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Diffstat (limited to 'font_api/font.lua')
| -rw-r--r-- | font_api/font.lua | 270 |
1 files changed, 270 insertions, 0 deletions
diff --git a/font_api/font.lua b/font_api/font.lua new file mode 100644 index 0000000..60563d8 --- /dev/null +++ b/font_api/font.lua @@ -0,0 +1,270 @@ +--[[ + 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/>. +--]] + + +--[[ + Margins, spacings, can be negative numbers +]]-- + +-- 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 + 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 + 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 + local lines = {} + for num = 1,maxlines do + lines[num] = splits[num] + end + return lines + else + return splits + end +end + +-------------------------------------------------------------------------------- +--- Font class + +font_api.Font = {} + +function font_api.Font:new(def) + + if type(def) ~= "table" then + minetest.log("error", "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.") + return nil + end + + if type(def.widths) ~= "table" then + minetest.log("error", "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).") + return nil + end + + local font = deep_copy(def) + setmetatable(font, self) + self.__index = self + return font +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) + -- Replace chars with no texture by the NULL(0) char + if self.widths[char] ~= nil then + return self.widths[char] + 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_api.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.margin_top or 0) + + (self.margin_bottom or 0) + ) * nb_of_lines + + (self.line_spacing 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_api.Font:get_width(line) + + local char + local width = 0 + local pos = 1 + + -- TODO: Use iterator + while pos <= #line do + char, pos = get_next_char(line, pos) + width = width + self:get_char_width(char) + end + + return width +end + +--- Builds texture part for a text line +-- @param line Text line to be rendered +-- @param texturew 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.Font:make_line_texture(line, texturew, x, y) + local texture = "" + local char + local pos = 1 + + -- TODO: Use iterator + while pos <= #text do + char, pos = get_next_char(line, pos) + + -- Replace chars with no texture by the NULL(0) char + if self.widths[char] == nil +or char == 88 --DEBUG + 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 + self.widths[char] >= 0 and x <= texturew then + texture = texture.. + string.format(":%d,%d=font_%s_%04x.png", + x, y, self.name, char) + end + x = x + self.widths[char] + end + + return texture +end + +--- Builds texture for a multiline colored text +-- @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.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) } + end + + textheight = self:get_height(#lines) + + if #lines then + if valign == "top" then + y = 0 + elseif valign == "bottom" then + y = textureh - textheight + else + y = (textureh - textheight) / 2 + end + end + + for _, line in pairs(lines) do + if halign == "left" then + texture = texture.. + self:make_line_texture(line.text, texturew, + 0, y) + elseif halign == "right" then + texture = texture.. + self:make_line_texture(line.text, texturew, + texturew - line.width, y) + else + texture = texture.. + self:make_line_texture(line.text, texturew, + (texturew - line.width) / 2, y) + end + + y = y + self:get_height() + (self.line_spacing or 0) + end + + texture = string.format("[combine:%dx%d", texturew, textureh)..texture + if color then texture = texture.."^[colorize:"..color end + return texture +end + |