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Support multiple sizes in ICO and improve code quality

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This commit is contained in:
Ethan Dalool 2017-11-03 12:51:25 -07:00
parent b5a1649bc0
commit f8fed4e41e
1 changed files with 209 additions and 131 deletions
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312
ICO/icoconvert.py
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@ -2,86 +2,123 @@
# All values in ICO/CUR files are represented in little-endian byte order.
# Header
#
# ICONDIR structure
# _________________________________________________________________________________
# | Offset | Size (in bytes) | Purpose |
# |--------|-----------------|------------------------------------------------------|
# Broad file structure:
# _______________________
# | ICO header |
# |-----------------------|
# | Icon directories 1..n |
# |-----------------------|
# | Image data 1..n |
# |_______________________|
# ICO header:
# _______________________________________________________________________________
# | Offset | Size (bytes) | Purpose |
# |--------|--------------|-------------------------------------------------------|
# | 0 | 2 | Reserved. Must always be 0. |
# |--------|-----------------|------------------------------------------------------|
# |--------|--------------|-------------------------------------------------------|
# | 2 | 2 | Specifies image type: 1 for icon (.ICO) image, |
# | | | 2 for cursor (.CUR) image. Other values are invalid. |
# |--------|-----------------|------------------------------------------------------|
# |--------|--------------|-------------------------------------------------------|
# | 4 | 2 | Specifies number of images in the file. |
# |________|_________________|______________________________________________________|
# |________|______________|_______________________________________________________|
# Structure of image directory
# _______________________________________
# | Image #1 | Entry for the first image |
# |----------|----------------------------|
# | Image #2 | Entry for the second image |
# |----------|----------------------------|
# | ... | |
# |----------|----------------------------|
# | Image #n | Entry for the last image |
# |__________|____________________________|
# Image entry
#
# ICONDIRENTRY structure
# _________________________________________________________________________________
# | Offset | Size (in bytes) | Purpose |
# |--------|-----------------|------------------------------------------------------|
# | 0 (06) | 1 | Specifies image width in pixels. Can be any number |
# Icon directory structure:
# _______________________________________________________________________________
# | Offset | Size (bytes) | Purpose |
# |--------|--------------|-------------------------------------------------------|
# | 0 | 1 | Specifies image width in pixels. Can be any number |
# | | | between 0 and 255. Value 0 means image width is 256 |
# | | | pixels. |
# |--------|-----------------|------------------------------------------------------|
# | 1 (07) | 1 | Specifies image height in pixels. Can be any number |
# |--------|--------------|-------------------------------------------------------|
# | 1 | 1 | Specifies image height in pixels. Can be any number |
# | | | between 0 and 255. Value 0 means image height is 256 |
# | | | pixels. |
# |--------|-----------------|------------------------------------------------------|
# | 2 (08) | 1 | Specifies number of colors in the color palette. |
# |--------|--------------|-------------------------------------------------------|
# | 2 | 1 | Specifies number of colors in the color palette. |
# | | | Should be 0 if the image does not use a color palette |
# |--------|-----------------|------------------------------------------------------|
# | 3 (09) | 1 | Reserved. Should be 0. |
# |--------|-----------------|------------------------------------------------------|
# | 4 (10) | 2 | In ICO format: Specifies color planes. |
# |--------|--------------|-------------------------------------------------------|
# | 3 | 1 | Reserved. Should be 0. |
# |--------|--------------|-------------------------------------------------------|
# | 4 | 2 | In ICO format: Specifies color planes. |
# | | | Should be 0 or 1. |
# | | | In CUR format: Specifies the horizontal coordinates |
# | | | of the hotspot in number of pixels from the left. |
# |--------|-----------------|------------------------------------------------------|
# | 6 (12) | 2 | In ICO format: Specifies bits per pixel. |
# |--------|--------------|-------------------------------------------------------|
# | 6 | 2 | In ICO format: Specifies bits per pixel. |
# | | | In CUR format: Specifies the vertical coordinates of |
# | | | the hotspot in number of pixels from the top. |
# |--------|-----------------|------------------------------------------------------|
# | 8 (14) | 4 | Specifies the size of the image's data in bytes |
# |--------|-----------------|------------------------------------------------------|
# |12 (18) | 4 | Specifies the offset of BMP or PNG data from the |
# |--------|--------------|-------------------------------------------------------|
# | 8 | 4 | Specifies the size of the image's data in bytes |
# |--------|--------------|-------------------------------------------------------|
# | 12 | 4 | Specifies the offset of BMP or PNG data from the |
# | | | beginning of the ICO/CUR file |
# |________|_________________|______________________________________________________|
# |________|______________|_______________________________________________________|
import binascii
