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Source code for imaging.images2swf

# -*- coding: utf-8 -*-
#   Copyright (C) 2012, Almar Klein
#
#   This code is subject to the (new) BSD license:
#
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#   modification, are permitted provided that the following conditions are met:
#     * Redistributions of source code must retain the above copyright
#       notice, this list of conditions and the following disclaimer.
#     * Redistributions in binary form must reproduce the above copyright
#       notice, this list of conditions and the following disclaimer in the
#       documentation and/or other materials provided with the distribution.
#     * Neither the name of the <organization> nor the
#       names of its contributors may be used to endorse or promote products
#       derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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""" Module images2swf

Provides a function (writeSwf) to store a series of PIL images or numpy
arrays in an SWF movie, that can be played on a wide range of OS's.

This module came into being because I wanted to store a series of images
in a movie that can be viewed by other people, and which I can embed in
flash presentations. For writing AVI or MPEG you really need a c/c++
library, and although the filesize is then very small, the quality is
sometimes not adequate. Besides I'd like to be independent of yet another
package. I tried writing animated gif using PIL (which is widely available),
but the quality is so poor because it only allows for 256 different colors.
[EDIT: thanks to Ant1, now the quality of animated gif isn't so bad!]
I also looked into MNG and APNG, two standards similar to the PNG stanard.
Both standards promise exactly what I need. However, hardly any application
can read those formats, and I cannot import them in flash.

Therefore I decided to check out the swf file format, which is very well
documented. This is the result: a pure python module to create an SWF file
that shows a series of images. The images are stored using the DEFLATE
algorithm (same as PNG and ZIP and which is included in the standard Python
distribution). As this compression algorithm is much more effective than
that used in GIF images, we obtain better quality (24 bit colors + alpha
channel) while still producesing smaller files (a test showed ~75%).
Although SWF also allows for JPEG compression, doing so would probably
require a third party library (because encoding JPEG is much harder).

This module requires Python 2.x and numpy.

sources and tools:

- SWF on wikipedia
- Adobes "SWF File Format Specification" version 10
  (http://www.adobe.com/devnet/swf/pdf/swf_file_format_spec_v10.pdf)
- swftools (swfdump in specific) for debugging
- iwisoft swf2avi can be used to convert swf to avi/mpg/flv with really
  good quality, while file size is reduced with factors 20-100.
  A good program in my opinion. The free version has the limitation
  of a watermark in the upper left corner.

"""

import os, sys, time
import zlib

try:
    import numpy as np
except ImportError:
    np = None

try:
    import PIL.Image
except ImportError:
    PIL = None


# True if we are running on Python 3.
# Code taken from six.py by Benjamin Peterson (MIT licensed)
import types
PY3 = sys.version_info[0] == 3
if PY3:
    string_types = str,
    integer_types = int,
    class_types = type,
    text_type = str
    binary_type = bytes
else:
    string_types = basestring,
    integer_types = (int, long)
    class_types = (type, types.ClassType)
    text_type = unicode
    binary_type = str


