79 lines
2.0 KiB
Python
79 lines
2.0 KiB
Python
"""Encoder and decoder for PNG files, using PyPNG (png.py).
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"""
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import array
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import itertools
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from pyglet.image import ImageData, ImageDecodeException
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from pyglet.image.codecs import ImageDecoder, ImageEncoder
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import pyglet.extlibs.png as pypng
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class PNGImageDecoder(ImageDecoder):
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def get_file_extensions(self):
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return ['.png']
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def decode(self, filename, file):
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if not file:
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file = open(filename, 'rb')
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try:
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reader = pypng.Reader(file=file)
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width, height, pixels, metadata = reader.asDirect()
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except Exception as e:
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raise ImageDecodeException('PyPNG cannot read %r: %s' % (filename or file, e))
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if metadata['greyscale']:
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if metadata['alpha']:
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fmt = 'LA'
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else:
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fmt = 'L'
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else:
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if metadata['alpha']:
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fmt = 'RGBA'
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else:
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fmt = 'RGB'
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pitch = len(fmt) * width
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pixels = array.array('BH'[metadata['bitdepth'] > 8], itertools.chain(*pixels))
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return ImageData(width, height, fmt, pixels.tobytes(), -pitch)
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class PNGImageEncoder(ImageEncoder):
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def get_file_extensions(self):
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return ['.png']
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def encode(self, image, filename, file):
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image = image.get_image_data()
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has_alpha = 'A' in image.format
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greyscale = len(image.format) < 3
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if has_alpha:
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if greyscale:
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image.format = 'LA'
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else:
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image.format = 'RGBA'
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else:
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if greyscale:
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image.format = 'L'
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else:
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image.format = 'RGB'
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image.pitch = -(image.width * len(image.format))
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writer = pypng.Writer(image.width, image.height, greyscale=greyscale, alpha=has_alpha)
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data = array.array('B')
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data.frombytes(image.get_data(image.format, image.pitch))
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writer.write_array(file, data)
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def get_decoders():
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return [PNGImageDecoder()]
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def get_encoders():
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return [PNGImageEncoder()]
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