MainDocs:Fonts

From ClanLib Game SDK

A Font is a collection of images that can be used to represent text on a screen.

There are various font classes that you can use.

• Default Font

The Default Font (provided by CL_Font ) uses CL_Font_System

• Freetype Font

The Freetype Font (provided by CL_Font_FreeType ) uses a truetype font, stored in a texture group ( CL_TextureGroup ).

• System Font

The system font (provided by CL_Font_System ) uses the operating system font, stored in a texture group ( CL_TextureGroup ).

• Vector Font

The vector font (provided by CL_Font_Vector ) uses a truetype font, stored as triangle primitives (drawn using CL_PrimitivesArray )

• Sprite Font

The sprite font (provided by CL_Font_Sprite ) uses a font stored as a CL_Sprite.

Constructing fonts

• Freetype Font

 
  CL_FontDescription font_desc;
  font_desc.set_typeface_name("myfont.ttf");
  CL_Font_Freetype freetype_font(gc, font_desc);
  freetype_font.draw_text(gc, 100, 100, "Hello World");

Via resources...

 
<font name="ClanFont">
    <freetype file="myfont.ttf" height="14" average_width="0" anti_alias="true" subpixel="true"/>
</font>

• System Font

 
  CL_FontDescription font_desc;
  font_desc.set_typeface_name("tahoma");
  CL_Font_System system_font(gc, font_desc);
  system_font.draw_text(gc, 100, 100, "Hello World");

• Vector Font

 
  CL_FontDescription font_desc;
  font_desc.set_typeface_name("myfont.ttf");
  CL_Font_Vector vector_font(font_desc);
  vector_font.draw_text(gc, 100, 100, "Hello World");

• Sprite Font

 
  CL_Font_Sprite sprite_font(gc, "ClanFont", &app_resources);
  sprite_font.draw_text(gc, 100, 100, "Hello World");

These are constructed from a resource file, using <font name="ClanFont">. Inside the <font> tag you need a <bitmap> tag that contains the following attributes:

• <glyphs> - The sprite description containing the glyphs. See Sprites Resources
• <letters> - The glyphs contained in <glyphs>
• <monospace> - If "true", then all letters have equal width
• <spacelen> - The width of unknown glyphs. If unset, this defaults to the average of the font glyphs. If monospace is used, then this always equals the widest glyph
• The font metrics can be set using: (value = floating point value, bool = true or false)
• <height="value">
• <ascent="value">
• <descent="value">
• <internal_leading="value">
• <external_leading="value">
• <average_character_width="value">
• <max_character_width="value">
• <weight="value">
• <overhang="value">
• <digitized_aspect_x="value">
• <digitized_aspect_y="value">
• <italic="bool">
• <underlined="bool">
• <struck_out="bool">
• <fixed_pitch="bool">

ClanGUI and Fonts

If you want ClanGUI to use a custom font, instead of a native font, you will first need to register the font as follows

 
CL_Font_Sprite sprite_font(gc, "ClanFont", &app_resources);
CL_FontDescription font_desc;
font_desc.set_typeface_name("GUI Font Name");
font_desc.set_height(32);
font_desc.set_weight(400);
gui->register_font(sprite_font, font_desc);

Font Metrics

All ClanLib fonts have a description detailing how the font glphs should be positioned. This is called CL_FontMetrics