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diff --git a/font_api/API.md b/font_api/API.md new file mode 100644 index 0000000..9900a80 --- /dev/null +++ b/font_api/API.md @@ -0,0 +1,145 @@ +# Font Lib API +This document describes Font Lib API. Font Lib creates textures for font display on entities. + +## Settings +### default_font +Name of the font to be used when no font is given. The font should be registered. + +If no default\_font given or if default\_font given but not registered, the first registered font will be used as default. + +## Provided methods + +### font_api.get_default_font_name() +Returns de default font name. + +### font_api.register_font(font_name, font_def) +Register a new font. +**font_name**: Name of the font to register. If registering different sizes of the same font, add size in the font name (e.g. times_10, times_12...). +**font_def**: Font definition table (see **Font definition table** below). + +### font_api.on_display_update(pos, objref) +Standard on_display_update entity callback. + +**pos**: Node position + +**objref**: Object reference of entity + +Node should have a corresponding display_entity with size, resolution and maxlines fields and optionally halign, valign and color fields. + +### Font definition table +Font definition table used by **font_api.register_font** and **font\_api.Font:new** may/can contain following elements: + +* **height** (required): Font height in pixels (all font textures should have the same height) . +* **widths** (required): Array of character widths in pixels, indexed by UTF codepoints. +* **margintop** (optional): Margin (in texture pixels) added on top of each char texture. +* **marginbottom** (optional): Margin (in texture pixels) added at bottom of each char texture. +* **linespacing** (optional): Spacing (in texture pixels) between each lines. + +**margintop**, **marginbottom** and **linespacing** can be negative numbers (default 0) and are to be used to adjust various font styles to each other. + +Font must have a char 0 which will be used to display any unknown char. + +All textures corresponding to the indexes in widths array should be present in textures directory with a name matching the pattern : + +> font\_**{font_name}**_**{utf_code}**.png + +**{font\_name}**: Name of the font as given in the first argument + +**{utf\_code}**: UTF code of the char in 4 hexadecimal digits + +Example : font_courrier_0041.png is for the "A" char in the "courrier" font. + +To ease that declaration (specially to build the **widths** array), a shell is provided to build a {font\_name}.lua file from the texture files (see provided tools). + +## Provided tools + +Still in early stage of development, these tools are helpers to create font mods. + +### make_font_texture.sh + +This scripts takes a .ttf file as input and create one .png file per char, that can be used as font texture. Launch it from your future font mod directory. + +__Advice__ + +This script works much better with pixels font, providing the correct height. There is no antialiasing at all, vector fonts and bad heights gives very ugly results. + +__Syntax__ + +**make\_font\_texture.sh {fontfile} {fontname} {fontsize}** + +**{fontfile}**: A TTF font file to use to create textures. +**{fontname}**: The font name to be used in font_api (should be simple, with no spaces). +**{fontsize}**: Font height to be rendered. + +### make_font_lua.sh + +This script analyses textures in textures directory and creates a font\_{font\_name}.lua files with a call to register_font with images information. Launch it from your future font mod directory. + +Once the font\_{font\_name}.lua created, it can be included by a init.lua file or directly renamed to init.lua if you are creating a simple font mod. + +__Syntax__ + +**make\_font_lua.sh {fontname}** + +**{fontname}**: The font name to be used in font_api (same as given to make\_font\_texture.sh) + +### An exemple generating a font mod + + mkdir font_myfont + cd font_myfont + /<path_to_font_api>/tools/make_font_texture.sh myfont.ttf myfont 12 + /<path_to_font_api>/tools/make_font_lua.sh myfont + mv font_myfont.lua init.lua + +## Font class +A font usable with font API. This class is supposed to be for internal use but who knows. + +### font\_api.Font:new(def) +Create a new font object. + +**def** is a table containing font definition. See **Font definition table** above. + +### font:get_char_width(char) +Returns the width of char **char** in texture pixels. + +**char**: Unicode codepoint of char. + +### font:get_height(nb_of_lines) +Returns line(s) height. Takes care of top and bottom margins and line spacing. + +**nb_of_lines**: Number of lines in the text. + +### font:get_width(line) + +Returns the width of a text line. Beware, if line contains any new line char, they are ignored. + +**line**: Line of text which the width will be computed. + +### font:make_line_texture(line, texturew, x, y) +Create a texture for a text line. + +**line**: Line of text to be rendered in texture. + +**texturew**: Width of the texture (extra text is not rendered). + +**x**: Starting x position in texture. + +**y**: Vertical position of the line in texture. + +### font:make_text_texture(text, texturew, textureh, maxlines, halign, valign, color) +Builds texture for a multiline colored text. + +**text**: Text to be rendered. + +**texturew**: Width of the texture (extra text will be truncated). + +**textureh**: Height of the texture. + +**maxlines**: Maximum number of lines. + +**halign**: Horizontal text align ("left"/"center"/"right") (optional). + +**valign**: Vertical text align ("top"/"center"/"bottom") (optional). + +**color**: Color of the text (optional). + |