Changed UTF8 routines and added char fallback mechanism

2 files changed, 269 insertions, 87 deletions

diff --git a/font_api/fallbacks.lua b/font_api/fallbacks.lua
new file mode 100644
index 0000000..480d865
--- /dev/null
+++ b/font_api/fallbacks.lua
@@ -0,0 +1,176 @@
+--[[
+    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/>.
+--]]
+
+-- This is the unicode char fallback map. If a char is not present in
+-- font, this maps indicates which char to try to use instead next.
+
+return {
+	-- Lowercase chars
+	['a'] = 'A',	['b'] = 'B',	['c'] = 'C',	['d'] = 'D',
+	['e'] = 'E',	['f'] = 'F',	['g'] = 'G',	['h'] = 'H',
+	['i'] = 'I',	['j'] = 'J',	['k'] = 'K',	['l'] = 'L',
+	['m'] = 'M',	['n'] = 'N',	['o'] = 'O',	['p'] = 'P',
+	['q'] = 'Q',	['r'] = 'R',	['s'] = 'S',	['t'] = 'T',
+	['u'] = 'U',	['v'] = 'V',	['w'] = 'W',	['x'] = 'X',
+	['y'] = 'Y',	['z'] = 'Z',
+
+	-- Special
+	['¢'] = 'c',	['£'] = 'L',	['¥'] = 'Y',	['€'] = 'E',
+	['©'] = '(C)',	['®'] = '(R)',	['™'] = 'TM',
+	['ª'] = 'a',	['º'] = 'o',
+	['«'] = '"',	['»'] = '"',	['´'] = '\'',
+	['¹'] = '1',	['²'] = '2',	['³'] = '3',
+	['µ'] = 'u',	['¤'] = 'o',
+	['¼'] = '1/4',	['½'] = '1/2',	['¾'] = '3/4',
+	['⅛'] = '1/8',	['⅜'] = '3/8',  ['⅝'] = '5/8',  ['⅞'] = '7/8',
+	['¿'] = '?',
+
+	-- Upper case accents
+	['À'] = 'A',	['Á'] = 'A',	['Â'] = 'A',	['Ã'] = 'A',
+	['Ä'] = 'A',	['Å'] = 'A',
+	['Æ'] = 'AE',	['Ç'] = 'C',
+	['È'] = 'E',	['É'] = 'E',	['Ê'] = 'E',	['Ë'] = 'E',
+	['Ì'] = 'I',	['Í'] = 'I',	['Î'] = 'I',	['Ï'] = 'I',
+	['Ð'] = 'D',	['Ñ'] = 'N',
+	['Ò'] = 'O',	['Ó'] = 'O',	['Ô'] = 'O',	['Õ'] = 'O',
+	['Ö'] = 'O',	['Ø'] = 'O',
+	['Ú'] = 'U',	['Ù'] = 'U',	['Û'] = 'U',	['Ü'] = 'U',
+	['×'] = 'x',	['Ý'] = 'Y',
+
+	-- Lower case accents
+	['à'] = 'a',	['à'] = 'a',	['á'] = 'a',	['â'] = 'a',
+	['ã'] = 'a',	['ä'] = 'a',	['å'] = 'a',
