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diff --git a/font_api/API.md b/font_api/API.md new file mode 100644 index 0000000..80b1121 --- /dev/null +++ b/font_api/API.md @@ -0,0 +1,201 @@ +# Font API +This document describes Font API. Font API 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. + +## Use font_api with display_api (to display text on nodes) +### Base setup +Font_api offers a direct integration with display_api to display text on nodes. + +First of all, create a display node with an entity. +To do this, refer to API.md in display_api mod, in particular "Howto register a display node". + +The only requirement then is to connect the `on_display_update` callback of the display entity to `font_api.on_display_update`: + +``` +minetest.register_node("mymod:test_text_node", { + ... + paramtype2 = "facedir", + ... + groups = { display_api = 1, ... }, + ... + display_entities = { + ["mymod:text"] = { + depth = -0.5 - display_api.entity_spacing, + on_display_update = font_api.on_display_update }, + } + ... + on_place = display_api.on_place, + on_construct = display_api.on_construct, + on_destruct = display_api.on_destruct, + on_rotate = display_api.on_rotate, + ... +}) +``` + +At this step, your node already displays text form "display_text" (by default) node meta. If you want to store your text into another meta data field, add a `meta_text` field to display entity definition. + +But it uses defaults (default font, default size, default color). Likely you need something more. + +### Style your text +Font style and size can be chosen by adding some more entries to the display_entities definition table. + +#### Font size +Font size can be defined in various ways (maybe more in the future). +Start with a number of lines, and font_api will make it fit to the entity size. + * `maxlines` or `lines`: Number of maximum lines of text to be displayed. The font height will be adjusted accordingly. + +Then specify the char width. Two methods available: + * `aspect_ratio`: Defines the aspect ratio of chars. Works with all fonts. Should not be used if `columns` is specified. + * `columns`: Only if using a fixed width font, specifies the number of columns to display. + +#### Font style + * `font_name`: name of the font to use. Should correspond to a registered font (from a font mod). If not specified or font not found, default font is used. + * `color`: color to be used (default black). + * `halign`: Horizontal alignment: "left", "center" or "right" (default "center"). + * `valign`: Vertical alignement: "top", "middle" or "bottom" (default "middle"). + +### Example +Using blue //botic// font, three lines height, aligned top left. Text stored in "text" node meta. +``` +minetest.register_node("mymod:test_text_node", { + ... + ... + display_entities = { + ["mymod:text"] = { + depth = -0.5 - display_api.entity_spacing, + on_display_update = font_api.on_display_update + meta_text = "text", + font_name = "botic", + color = "#0000FF", + maxlines = 3, + aspect_ratio = 0.5, + halign = "left", + valign = "top", + }, + } + ... +}) +``` +## 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 attributes around a single char:\ + + +Font attributes effects on several lines:\ + + +#### Additional requirements + +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(codepoint) +Returns the width of char `codepoint` in texture pixels. + * `codepoint`: 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:renter(text, texturew, textureh, style) +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 (extra text will be truncated). + * `style`: A table with style indications: + - `lines` or `maxlines`: Maximum number of lines (default none). + - `halign`: Horizontal text align: "left"/"center"/"right" (default "center") + - `valign`: Vertical text align: "top"/"middle"/"bottom" (default "middle") + - `color`: Color of the text (default black) |