Merge pull request #417 from wiredfool/libtiff-save2

Updates for saving color tiffs w/compression using libtiff

PIL/TiffImagePlugin.py

@@ -54,7 +54,9 @@ import collections
 import itertools
 import os
 
-
+# Set these to true to force use of libtiff for reading or writing. 
+READ_LIBTIFF = False
+WRITE_LIBTIFF= False
 
 II = b"II" # little-endian (intel-style)
 MM = b"MM" # big-endian (motorola-style)
@@ -149,6 +151,7 @@ OPEN_INFO = {
     (II, 1, 1, 1, (8,), ()): ("L", "L"),
     (II, 1, 1, 1, (8,8), (2,)): ("LA", "LA"),
     (II, 1, 1, 2, (8,), ()): ("L", "L;R"),
+    (II, 1, 1, 1, (12,), ()): ("I;16", "I;12"),
     (II, 1, 1, 1, (16,), ()): ("I;16", "I;16"),
     (II, 1, 2, 1, (16,), ()): ("I;16S", "I;16S"),
     (II, 1, 1, 1, (32,), ()): ("I", "I;32N"),
@@ -675,8 +678,8 @@ class TiffImageFile(ImageFile.ImageFile):
         return args
 
     def _load_libtiff(self):
-        """ Overload method triggered when we detect a g3/g4 tiff
-            Calls out to lib tiff """
+        """ Overload method triggered when we detect a compressed tiff
+            Calls out to libtiff """
 
         pixel = Image.Image.load(self)
 
@@ -691,7 +694,7 @@ class TiffImageFile(ImageFile.ImageFile):
             raise IOError("Not exactly one tile")
 
         d, e, o, a = self.tile[0]
-        d = Image._getdecoder(self.mode, d, a, self.decoderconfig)
+        d = Image._getdecoder(self.mode, 'libtiff', a, self.decoderconfig)
         try:
             d.setimage(self.im, e)
         except ValueError:
@@ -817,7 +820,7 @@ class TiffImageFile(ImageFile.ImageFile):
             offsets = self.tag[STRIPOFFSETS]
             h = getscalar(ROWSPERSTRIP, ysize)
             w = self.size[0]
-            if self._compression in ["tiff_ccitt", "group3", "group4",
+            if READ_LIBTIFF or self._compression in ["tiff_ccitt", "group3", "group4",
                                                      "tiff_jpeg", "tiff_adobe_deflate",
                                                      "tiff_thunderscan", "tiff_deflate",
                                                      "tiff_sgilog", "tiff_sgilog24",
@@ -868,7 +871,7 @@ class TiffImageFile(ImageFile.ImageFile):
                 # we're expecting image byte order. So, if the rawmode
                 # contains I;16, we need to convert from native to image
                 # byte order.
-                if self.mode in ('I;16B', 'I;16'):
+                if self.mode in ('I;16B', 'I;16') and 'I;16' in rawmode:
                     rawmode = 'I;16N'
 
                 # Offset in the tile tuple is 0, we go from 0,0 to
@@ -975,12 +978,16 @@ def _save(im, fp, filename):
     ifd = ImageFileDirectory(prefix)
 
     compression = im.encoderinfo.get('compression',im.info.get('compression','raw'))
-    libtiff = compression in ["tiff_ccitt", "group3", "group4",
+
+    libtiff = WRITE_LIBTIFF or compression in ["tiff_ccitt", "group3", "group4",
                                                "tiff_jpeg", "tiff_adobe_deflate",
                                                "tiff_thunderscan", "tiff_deflate",
                                                "tiff_sgilog", "tiff_sgilog24",
                                                "tiff_raw_16"]
 
+    # required for color libtiff images
+    ifd[PLANAR_CONFIGURATION] = getattr(im, '_planar_configuration', 1)
+    
     # -- multi-page -- skip TIFF header on subsequent pages
     if not libtiff and fp.tell() == 0:
         # tiff header (write via IFD to get everything right)
@@ -1083,6 +1090,8 @@ def _save(im, fp, filename):
 