+	['æ'] = 'ae',	['ç'] = 'c',
+	['è'] = 'e',	['é'] = 'e',	['ê'] = 'e',	['ë'] = 'e',
+	['ì'] = 'i',	['í'] = 'i',	['î'] = 'i',	['ï'] = 'i',
+	['ð'] = 'd',	['ñ'] = 'n',
+	['ò'] = 'o',	['ó'] = 'o',	['ô'] = 'o',	['õ'] = 'o',
+	['ö'] = 'o',	['ø'] = 'o',
+	['ù'] = 'u',	['ú'] = 'u',	['û'] = 'u',	['ü'] = 'u',
+	['ý'] = 'y',	['ÿ'] = 'y',
+
+	-- Extended latin A
+
+	['Ā'] = 'A',	['ā'] = 'a',	['Ă'] = 'A',	['ă'] = 'a',
+	['Ą'] = 'A',	['ą'] = 'a',	['Ć'] = 'C',	['ć'] = 'c',
+	['Ĉ'] = 'C',	['ĉ'] = 'c',	['Ċ'] = 'C',	['ċ'] = 'c',
+	['Č'] = 'C',	['č'] = 'c',	['Ď'] = 'D',	['ď'] = 'd',
+	['Đ'] = 'D',	['đ'] = 'd',	['Ē'] = 'E',	['ē'] = 'e',
+	['Ĕ'] = 'E',	['ĕ'] = 'e',	['Ė'] = 'E',	['ė'] = 'e',
+	['Ę'] = 'E',	['ę'] = 'e',	['Ě'] = 'E',	['ě'] = 'e',
+	['Ĝ'] = 'G',	['Ğ'] = 'G',	['ğ'] = 'g',	['ĝ'] = 'g',
+	['Ġ'] = 'G',	['ġ'] = 'g',	['Ģ'] = 'G',	['ģ'] = 'g',
+	['Ĥ'] = 'H',	['ĥ'] = 'h',	['Ħ'] = 'H',	['ħ'] = 'h',
+	['Ĩ'] = 'I',	['ĩ'] = 'i',	['Ī'] = 'I',	['ī'] = 'i',
+	['Ĭ'] = 'I',	['ĭ'] = 'i',	['Į'] = 'I',	['į'] = 'i',
+	['ı'] = 'i',	['İ'] = 'I',	['IJ'] = 'IJ',	['ij'] = 'ij',
+	['Ĵ'] = 'J',	['ĵ'] = 'j',	['ķ'] = 'k',	['Ķ'] = 'K',
+	['ĸ'] = 'k',
+	['Ĺ'] = 'L',	['ĺ'] = 'l',	['Ļ'] = 'L',	['ļ'] = 'l',
+	['Ľ'] = 'L',	['ľ'] = 'l',	['Ŀ'] = 'L',	['ŀ'] = 'l',
+	['Ł'] = 'L',	['ł'] = 'l',	['Ń'] = 'N',	['ń'] = 'n',
+	['Ņ'] = 'N',	['ņ'] = 'n',	['Ň'] = 'N',	['ň'] = 'n',
+	['ʼn'] = 'n',	['Ŋ'] = 'n',	['ŋ'] = 'n',
+	['Ō'] = 'O',	['ō'] = 'o',	['Ŏ'] = 'O',	['ŏ'] = 'o',
+	['ő'] = 'o',	['Ő'] = 'O',	['œ'] = 'oe',	['Œ'] = 'OE',
+	['Ŕ'] = 'R',	['ŕ'] = 'r',	['Ŗ'] = 'R',	['ŗ'] = 'r',
+	['Ř'] = 'R',	['ř'] = 'r',	['Ś'] = 'S',	['ś'] = 's',
+	['Ŝ'] = 'S',	['ŝ'] = 's',	['Ş'] = 'S',	['ş'] = 's',
+	['Š'] = 'S',	['š'] = 's',	['Ţ'] = 'T',	['ţ'] = 't',
+	['ť'] = 't',	['Ŧ'] = 'T',	['Ť'] = 'T',	['ŧ'] = 't',
+	['Ũ'] = 'U',	['ũ'] = 'u',	['Ū'] = 'U',	['ū'] = 'u',
