我目前正在使用图像,其中一些是 DXT 压缩的,我需要一种简单的方法来使用 Python 解压缩和压缩这些文件。不幸的是,我找不到任何为我做这件事的图书馆。
有谁知道一个好的 Python 的 DXT-Compression 库,或者一个压缩库的接口?
-- dav1d
编辑:
libsquish 是去这里的方式,但不幸的是 Python-Bindings 不起作用,所以这里是解决方案。
在 C++ 中创建一个 squish-Wrapper,它导出内部访问 libsquish 的函数:
#include <squish.h>
typedef unsigned char u8;
extern "C" {
void CompressMasked( u8 const* rgba, int mask, void* block, int flags ) {
squish::CompressMasked(rgba, mask, block, flags);
}
void Compress( u8 const* rgba, void* block, int flags ) {
squish::Compress(rgba, block, flags);
}
void Decompress( u8* rgba, void const* block, int flags ) {
squish::Decompress(rgba, block, flags);
}
int GetStorageRequirements( int width, int height, int flags ) {
return squish::GetStorageRequirements(width, height, flags);
}
void CompressImage( u8 const* rgba, int width, int height, void* blocks, int flags ) {
squish::CompressImage(rgba, width, height, blocks, flags);
}
void DecompressImage( u8* rgba, int width, int height, void const* blocks, int flags ) {
squish::DecompressImage(rgba, width, height, blocks, flags);
}
}
创建一个动态库(windows 上的 dll,或者 linux 上的等等,我称之为libsquishc.so
)并用ctypes
.
我的方法(只导出我需要的功能):
from ctypes import CDLL, c_int, byref, create_string_buffer
import os.path
libsquish_path = os.path.join(os.path.split(os.path.abspath(__file__))[0], 'libsquishc.so')
libsquish = CDLL(libsquish_path)
DXT1 = 1 << 0
DXT3 = 1 << 1
DXT5 = 1 << 2
COLOR_ITERATIVE_CLUSTER_FIT = 1 << 8
COLOR_CLUSTER_FIT = 1 << 3
COLOR_RANGE_FIT = 1 << 4
WEIGHT_COLOR_BY_ALPHA = 1 << 7
GetStorageRequirements = libsquish.GetStorageRequirements
GetStorageRequirements.argtypes = [c_int, c_int, c_int]
GetStorageRequirements.restype = c_int
def compress_image(rgba, width, height, flags):
rgba = create_string_buffer(rgba)
c = GetStorageRequirements(width, height, flags)
buffer = create_string_buffer(c)
libsquish.Compress(byref(rgba), byref(buffer), c_int(flags))
return buffer.raw
def decompress_image(block, width, height, flags):
block = create_string_buffer(block)
c = width*height*4
rgba = create_string_buffer(c)
libsquish.DecompressImage(byref(rgba), c_int(width), c_int(height), byref(block), c_int(flags))
return rgba.raw