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Diffstat (limited to 'font_api/init.lua')
| -rw-r--r-- | font_api/init.lua | 343 |
1 files changed, 343 insertions, 0 deletions
diff --git a/font_api/init.lua b/font_api/init.lua new file mode 100644 index 0000000..f407f8b --- /dev/null +++ b/font_api/init.lua @@ -0,0 +1,343 @@ +--[[ + font_api mod for Minetest - Library to add font display capability + to display_api mod. + (c) Pierre-Yves Rollo + + This program is free software: you can redistribute it and/or modify + it under the terms of the GNU General Public License as published by + the Free Software Foundation, either version 3 of the License, or + (at your option) any later version. + + This program is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License + along with this program. If not, see <http://www.gnu.org/licenses/>. +--]] + +-- Global variables +------------------- + +font_api = {} +font_api.name = minetest.get_current_modname() +font_api.path = minetest.get_modpath(font_api.name) +font_api.registered_fonts = {} + +-- Local variables +------------------ + +local default_font = false + +-- Local functions +------------------ + +-- Split multiline text into array of lines, with <maxlines> maximum lines. + +local function split_lines(text, maxlines) + local splits = text:split("\n") + if maxlines then + local lines = {} + for num = 1,maxlines do + lines[num] = splits[num] + end + return lines + else + return splits + end +end + +-- Gets a default (settings or fist font) + +local function get_default_font() + -- First call + if default_font == false then + default_font = nil + + -- First, try with settings + local settings_font = minetest.settings:get("default_font") + + if settings_font ~= nil and settings_font ~= "" then + default_font = font_api.registered_fonts[settings_font] + + if default_font == nil then + minetest.log("warning", "Default font in settings (\"".. + settings_font.."\") is not registered.") + end + end + + -- If failed, choose first font + if default_font == nil then + for _, font in pairs(font_api.registered_fonts) do + default_font = font + break + end + end + + -- Error, no font registered + if default_font == nil then + minetest.log("error", + "No font registred, unable to choose a default font.") + end + end + + return default_font +end + +-- Returns font properties to be used according to font_name + +local function get_font(font_name) + local font = font_api.registered_fonts[font_name] + + if font == nil then + local message + + if font_name == nil then + message = "No font given" + else + message = "Font \""..font_name.."\" unregistered" + end + + font = get_default_font() + + if font ~= nil then + minetest.log("info", message..", using font \""..font.name.."\".") + end + end + + return font +end + +-- Returns next char, managing ascii and unicode plane 0 (0000-FFFF). + +local function get_next_char(text, pos) + + local msb = text:byte(pos) + -- 1 byte char, ascii equivalent codepoints + if msb < 0x80 then + return msb, pos + 1 + end + + -- 4 bytes char not managed (Only 16 bits codepoints are managed) + if msb >= 0xF0 then + return 0, pos + 4 + end + + -- 3 bytes char + if msb >= 0xE0 then + return (msb - 0xE0) * 0x1000 + + text:byte(pos + 1) % 0x40 * 0x40 + + text:byte(pos + 2) % 0x40, + pos + 3 + end + + -- 2 bytes char (little endian) + if msb >= 0xC2 then + return (msb - 0xC2) * 0x40 + text:byte(pos + 1), + pos + 2 + end + + -- Not an UTF char + return 0, pos + 1 +end + +-- API functions +---------------- + +-- Computes text size for a given font and text (ignores new lines) +-- @param font_name Font to be used +-- @param text Text to be rendered +-- @return Rendered text (width, height) + +function font_api.get_text_size(font_name, text) + local char + local width = 0 + local pos = 1 + local font = get_font(font_name) + + if font == nil then + return 0, 0 + else + while pos <= #text do + char, pos = get_next_char(text, pos) + -- Replace chars with no texture by the NULL(0) char + if font.widths[char] ~= nil then + width = width + font.widths[char] + else + width = width + font.widths[0] + end + end + end + + return width, font.height +end + +--- Builds texture part for a text line +-- @param font_name Font to be used +-- @param text Text to be rendered +-- @param width Width of the texture (extra text is not rendered) +-- @param x Starting x position in texture +-- @param y Vertical position of the line in texture +-- @return Texture string + +function font_api.make_line_texture(font_name, text, width, x, y) + local