def copy_global_ct(inputgif):
"""
This function creates a copy of the global colour table
:param inputgif: the input gif object
:return: new table which is a deep copy of the global color table
"""
global_table = inputgif.global_color_table
new_table = Gif.ColorTable(global_table._io)
for i in global_table.entries:
newcolor = Gif.ColorTableEntry(None)
newcolor.red = i.red
newcolor.green = i.green
newcolor.blue = i.blue
new_table.entries.append(newcolor)
return new_table
def checkGCT(inputgif):
"""
This function checks if the GIF has GCT and if it is of size 256
Called in count_available_storage
:param inputgif: GIF object
:return: GIF object
"""
flag = inputgif.logical_screen_descriptor.flags
if (flag & 128) != 0: # if there is GCT
global_table = inputgif.global_color_table
if len(global_table.entries) == 256: # if size of GCT is 256
return inputgif
else: # if size not 256
old_table = global_table.entries
new_table = Gif.ColorTable(
global_table._io) # create new empty table
for i in range(256):
if i < len(old_table): # append the old table RGB values
newcolor = Gif.ColorTableEntry(None)
newcolor.red = old_table[i].red
newcolor.green = old_table[i].green
newcolor.blue = old_table[i].blue
new_table.entries.append(newcolor)
else: # create empty RGB values for new entries
newcolor = Gif.ColorTableEntry(None)
newcolor.red = 0
newcolor.green = 0
newcolor.blue = 0
new_table.entries.append(newcolor)
inputgif.global_color_table = new_table
inputgif.logical_screen_descriptor.flags = 247 # change the flag value to indicate correct size of gct
# else no gct just return inputgif
return inputgif
