Module refinery.units.formats.stego

Expand source code Browse git 
#!/usr/bin/env python3
# -*- coding: utf-8 -*-
from enum import IntEnum

from refinery.units import Unit, Arg
from refinery.lib.structures import MemoryFile


class PIXEL_PART(IntEnum):
    r = 0
    g = 1
    b = 2
    a = 3


class stego(Unit):
    """
    Decodes the RGBA (red/green/blue/alpha) values of the pixels of a given image file and outputs
    these values as bytes. By default, the pixels are converted left to right, top to bottom. When
    the input image is grayscale, the color channels are ignored. Colored images are converted to
    RGBA mode.
    """
    def __init__(
        self,
        split: Arg.Switch('-m', help='Emit the individual rows or columns as separate outputs.') = False,
        parts: Arg('parts', nargs='?', type=str, help=(
            'A string containing any ordering of the letters R, G, B, and A (case-insensitive). '
            'These pixel components will be extracted from every pixel in the given order. The '
            'default value is {default}.'
        )) = 'RGB'
    ):
        super().__init__(
            split=split,
            parts=tuple(Arg.AsOption(p, PIXEL_PART) for p in parts)
        )

    @Unit.Requires('Pillow', 'formats')
    def _image():
        from PIL import Image
        return Image

    def process(self, data):
        split = self.args.split
        parts = self.args.parts
        image = self._image.open(MemoryFile(data, read_as_bytes=True))

        grayscale = image.mode.startswith('L')
        bw_bitmap = image.mode.startswith('1')
        no_colors = grayscale or bw_bitmap

        if not no_colors:
            image = image.convert('RGBA')

        width, height = image.size
        chunk_size = 1 if no_colors else len(parts)
        output = MemoryFile()
        buffer = bytearray(chunk_size * width)
        pixels = iter(image.getdata())

        for _ in range(height):
            offset = 0
            for _ in range(width):
                pixel = next(pixels)
                next_offset = offset + chunk_size
                if no_colors:
                    buffer[offset] = pixel
                else:
                    buffer[offset:next_offset] = (pixel[p] for p in parts)
                offset = next_offset
            if split:
                yield buffer
            else:
                output.write(buffer)
        if not split:
            yield output.getvalue()

Classes

class PIXEL_PART (value, names=None, *, module=None, qualname=None, type=None, start=1)

An enumeration.

Expand source code Browse git 
class PIXEL_PART(IntEnum):
    r = 0
    g = 1
    b = 2
    a = 3

Ancestors

  • enum.IntEnum
  • builtins.int
  • enum.Enum

Class variables

var r
var g
var b
var a
class stego (split=False, parts='RGB')

Decodes the RGBA (red/green/blue/alpha) values of the pixels of a given image file and outputs these values as bytes. By default, the pixels are converted left to right, top to bottom. When the input image is grayscale, the color channels are ignored. Colored images are converted to RGBA mode.

Expand source code Browse git 
class stego(Unit):
    """
    Decodes the RGBA (red/green/blue/alpha) values of the pixels of a given image file and outputs
    these values as bytes. By default, the pixels are converted left to right, top to bottom. When
    the input image is grayscale, the color channels are ignored. Colored images are converted to
    RGBA mode.
    """
    def __init__(
        self,
        split: Arg.Switch('-m', help='Emit the individual rows or columns as separate outputs.') = False,
        parts: Arg('parts', nargs='?', type=str, help=(
            'A string containing any ordering of the letters R, G, B, and A (case-insensitive). '
            'These pixel components will be extracted from every pixel in the given order. The '
            'default value is {default}.'
        )) = 'RGB'
    ):
        super().__init__(
            split=split,
            parts=tuple(Arg.AsOption(p, PIXEL_PART) for p in parts)
        )

    @Unit.Requires('Pillow', 'formats')
    def _image():
        from PIL import Image
        return Image

    def process(self, data):
        split = self.args.split
        parts = self.args.parts
        image = self._image.open(MemoryFile(data, read_as_bytes=True))

        grayscale = image.mode.startswith('L')
        bw_bitmap = image.mode.startswith('1')
        no_colors = grayscale or bw_bitmap

        if not no_colors:
            image = image.convert('RGBA')

        width, height = image.size
        chunk_size = 1 if no_colors else len(parts)
        output = MemoryFile()
        buffer = bytearray(chunk_size * width)
        pixels = iter(image.getdata())

        for _ in range(height):
            offset = 0
            for _ in range(width):
                pixel = next(pixels)
                next_offset = offset + chunk_size
                if no_colors:
                    buffer[offset] = pixel
                else:
                    buffer[offset:next_offset] = (pixel[p] for p in parts)
                offset = next_offset
            if split:
                yield buffer
            else:
                output.write(buffer)
        if not split:
            yield output.getvalue()

Ancestors

Class variables

var required_dependencies
var optional_dependencies

Inherited members