# Image data structure
# BMP, starting from the BITMAPINFOHEADER, ignoring normal file header:
# _______________________________________________________________________________
# | Offset | Size (bytes) | Purpose |
# |--------|--------------|-------------------------------------------------------|
# | 0 | 4 | The size of this header. Always 40. |
# |--------|--------------|-------------------------------------------------------|
# | 4 | 4 | Image width in pixels, signed. |
# |--------|--------------|-------------------------------------------------------|
# | 8 | 4 | Image height in pixels, signed. |
# |--------|--------------|-------------------------------------------------------|
# | 12 | 2 | Number of color planes. Always 1. |
# |--------|--------------|-------------------------------------------------------|
# | 14 | 2 | Bits per pixel aka color depth. |
# |--------|--------------|-------------------------------------------------------|
# | 16 | 4 | Compression method. 0 for None aka BI_RGB. |
# |--------|--------------|-------------------------------------------------------|
# | 20 | 4 | Image bytes length. 0 for BI_RGB because inferred. |
# |--------|--------------|-------------------------------------------------------|
# | 24 | 4 | Horizontal print resolution. |
# |--------|--------------|-------------------------------------------------------|
# | 28 | 4 | Vertical print resolution |
# |--------|--------------|-------------------------------------------------------|
# | 32 | 4 | Number of colors in palette. 0 for 2^n. |
# |--------|--------------|-------------------------------------------------------|
# | 36 | 4 | Number of important colors. 0 for all. |
# |--------|--------------|-------------------------------------------------------|
# | 40 | n | Pixel bytes, r, g, b, a. |
# |________|______________|_______________________________________________________|
import os
import sys
from PIL import Image
import os
print(os.getcwd())
try:
INPUTFILE = sys.argv[1]
except:
print('Please provide an image file')
quit()
def little_endian(hexstring):
#print(hexstring)
assert len(hexstring) % 2 == 0
doublets = [hexstring[x*2:(x*2)+2] for x in range(len(hexstring)//2)]
#print(doublets)
doublets.reverse()
hexstring = ''.join(doublets)
return hexstring
def fit_into_bounds(self, iw, ih, fw, fh):
ICO_HEADER_LENGTH = 6
ICON_DIRECTORY_ENTRY_LENGTH = 16
BMP_HEADER_LENGTH = 40
def chunk_sequence(sequence, chunk_length, allow_incomplete=True):
'''
Given a sequence, divide it into sequences of length `chunk_length`.
allow_incomplete:
If True, allow the final chunk to be shorter if the
given sequence is not an exact multiple of `chunk_length`.
If False, the incomplete chunk will be discarded.
'''
(complete, leftover) = divmod(len(sequence), chunk_length)
if not allow_incomplete:
leftover = 0
chunk_count = complete + min(leftover, 1)
chunks = []
for x in range(chunk_count):
left = chunk_length * x
right = left + chunk_length
chunks.append(sequence[left:right])
return chunks
def fit_into_bounds(iw, ih, fw, fh):
'''
Given the w+h of the image and the w+h of the frame,
return new w+h that fits the image into the frame
@ -94,72 +131,113 @@ def fit_into_bounds(self, iw, ih, fw, fh):
h = int(ih * ratio)
return (w, h)
def image_to_ico(filename):
print('Icofying %s' % filename)
def little(x, length):
return x.to_bytes(length, byteorder='little')
def load_image(filename):
image = Image.open(filename)
if min(image.size) > 256:
w = image.size[0]
h = image.size[1]
image = image.resize((256, 256), resample=Image.ANTIALIAS)
(w, h) = image.size
image = image.resize(fit_into_bounds(w, h, 256, 256), resample=Image.ANTIALIAS)
image = image.convert('RGBA')
return image
print('Building ico header')
output_bytes = ''
output_bytes += '00' '00' # reserved 0
output_bytes += '01' '00' # 1 = ico
output_bytes += '01' '00' # number of images
#### ICO HEADER ####
def build_ico_header_blob(image_count):
datablob = (b''
+ little(0, 2) # reserved
+ little(1, 2) # 1 = ico type
+ little(image_count, 2)
)
return datablob
print('Building image entry')
# width and height. 00 acts as 256
output_bytes += '%02x' % image.size[0] if image.size[0] < 256 else '00'
output_bytes += '%02x' % image.size[1] if image.size[1] < 256 else '00'
output_bytes += '00' # colors in palette
output_bytes += '00' # reserved 0
output_bytes += '01' '00' # color planes
output_bytes += '20' '00' # bits per pixel (32)
output_bytes += little_endian('%08x' % ((image.size[0] * image.size[1] * 4)+8192)) # image bytes size
output_bytes += '16' '00' '00' '00' # image offset from start of file (begins right after this)
#### IMAGE ENTRY ####
def build_icon_directory_blob(image, offset_from_start):
(width, height) = image.size
datablob = (b''
+ little(width if width < 256 else 0, 1)
+ little(height if height < 256 else 0, 1)
+ little(0, 1) # colors in palette
+ little(0, 1) # reserved
+ little(1, 2) # color planes
+ little(32, 2) # bit depth
+ little((width * height * 4) + BMP_HEADER_LENGTH, 4) # image bytes length
+ little(offset_from_start, 4)
)
return datablob
print('Building image header')
output_bytes += '28' '00' '00' '00' # BMP DIB header size (always 40)
output_bytes += little_endian('%08x' % image.size[0])
output_bytes += little_endian('%08x' % (image.size[1] * 2)) # I'm not sure why * 2
output_bytes += '01' '00' # color planes
output_bytes += '20' '00' # bits per pixel (32)
output_bytes += '00' '00' '00' '00' # Compression (None)