+	['Ŭ'] = 'U',	['ŭ'] = 'u',	['Ů'] = 'U',	['ů'] = 'u',
+	['Ű'] = 'U',	['ű'] = 'u',	['Ų'] = 'U',	['ų'] = 'u',
+	['Ŵ'] = 'W',	['ŵ'] = 'w',	['Ŷ'] = 'Y',	['ŷ'] = 'y',
+	['Ÿ'] = 'Y',
+	['Ź'] = 'Z',	['ź'] = 'z',	['Ż'] = 'Z',	['ż'] = 'z',
+	['Ž'] = 'Z',	['ž'] = 'z',	['ſ'] = 's',
+
+	-- Extended latin B
+	['ƀ'] = 'b',	['Ɓ'] = 'B',	['Ƃ'] = 'B',	['ƃ'] = 'b',
+	['Ɔ'] = 'O',
+	['Ƈ'] = 'C',	['ƈ'] = 'c',	['Ɖ'] = 'D',	['Ɗ'] = 'D',
+	['Ƌ'] = 'D',	['ƌ'] = 'd',	['Ǝ'] = 'E',	['Ə'] = 'e',
+	['Ɛ'] = 'E',
+	['Ƒ'] = 'F',	['ƒ'] = 'f',	['Ɠ'] = 'G',
+	['ƕ'] = 'hv',	['Ɨ'] = 'I',	['Ƙ'] = 'K',	['ƙ'] = 'k',
+	['ƚ'] = 'l',	['Ɯ'] = 'M',	['Ɲ'] = 'N',	['ƞ'] = 'n',
+	['Ɵ'] = 'O',
+	['Ơ'] = 'O',	['ơ'] = 'o',	['Ƣ'] = 'OI',	['ƣ'] = 'oi',
+	['Ƥ'] = 'P',	['ƥ'] = 'p',	['Ʀ'] = 'YR',
+	['Ƨ'] = 'S',	['ƨ'] = 's',	['ƫ'] = 't',
+	['Ƭ'] = 'T',	['ƭ'] = 't',	['Ʈ'] = 'T',
+	['Ư'] = 'U',	['ư'] = 'u',	['Ʋ'] = 'V',
+	['Ƴ'] = 'Y',	['ƴ'] = 'y',	['Ƶ'] = 'Z',	['ƶ'] = 'z',
+	['ƻ'] = '2',	['Ƽ'] = '5',	['ƽ'] = '5',
+	['DŽ'] = 'DZ',	['Dž'] = 'Dz',	['dž'] = 'dz',
+	['LJ'] = 'LJ',	['Lj'] = 'Lj',	['lj'] = 'lj',
+	['NJ'] = 'NJ',	['Nj'] = 'Nj',	['nj'] = 'nj',
+	['Ǎ'] = 'A',	['ǎ'] = 'a',	['Ǐ'] = 'I',	['ǐ'] = 'i',
+	['Ǒ'] = 'O',	['ǒ'] = 'o',	['Ǔ'] = 'U',	['ǔ'] = 'u',
+	['Ǖ'] = 'U',	['ǖ'] = 'u',	['Ǘ'] = 'U',	['ǘ'] = 'u',
+	['Ǚ'] = 'U',	['ǚ'] = 'u',	['Ǜ'] = 'U',	['ǜ'] = 'u',
+	['ǝ'] = 'e',
+	['Ǟ'] = 'A',	['ǟ'] = 'a',	['Ǡ'] = 'A',	['ǡ'] = 'a',
+	['Ǣ'] = 'Æ',	['ǣ'] = 'æ',	['Ǥ'] = 'G',	['ǥ'] = 'g',
+	['Ǧ'] = 'G',	['ǧ'] = 'g',	['Ǩ'] = 'K',	['ǩ'] = 'k',
+	['Ǫ'] = 'Q',	['ǫ'] = 'q',	['Ǭ'] = 'Q',	['ǭ'] = 'q',
+	['ǰ'] = 'J',
+	['DZ'] = 'DZ',	['Dz'] = 'Dz',	['dz'] = 'dz',
+	['Ǵ'] = 'G',	['ǵ'] = 'g',	['Ƕ'] = 'H',
+	['Ǹ'] = 'N',	['ǹ'] = 'n',	['Ǻ'] = 'A',	['ǻ'] = 'a',
+	['Ǽ'] = 'Æ',	['ǽ'] = 'æ',	['Ǿ'] = 'Ø',	['ǿ'] = 'ø',
