astc-encoder-py

astc-encoder-py is a Python binding of astc-encoder. It can compress images into astc textures and decompress astc textures into images.

Installation

Python 3.7+

pip install astc-encoder-py

There are prebuild wheels for all platforms covered by cibuildwheel.

Examples

simple astc via PIL.Image

# import following once to register the codec
import astc_encoder.pil_codec

# pass the relevant data to the decoder via the decoder args as below
profile: int = 1 # LDR_SRGB = 0, LDR = 1, HDR_RGB_LDR_A = 2, HDR = 3
block_width: int = 4
block_height: int = 4
# the target mode should always be RGBA, even for RGB, as the decompression always returns RGBA
Image.frombytes("RGBA", (512, 512), comp, "astc", (profile, block_width, block_height)).show()
# compress Image to astc, the Image.mode has to be RGB or RGBA
quality: float = 100 # 0-100, medium is 60
Image.tobytes("astc", (profile, quality, block_width, block_height))

compressing and decompressing using astc_encoder

from PIL import Image

from astc_encoder import (
 ASTCConfig,
 ASTCContext,
 ASTCImage,
 ASTCProfile,
 ASTCSwizzle,
 ASTCType,
)

# create config like astcenc_config_init,
# color profile, block dimensions, quality, flags
# and then allow editing by hand afterward
# optional args:
#   block depth = 1, quality = 60, flags = 0
config = ASTCConfig(ASTCProfile.LDR_SRGB, 4, 4)

# create a context from the config
# as the context creation is expensive,
# this solution allows re-using the context
context = ASTCContext(config)

# create a new image for testing
img = Image.new("RGBA", (512, 512), (255, 0, 0, 255))

# put it's data into an ASTCImage for handling 
image = ASTCImage(ASTCType.U8, *img.size, data=img.tobytes())

# create a RGBA swizzle
swizzle = ASTCSwizzle.from_str("RGBA")

# compress the image with the given context
comp = context.compress(image, swizzle)

# create a destination image with the correct arguments
image_dec = ASTCImage(ASTCType.U8, *img.size)

# decompress the data into the image
# the result has always 4 channels
context.decompress(comp, image_dec, swizzle)

# load the decompressed image into PIL
img = Image.frombytes("RGBA", img.size, image_dec.data)

TODO

• figuring out segfault for re-using ASTCImage
• creating ASTCSwizzle from strings instead of from ints
• creating ASTCImage directly from PIL.Image
• export ASTCImage directly to PIL.Image via PIL.ImageDecoder
• SVE support for arm
• tests
• docs page