# todo: use imageio/FreeImage to support reading JPEG images from SWF?


[docs]def checkImages(images): """ checkImages(images) Check numpy images and correct intensity range etc. The same for all movie formats. """ # Init results images2 = [] for im in images: if PIL and isinstance(im, PIL.Image.Image): # We assume PIL images are allright images2.append(im) elif np and isinstance(im, np.ndarray): # Check and convert dtype if im.dtype == np.uint8: images2.append(im) # Ok elif im.dtype in [np.float32, np.float64]: theMax = im.max() if theMax > 128 and theMax < 300: pass # assume 0:255 else: im = im.copy() im[im < 0] = 0 im[im > 1] = 1 im *= 255 images2.append(im.astype(np.uint8)) else: im = im.astype(np.uint8) images2.append(im) # Check size if im.ndim == 2: pass # ok elif im.ndim == 3: if im.shape[2] not in [3, 4]: raise ValueError('This array can not represent an image.') else: raise ValueError('This array can not represent an image.') else: raise ValueError('Invalid image type: ' + str(type(im))) # Done return images2 ## Base functions and classes
[docs]class BitArray: """Dynamic array of bits that automatically resizes with factors of two. Append bits using .Append() or += You can reverse bits using .Reverse() """ def __init__(self, initvalue=None): self.data = np.zeros((16,), dtype=np.uint8) self._len = 0 if initvalue is not None: self.Append(initvalue) def __len__(self): return self._len # self.data.shape[0] def __repr__(self): fn = getattr(self.data[:self._len], "tobytes", getattr(self.data[:self._len], "tostring")) return fn().decode('ascii') def _checkSize(self): # check length... grow if necessary arraylen = self.data.shape[0] if self._len >= arraylen: tmp = np.zeros((arraylen*2,), dtype=np.uint8) tmp[:self._len] = self.data[:self._len] self.data = tmp def __add__(self, value): self.Append(value) return self
[docs] def Append(self, bits): # check input if isinstance(bits, BitArray): bits = str(bits) if isinstance(bits, int): bits = str(bits) if not isinstance(bits, string_types): raise ValueError("Append bits as strings or integers!") # add bits for bit in bits: self.data[self._len] = ord(bit) self._len += 1 self._checkSize()
[docs] def Reverse(self): """ In-place reverse. """ tmp = self.data[:self._len].copy() self.data[:self._len] = np.flipud(tmp)
[docs] def ToBytes(self): """ Convert to bytes. If necessary, zeros are padded to the end (right side). """ bits = str(self) # determine number of bytes nbytes = 0 while nbytes * 8 < len(bits): nbytes += 1 # pad bits = bits.ljust(nbytes * 8, '0') # go from bits to bytes bb = binary_type() for i in range(nbytes): tmp = int(bits[i * 8: (i + 1) * 8], 2) bb += intToUint8(tmp) # done return bb
if PY3: def intToUint32(i): return int(i).to_bytes(4, 'little') def intToUint16(i): return int(i).to_bytes(2, 'little') def intToUint8(i): return int(i).to_bytes(1, 'little') else:
[docs] def intToUint32(i): number = int(i) n1, n2, n3, n4 = 1, 256, 256 * 256, 256 * 256 * 256 b4, number = number // n4, number % n4 b3, number = number // n3, number % n3 b2, number = number // n2, number % n2 b1 = number return chr(b1) + chr(b2) + chr(b3) + chr(b4)
[docs] def intToUint16(i): i = int(i) # divide in two parts (bytes) i1 = i % 256 i2 = int(i // 256) # make string (little endian) return chr(i1) + chr(i2)
[docs] def intToUint8(i): return chr(int(i))
[docs]def intToBits(i, n=None): """ convert int to a string of bits (0's and 1's in a string), pad to n elements. Convert back using int(ss,2). """ ii = i # make bits bb = BitArray() while ii > 0: bb += str(ii % 2) ii = ii >> 1 bb.Reverse() # justify if n is not None: if len(bb) > n: raise ValueError("intToBits fail: len larger than padlength.") bb = str(bb).rjust(n, '0') # done return BitArray(bb)
[docs]def bitsToInt(bb, n=8): # Init value = '' # Get value in bits for i in range(len(bb)): b = bb[i:i+1] tmp = bin(ord(b))[2:] #value += tmp.rjust(8,'0') value = tmp.rjust(8, '0') + value # Make decimal return(int(value[:n], 2))