+	['Ȁ'] = 'A',	['ȁ'] = 'a',	['Ȃ'] = 'A',	['ȃ'] = 'a',
+	['Ȅ'] = 'E',	['ȅ'] = 'e',	['Ȇ'] = 'E',	['ȇ'] = 'e',
+	['Ȉ'] = 'I',	['ȉ'] = 'i',	['Ȋ'] = 'I',	['ȋ'] = 'i',
+	['Ȍ'] = 'O',	['ȍ'] = 'o',	['Ȏ'] = 'O',	['ȏ'] = 'o',
+	['Ȑ'] = 'R',	['ȑ'] = 'r',	['Ȓ'] = 'R',	['ȓ'] = 'r',
+	['Ȕ'] = 'U',	['ȕ'] = 'u',	['Ȗ'] = 'U',	['ȗ'] = 'u',
+	['Ș'] = 'S',	['ș'] = 's',	['Ț'] = 'T',	['ț'] = 't',
+	['Ȟ'] = 'H',	['ȟ'] = 'h',	['Ƞ'] = 'N',
+	['ȡ'] = 'd',
+	['Ȣ'] = 'OU',	['ȣ'] = 'ou',	['Ȥ'] = 'Z',	['ȥ'] = 'z',
+	['Ȧ'] = 'A',	['ȧ'] = 'a',	['Ȩ'] = 'E',	['ȩ'] = 'e',
+	['Ȫ'] = 'O',	['ȫ'] = 'o',	['Ȭ'] = 'O',	['ȭ'] = 'o',
+	['Ȯ'] = 'O',	['ȯ'] = 'o',	['Ȱ'] = 'O',	['ȱ'] = 'o',
+	['Ȳ'] = 'Y',	['ȳ'] = 'y',	['ȴ'] = 'l',
+	['ȵ'] = 'n',	['ȶ'] = 't',	['ȷ'] = 'j',
+	['ȸ'] = 'db',	['ȹ'] = 'qp',	['Ⱥ'] = 'A',
+	['Ȼ'] = 'C',	['ȼ'] = 'c',	['Ƚ'] = 'L',
+	['Ⱦ'] = 'T',	['ȿ'] = 's',	['ɀ'] = 'z',
+	['Ƀ'] = 'B',	['Ʉ'] = 'U',	['Ʌ'] = 'V',
+	['Ɇ'] = 'E',	['ɇ'] = 'e',	['Ɉ'] = 'J',	['ɉ'] = 'j',
+	['Ɋ'] = 'Q',	['ɋ'] = 'q',	['Ɍ'] = 'R',	['ɍ'] = 'r',
+	['Ɏ'] = 'Y',	['ɏ'] = 'y',	['ɐ'] = 'a',
+	['ɓ'] = 'b',	['ɔ'] = 'o',
+	['ɕ'] = 'c',	['ɖ'] = 'd',	['ɗ'] = 'd',
+	['ɘ'] = 'e',	['ə'] = 'e',	['ɚ'] = 'e',
+	['ɛ'] = 'e',	['ɜ'] = 'e',	['ɝ'] = 'e',	['ɞ'] = 'e',
+	['ɟ'] = 'j',
+	['ɠ'] = 'g',	['ɡ'] = 'g',	['ɢ'] = 'G',
+	['ɥ'] = 'h',	['ɦ'] = 'h',	['ɧ'] = 'h',
+	['ɨ'] = 'i',	['ɪ'] = 'I',
+	['ɫ'] = 'l',	['ɬ'] = 'l',	['ɭ'] = 'l',
+	['ɮ'] = 'lz',
+	['ɯ'] = 'm',	['ɰ'] = 'm',	['ɱ'] = 'm',
+	['ɲ'] = 'n',	['ɳ'] = 'n',	['ɴ'] = 'N',
+	['ɵ'] = 'o',	['ɶ'] = 'Œ',
+	['ɹ'] = 'r',	['ɺ'] = 'r',	['ɻ'] = 'r',
+	['ɼ'] = 'r',	['ɽ'] = 'r',	['ɾ'] = 'r',	['ɿ'] = 'r',
+}
diff --git a/font_api/font.lua b/font_api/font.lua
index 580744d..db12dba 100644
--- a/font_api/font.lua
+++ b/font_api/font.lua
@@ -17,59 +17,44 @@
     along with this program.  If not, see <http://www.gnu.org/licenses/>.
 --]]
 
