# File lib/native_file_types/ti99/TiRLE.rb, line 33
def to_picture 
        buffer=contents
        cols=picture_width 
        rows=picture_height 
        canvas = PNG::Canvas.new cols, rows, PNG::Color::Black  
        p=3     
        colour_index=0 
        done=false 
        bit_index=0 
        while !(buffer[p]).nil? 
                if buffer[p]>=0x20 then #skip over any control characters 
                        run_length=(buffer[p]-0x20) 
                        run_length.times do 
                                x=bit_index % cols 
                                y=bit_index / cols 
                                break if y>=rows 
                                canvas[x, y]= RLE_COLOURS[colour_index] 
                                bit_index+=1            
                        end 
                        colour_index=((colour_index+1)%2) 
                end 
                p+=1 
        end 
        
        png = PNG.new canvas 
        result=png.raw_bytes 
        result 
      end