In this format, programs are stored in the raw format, inside a bloc of metadata with a fix size. Those metadata contain the name of the program and if the program use bas operations or not. Programs and metadata can be extracted from a g1r file with a regular expression (here in python with the re module):

g1r_file = open(filename, 'r')
# Regular expression:
data_pattern = re.compile('''
    (PROGRAM)      # kind of data (only programs with this regexp)
    [\x00]{12}     # Separator
    [\x01]         # one 0x01 (separator)
    system         # The 'system' string
    [\x00]{2}      # Separator
    ([^\x00]{1,8}) # name of the program
    [\x00]{0,7}    # 0x00 to complete the name
    [\x01]         # mark of the end of the name
    [\x00]{2}      # Separator
    .{2}           # two characters (?)
    [\x00]{11}     # Separation
    (\x00|\x01)    # Base (0x01) or not (0x00)
    (.*[^\x00])    # all characters, ended by a non 0x00 characters: raw data without the 0xFF end character
    [\x00]{2}      # end of the record
''', re.VERBOSE)
# extract data from the file
data_list = data_pattern.findall(g1r_file.read())
g1r_file.close()
for record in data_list:
    # record = ('DATA TYPE', 'FILE NAME', 'BASE', 'RAW DATA')
    data_type = record[0]
    data_name = record[1]
    if record[2] == '\x01':
        use_base = True
    else:
        use_base = False
    raw_data = record[3] + '\x0d\xff' #adding the raw end character

The extraction of a picture from a g1r file is done in two steps.

This may be done with a regular expression, here in python, with the re module:

# Make the regular expression
picture_pattern = re.compile('''
    (PICTURE[ ][1-6])   # data name
    [\x00]{10}          # Separator
    [\x01]              # one 0x01 character
    main                # The 'main' string
    [\x00]{4}           # Separator
    (PICT[1-6])         # name (#2)
    [\x00]{3}           # Separator
    [\x07][\x00]{2}
    [\x08][\x00]{4}
    (.{1024})           # Sheet1
    (.{1024})           # Sheet2
''', re.VERBOSE | re.DOTALL)
g1r_file = open(filename, 'r')
picture_list = picture_pattern.findall(g1r_file.read())
g1r_file.close()
for record in picture_list:
    # record = ('DATA NAME #1', 'DATA NAME #2', 'SHEET1', 'SHEET2')
    data_name = 'Picture' + record[0][-1]
    sheet1 = record[2]
    sheet2 = record[3]

You get the picture under the form of two sheet, each one code a color.

Each sheet is 1024 byte long. 16 following byte represent a row, where each bit represents one pixel: if the value of the bit is 1, the value of the pixel is the color of the sheet. Bit are sorted in row from the left to the right ; row are sorted from the top to the bottom.