         blocklist =  [STRIPOFFSETS, STRIPBYTECOUNTS, ROWSPERSTRIP, ICCPROFILE] # ICC Profile crashes.
         atts={}
+        # bits per sample is a single short in the tiff directory, not a list. 
+        atts[BITSPERSAMPLE] = bits[0]
         # Merge the ones that we have with (optional) more bits from
         # the original file, e.g x,y resolution so that we can
         # save(load('')) == original file.
@@ -1100,8 +1109,8 @@ def _save(im, fp, filename):
                     continue
                 if type(v) == tuple and len(v) > 2:
                     # List of ints?
-                    # BitsPerSample is one example, I get (8,8,8)
-                    # UNDONE
+                    if type(v[0]) in (int, float):
+                        atts[k] = list(v)
                     continue
                 if type(v) == tuple and len(v) == 2:
                     # one rational tuple
@@ -1121,8 +1130,8 @@ def _save(im, fp, filename):
         if Image.DEBUG:
             print (atts)
 
-        # libtiff always returns the bytes in native order.
-        # we're expecting image byte order. So, if the rawmode
+        # libtiff always expects the bytes in native order.
+        # we're storing image byte order. So, if the rawmode
         # contains I;16, we need to convert from native to image
         # byte order.
         if im.mode in ('I;16B', 'I;16'):
@@ -1130,7 +1139,7 @@ def _save(im, fp, filename):
 
         a = (rawmode, compression, _fp, filename, atts)
         # print (im.mode, compression, a, im.encoderconfig)
-        e = Image._getencoder(im.mode, compression, a, im.encoderconfig)
+        e = Image._getencoder(im.mode, 'libtiff', a, im.encoderconfig)
         e.setimage(im.im, (0,0)+im.size)
         while 1:
             l, s, d = e.encode(16*1024) # undone, change to self.decodermaxblock

Tests/test_file_libtiff.py

@@ -1,10 +1,10 @@
 from tester import *
 
-from PIL import Image
+from PIL import Image, TiffImagePlugin
 
 codecs = dir(Image.core)
 
-if "group4_encoder" not in codecs or "group4_decoder" not in codecs:
+if "libtiff_encoder" not in codecs or "libtiff_decoder" not in codecs:
     skip("tiff support not available")
 
 def _assert_noerr(im):
@@ -141,7 +141,7 @@ def test_g3_compression():
     assert_image_equal(reread, i)
 
 def test_little_endian():
-    im = Image.open('Tests/images/12bit.deflate.tif')
+    im = Image.open('Tests/images/16bit.deflate.tif')
     assert_equal(im.getpixel((0,0)), 480)
     assert_equal(im.mode, 'I;16')
 
@@ -156,7 +156,7 @@ def test_little_endian():
         
 
     out = tempfile("temp.tif")
-    out = "temp.le.tif"
+    #out = "temp.le.tif"
     im.save(out)
     reread = Image.open(out)
 
@@ -166,7 +166,7 @@ def test_little_endian():
     # on big endian, we'll get back mode = 'I;16B' here. 
     
 def test_big_endian():
-    im = Image.open('Tests/images/12bit.MM.deflate.tif')
+    im = Image.open('Tests/images/16bit.MM.deflate.tif')
 
     assert_equal(im.getpixel((0,0)), 480)
     assert_equal(im.mode, 'I;16B')
@@ -201,4 +201,87 @@ def test_g4_string_info():
     reread = Image.open(out)
     assert_equal('temp.tif', reread.tag[269])
 