image_bytesize = image.size[0] * image.size[1] * 4
# BMP pixel array must always end on a 4th byte.
image_nullpadding = 4 - (image_bytesize % 4)
image_nullpadding = 0 if image_nullpadding == 4 else image_nullpadding
output_bytes += little_endian('%08x' % (image_bytesize + image_nullpadding)) # BMP file size
output_bytes += '00' '00' '00' '00' # Print width (unnecessary)
output_bytes += '00' '00' '00' '00' # Print height (unecessary)
output_bytes += '00' '00' '00' '00' # colors in palette
output_bytes += '00' '00' '00' '00' # "important colors"
#### IMAGE HEADER ####
def build_image_data_blob(image):
datablob = (b''
+ little(40, 4) # header size
+ little(image.size[0], 4)
# "Even if the AND mask is not supplied, if the image is in Windows BMP
# format, the BMP header must still specify a doubled height." - wikipedia
+ little(image.size[1] * 2, 4)
+ little(1, 2) # color planes
+ little(32, 2) # bit depth
+ little(0, 4) # no compression
+ little(0, 4) # bytes length, inferred
+ little(0, 4) # hor print
+ little(0, 4) # ver print
+ little(0, 4) # palette
+ little(0, 4) # important palette
)
pixeldata = []
# Image.getdata() is a list of (r, g, b, a) channels
# But the BMP are written (b, g, r, a)
# Also they are written from bottom to top.
pixels = list(image.getdata())
pixels = reversed(chunk_sequence(pixels, image.size[0]))
pixels = [line for chunk in pixels for line in chunk]
for pixel in pixels:
(r, g, b, a) = pixel
pixeldata.extend((b, g, r, a))
datablob += bytes(pixeldata)
return datablob
print('Writing pixels')
image_data = ''
for y in range(image.size[1]-1, -1, -1):
for x in range(image.size[0]):
pixel = image.getpixel( (x, y) )
#print(pixel)
r = '%02x' % pixel[0]
g = '%02x' % pixel[1]
b = '%02x' % pixel[2]
o = '%02x' % pixel[3]
image_data += b + g + r + o
def images_to_ico(images):
# For some reason Windows reads the icons in reverse order.
images.reverse()
image_data += '00' * 8192
output_bytes += image_data
output_bytes = binascii.a2b_hex(output_bytes)
name = filename.split('.')[0] + '.ico'
# The directory entries need to know their image's address, so therefore
# we must know the lengths of all the image binaries before we can write
# any directory entries.
# We will calculate the image blobs first, store them separately,
# and then put them after the directory blobs.
datablobs = []
imageblobs = []
ico_header_blob = build_ico_header_blob(image_count=len(images))
datablobs.append(ico_header_blob)
for (index, image) in enumerate(images):
imageblob = build_image_data_blob(image)
imageblobs.append(imageblob)
# Since the ICO header and directory entries are of fixed length, we know
# the location of the first image.
# After that, the offset just gains the size of the previous image.
offset_from_start = ICO_HEADER_LENGTH + (len(images) * ICON_DIRECTORY_ENTRY_LENGTH)
for (index, (image, imageblob)) in enumerate(zip(images, imageblobs)):
directoryblob = build_icon_directory_blob(image, offset_from_start=offset_from_start)
datablobs.append(directoryblob)
offset_from_start += len(imageblob)
datablobs.extend(imageblobs)
final_data = b''.join(datablobs)
return final_data
if __name__ == '__main__':
try:
inputfiles = sys.argv[1:]
except:
print('Please provide an image file')
raise SystemExit
print('Iconifying', inputfiles)
images = [load_image(filename) for filename in inputfiles]
final_data = images_to_ico(images)
name = os.path.splitext(inputfiles[0])[0] + '.ico'
output_file = open(name, 'wb')
output_file.write(output_bytes)
output_file.write(final_data)
output_file.close()
print('Finished %s.' % name)
image_to_ico(INPUTFILE)