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MLEM/Docs/articles/text_formatting.md

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Text Formatting

The MLEM package contains a simple text formatting system that supports coloring, bold and italic font modifiers, in-text icons and text animations.

Text formatting makes use of generic fonts.

It should also be noted that MLEM.Ui's Paragraphs support text formatting out of the box.

Formatting codes

To format your text, you can insert formatting codes into it. Almost all of these codes are single letters surrounded by <>, and some formatting codes can accept additional parameters after their letter representation.

By default, the following formatting options are available:

  • Colors using <c ColorName>. All default MonoGame colors are supported, for example <c CornflowerBlue>. Reset using </c>.
  • Bold and italic text using <b> and <i>, respectively. Reset using </b> and </i>.
  • Drop shadows using <s>. Optional parameters for the shadow's color and positional offset are accepted: <s #AARRGGBB 2.5>. Reset using </s>.
  • Underlined and strikethrough text using <u> and <st>, respectively. Reset using </u> and </st>.
  • A wobbly sine wave animation using <a wobbly>. Optional parameters for the wobble's intensity and height are accepted: <a wobbly 10 0.25>. Reset using </a>.

Getting your text ready

To get your text ready for rendering with formatting codes, it has to be tokenized. For that, you need to create a new text formatter first. Additionally, you need to have a generic font ready:

var font = new GenericSpriteFont(this.Content.Load<SpriteFont>("Fonts/ExampleFont"));
var formatter = new TextFormatter();

You can then tokenize your string like so:

var tokenizedString = formatter.Tokenize(font, "This is a <c Green>formatted</c> string!");

Additionally, if you want your tokenized string to be split based on a certain maximum width automatically, you can split it like so:

tokenizedString.Split(font, maxWidth, scale);

Drawing the formatted text

To draw your tokenized text, all you have to do is call its Draw method like so:

tokenizedString.Draw(gameTime, spriteBatch, position, font, color, scale, depth); 

Note that, if your tokenized text contains any animations, you have to updated the tokenized string every Update call like so:

tokenizedString.Update(gameTime);

Adding custom codes

Adding custom formatting codes is easy! There are two things that a custom formatting code requires:

  • A class that extends Code that does what your formatting code should do (we'll use MyCustomCode in this case)
  • A regex that determines what strings your formatting code matches
  • A formatting code constructor that creates a new instance of your code's class

You can then register your formatting code like this:

formatter.Codes.Add(new Regex("<matchme>"), (form, match, regex) => new MyCustomCode(match, regex));

To add an in-text image formatting code, you can use the ImageCodeExtensions.AddImage extension. All you have to do is supply the texture region and a name:

formatter.AddImage("ImageName", new TextureRegion(texture, 0, 0, 8, 8));

After doing so, the image can be displayed using the code <i ImageName>.

Macros

The text formatting system additionally supports macros: Regular expressions that cause the matched text to expand into a different string. Macros are resolved recursively, meaning that you can have macros that resolve into other macros, and so on.

By default, the following macros are available:

  • ~ expands into a non-breaking space, much like in LaTeX.

Adding custom macros is very similar to adding custom formatting codes:

formatter.Macros.Add(new Regex("matchme"), (form, match, regex) => "replacement string");