xpm.lua

-- Lua XPM generating library
-- (C) 2009 Matthew Wild <mwild1@gmail.com>
-- Released under the MIT/X11 license

module("xpm", package.seeall);
_M.__index = _M;

function new(width, height, name)
	return setmetatable({
			name = name,
			width = width,
			height = height,
			colours = { [false] = true }, ncolours = 1;
		}, _M);
end

function setpixel(xpm, x, y, colour)
	if not xpm[y] then
		xpm[y] = { [x] = colour };
	else
		xpm[y][x] = colour;
	end
	if colour and not xpm.colours[colour] then
		xpm.colours[colour] = true;
		xpm.ncolours = xpm.ncolours + 1;
	end
end

function render(xpm, f)
	local err;
	if type(f) == "string" then
		f = io.open(f, "w+");
	end
	if io.type(f) ~= "file" then
		error("No valid output file", 2);
	end
	
	f:write("/* XPM */\n");
	f:write("static char * ", name or "xpm", "[] = {\n");
	f:write(string.format([["%d %d %d %d",]], xpm.width, xpm.height, xpm.ncolours, 1), "\n");

	local colourmap = new_colourmap(xpm.colours);

	for colour in pairs(xpm.colours) do
		f:write('"', colourmap[colour], "      c ", colour or "None", '",\n');
	end

	for y=1,xpm.height do
		if xpm[y] then
			f:write('"');
			for x=1,xpm.width do
				local pixel = xpm[y][x];
				if pixel then
					f:write(colourmap[pixel]);
				else
					f:write(" ");
				end
			end
			f:write('"', y == xpm.height and "" or ",",'\n');
		else
			f:write('"', string.rep(" ", xpm.width), '"', y == xpm.height and "" or ",", '\n');
		end
	end
	f:write("};\n");
end

function new_colourmap(colours)
	return setmetatable({ [false] = " ", curr = 35 }, { __index = 
		function (cm, colour)
			cm.curr = cm.curr + 1;
			cm[colour] = string.char(cm.curr);
			return rawget(cm, colour);
		end; });
end

return _M;