+def test_12bit_rawmode():
+    """ Are we generating the same interpretation of the image as Imagemagick is? """
+    TiffImagePlugin.READ_LIBTIFF = True
+    #Image.DEBUG = True
+    im = Image.open('Tests/images/12bit.cropped.tif')
+    im.load()
+    TiffImagePlugin.READ_LIBTIFF = False
+    # to make the target --
+    # convert 12bit.cropped.tif -depth 16 tmp.tif
+    # convert tmp.tif -evaluate RightShift 4 12in16bit2.tif
+    # imagemagick will auto scale so that a 12bit FFF is 16bit FFF0,
+    # so we need to unshift so that the integer values are the same. 
+    
+    im2 = Image.open('Tests/images/12in16bit.tif')
+
+    if Image.DEBUG:
+        print (im.getpixel((0,0)))
+        print (im.getpixel((0,1)))
+        print (im.getpixel((0,2)))
+
+        print (im2.getpixel((0,0)))
+        print (im2.getpixel((0,1)))
+        print (im2.getpixel((0,2)))
+  
+    assert_image_equal(im, im2)
+
+def test_blur():
+    # test case from irc, how to do blur on b/w image and save to compressed tif. 
+    from PIL import ImageFilter
+    out = tempfile('temp.tif')
+    im = Image.open('Tests/images/pport_g4.tif')
+    im = im.convert('L')
+
+    im=im.filter(ImageFilter.GaussianBlur(4))
+    im.save(out, compression='tiff_adobe_deflate')
+
+    im2 = Image.open(out)
+    im2.load()
+
+    assert_image_equal(im, im2)
+
+
+def test_compressions():
+    im = lena('RGB')
+    out = tempfile('temp.tif')
+
+    TiffImagePlugin.READ_LIBTIFF = True
+    TiffImagePlugin.WRITE_LIBTIFF = True
+
+    for compression in ('packbits', 'tiff_lzw'):
+        im.save(out, compression=compression)
+        im2 = Image.open(out)
+        assert_image_equal(im, im2)
+
+    im.save(out, compression='jpeg')
+    im2 = Image.open(out)
+    assert_image_similar(im, im2, 30)
+                            
+    TiffImagePlugin.READ_LIBTIFF = False
+    TiffImagePlugin.WRITE_LIBTIFF = False
+
+
+
+
+def test_cmyk_save():
+    im = lena('CMYK')
+    out = tempfile('temp.tif')
+
+    im.save(out, compression='tiff_adobe_deflate')
+    im2 = Image.open(out)
+    assert_image_equal(im, im2)
+
+def xtest_bw_compression_wRGB():
+    """ This test passes, but when running all tests causes a failure due to
+        output on stderr from the error thrown by libtiff. We need to capture that
+        but not now"""
+    
+    im = lena('RGB')
+    out = tempfile('temp.tif')
+
+    assert_exception(IOError, lambda: im.save(out, compression='tiff_ccitt'))
+    assert_exception(IOError, lambda: im.save(out, compression='group3'))
+    assert_exception(IOError, lambda: im.save(out, compression='group4'))
 

Tests/test_file_libtiff_small.py

@@ -6,7 +6,7 @@ from test_file_libtiff import _assert_noerr
 
 codecs = dir(Image.core)
 
-if "group4_encoder" not in codecs or "group4_decoder" not in codecs:
+if "libtiff_encoder" not in codecs or "libtiff_decoder" not in codecs:
     skip("tiff support not available")
 
 """ The small lena image was failing on open in the libtiff

Tests/test_file_tiff.py

@@ -74,7 +74,7 @@ def test_xyres_tiff():
 
 
 def test_little_endian():
-	im = Image.open('Tests/images/12bit.cropped.tif')
+	im = Image.open('Tests/images/16bit.cropped.tif')
 	assert_equal(im.getpixel((0,0)), 480)
 	assert_equal(im.mode, 'I;16')
 
@@ -89,7 +89,7 @@ def test_little_endian():
 		
 
 def test_big_endian():
-	im = Image.open('Tests/images/12bit.MM.cropped.tif')
+	im = Image.open('Tests/images/16bit.MM.cropped.tif')
 	assert_equal(im.getpixel((0,0)), 480)
 	assert_equal(im.mode, 'I;16B')
 
@@ -102,3 +102,29 @@ def test_big_endian():
 	else:
 		assert_equal(b[0], b'\x01')
 		assert_equal(b[1], b'\xe0')
+
+
+def test_12bit_rawmode():
+    """ Are we generating the same interpretation of the image as Imagemagick is? """
+
+    #Image.DEBUG = True
+    im = Image.open('Tests/images/12bit.cropped.tif')
+
+    # to make the target --
+    # convert 12bit.cropped.tif -depth 16 tmp.tif
+    # convert tmp.tif -evaluate RightShift 4 12in16bit2.tif
+    # imagemagick will auto scale so that a 12bit FFF is 16bit FFF0,
+    # so we need to unshift so that the integer values are the same. 
+    
+    im2 = Image.open('Tests/images/12in16bit.tif')
+
+    if Image.DEBUG:
+        print (im.getpixel((0,0)))
+        print (im.getpixel((0,1)))
+        print (im.getpixel((0,2)))
+
+        print (im2.getpixel((0,0)))
+        print (im2.getpixel((0,1)))
+        print (im2.getpixel((0,2)))
+  
+    assert_image_equal(im, im2)

