123 lines
3.9 KiB
Python
123 lines
3.9 KiB
Python
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import struct
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import os
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import os.path
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from io import BytesIO
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from .pdftypes import LITERALS_DCT_DECODE
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from .pdfcolor import LITERAL_DEVICE_GRAY
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from .pdfcolor import LITERAL_DEVICE_RGB
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from .pdfcolor import LITERAL_DEVICE_CMYK
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def align32(x):
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return ((x+3)//4)*4
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## BMPWriter
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##
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class BMPWriter(object):
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def __init__(self, fp, bits, width, height):
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self.fp = fp
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self.bits = bits
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self.width = width
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self.height = height
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if bits == 1:
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ncols = 2
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elif bits == 8:
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ncols = 256
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elif bits == 24:
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ncols = 0
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else:
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raise ValueError(bits)
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self.linesize = align32((self.width*self.bits+7)//8)
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self.datasize = self.linesize * self.height
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headersize = 14+40+ncols*4
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info = struct.pack('<IiiHHIIIIII', 40, self.width, self.height, 1, self.bits, 0, self.datasize, 0, 0, ncols, 0)
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assert len(info) == 40, str(len(info))
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header = struct.pack('<ccIHHI', b'B', b'M', headersize+self.datasize, 0, 0, headersize)
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assert len(header) == 14, str(len(header))
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self.fp.write(header)
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self.fp.write(info)
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if ncols == 2:
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# B&W color table
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for i in (0, 255):
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self.fp.write(struct.pack('BBBx', i, i, i))
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elif ncols == 256:
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# grayscale color table
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for i in range(256):
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self.fp.write(struct.pack('BBBx', i, i, i))
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self.pos0 = self.fp.tell()
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self.pos1 = self.pos0 + self.datasize
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return
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def write_line(self, y, data):
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self.fp.seek(self.pos1 - (y+1)*self.linesize)
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self.fp.write(data)
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return
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## ImageWriter
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##
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class ImageWriter(object):
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def __init__(self, outdir):
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self.outdir = outdir
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if not os.path.exists(self.outdir):
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os.makedirs(self.outdir)
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return
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def export_image(self, image):
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stream = image.stream
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filters = stream.get_filters()
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(width, height) = image.srcsize
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if len(filters) == 1 and filters[0][0] in LITERALS_DCT_DECODE:
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ext = '.jpg'
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elif (image.bits == 1 or
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image.bits == 8 and image.colorspace in (LITERAL_DEVICE_RGB, LITERAL_DEVICE_GRAY)):
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ext = '.%dx%d.bmp' % (width, height)
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else:
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ext = '.%d.%dx%d.img' % (image.bits, width, height)
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name = image.name+ext
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path = os.path.join(self.outdir, name)
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fp=open(path, 'wb')
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if ext == '.jpg':
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raw_data = stream.get_rawdata()
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if LITERAL_DEVICE_CMYK in image.colorspace:
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from PIL import Image
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from PIL import ImageChops
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ifp = BytesIO(raw_data)
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i = Image.open(ifp)
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i = ImageChops.invert(i)
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i = i.convert('RGB')
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i.save(fp, 'JPEG')
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else:
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fp.write(raw_data)
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elif image.bits == 1:
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bmp = BMPWriter(fp, 1, width, height)
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data = stream.get_data()
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i = 0
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width = (width+7)//8
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for y in range(height):
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bmp.write_line(y, data[i:i+width])
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i += width
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elif image.bits == 8 and image.colorspace is LITERAL_DEVICE_RGB:
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bmp = BMPWriter(fp, 24, width, height)
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data = stream.get_data()
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i = 0
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width = width*3
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for y in range(height):
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bmp.write_line(y, data[i:i+width])
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i += width
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elif image.bits == 8 and image.colorspace is LITERAL_DEVICE_GRAY:
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bmp = BMPWriter(fp, 8, width, height)
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data = stream.get_data()
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i = 0
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for y in range(height):
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bmp.write_line(y, data[i:i+width])
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i += width
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else:
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fp.write(stream.get_data())
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fp.close()
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return name
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