forked from mtcontrib/display_modpack
270 lines
6.6 KiB
Lua
270 lines
6.6 KiB
Lua
--[[
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font_api mod for Minetest - Library to add font display capability
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to display_api mod.
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(c) Pierre-Yves Rollo
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>.
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--]]
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--[[
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Margins, spacings, can be negative numbers
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]]--
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-- Local functions
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------------------
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-- Table deep copy
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local function deep_copy(input)
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local output = {}
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local key, value
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for key, value in pairs(input) do
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if type(value) == 'table' then
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output[key] = deep_copy(value)
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else
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output[key] = value
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end
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end
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return output
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end
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-- Returns next char, managing ascii and unicode plane 0 (0000-FFFF).
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local function get_next_char(text, pos)
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local msb = text:byte(pos)
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-- 1 byte char, ascii equivalent codepoints
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if msb < 0x80 then
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return msb, pos + 1
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end
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-- 4 bytes char not managed (Only 16 bits codepoints are managed)
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if msb >= 0xF0 then
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return 0, pos + 4
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end
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-- 3 bytes char
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if msb >= 0xE0 then
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return (msb - 0xE0) * 0x1000
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+ text:byte(pos + 1) % 0x40 * 0x40
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+ text:byte(pos + 2) % 0x40,
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pos + 3
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end
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-- 2 bytes char (little endian)
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if msb >= 0xC2 then
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return (msb - 0xC2) * 0x40 + text:byte(pos + 1),
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pos + 2
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end
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-- Not an UTF char
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return 0, pos + 1
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end
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-- Split multiline text into array of lines, with <maxlines> maximum lines.
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local function split_lines(text, maxlines)
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local splits = text:split("\n")
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if maxlines then
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local lines = {}
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for num = 1,maxlines do
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lines[num] = splits[num]
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end
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return lines
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else
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return splits
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end
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end
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--------------------------------------------------------------------------------
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--- Font class
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font_api.Font = {}
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function font_api.Font:new(def)
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if type(def) ~= "table" then
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minetest.log("error", "Font definition must be a table.")
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return nil
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end
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if def.height == nil or def.height <= 0 then
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minetest.log("error", "Font definition must have a positive height.")
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return nil
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end
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if type(def.widths) ~= "table" then
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minetest.log("error", "Font definition must have a widths array.")
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return nil
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end
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if def.widths[0] == nil then
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minetest.log("error",
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"Font must have a char with codepoint 0 (=unknown char).")
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return nil
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end
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local font = deep_copy(def)
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setmetatable(font, self)
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self.__index = self
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return font
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end
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--- Returns the width of a given char
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-- @param char : codepoint of the char
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-- @return Char width
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function font_api.Font:get_char_width(char)
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-- Replace chars with no texture by the NULL(0) char
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if self.widths[char] ~= nil then
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return self.widths[char]
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else
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return self.widths[0]
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end
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end
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--- Text height for multiline text including margins and line spacing
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-- @param nb_of_lines : number of text lines (default 1)
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-- @return Text height
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function font_api.Font:get_height(nb_of_lines)
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if nb_of_lines == nil then nb_of_lines = 1 end
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if nb_of_lines > 0 then
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return
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(
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(self.height or 0) +
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(self.margin_top or 0) +
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(self.margin_bottom or 0)
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) * nb_of_lines +
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(self.line_spacing or 0) * (nb_of_lines -1)
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else
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return nb_of_lines == 0 and 0 or nil
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end
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end
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--- Computes text width for a given text (ignores new lines)
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-- @param line Line of text which the width will be computed.
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-- @return Text width
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function font_api.Font:get_width(line)
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local char
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local width = 0
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local pos = 1
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-- TODO: Use iterator
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while pos <= #line do
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char, pos = get_next_char(line, pos)
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width = width + self:get_char_width(char)
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end
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return width
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end
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--- Builds texture part for a text line
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-- @param line Text line to be rendered
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-- @param texturew Width of the texture (extra text is not rendered)
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-- @param x Starting x position in texture
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-- @param y Vertical position of the line in texture
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-- @return Texture string
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function font_api.Font:make_line_texture(line, texturew, x, y)
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local texture = ""
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local char
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local pos = 1
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-- TODO: Use iterator
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while pos <= #line do
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char, pos = get_next_char(line, pos)
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-- Replace chars with no texture by the NULL(0) char
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if self.widths[char] == nil
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then
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print(string.format("["..font_api.name
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.."] Missing char %d (%04x)",char,char))
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char = 0
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end
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-- Add image only if it is visible (at least partly)
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if x + self.widths[char] >= 0 and x <= texturew then
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texture = texture..
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string.format(":%d,%d=font_%s_%04x.png",
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x, y, self.name, char)
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end
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x = x + self.widths[char]
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end
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return texture
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end
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--- Builds texture for a multiline colored text
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-- @param text Text to be rendered
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-- @param texturew Width of the texture (extra text will be truncated)
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-- @param textureh Height of the texture
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-- @param maxlines Maximum number of lines
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-- @param halign Horizontal text align ("left"/"center"/"right") (optional)
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-- @param valign Vertical text align ("top"/"center"/"bottom") (optional)
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-- @param color Color of the text (optional)
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-- @return Texture string
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function font_api.Font:make_text_texture(text, texturew, textureh, maxlines,
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halign, valign, color)
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local texture = ""
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local lines = {}
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local textheight = 0
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local y
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-- Split text into lines (limited to maxlines fist lines)
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for num, line in pairs(split_lines(text, maxlines)) do
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lines[num] = { text = line, width = self:get_width(line) }
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end
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textheight = self:get_height(#lines)
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if #lines then
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if valign == "top" then
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y = 0
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elseif valign == "bottom" then
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y = textureh - textheight
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else
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y = (textureh - textheight) / 2
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end
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end
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for _, line in pairs(lines) do
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if halign == "left" then
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texture = texture..
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self:make_line_texture(line.text, texturew,
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0, y)
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elseif halign == "right" then
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texture = texture..
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self:make_line_texture(line.text, texturew,
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texturew - line.width, y)
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else
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texture = texture..
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self:make_line_texture(line.text, texturew,
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(texturew - line.width) / 2, y)
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end
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y = y + self:get_height() + (self.line_spacing or 0)
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end
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texture = string.format("[combine:%dx%d", texturew, textureh)..texture
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if color then texture = texture.."^[colorize:"..color end
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return texture
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end
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