flame/doc/text.md

Text Rendering

Flame has some dedicated classes to help you render text.

TextRenderer

TextRenderer is the abstract class used by Flame to render text. Flame provides one implementation for this called TextPaint but anyone can implement this abstraction and create a custom way to render text.

TextPaint

A Text Paint is the built in implementation of text rendering on Flame, it is based on top of Flutter's TextPainter class (hence the name), it can be configured by its config class TextPaintConfig which contains all typographical information required to render text; i.e., font size and color, family, etc.

Example usage:

const TextPaint textPaint = TextPaint(
  config: TextPaintConfig(
    fontSize: 48.0,
    fontFamily: 'Awesome Font',
  ),
);

• fontFamily: a commonly available font, like Arial (default), or a custom font added in your pubspec (see here how to do it).
• fontSize: font size, in pts (default 24.0).
• lineHeight: height of text line, as a multiple of font size (default null).
• color: the color, as a ui.Color (default black).

For more information regarding colors and how to create then, see the Colors and the Palette guide.

After the creation of the text paint you can use its render method to draw some string on a canvas:

textPaint.render(canvas, "Flame is awesome", Vector2(10, 10));

If you want to set the anchor of the text you can also do that in the render call, with the optional anchor parameter:

textPaint.render(canvas, 'Flame is awesome', Vector2(10, 10), anchor: Anchor.topCenter);

Text Components

Flame provides two text components that make it even easier to render text in your game: TextComponent and TextBoxComponent.

TextComponent

TextComponent is a simple component that renders a single line of text.

Example usage:

TextPaint regular = TextPaint(color: BasicPalette.white.color);

class MyGame extends FlameGame {
  @override
  Future<void> onLoad() async {
    add(TextComponent('Hello, Flame', textRenderer: regular)
      ..anchor = Anchor.topCenter
      ..x = size.width / 2 // size is a property from game
      ..y = 32.0);
  }
}

TextBoxComponent

TextBoxComponent is very similar to TextComponent, but as its name suggest it is used to render text inside a bounding box, creating line breaks according to the provided box size.

You can decide if the box should grow as the text is written or if it should be static by the growingBox variable in the TextBoxConfig.

If you want to change the margins of the box use the margins variable in the TextBoxConfig.

Example usage:

class MyTextBox extends TextBoxComponent {
  MyTextBox(String text) : super(text, textRenderer: tiny, boxConfig: TextBoxConfig(timePerChar: 0.05));

  @override
  void drawBackground(Canvas c) {
    Rect rect = Rect.fromLTWH(0, 0, width, height);
    c.drawRect(rect, Paint()..color = Color(0xFFFF00FF));
    c.drawRect(
        rect.deflate(boxConfig.margin),
        Paint()
          ..color = BasicPalette.black.color
          ..style = PaintingStyle.stroke);
  }
}

Both components are showcased in an example here