etcpak

A python wrapper for wolfpld/etcpak

Some changes were made to the original code to make it cross-platform compatible.

1. Installation
2. Example
3. Functions

Installation

pip install etcpak

or download/clone the git and use

python setup.py install

Example

from PIL import Image
import etcpak

# load image
img = Image.open(file_path)

# get image data
img_data = img.convert("RGBA").tobytes()

# compress data
compressed = etcpak.compress_to_dxt5(img_data, img.width, img.height)

composite image for format comparission

import os
import etcpak
import texture2ddecoder
from PIL import Image

FORMATS = [
    ("DXT1", etcpak.compress_to_dxt1, texture2ddecoder.decode_bc1),
    ("DXT1 Dither", etcpak.compress_to_dxt1_dither, texture2ddecoder.decode_bc1),
    ("DXT5", etcpak.compress_to_dxt5, texture2ddecoder.decode_bc3),
    ("ETC1", etcpak.compress_to_etc1, texture2ddecoder.decode_etc1),
    ("ETC1 Dither", etcpak.compress_to_etc1_dither, texture2ddecoder.decode_etc1),
    ("ETC2 RGB", etcpak.compress_to_etc2_rgb, texture2ddecoder.decode_etc2),
    ("ETC2 RGBA", etcpak.compress_to_etc2_rgba, texture2ddecoder.decode_etc2a8)
]

p = "S:\\Pictures"
for fp in os.listdir(p):
    if not fp[-4:] in [".png", ".jpg", ".bmp", "jpeg"]:
        continue
    # load image and adjust format and size
    print(fp)
    img = Image.open(os.path.join(p, fp)).convert("RGBA")
    img = img.crop((0,0,img.width-img.width%4, img.height-img.height%4))
    
    # create composite image
    comp = Image.new("RGBA", (img.width*8, img.height))
    comp.paste(img, (0, 0))
    print(img.width * img.height * 4)

    # iterate over all formats
    for i, (name, enc, dec) in enumerate(FORMATS):
        print(name)
        # make sure that the channel order is correct for the compression
        if name[:3] == "DXT":
            raw = img.tobytes()
        elif name[:3] == "ETC":
            r,g,b,a = img.split()
            raw = Image.merge('RGBA', (b,g,r,a)).tobytes()
        
        # compress
        data = enc(raw, img.width, img.height)

        # decompress
        dimg = Image.frombytes("RGBA", img.size, dec(data, img.width, img.height), "raw", "BGRA")

        # add to composite image
        comp.paste(dimg, (img.width*(i+1), 0))

    # save composite image
    comp.save(os.path.splitext(fp)[0]+".png")

Functions

• all functions accept only arguments, no keywords
• the data has to be RGBA/BGRA for the RGB functions as well
• all DXT compressions require data in the RGBA format
• all ETC compressions require data in the BGRA format

compress_to_dxt1

Compresses RGBA to DXT1

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_dxt1_dither

Compresses RGBA to DXT1 Dither

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_dxt5

Compresses RGBA to DXT5

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_etc1

Compresses RGBA to ETC1 RGB

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_etc1_dither

Compresses RGBA to ETC1 Dither

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_etc1_alpha

Compresses A to ETC1 Alpha

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_etc2_rgb

Compresses RGBA to ETC2 RGB

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_etc2_rgba

Compresses RGBA to ETC2 RGBA

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"

compress_to_etc2_alpha

Compresses RGBA to ETC2 Alpha

:param data: RGBA data of the image
:type data: bytes
:param width: width of the image
:type width: int
:param height: height of the image
:type height: int
:returns: compressed data
:rtype: bytes"