texture = "" + local char + local pos = 1 + local font = get_font(font_name) + + if font ~= nil then + while pos <= #text do + char, pos = get_next_char(text, pos) + + -- Replace chars with no texture by the NULL(0) char + if font.widths[char] == nil then + print(string.format("["..font_api.name + .."] Missing char %d (%04x)",char,char)) + char = 0 + end + + -- Add image only if it is visible (at least partly) + if x + font.widths[char] >= 0 and x <= width then + texture = texture.. + string.format(":%d,%d=font_%s_%04x.png", + x, y, font.name, char) + end + x = x + font.widths[char] + end + end + + return texture +end + +--- Builds texture for a multiline colored text +-- @param font_name Font to be used +-- @param text Text to be rendered +-- @param texturew Width of the texture (extra text will be truncated) +-- @param textureh Height of the texture +-- @param maxlines Maximum number of lines +-- @param halign Horizontal text align ("left"/"center"/"right") (optional) +-- @param valign Vertical text align ("top"/"center"/"bottom") (optional) +-- @param color Color of the text (optional) +-- @return Texture string + +function font_api.make_multiline_texture(font_name, text, width, height, + maxlines, halign, valign, color) + local texture = "" + local lines = {} + local textheight = 0 + local y, w, h + + for num, line in pairs(split_lines(text, maxlines)) do + w, h = font_api.get_text_size(font_name, line) + lines[num] = { text = line, width = w, height = h, } + textheight = textheight + h + end + + if #lines then + if valign == "top" then + y = 0 + elseif valign == "bottom" then + y = height - textheight + else + y = (height - textheight) / 2 + end + end + + for _, line in pairs(lines) do + if halign == "left" then + texture = texture.. + font_api.make_line_texture(font_name, line.text, width, + 0, y) + elseif halign == "right" then + texture = texture.. + font_api.make_line_texture(font_name, line.text, width, + width - line.width, y) + else + texture = texture.. + font_api.make_line_texture(font_name, line.text, width, + (width - line.width) / 2, y) + end + y = y + line.height + end + + texture = string.format("[combine:%dx%d", width, height)..texture + if color then texture = texture.."^[colorize:"..color end + return texture +end + +--- Register a new font +-- Textures corresponding to the font should be named after following patern : +-- font_<name>_<code>.png +-- <name> : name of the font +-- <code> : 4 digit hexadecimal unicode of the char +-- @param 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...). +-- @param height Font height in pixels +-- @param widths Array of character widths in pixels, indexed by UTF codepoints + +function font_api.register_font(font_name, height, widths) + + if font_api.registered_fonts[font_name] ~= nil then + minetest.log("error", "Font \""..font_name.."\" already registered.") + return + end + + if height == nil or height <= 0 then + minetest.log("error", "Font \""..font_name.. + "\" must have a positive height.") + return + end + + if type(widths) ~= "table" then + minetest.log("error", "Font \""..font_name.. + "\" must have a widths array.") + return + end + + if widths[0] == nil then + minetest.log("error", "Font \""..font_name.. + "\" must have a char with codepoint 0 (=unknown char).") + return + end + + font_api.registered_fonts[font_name] = + { name = font_name, height = height, widths = widths } + + -- Force to choose again default font + -- (allows use of fonts registered after start) + default_font = false +end + +--- Standard on_display_update entity callback. +-- Node should have a corresponding display_entity with size, resolution and +-- maxlines fields and optionally halign, valign and color fields +-- @param pos Node position +-- @param objref Object reference of entity + +function font_api.on_display_update(pos, objref) + local meta = minetest.get_meta(pos) + local text = meta:get_string("display_text") + local ndef = minetest.registered_nodes[minetest.get_node(pos).name] + local entity = objref:get_luaentity() + + if entity and ndef.display_entities[entity.name] then + local def = ndef.display_entities[entity.name] + local font = get_font(def.font_name) + + objref:set_properties({ + textures={font_api.make_multiline_texture( + def.font_name, text, + def.size.x * def.resolution.x * font.height, + def.size.y * def.resolution.y * font.height, + def.maxlines, def.halign, def.valign, def.color)}, + visual_size = def.size + }) + end +end + +-- Compatibility +font_lib = font_api + |