Tests/test_image_convert.py

@@ -38,12 +38,12 @@ def test_8bit():
     im = Image.open('Images/lena.jpg')
     _test_float_conversion(im.convert('L'))
 
-def test_12bit():
-    im = Image.open('Tests/images/12bit.cropped.tif')
+def test_16bit():
+    im = Image.open('Tests/images/16bit.cropped.tif')
     _test_float_conversion(im)
 
-def test_12bit_workaround():
-    im = Image.open('Tests/images/12bit.cropped.tif')
+def test_16bit_workaround():
+    im = Image.open('Tests/images/16bit.cropped.tif')
     _test_float_conversion(im.convert('I'))
     
 

Tests/test_numpy.py

@@ -75,7 +75,7 @@ def _test_img_equals_nparray(img, np):
 
 
 def test_16bit():
-    img = Image.open('Tests/images/12bit.cropped.tif')
+    img = Image.open('Tests/images/16bit.cropped.tif')
     np_img = numpy.array(img)
     _test_img_equals_nparray(img, np_img)
     assert_equal(np_img.dtype, numpy.dtype('<u2'))

_imaging.c

@@ -3317,27 +3317,8 @@ static PyMethodDef functions[] = {
 #endif
     {"tiff_lzw_decoder", (PyCFunction)PyImaging_TiffLzwDecoderNew, 1},
 #ifdef HAVE_LIBTIFF
-    {"tiff_ccitt_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"group3_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"group4_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_jpeg_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_adobe_deflate_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_thunderscan_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_deflate_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_sgilog_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_sgilog24_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-    {"tiff_raw_16_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
-
-    {"tiff_ccitt_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"group3_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"group4_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_jpeg_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_adobe_deflate_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_thunderscan_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_deflate_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_sgilog_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_sgilog24_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
-    {"tiff_raw_16_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
+    {"libtiff_decoder", (PyCFunction)PyImaging_LibTiffDecoderNew, 1},
+    {"libtiff_encoder", (PyCFunction)PyImaging_LibTiffEncoderNew, 1},
 #endif
     {"msp_decoder", (PyCFunction)PyImaging_MspDecoderNew, 1},
     {"packbits_decoder", (PyCFunction)PyImaging_PackbitsDecoderNew, 1},

decode.c

@@ -427,7 +427,6 @@ PyImaging_LibTiffDecoderNew(PyObject* self, PyObject* args)
     char* mode;
     char* rawmode;
     char* compname;
-    int compression;
     int fp;
 
     if (! PyArg_ParseTuple(args, "sssi", &mode, &rawmode, &compname, &fp))
@@ -435,46 +434,6 @@ PyImaging_LibTiffDecoderNew(PyObject* self, PyObject* args)
 
     TRACE(("new tiff decoder %s\n", compname));
 
-    /* UNDONE -- we can probably do almost any arbitrary compression here,
-     * since we're effective passing in the whole file in one shot and
-     * getting back the data row by row. V2 maybe
-     */
-
-    if (strcasecmp(compname, "tiff_ccitt") == 0) {
-        compression = COMPRESSION_CCITTRLE;
-
-    } else if (strcasecmp(compname, "group3") == 0) {
-        compression = COMPRESSION_CCITTFAX3;
-
-    } else if (strcasecmp(compname, "group4") == 0) {
-        compression = COMPRESSION_CCITTFAX4;
-
-    } else if (strcasecmp(compname, "tiff_jpeg") == 0) {
-        compression = COMPRESSION_OJPEG;
-
-    } else if (strcasecmp(compname, "tiff_adobe_deflate") == 0) {
-        compression = COMPRESSION_ADOBE_DEFLATE;
-
-    } else if (strcasecmp(compname, "tiff_thunderscan") == 0) {
-        compression = COMPRESSION_THUNDERSCAN;
-
-    } else if (strcasecmp(compname, "tiff_deflate") == 0) {
-        compression = COMPRESSION_DEFLATE;
-
-    } else if (strcasecmp(compname, "tiff_sgilog") == 0) {
-        compression = COMPRESSION_SGILOG;
-
-    } else if (strcasecmp(compname, "tiff_sgilog24") == 0) {
-        compression = COMPRESSION_SGILOG24;
-
-    } else if (strcasecmp(compname, "tiff_raw_16") == 0) {
-        compression = COMPRESSION_CCITTRLEW;
-
-    } else {
-        PyErr_SetString(PyExc_ValueError, "unknown compession");
-        return NULL;
-    }
-
     decoder = PyImaging_DecoderNew(sizeof(TIFFSTATE));
     if (decoder == NULL)
         return NULL;
@@ -482,7 +441,7 @@ PyImaging_LibTiffDecoderNew(PyObject* self, PyObject* args)
     if (get_unpacker(decoder, mode, rawmode) < 0)
         return NULL;
 