[docs]def getTypeAndLen(bb): """ bb should be 6 bytes at least Return (type, length, length_of_full_tag) """ # Init value = '' # Get first 16 bits for i in range(2): b = bb[i:i + 1] tmp = bin(ord(b))[2:] #value += tmp.rjust(8,'0') value = tmp.rjust(8, '0') + value # Get type and length type = int(value[:10], 2) L = int(value[10:], 2) L2 = L + 2 # Long tag header? if L == 63: # '111111' value = '' for i in range(2, 6): b = bb[i:i + 1] # becomes a single-byte bytes() on both PY3 and PY2 tmp = bin(ord(b))[2:] #value += tmp.rjust(8,'0') value = tmp.rjust(8, '0') + value L = int(value, 2) L2 = L + 6 # Done return type, L, L2
[docs]def signedIntToBits(i, n=None): """ convert signed int to a string of bits (0's and 1's in a string), pad to n elements. Negative numbers are stored in 2's complement bit patterns, thus positive numbers always start with a 0. """ # negative number? ii = i if i < 0: # A negative number, -n, is represented as the bitwise opposite of ii = abs(ii) - 1 # the positive-zero number n-1. # make bits bb = BitArray() while ii > 0: bb += str(ii % 2) ii = ii >> 1 bb.Reverse() # justify bb = '0' + str(bb) # always need the sign bit in front if n is not None: if len(bb) > n: raise ValueError("signedIntToBits fail: len larger than padlength.") bb = bb.rjust(n, '0') # was it negative? (then opposite bits) if i < 0: bb = bb.replace('0', 'x').replace('1', '0').replace('x', '1') # done return BitArray(bb)
[docs]def twitsToBits(arr): """ Given a few (signed) numbers, store them as compactly as possible in the wat specifief by the swf format. The numbers are multiplied by 20, assuming they are twits. Can be used to make the RECT record. """ # first determine length using non justified bit strings maxlen = 1 for i in arr: tmp = len(signedIntToBits(i*20)) if tmp > maxlen: maxlen = tmp # build array bits = intToBits(maxlen, 5) for i in arr: bits += signedIntToBits(i * 20, maxlen) return bits
[docs]def floatsToBits(arr): """ Given a few (signed) numbers, convert them to bits, stored as FB (float bit values). We always use 16.16. Negative numbers are not (yet) possible, because I don't know how the're implemented (ambiguity). """ bits = intToBits(31, 5) # 32 does not fit in 5 bits! for i in arr: if i < 0: raise ValueError("Dit not implement negative floats!") i1 = int(i) i2 = i - i1 bits += intToBits(i1, 15) bits += intToBits(i2 * 2 ** 16, 16) return bits
def _readFrom(fp, n): bb = binary_type() try: while len(bb) < n: tmp = fp.read(n-len(bb)) bb += tmp if not tmp: break except EOFError: pass return bb ## Base Tag
[docs]class Tag: def __init__(self): self.bytes = binary_type() self.tagtype = -1
[docs] def ProcessTag(self): """ Implement this to create the tag. """ raise NotImplemented()
[docs] def GetTag(self): """ Calls processTag and attaches the header. """ self.ProcessTag() # tag to binary bits = intToBits(self.tagtype, 10) # complete header uint16 thing bits += '1' * 6 # = 63 = 0x3f # make uint16 bb = intToUint16(int(str(bits), 2)) # now add 32bit length descriptor bb += intToUint32(len(self.bytes)) # done, attach and return bb += self.bytes return bb
[docs] def MakeRectRecord(self, xmin, xmax, ymin, ymax): """ Simply uses makeCompactArray to produce a RECT Record. """ return twitsToBits([xmin, xmax, ymin, ymax])
[docs] def MakeMatrixRecord(self, scale_xy=None, rot_xy=None, trans_xy=None): # empty matrix? if scale_xy is None and rot_xy is None and trans_xy is None: return "0"*8 # init bits = BitArray() # scale if scale_xy: bits += '1' bits += floatsToBits([scale_xy[0], scale_xy[1]]) else: bits += '0' # rotation if rot_xy: bits += '1' bits += floatsToBits([rot_xy[0], rot_xy[1]]) else: bits += '0' # translation (no flag here) if trans_xy: bits += twitsToBits([trans_xy[0], trans_xy[1]]) else: bits += twitsToBits([0, 0]) # done return bits ## Control tags
[docs]class ControlTag(Tag): def __init__(self): Tag.__init__(self)
[docs]class FileAttributesTag(ControlTag): def __init__(self): ControlTag.__init__(self) self.tagtype = 69
[docs] def ProcessTag(self): self.bytes = '\x00'.encode('ascii') * (1+3)
