display_modpack/font_lib/init.lua

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--[[
font_lib mod for Minetest - Library to add font display capability
to display_lib 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_lib = {}
font_lib.path = minetest.get_modpath("font_lib")
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font_lib.registered_fonts = {}
-- Local functions
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------------------
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-- 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
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-- Returns next char, managing ascii and unicode plane 0 (0000-FFFF).
local function get_next_char(text, pos)
pos = pos + 1
local char = text:sub(pos, pos):byte()
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-- 1 byte char
if char < 0x80 then
return char, pos
end
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-- 4 bytes char not managed
if char >= 0xF0 then
pos = pos + 3
return 0, pos
end
-- 3 bytes char not managed
if char >= 0xE0 then
pos = pos + 2
return 0, pos
end
-- 2 bytes char (little endian)
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if char >= 0xC2 then
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pos = pos + 1
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return (char - 0xC2) * 0x40 + text:sub(pos, pos):byte(), pos
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end
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-- Not an UTF char
return 0, pos
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end
-- Returns font properties to be used according to font_name
local function get_font(font_name)
local font = font_lib.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
if font_lib.fallback_font == nil then
minetest.log("error", message.." and no other font registered.")
else
minetest.log("info", message..", using font \""..font_lib.fallback_font.."\".")
font = font_lib.registered_fonts[font_lib.fallback_font]
end
end
return font
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
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-- @return Rendered text (width, height)
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function font_lib.get_text_size(font_name, text)
local char
local width = 0
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local pos = 0
local font = get_font(font_name)
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if font == nil then
return 0, 0
else
while pos < #text do
char, pos = get_next_char(text, pos)
-- Ignore chars with no texture
if font.widths[char] ~= nil then
width = width + font.widths[char]
end
end
end
return width, font.height
end
--- Builds texture part for a text line
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-- @param font_name Font to be used
-- @param text Text to be rendered
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-- @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
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--> ADD ALIGN
function font_lib.make_line_texture(font_name, text, width, x, y)
local texture = ""
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local char
local pos = 0
local font = get_font(font_name)
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if font ~= nil then
while pos < #text do
char, pos = get_next_char(text, pos)
-- Ignore chars with no texture
if font.widths[char] ~= nil then
-- 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]
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else
print(string.format("Missing char %d (%04x)",char,char))
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end
end
end
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return texture
end
--- Builds texture for a multiline colored text
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-- @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 valign Vertical text align ("top" or "center")
-- @param color Color of the text
-- @return Texture string
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function font_lib.make_multiline_texture(font_name, text, width, height,
maxlines, valign, color)
local texture = ""
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local lines = {}
local textheight = 0
local y, w, h
for num, line in pairs(split_lines(text, maxlines)) do
w, h = font_lib.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
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texture = texture..
font_lib.make_line_texture(font_name, line.text, width,
(width - line.width) / 2, y)
y = y + line.height
end
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texture = string.format("[combine:%dx%d", width, height)..texture
if color then texture = texture.."^[colorize:"..color end
return texture
end
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--- 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
-- If registering different sizes, 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 pixel, indexed by unicode number.
function font_lib.register_font(font_name, height, widths)
if font_lib.registered_fonts[font_name] ~= nil then
minetest.log("error", "Font \""..font_name.."\" already registered.")
return
end
font_lib.registered_fonts[font_name] =
{ name = font_name, height = height, widths = widths }
-- If no fallback font, set it (so, first font registered will be the default fallback font)
if font_lib.fallback_font == nil then
font_lib.fallback_font = font_name
end
end
--- Define the fallback font
-- This font will be used instead of given font if not registered.
-- @param font_name Name of the font to be used as fallback font (has to be registered).
function font_lib.set_fallback_font(font_name)
if font_lib.registered_fonts[font_name] == nil then
minetest.log("error", "Fallback font \""..font_name.."\" not registered.")
else
font_lib.fallback_font = font_name
end
end
--- Standard on_display_update entity callback.
-- Node should have a corresponding display_entity with size, resolution and maxlines fields and
-- optionally valign and color fields
-- @param pos Node position
-- @param objref Object reference of entity
function font_lib.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()
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if entity and ndef.display_entities[entity.name] then
local def = ndef.display_entities[entity.name]
objref:set_properties({
textures={font_lib.make_multiline_texture(
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def.font_name, text, def.size.x*def.resolution.x, def.size.y*def.resolution.y,
def.maxlines, def.valign, def.color)},
visual_size = def.size
})
end
end
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dofile(font_lib.path.."/font_default.lua")