#-- # Rubygame -- Ruby code and bindings to SDL to facilitate game creation # Copyright (C) 2004-2007 John Croisant # # This library is free software; you can redistribute it and/or # modify it under the terms of the GNU Lesser General Public # License as published by the Free Software Foundation; either # version 2.1 of the License, or (at your option) any later version. # # This library 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 # Lesser General Public License for more details. # # You should have received a copy of the GNU Lesser General Public # License along with this library; if not, write to the Free Software # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA #++ module Rubygame # *NOTE*: you must require 'rubygame/sfont' manually to gain access to # Rubygame::SFont. It is not imported with Rubygame by default! # # SFont is a type of bitmapped font, which is loaded from an image file # with a meaningful top row of pixels, and the font itself below that. The # top row provides information about what parts of of the lower area # contains font data, and which parts are empty. # # The image file should contain all of the glyphs on one row, with the # colorkey color at the bottom-left pixel and the "skip" color at the # top-left pixel. # # The colorkey color is applied to the image file when it is loaded, so # that all pixels of that color appear transparent. Alternatively, if the # alpha value of pixel [0,0] is 0 (that is, if it is fully transparent), # the image file is assumed to have a proper alpha channel, and no colorkey # is applied. The skip color is used in the top row of pixels to indicate # that all the pixels below it contain empty space, and that the next # pixel that is not the skip color marks the beginning of the next glyph. # # The official SFont homepage, with information on SFont and sample font # files, can be found at http://www.linux-games.com/sfont/. More # information on SFont, and a useful utility for automatically generating # the top row for a font, can be found at: http://www.nostatic.org/sfont/ class SFont @@default_glyphs = [\ "!",'"',"#","$","%","&","'","(",")","*","+",",","-",".","/","0", "1","2","3","4","5","6","7","8","9",":",";","<","=",">","?","@", "A","B","C","D","E","F","G","H","I","J","K","L","M","N","O","P", "Q","R","S","T","U","V","W","X","Y","Z","[","\\","]","^","_","`", "a","b","c","d","e","f","g","h","i","j","k","l","m","n","o","p", "q","r","s","t","u","v","w","x","y","z","{","|","}","~"] # Returns an array of strings, each string a single ASCII character # from ! (33) to ~ (126). This is the default set of characters in a # SFont. The full set is as follows: # # ! " # $ % & ' ( ) * + , - . / 0 1 2 3 4 5 6 7 8 9 : ; < = > ? @ # A B C D E F G H I J K L M N O P Q R S T U V W X Y Z [ \ ] ^ _ ` # a b c d e f g h i j k l m n o p q r s t u v w x y z { | } ~ def SFont.default_glyphs @@default_glyphs end # Create a now SFont instance. # # This function takes these arguments: # filename:: the name of the image file from which the font should be # loaded. Or, a Surface with a font image on it. The # Surface will be copied onto separate Surfaces for each # glyph, so the original Surface can be recycled. # glyphs:: array of strings, one for each glyph, in the order they # are found in the image file. If glyphs is not provided, # or is nil, it is assumed to be the normal SFont order; # that is, ASCII characters ! (33) to ~ (126). See # SFont.default_glyphs for a full list. # spacew:: represents the width of a space character ( ). You can # either specify the width in pixels, or specify a # character whose width, as found in the image, should be # used. Alternatively, you could add a space character to # the list of glyphs, and to the image file. If +spacew+ # is not given or is nil, and the space character is not # in the list of glyphs, it will have the same width as # the double-quote character ("). def initialize(filename,glyphs=nil,spacew=nil) # load the surface containing all the glyphs surface = nil if filename.is_a? String surface = Surface.load_image(filename) elsif filename.is_a? Surface surface = filename end @height = surface.height colorkey = surface.get_at(0,@height-1) # set colorkey if "transparent" color is not actually transparent if colorkey[3] != 0 surface.set_colorkey(colorkey[0..2]) end @glyphs = {} @skip = surface.get_at(0,0)[0..2] # split the glyphs into separate surfaces glyphs = (glyphs or @@default_glyphs) start_x = 2 glyphs.each{ |glyph| start_x = load_glyph(surface,glyph,start_x) } if not glyphs.include?(" ") if spacew == nil spacew = @glyphs['"'].width elsif spacew.kind_of? Numeric spacew = spacew.to_i elsif spacew.kind_of? String if glyphs.include? spacew spacew = @glyphs[spacew].width else spacew = @glyphs['"'].width end else raise(ArgumentError,"spacew must be Numeric, String, \ or nil (got %s)"%[spacew.class]) end @glyphs[" "] = Surface.new([spacew,@height]) end end # Return the height of the font, in pixels. This is the same as the # height of the image file (all glyphs are the same height). attr_reader :height # This is a private function which is used to parse the font image. # # Create a Surface for a single glyph, and store it as a value in the # +@glyphs+ hash, indexed by the glyph (string) it represents. # # Starting at a pixel in the "skip" region to the left of the glyph. # Scans to the right along the top row until it finds a non-skip pixel # (this is where the glyph starts) and then scans until it finds a skip # pixel (this is where the glyph ends. # # Returns the x value it stops at, plus 1. This should be fed back in # for the +start_x+ of the next glyph. # # This _private_ method takes these arguments: # surface:: the Surface containing all glyph image data. # glyph:: a string containing the current glyph # start_x:: the x position to start scanning at. def load_glyph(surface,glyph,start_x) # :doc: # find where this glyph starts begin while(surface.get_at(start_x,0)[0..2] == @skip) start_x += 1 end rescue IndexError return -1 end end_x = start_x # find how wide this glyph is begin while(surface.get_at(end_x,0)[0..2] != @skip) end_x += 1 end rescue IndexError return -1 end # make a new surface for the glyph and blit the image onto it rect = Rect.new(start_x, 0, end_x-start_x, surface.h) @glyphs[glyph] = Surface.new(rect.size) surface.blit(@glyphs[glyph],[0,0],rect) return end_x+1 end private :load_glyph # This is a private function which is used to render a string. # # Blit a single glyph to a Surface at the given position. # # This _private_ method takes these arguments: # glyph:: a string containing the glyph to blit. # surface:: the target surface to blit onto. # pos:: an Array of the x and y values to blit the glyph to. def blit_glyph(glyph,surface,pos) # :doc: @glyphs[glyph].blit(surface,pos) end private :blit_glyph # Pretends to render the given string, and returns the width in pixels # of the surface that would be created if it were rendered using # SFont#render. If you want the height too, you can get it with # SFont#height (the height is contant). # # This method takes this argument: # string:: the string to pretend to render. def string_width(string) w = 0 string.each_byte { |glyph| w += @glyphs["%c"%[glyph]].width } return w end # Renders the given string to a Surface, and returns that surface. # # This method takes this argument: # string:: the text string to render. def render(string) size = [self.string_width(string),self.height] render = Surface.new(size) x = 0 string.each_byte { |glyph| blit_glyph("%c"%[glyph],render,[x,0]) x += @glyphs["%c"%[glyph]].width } return render end end # class SFont end # module Rubygame