Add 'font_api/' from commit '4c872e829d716014e601bdf0707edd11a9abbc17'

git-subtree-dir: font_api
git-subtree-mainline: f27b5478b9b67d0867098ef9f30801a7fc0c04ee
git-subtree-split: 4c872e829d716014e601bdf0707edd11a9abbc17

1 files changed, 274 insertions, 0 deletions

diff --git a/font_api/font.lua b/font_api/font.lua
new file mode 100644
index 0000000..5794867
--- /dev/null
+++ b/font_api/font.lua
@@ -0,0 +1,274 @@
+--[[
+	font_api mod for Minetest - Library creating textures with fonts and text
+	(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/>.
+--]]
+
+-- Fallback table
+local fallbacks = dofile(font_api.path.."/fallbacks.lua")
+
+-- Local functions
+------------------
+
+-- 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
+end
+
+-- 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 and str:byte(2) ~= nil then
+		return (str:byte(1) - 0xC2) * 0x40
+			+ str:byte(2)
+	elseif bytes == 3 and str:byte(2) ~= nil and str:byte(3) ~= nil then
+		return (str:byte(1) - 0xE0) * 0x1000
+			+ str:byte(2) % 0x40 * 0x40
+			+ str:byte(3) % 0x40
+	elseif bytes == 4 and str:byte(2) ~= nil and str:byte(3) ~= nil
+		and str:byte(4) ~= nil then -- Not tested
+		return (str:byte(1) - 0xF0) * 0x40000
+			+ str:byte(2) % 0x40 * 0x1000
+			+ str:byte(3) % 0x40 * 0x40
+			+ str:byte(4) % 0x40
+	end
+end
+
+--------------------------------------------------------------------------------
+--- Font class
+
+local Font = {}
+font_api.Font = Font
+
+function Font:new(def)
+
+	if type(def) ~= "table" then
+		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_api] Font definition must have a positive height.")
+		return nil
+	end
+
+	if type(def.widths) ~= "table" then
+		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_api] Font must have a char with codepoint 0 (=unknown char).")
+		return nil
+	end
+
+	local font = table.copy(def)
+	setmetatable(font, self)
+	self.__index = self
+
+	-- Check if fixedwidth
+	for codepoint, width in pairs(font.widths) do
+		font.fixedwidth = font.fixedwidth or width
+		if width ~= font.fixedwidth then
+			font.fixedwidth = nil
+			break
+		end
+	end
+
+	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)
+
+	if codepoint == nil then
+		minetest.log("warning",
+			"[font_api] Encountered a non UTF char, not displaying text.")
+		return nil, ''
+	end
+
+	-- 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:get_char_width(codepoint)
+	if self.fixedwidth then
+		return self.fixedwidth
+	elseif self.widths[codepoint] then
+		return self.widths[codepoint]
+	else
+		return self.widths[0]
+	end
+end
+
+--- Text height for multiline text including margins and line spacing
+-- @param nb_of_lines : number of text lines (default 1)
+-- @return Text height
+
+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
+			(
+				(self.height or 0) +
+				(self.margintop or 0) +
+				(self.marginbottom or 0)
+			) * nb_of_lines +
+			(self.linespacing or 0) * (nb_of_lines -1)
+	else
+		return nb_of_lines == 0 and 0 or nil
+	end
+end
+
+--- Computes text width for a given text (ignores new lines)
+-- @param line Line of text which the width will be computed.
+-- @return Text width
+
+function Font:get_width(line)
+	local codepoint
+	local width = 0
+	line = line or ''
+
+	while line ~= "" do
+		codepoint, line = self:get_next_char(line)
+		if codepoint == nil then return 0 end -- UTF Error
+		width = width + self:get_char_width(codepoint)
+	end
+
+	return width
+end
+
+--- Legacy make_text_texture method (replaced by "render" - Dec 2018)
+
+function Font:make_text_texture(text, texturew, textureh, maxlines,
+		halign, valign, color)
+		return self:render(text, texturew, textureh, {
+			lines = maxlines,
+			valign = valign,
+			halign = halign,
+			color = color
+		})
+end
+
+--- Render text with the font in a view
+-- @param text Text to be rendered
+-- @param texturew Width (in pixels) of the texture (extra text will be truncated)
+-- @param textureh Height (in pixels) of the texture (extra text will be truncated)
+-- @param style Style of the rendering:
+--		- lines: maximum number of text lines (if text is limited)
+--		- halign: horizontal align ("left"/"center"/"right")
+--		- valign: vertical align ("top"/"center"/"bottom")
+--		- color: color of the text ("#rrggbb")
+-- @return Texture string
+
+function Font:render(text, texturew, textureh, style)
+	local style = style or {}
+
+	-- Split text into lines (and limit to style.lines # of lines)
+	local lines = {}
+	local pos = 1
+	local found, line
+	repeat
+		found = string.find(text, "\n", pos) or (#text + 1)
+		line = string.sub(text, pos, found - 1)
+		lines[#lines + 1] = { text = line, width = self:get_width(line) }
+		pos = found + 1
+	until (style.lines and (#lines >= style.lines)) or (pos > (#text + 1))
+
+	if not #lines then
+		return ""
+	end
+
+	local x, y, codepoint
+	local texture = ""
+	local textheight = self:get_height(#lines)
+
+	if style.valign == "top" then
+		y = 0
+	elseif style.valign == "bottom" then
+		y = textureh - textheight
+	else
+		y = (textureh - textheight) / 2
+	end
+
+	y = y + (self.margintop or 0)
+
+	for _, line in pairs(lines) do
+		if style.halign == "left" then
+			x = 0
+		elseif style.halign == "right" then
+			x = texturew - line.width
+		else
+			x = (texturew - line.width) / 2
+		end
+
+		while line.text ~= '' do
+			codepoint, line.text = self:get_next_char(line.text)
+			if codepoint == nil then return '' end -- UTF Error
+
+			-- Add image only if it is visible (at least partly)
+			if x + self.widths[codepoint] >= 0 and x <= texturew then
+				texture = texture..
+					string.format(":%d,%d=font_%s_%04x.png", x, y, self.name, codepoint)
+			end
+			x = x + self.widths[codepoint]
+		end
+
+		y = y + self:get_height() + (self.linespacing or 0)
+	end
+	texture = string.format("[combine:%dx%d", texturew, textureh)..texture
+	if style.color then
+		texture = texture.."^[colorize:"..style.color
+	end
+	return texture
+end