+-- Fallback table
+local fallbacks = dofile(font_api.path.."/fallbacks.lua")
+
 -- Local functions
 ------------------
 
--- Table deep copy
-
-local function deep_copy(input)
-	local output = {}
-	local key, value
-	for key, value in pairs(input) do
-		if type(value) == 'table' then
-			output[key] = deep_copy(value)
-		else
-			output[key] = value
-		end
+-- Returns number of UTF8 bytes of the first char of the string
+local function get_char_bytes(str)
+	local msb = str:byte(1)
+	if msb ~= nil then
+		if msb <  0x80 then return 1 end
+		if msb >= 0xF0 then return 4 end
+		if msb >= 0xE0 then	return 3 end
+		if msb >= 0xC2 then	return 2 end
 	end
-	return output
 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
+-- Returns the unicode codepoint of the first char of the string
+local function char_to_codepoint(str)
+	local bytes = get_char_bytes(str)
+	if bytes == 1 then
+	    return str:byte(1)
+	elseif bytes == 2 then
+		return (str:byte(1) - 0xC2) * 0x40
+			+ str:byte(2)
+	elseif bytes == 3 then
+		return (str:byte(1) - 0xE0) * 0x1000
+			+ str:byte(2) % 0x40 * 0x40
+			+ str:byte(3) % 0x40
+	elseif bytes == 4 then -- Not tested
+		return (str:byte(1) - 0xF0) * 0x40000
+			+ str:byte(2) % 0x40 * 0x1000
+			+ str:byte(3) % 0x40 * 0x40
+			+ str:byte(4) % 0x40
 	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
 
 -- 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
@@ -86,42 +71,75 @@ end
 --------------------------------------------------------------------------------
 --- Font class
 
-font_api.Font = {}
+local Font = {}
+font_api.Font = Font
 
-function font_api.Font:new(def)
+function Font:new(def)
 
 	if type(def) ~= "table" then
-		minetest.log("error", "Font definition must be a table.")
+		minetest.log("error",
+			"[font_api] Font definition must be a table.")
 		return nil
 	end
-	
+
 	if def.height == nil or def.height <= 0 then
-		minetest.log("error", "Font definition must have a positive height.")
+		minetest.log("error",
+			"[font_api] Font definition must have a positive height.")
 		return nil
 	end
 
 	if type(def.widths) ~= "table" then
-		minetest.log("error", "Font definition must have a widths array.")
+		minetest.log("error",
+			"[font_api] Font definition must have a widths array.")
 		return nil
 	end
 
 	if def.widths[0] == nil then
-		minetest.log("error", 
-			"Font must have a char with codepoint 0 (=unknown char).")
+		minetest.log("error",
+			"[font_api] Font must have a char with codepoint 0 (=unknown char).")
 		return nil
 	end
 
-	local font = deep_copy(def)
+	local font = table.copy(def)
 	setmetatable(font, self)
 	self.__index = self
 	return font
 end
 
+--- Gets the next char of a text
+-- @return Codepoint of first char,
+-- @return Remaining string without this first char
+
+function Font:get_next_char(text)
+	local bytes = get_char_bytes(text)
+
+	if bytes == nil then
+		minetest.log("warning",
+			"[font_api] Encountered a non UTF char, not displaying text.")
+		return nil, ''
+	end
+
+	local codepoint = char_to_codepoint(text)
+
+	-- Fallback mechanism
+	if self.widths[codepoint] == nil then
+		local char = text:sub(1, bytes)
+
+		if fallbacks[char] then
+			return self:get_next_char(fallbacks[char]..text:sub(bytes+1))
+		else
+			return 0, text:sub(bytes+1) -- Ultimate fallback
+		end
+	else
+		return codepoint, text:sub(bytes+1)
+	end
+end
+
 --- Returns the width of a given char
 -- @param char : codepoint of the char
 -- @return Char width
 