-    if (! ImagingLibTiffInit(&decoder->state, compression, fp)) {
+    if (! ImagingLibTiffInit(&decoder->state, fp)) {
         Py_DECREF(decoder);
         PyErr_SetString(PyExc_RuntimeError, "tiff codec initialization failed");
         return NULL;

encode.c

@@ -673,7 +673,6 @@ PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args)
     char* rawmode;
     char* compname;
     char* filename;
-    int compression;
     int fp;
 
     PyObject *dir;
@@ -706,47 +705,6 @@ PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args)
 
     TRACE(("new tiff encoder %s fp: %d, filename: %s \n", compname, fp, filename));
 
-    /* UNDONE -- we can probably do almost any arbitrary compression here,
-     *  so long as we're doing row/stripe based actions and not tiles.
-     */
-
-    if (strcasecmp(compname, "tiff_ccitt") == 0) {
-        compression = COMPRESSION_CCITTRLE;
-
-    } else if (strcasecmp(compname, "group3") == 0) {
-        compression = COMPRESSION_CCITTFAX3;
-
-    } else if (strcasecmp(compname, "group4") == 0) {
-        compression = COMPRESSION_CCITTFAX4;
-
-    } else if (strcasecmp(compname, "tiff_jpeg") == 0) {
-        compression = COMPRESSION_OJPEG;
-
-    } else if (strcasecmp(compname, "tiff_adobe_deflate") == 0) {
-        compression = COMPRESSION_ADOBE_DEFLATE;
-
-    } else if (strcasecmp(compname, "tiff_thunderscan") == 0) {
-        compression = COMPRESSION_THUNDERSCAN;
-
-    } else if (strcasecmp(compname, "tiff_deflate") == 0) {
-        compression = COMPRESSION_DEFLATE;
-
-    } else if (strcasecmp(compname, "tiff_sgilog") == 0) {
-        compression = COMPRESSION_SGILOG;
-
-    } else if (strcasecmp(compname, "tiff_sgilog24") == 0) {
-        compression = COMPRESSION_SGILOG24;
-
-    } else if (strcasecmp(compname, "tiff_raw_16") == 0) {
-        compression = COMPRESSION_CCITTRLEW;
-
-    } else {
-        PyErr_SetString(PyExc_ValueError, "unknown compession");
-        return NULL;
-    }
-
-    TRACE(("Found compression: %d\n", compression));
-
     encoder = PyImaging_EncoderNew(sizeof(TIFFSTATE));
     if (encoder == NULL)
         return NULL;
@@ -780,8 +738,23 @@ PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args)
         } else if(PyList_Check(value)) {
             int len,i;
             float *floatav;
+            int *intav;
             TRACE(("Setting from List: %d \n", (int)PyInt_AsLong(key)));
             len = (int)PyList_Size(value);
+            if (len) {
+                if (PyInt_Check(PyList_GetItem(value,0))) {
+                    TRACE((" %d elements, setting as ints \n", len));
+                    intav = malloc(sizeof(int)*len);
+                    if (intav) {
+                        for (i=0;i<len;i++) {
+                            intav[i] = (int)PyInt_AsLong(PyList_GetItem(value,i));
+                        }
+                        status = ImagingLibTiffSetField(&encoder->state,
+                                                        (ttag_t) PyInt_AsLong(key),
+                                                        intav);
+                        free(intav);
+                    }       
+                } else {
                     TRACE((" %d elements, setting as floats \n", len));
                     floatav = malloc(sizeof(float)*len);
                     if (floatav) {
@@ -793,6 +766,8 @@ PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args)
                                                         floatav);
                         free(floatav);
                     }
+                }
+            }
         } else if (PyFloat_Check(value)) {
             TRACE(("Setting from Float: %d, %f \n", (int)PyInt_AsLong(key),PyFloat_AsDouble(value)));
             status = ImagingLibTiffSetField(&encoder->state,

libImaging/TiffDecode.c

@@ -142,11 +142,11 @@ void _tiffUnmapProc(thandle_t hdata, tdata_t base, toff_t size) {
 	(void) hdata; (void) base; (void) size;
 }
 