[docs]class ShowFrameTag(ControlTag): def __init__(self): ControlTag.__init__(self) self.tagtype = 1
[docs] def ProcessTag(self): self.bytes = binary_type()
[docs]class SetBackgroundTag(ControlTag): """ Set the color in 0-255, or 0-1 (if floats given). """ def __init__(self, *rgb): self.tagtype = 9 if len(rgb) == 1: rgb = rgb[0] self.rgb = rgb
[docs] def ProcessTag(self): bb = binary_type() for i in range(3): clr = self.rgb[i] if isinstance(clr, float): clr = clr * 255 bb += intToUint8(clr) self.bytes = bb
[docs]class DoActionTag(Tag): def __init__(self, action='stop'): Tag.__init__(self) self.tagtype = 12 self.actions = [action]
[docs] def Append(self, action): self.actions.append(action)
[docs] def ProcessTag(self): bb = binary_type() for action in self.actions: action = action.lower() if action == 'stop': bb += '\x07'.encode('ascii') elif action == 'play': bb += '\x06'.encode('ascii') else: print("warning, unknown action: %s" % action) bb += intToUint8(0) self.bytes = bb ## Definition tags
[docs]class DefinitionTag(Tag): counter = 0 # to give automatically id's def __init__(self): Tag.__init__(self) DefinitionTag.counter += 1 self.id = DefinitionTag.counter # id in dictionary
[docs]class BitmapTag(DefinitionTag): def __init__(self, im): DefinitionTag.__init__(self) self.tagtype = 36 # DefineBitsLossless2 # convert image (note that format is ARGB) # even a grayscale image is stored in ARGB, nevertheless, # the fabilous deflate compression will make it that not much # more data is required for storing (25% or so, and less than 10% # when storing RGB as ARGB). if len(im.shape) == 3: if im.shape[2] in [3, 4]: tmp = np.ones((im.shape[0], im.shape[1], 4), dtype=np.uint8) * 255 for i in range(3): tmp[:, :, i + 1] = im[:, :, i] if im.shape[2] == 4: tmp[:, :, 0] = im[:, :, 3] # swap channel where alpha is in else: raise ValueError("Invalid shape to be an image.") elif len(im.shape) == 2: tmp = np.ones((im.shape[0], im.shape[1], 4), dtype=np.uint8)*255 for i in range(3): tmp[:, :, i + 1] = im[:, :] else: raise ValueError("Invalid shape to be an image.") # we changed the image to uint8 4 channels. # now compress! self._data = zlib.compress(tmp.tostring(), zlib.DEFLATED) self.imshape = im.shape
[docs] def ProcessTag(self): # build tag bb = binary_type() bb += intToUint16(self.id) # CharacterID bb += intToUint8(5) # BitmapFormat bb += intToUint16(self.imshape[1]) # BitmapWidth bb += intToUint16(self.imshape[0]) # BitmapHeight bb += self._data # ZlibBitmapData self.bytes = bb
[docs]class PlaceObjectTag(ControlTag): def __init__(self, depth, idToPlace=None, xy=(0, 0), move=False): ControlTag.__init__(self) self.tagtype = 26 self.depth = depth self.idToPlace = idToPlace self.xy = xy self.move = move
[docs] def ProcessTag(self): # retrieve stuff depth = self.depth xy = self.xy id = self.idToPlace # build PlaceObject2 bb = binary_type() if self.move: bb += '\x07'.encode('ascii') else: bb += '\x06'.encode('ascii') # (8 bit flags): 4:matrix, 2:character, 1:move bb += intToUint16(depth) # Depth bb += intToUint16(id) # character id bb += self.MakeMatrixRecord(trans_xy=xy).ToBytes() # MATRIX record self.bytes = bb
[docs]class ShapeTag(DefinitionTag): def __init__(self, bitmapId, xy, wh): DefinitionTag.__init__(self) self.tagtype = 2 self.bitmapId = bitmapId self.xy = xy self.wh = wh
[docs] def ProcessTag(self): """ Returns a defineshape tag. with a bitmap fill """ bb = binary_type() bb += intToUint16(self.id) xy, wh = self.xy, self.wh tmp = self.MakeRectRecord(xy[0], wh[0], xy[1], wh[1]) # ShapeBounds bb += tmp.ToBytes() # make SHAPEWITHSTYLE structure # first entry: FILLSTYLEARRAY with in it a single fill style bb += intToUint8(1) # FillStyleCount bb += '\x41'.encode('ascii') # FillStyleType (0x41 or 0x43, latter is non-smoothed) bb += intToUint16(self.bitmapId) # BitmapId #bb += '\x00' # BitmapMatrix (empty matrix with leftover bits filled) bb += self.MakeMatrixRecord(scale_xy=(20, 20)).ToBytes() # # first entry: FILLSTYLEARRAY with in it a single fill style # bb += intToUint8(1) # FillStyleCount # bb += '\x00' # solid