-function font_api.Font:get_char_width(char)
+function Font:get_char_width(char)
 	-- Replace chars with no texture by the NULL(0) char
 	if self.widths[char] ~= nil then
 		return self.widths[char]
@@ -134,13 +152,13 @@ end
 -- @param nb_of_lines : number of text lines (default 1)
 -- @return Text height
 
-function font_api.Font:get_height(nb_of_lines)
+function Font:get_height(nb_of_lines)
 	if nb_of_lines == nil then nb_of_lines = 1 end
-	
+
 	if nb_of_lines > 0 then
-		return 
+		return
 			(
-				(self.height or 0) + 
+				(self.height or 0) +
 				(self.margintop or 0) +
 				(self.marginbottom or 0)
 			) * nb_of_lines +
@@ -154,16 +172,14 @@ end
 -- @param line Line of text which the width will be computed.
 -- @return Text width
 
-function font_api.Font:get_width(line)
-
-	local char
+function Font:get_width(line)
+	local codepoint
 	local width = 0
-	local pos = 1
+	line = line or ''
 
-	-- TODO: Use iterator
-	while pos <= #line do
-		char, pos = get_next_char(line, pos)
-		width = width + self:get_char_width(char)
+	while line ~= "" do
+		codepoint, line = self:get_next_char(line)
+		width = width + self:get_char_width(codepoint)
 	end
 
 	return width
@@ -176,30 +192,21 @@ end
 -- @param y Vertical position of the line in texture
 -- @return Texture string
 
-function font_api.Font:make_line_texture(line, texturew, x, y)
+function Font:make_line_texture(line, texturew, x, y)
+	local codepoint
 	local texture = ""
-	local char
-	local pos = 1
-
-	-- TODO: Use iterator
-	while pos <= #line do
-		char, pos = get_next_char(line, pos)
-
-		-- Replace chars with no texture by the NULL(0) char
-		if self.widths[char] == nil 
-		then
-			print(string.format("["..font_api.name
-                                .."] Missing char %d (%04x)",char,char))
-			char = 0
-		end
+	line = line or ''
+
+	while line ~= '' do
+		codepoint, line = self:get_next_char(line)
 
 		-- Add image only if it is visible (at least partly)
-		if x + self.widths[char] >= 0 and x <= texturew then
+		if x + self.widths[codepoint] >= 0 and x <= texturew then
 			texture = texture..
 				string.format(":%d,%d=font_%s_%04x.png",
-				              x, y, self.name, char)
+				              x, y, self.name, codepoint)
 		end
-		x = x + self.widths[char]
+		x = x + self.widths[codepoint]
 	end
 
 	return texture
@@ -215,13 +222,13 @@ end
 -- @param color Color of the text (optional)
 -- @return Texture string
 
-function font_api.Font:make_text_texture(text, texturew, textureh, maxlines,
+function Font:make_text_texture(text, texturew, textureh, maxlines,
                                          halign, valign, color)
 	local texture = ""
 	local lines = {}
 	local textheight = 0
 	local y
-    
+
 	-- Split text into lines (limited to maxlines fist lines)
 	for num, line in pairs(split_lines(text, maxlines)) do
 		lines[num] = { text = line, width = self:get_width(line) }
@@ -238,7 +245,7 @@ function font_api.Font:make_text_texture(text, texturew, textureh, maxlines,
 			y = (textureh - textheight) / 2
 		end
 	end
-    
+
 	y = y + (self.margintop or 0)
 
 	for _, line in pairs(lines) do
@@ -263,4 +270,3 @@ function font_api.Font:make_text_texture(text, texturew, textureh, maxlines,
 	if color then texture = texture.."^[colorize:"..color end
 	return texture
 end
-