Class: TiRLE

Inherits:
Ti99File show all
Defined in:
lib/native_file_types/ti99/TiRLE.rb

Constant Summary collapse

RLE_COLOURS = 
[PNG::Color::Black,PNG::Color::White]

Instance Attribute Summary

Attributes inherited from NativeFileType

#aux_code, #contents, #file_system_image, #file_type, #filename, #meta_data

Instance Method Summary collapse

Methods inherited from Ti99File

file_system_file_types, #type_description

Methods inherited from NativeFileType

#<=>, #==, all_native_file_types, best_fit, code_for_tests, compatability_score, #data_without_header, file_type_matches?, #full_filename, #header_length, #initialize, is_valid_file_if, #load_address, load_address, matching_score, native_file_types_possible_on_file_system, non_matching_score, #to_hex_dump, #to_info_dump, #type_description

Methods included from SubclassTracking

extended

Constructor Details

This class inherits a constructor from NativeFileType

Instance Method Details

#picture_format ⇒ Object 



62
63
64
 
# File 'lib/native_file_types/ti99/TiRLE.rb', line 62

def picture_format
  :png
end

#picture_height ⇒ Object 



23
24
25
26
27
28
29
 
# File 'lib/native_file_types/ti99/TiRLE.rb', line 23

def picture_height 
        case contents[2] 
                when 0x48 then return 192 #H=High Resolution 
                when 0x4D then return 96  #M=Medium Resolution 
        end 
        raise "invalid RLE graphic mode #{buffer[2].chr}" 
end

#picture_width ⇒ Object 



16
17
18
19
20
21
22
 
# File 'lib/native_file_types/ti99/TiRLE.rb', line 16

def picture_width 
        case contents[2] 
                when 0x48 then return 256 #H=High Resolution 
                when 0x4D then return 128 #M=Medium Resolution 
        end 
        raise "invalid RLE graphic mode #{buffer[2].chr}" 
end

#to_picture ⇒ Object 



33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
 
# 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