is the name of the font we set when we compiled the swf containing our font, and this is how the Flex SDK will know which font we would like to use. On the same line, we set the font-size to 22 and the colour to a dark grey (0x333333). Finally on line 25, we give the TextField some text. All that is left is to compile the class and marvel at the wonder of loading fonts at runtime... a truly beautiful thing.

Download Runtime Font Files Here


← back

Most recent posts

  1. Convert Font Suitcase to TTF in 3 Easy Steps
  2. Rain or Shine - Weather Forecast Available Now!
  3. Getting around Apple's silly rules for iOS 10
  4. Localising App Names for iOS and Android
  5. Today - Powerful To-Do App Now Available on iOS & Android

Search site:

Apps by Ubacoda.com

Click the app icons to see more info


Archives

Categories