Added support for saving colormaps

Author: wiredfool

PIL/TiffTags.py

@@ -434,16 +434,13 @@ def _populate():
                 269  # this has been in our tests forever, and works
                 }
 
-LIBTIFF_CORE.remove(320)  # Array of short, crashes
-LIBTIFF_CORE.remove(301)  # Array of short, crashes
-#LIBTIFF_CORE.remove(532)  # Array of long, crashes
-
 LIBTIFF_CORE.remove(330)  # subifd, requires extra support for uint64 payload
 
 LIBTIFF_CORE.remove(255)  # We don't have support for subfiletypes
 LIBTIFF_CORE.remove(322)  # We don't have support for tiled images in libtiff
 LIBTIFF_CORE.remove(323)  # Tiled images
 LIBTIFF_CORE.remove(333)  # Ink Names either
+LIBTIFF_CORE.remove(301)  # Transfer Function. No support as of yet.
 
 # Note to advanced users: There may be combinations of these
 # parameters and values that when added properly, will work and

Tests/test_file_libtiff.py

@@ -194,6 +194,7 @@ def test_additional_metadata(self):
                 del(core_items[tag])
             except:
                 pass
+        del(core_items[320])  # colormap is special, tested below
 
         # Type codes:
         #     2: "ascii",
@@ -354,6 +355,19 @@ def test_cmyk_save(self):
         im2 = Image.open(out)
         self.assert_image_equal(im, im2)
 
+    def test_palette_save(self):
+        im = hopper('P')
+        out = self.tempfile('temp.tif')
+        TiffImagePlugin.WRITE_LIBTIFF = True
+        im.save(out)
+        TiffImagePlugin.WRITE_LIBTIFF = False
+
+        reloaded = Image.open(out)
+        # colormap/palette tag
+        self.assertTrue(len(reloaded.tag_v2[320]), 768)
+        self.assert_image_equal(im, reloaded)
+        
+
     def xtest_bw_compression_w_rgb(self):
         """ 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

encode.c

@@ -936,6 +936,26 @@ PyImaging_LibTiffEncoderNew(PyObject* self, PyObject* args)
                 break;
             case TIFFTAG_COLORMAP:
                 /* 3x uint16 * arrays of r,g,b palette values, len=2^^bpp */
+                {
+                    int stride = 256;
+                    TRACE(("Setting ColorMap\n"));
+                  if (len != 768) {
+                        PyErr_SetString(PyExc_ValueError, "Requiring 768 items for for Colormap");
+                        return NULL;
+                    }
+                    arrav = calloc(len, sizeof(uint16)); 
+                    if (arrav) {                        
+                        for (i=0;i<len;i++) {
+                            ((uint16 *)arrav)[i] = (uint16)PyInt_AsLong(PyTuple_GetItem(value,i));
+                        }                                                   
+                        status = ImagingLibTiffSetField(&encoder->state,
+                                                        tag,
+                                                        arrav,
+                                                        ((uint16 *)arrav) + stride,
+                                                        ((uint16 *)arrav) + 2 * stride);
+                        free(arrav);
+                    }
+                }
                 break;
             case TIFFTAG_SUBIFD:
                 /* int short length, uint32* data */