如何使用 Python 中的原始数据字符串使用魔杖创建图像

Question

我有一个原始数据字符串，例如这样的：

raw_data = "FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF3300005CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFF9500B158DFFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFB200000003FFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFB100000002FFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFF643040B80FFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF3300002BFFED843913051B59D1FFFFFFFFFFFF03000184FFFF3300002BAB0F00000000000007BBFFFFFFFFFF03000057FFFF330000080100000000000000001DF8FFFFFFFF03000057FFFF330000000042A9D4D08D0D000000ADFFFFFFFF03000057FFFF330000059DFFFFFFFFFFAA00000070FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFA05000051FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF18000045FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF1B000043FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF1B000043FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF1B000043FFFFFFFF03000057"

我想知道如何从中创建可查看的 .png。

我尝试使用 Image class

with wand.image.Image (???) as img:

但我不确定要将什么放在括号中。我试过了 file=raw_data, width=25,height=25,depth=8

无论我尝试什么，它都会给我一个错误。

有什么想法吗？

Answer 1

您需要将字符串转换为字节，并实现 ImageMagick 的 MagickImportImagePixels C-API 方法。

import binascii
import ctypes

from wand.api import library
from wand.image import Image
from wand.color import Color

# Map C-API to Python
# -------------------
# magick-image.h
# WandExport MagickBooleanType MagickImportImagePixels(MagickWand *wand,
#   const ssize_t x,const ssize_t y,const size_t columns,const size_t rows,
#   const char *map,const StorageType storage,const void *pixels)
library.MagickImportImagePixels.argtypes = (ctypes.c_void_p,
                                            ctypes.c_ssize_t,
                                            ctypes.c_ssize_t,
                                            ctypes.c_size_t,
                                            ctypes.c_size_t,
                                            ctypes.c_char_p,
                                            ctypes.c_int,
                                            ctypes.c_void_p)


# Map enum StorageType
StorageType = ('undefined', 'char', 'double', 'float',
               'integer', 'long', 'quantum', 'short')

# Extend wand.image.Image to implement import_pixels method
class MyImage(Image):
    def import_pixels(self, blob, pixel_format='RGBA', pixel_size='char'):
        storage_type = StorageType.index(pixel_size)
        library.MagickImportImagePixels(self.wand,
                                        0,
                                        0,
                                        self.width,
                                        self.height,
                                        pixel_format.encode(),
                                        storage_type,
                                        blob)
# Usage
raw_data_string = 'FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF3300005CFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFF9500B158DFFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFB200000003FFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFB100000002FFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFF643040B80FFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEFFFFFFFF3300002BFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF3300002BFFED843913051B59D1FFFFFFFFFFFF03000184FFFF3300002BAB0F00000000000007BBFFFFFFFFFF03000057FFFF330000080100000000000000001DF8FFFFFFFF03000057FFFF330000000042A9D4D08D0D000000ADFFFFFFFF03000057FFFF330000059DFFFFFFFFFFAA00000070FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFA05000051FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF18000045FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF1B000043FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF1B000043FFFFFFFF03000057FFFF3300002BFFFFFFFFFFFFFF1B000043FFFFFFFF03000057'
raw_data_bytes = binascii.unhexlify(raw_data_string)

with MyImage(width=25, height=25, background=Color('WHITE')) as img:
    img.import_pixels(raw_data_bytes, pixel_format='R', pixel_size='char')
    img.save(filename='output.png')

正如评论中指出的那样，您将负责了解/定义通道布局（即 RGBA、BGR、ARBG &tc）、数据类型大小（即 char/short/int/long，或 float/double），数据流布局（如 interlacing），当然还有预期图像的实际 width/height。

如何使用 Python 中的原始数据字符串使用魔杖创建图像

How to create an image with magick wand from raw data string in Python

python

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raw-data

wand