fill # bb += '\x00\x00\xff' # color # second entry: LINESTYLEARRAY with a single line style bb += intToUint8(0) # LineStyleCount #bb += intToUint16(0*20) # Width #bb += '\x00\xff\x00' # Color # third and fourth entry: NumFillBits and NumLineBits (4 bits each) # I each give them four bits, so 16 styles possible. bb += '\x44'.encode('ascii') self.bytes = bb # last entries: SHAPERECORDs ... (individual shape records not aligned) # STYLECHANGERECORD bits = BitArray() bits += self.MakeStyleChangeRecord(0, 1, moveTo=(self.wh[0], self.wh[1])) # STRAIGHTEDGERECORD 4x bits += self.MakeStraightEdgeRecord(-self.wh[0], 0) bits += self.MakeStraightEdgeRecord(0, -self.wh[1]) bits += self.MakeStraightEdgeRecord(self.wh[0], 0) bits += self.MakeStraightEdgeRecord(0, self.wh[1]) # ENDSHAPRECORD bits += self.MakeEndShapeRecord() self.bytes += bits.ToBytes() # done #self.bytes = bb
[docs] def MakeStyleChangeRecord(self, lineStyle=None, fillStyle=None, moveTo=None): # first 6 flags # Note that we use FillStyle1. If we don't flash (at least 8) does not # recognize the frames properly when importing to library. bits = BitArray() bits += '0' # TypeFlag (not an edge record) bits += '0' # StateNewStyles (only for DefineShape2 and Defineshape3) if lineStyle: bits += '1' # StateLineStyle else: bits += '0' if fillStyle: bits += '1' # StateFillStyle1 else: bits += '0' bits += '0' # StateFillStyle0 if moveTo: bits += '1' # StateMoveTo else: bits += '0' # give information # todo: nbits for fillStyle and lineStyle is hard coded. if moveTo: bits += twitsToBits([moveTo[0], moveTo[1]]) if fillStyle: bits += intToBits(fillStyle, 4) if lineStyle: bits += intToBits(lineStyle, 4) return bits #return bitsToBytes(bits)
[docs] def MakeStraightEdgeRecord(self, *dxdy): if len(dxdy) == 1: dxdy = dxdy[0] # determine required number of bits xbits = signedIntToBits(dxdy[0] * 20) ybits = signedIntToBits(dxdy[1] * 20) nbits = max([len(xbits), len(ybits)]) bits = BitArray() bits += '11' # TypeFlag and StraightFlag bits += intToBits(nbits-2, 4) bits += '1' # GeneralLineFlag bits += signedIntToBits(dxdy[0] * 20, nbits) bits += signedIntToBits(dxdy[1] * 20, nbits) # note: I do not make use of vertical/horizontal only lines... return bits #return bitsToBytes(bits)
[docs] def MakeEndShapeRecord(self): bits = BitArray() bits += "0" # TypeFlag: no edge bits += "0"*5 # EndOfShape return bits #return bitsToBytes(bits) ## Last few functions
[docs]def buildFile(fp, taglist, nframes=1, framesize=(500, 500), fps=10, version=8): """ Give the given file (as bytes) a header. """ # compose header bb = binary_type() bb += 'F'.encode('ascii') # uncompressed bb += 'WS'.encode('ascii') # signature bytes bb += intToUint8(version) # version bb += '0000'.encode('ascii') # FileLength (leave open for now) bb += Tag().MakeRectRecord(0, framesize[0], 0, framesize[1]).ToBytes() bb += intToUint8(0) + intToUint8(fps) # FrameRate bb += intToUint16(nframes) fp.write(bb) # produce all tags for tag in taglist: fp.write(tag.GetTag()) # finish with end tag fp.write('\x00\x00'.encode('ascii')) # set size sze = fp.tell() fp.seek(4) fp.write(intToUint32(sze))
[docs]def writeSwf(filename, images, duration=0.1, repeat=True): """Write an swf-file from the specified images. If repeat is False, the movie is finished with a stop action. Duration may also be a list with durations for each frame (note that the duration for each frame is always an integer amount of the minimum duration.) Images should be a list consisting of PIL images or numpy arrays. The latter should be between 0 and 255 for integer types, and between 0 and 1 for float types. """ # Check Numpy if np is None: raise RuntimeError("Need Numpy to write an SWF file.") # Check images (make all Numpy) images2 = [] images = checkImages(images) if not images: raise ValueError("Image list is empty!") for im in images: if PIL and isinstance(im, PIL.Image.Image): if im.mode == 'P': im = im.convert() im = np.asarray(im) if len(im.shape) == 0: raise MemoryError("Too little memory to convert PIL image