-int ImagingLibTiffInit(ImagingCodecState state, int compression, int fp) {
+int ImagingLibTiffInit(ImagingCodecState state, int fp) {
 	TIFFSTATE *clientstate = (TIFFSTATE *)state->context;
 
     TRACE(("initing libtiff\n"));
-	TRACE(("Compression: %d, filepointer: %d \n", compression, fp));
+	TRACE(("filepointer: %d \n",  fp));
 	TRACE(("State: count %d, state %d, x %d, y %d, ystep %d\n", state->count, state->state,
 		   state->x, state->y, state->ystep));
 	TRACE(("State: xsize %d, ysize %d, xoff %d, yoff %d \n", state->xsize, state->ysize,

libImaging/TiffDecode.h

@@ -38,7 +38,7 @@ typedef struct {
 
 
 
-extern int ImagingLibTiffInit(ImagingCodecState state, int compression, int fp);
+extern int ImagingLibTiffInit(ImagingCodecState state, int fp);
 extern int ImagingLibTiffEncodeInit(ImagingCodecState state, char *filename, int fp);
 extern int ImagingLibTiffSetField(ImagingCodecState state, ttag_t tag, ...);
 

libImaging/Unpack.c

@@ -795,6 +795,60 @@ unpackI16N_I16(UINT8* out, const UINT8* in, int pixels){
     }
 }
 
+static void
+unpackI12_I16(UINT8* out, const UINT8* in, int pixels){
+    /*  Fillorder 1/MSB -> LittleEndian, for 12bit integer greyscale tiffs. 
+        
+        According to the TIFF spec: 
+
+        FillOrder = 2 should be used only when BitsPerSample = 1 and
+        the data is either uncompressed or compressed using CCITT 1D
+        or 2D compression, to avoid potentially ambigous situations.
+
+        Yeah. I thought so. We'll see how well people read the spec. 
+        We've got several fillorder=2 modes in TiffImagePlugin.py
+
+        There's no spec I can find. It appears that the in storage
+        layout is: 00 80 00 ... -> (128 , 0 ...). The samples are
+        stored in a single big bitian 12bit block, but need to be
+        pulled out to little endian format to be stored in a 2 byte
+        int.
+     */
+
+    int i;
+    UINT16 pixel;
+#ifdef WORDS_BIGENDIAN
+    UINT8* tmp = (UINT8 *)&pixel;
+#endif
+    UINT16* out16 = (UINT16 *)out;
+    for (i = 0; i < pixels-1; i+=2) {
+        pixel = (((UINT16) in[0]) << 4 ) + (in[1] >>4);
+#ifdef WORDS_BIGENDIAN
+        out[0] = tmp[1];  out[1] = tmp[0];
+#else
+        out16[0] = pixel;
+#endif
+
+        pixel = (((UINT16) (in[1] & 0x0F)) << 8) + in[2];
+#ifdef WORDS_BIGENDIAN
+        out[2] = tmp[1];  out[3] = tmp[0];
+#else
+        out16[1] = pixel;
+#endif
+  
+		in += 3; out16 += 2; out+=4;
+    }
+    if (i == pixels-1) {
+        pixel = (((UINT16) in[0]) << 4 ) + (in[1] >>4);
+#ifdef WORDS_BIGENDIAN
+        out[0] = tmp[1];  out[1] = tmp[0];
+#else
+        out16[0] = pixel;
+#endif
+    }
+}
+
+
 static void
 copy1(UINT8* out, const UINT8* in, int pixels)
 {
@@ -1163,6 +1217,8 @@ static struct {
     {"I;16L", 	"I;16N",	    16,	    unpackI16N_I16}, // LibTiff native->image endian.
     {"I;16B", 	"I;16N",	    16,	    unpackI16N_I16B},
 
+    {"I;16", 	"I;12",	        12,	    unpackI12_I16}, // 12 bit Tiffs stored in 16bits.
+
     {NULL} /* sentinel */
 };