to array") images2.append(im) # Init taglist = [FileAttributesTag(), SetBackgroundTag(0, 0, 0)] # Check duration if hasattr(duration, '__len__'): if len(duration) == len(images2): duration = [d for d in duration] else: raise ValueError("len(duration) doesn't match amount of images.") else: duration = [duration for im in images2] # Build delays list minDuration = float(min(duration)) delays = [round(d/minDuration) for d in duration] delays = [max(1, int(d)) for d in delays] # Get FPS fps = 1.0/minDuration # Produce series of tags for each image nframes = 0 for im in images2: bm = BitmapTag(im) wh = (im.shape[1], im.shape[0]) sh = ShapeTag(bm.id, (0, 0), wh) po = PlaceObjectTag(1, sh.id, move=nframes > 0) taglist.extend([bm, sh, po]) for i in range(delays[nframes]): taglist.append(ShowFrameTag()) nframes += 1 if not repeat: taglist.append(DoActionTag('stop')) # Build file fp = open(filename, 'wb') try: buildFile(fp, taglist, nframes=nframes, framesize=wh, fps=fps) except Exception: raise finally: fp.close()
def _readPixels(bb, i, tagType, L1): """ With pf's seed after the recordheader, reads the pixeldata. """ # Check Numpy if np is None: raise RuntimeError("Need Numpy to read an SWF file.") # Get info charId = bb[i:i + 2]; i += 2 format = ord(bb[i:i + 1]); i += 1 width = bitsToInt(bb[i:i + 2], 16); i += 2 height = bitsToInt(bb[i:i + 2], 16); i += 2 # If we can, get pixeldata and make nunmpy array if format != 5: print("Can only read 24bit or 32bit RGB(A) lossless images.") else: # Read byte data offset = 2 + 1 + 2 + 2 # all the info bits bb2 = bb[i:i+(L1-offset)] # Decompress and make numpy array data = zlib.decompress(bb2) a = np.frombuffer(data, dtype=np.uint8) # Set shape if tagType == 20: # DefineBitsLossless - RGB data try: a.shape = height, width, 3 except Exception: # Byte align stuff might cause troubles print("Cannot read image due to byte alignment") if tagType == 36: # DefineBitsLossless2 - ARGB data a.shape = height, width, 4 # Swap alpha channel to make RGBA b = a a = np.zeros_like(a) a[:, :, 0] = b[:, :, 1] a[:, :, 1] = b[:, :, 2] a[:, :, 2] = b[:, :, 3] a[:, :, 3] = b[:, :, 0] return a
[docs]def readSwf(filename, asNumpy=True): """Read all images from an SWF (shockwave flash) file. Returns a list of numpy arrays, or, if asNumpy is false, a list if PIL images. Limitation: only read the PNG encoded images (not the JPG encoded ones). """ # Check whether it exists if not os.path.isfile(filename): raise IOError('File not found: '+str(filename)) # Check PIL if (not asNumpy) and (PIL is None): raise RuntimeError("Need PIL to return as PIL images.") # Check Numpy if np is None: raise RuntimeError("Need Numpy to read SWF files.") # Init images images = [] # Open file and read all fp = open(filename, 'rb') bb = fp.read() try: # Check opening tag tmp = bb[0:3].decode('ascii', 'ignore') if tmp.upper() == 'FWS': pass # ok elif tmp.upper() == 'CWS': # Decompress movie bb = bb[:8] + zlib.decompress(bb[8:]) else: raise IOError('Not a valid SWF file: ' + str(filename)) # Set filepointer at first tag (skipping framesize RECT and two uin16's i = 8 nbits = bitsToInt(bb[i: i + 1], 5) # skip FrameSize nbits = 5 + nbits * 4 Lrect = nbits / 8.0 if Lrect % 1: Lrect += 1 Lrect = int(Lrect) i += Lrect+4 # Iterate over the tags counter = 0 while True: counter += 1 # Get tag header head = bb[i:i+6] if not head: break # Done (we missed end tag) # Determine type and length T, L1, L2 = getTypeAndLen(head) if not L2: print('Invalid tag length, could not proceed') break #print(T, L2) # Read image if we can if T in [20, 36]: im = _readPixels(bb, i+6, T, L1) if im is not None: images.append(im) elif T in [6, 21, 35, 90]: print('Ignoring JPEG image: cannot read JPEG.') else: pass # Not an image tag # Detect end tag if T == 0: break # Next tag! i += L2 finally: fp.close() # Convert to normal PIL images if needed if not asNumpy: images2 = images images = [] for im in images2: images.append(PIL.Image.fromarray(im)) # Done return images

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