beginning icc support

Signed-off-by: Mattias Andrée <maandree@operamail.com>

1 files changed, 95 insertions, 0 deletions

diff --git a/src/icc.py b/src/icc.py
new file mode 100644
index 0000000..705d135
--- /dev/null
+++ b/src/icc.py
@@ -0,0 +1,95 @@
+#!/usr/bin/env python3
+
+# Copyright © 2014  Mattias Andrée (maandree@member.fsf.org)
+# 
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+# 
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+# 
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+
+def load_icc(pathname):
+    '''
+    Load ICC profile from a file
+    
+    @param   pathname  The ICC profile file
+    @return            Function to invoke, parameterless, to apply the ICC profile to the colour curves
+    '''
+    MLUT_TAG = 0x6d4c5554
+    VCGT_TAG = 0x76636774
+    
+    def make_f(R_curve, G_curve, B_curve):
+        pass ## TODO
+    
+    int_ = lambda bs : sum([bs[len(bs) - 1 - i] << (8 * i) for i in range(len(bs))])
+    def read(n):
+        if len(content) < n:
+            raise Except("Premature end of file: %s" % pathname)
+        rc, content[:] = content[:n], content[n:]
+        return rc
+    
+    content = None
+    with open(pathname, 'rb') as file:
+        content = file.read()
+    content = list(content)
+    read(128)
+    
+    n_tags, ptr = int_(read(4)), 128 + 4
+    for i_tag in range(n_tags):
+        tag_name   = int_(read(4))
+        tag_offset = int_(read(4))
+        tag_size   = int_(read(4))
+        ptr += 3 * 4
+        if tag_name == MLUT_TAG:
+            read(tag_offset - ptr)
+            R_curve, G_curve, B_curve = [], [], []
+            for i in range(256):  R_curve.append(int_(read(2)))
+            for i in range(256):  G_curve.append(int_(read(2)))
+            for i in range(256):  B_curve.append(int_(read(2)))
+            return make_f(R_curve, G_curve, B_curve)
+        elif tag_name == VCGT_TAG:
+            read(tag_offset - ptr)
+            tag_name = int_(read(4))
+            if not tag_name == VCGT_TAG:
+                break
+            read(4)
+            gamma_type = int_(read(4))
+            if gamma_type == 0:
+                n_channels = int_(read(2))
+                n_entries  = int_(read(2))
+                entry_size = int_(read(2))
+                if tag_size == 1584:
+                    n_channels, n_entries, entry_size = 3, 256, 2
+                if not n_channels == 3: # assuming sRGB
+                    break
+                int__ = lambda m : float(int(int_(read(m)) * 8 ** (2 - m)))
+                for i in range(n_entries):  R_curve.append(int__(entry_size))
+                for i in range(n_entries):  G_curve.append(int__(entry_size))
+                for i in range(n_entries):  B_curve.append(int__(entry_size))
+                return make_f(R_curve, G_curve, B_curve)
+            elif gamma_type == 1:
+                r_gamma = int_(read(4)) / 65535
+                r_min   = int_(read(4)) / 65535
+                r_max   = int_(read(4)) / 65535
+                g_gamma = int_(read(4)) / 65535
+                g_min   = int_(read(4)) / 65535
+                g_max   = int_(read(4)) / 65535
+                b_gamma = int_(read(4)) / 65535
+                b_min   = int_(read(4)) / 65535
+                b_max   = int_(read(4)) / 65535
+                def f():
+                    gamma(r_gamma, g_gamma, b_gamma)
+                    rgb_limits(r_min, r_max, g_min, g_max, b_min, b_max)
+                return f
+            break
+    
+    raise Exception("Unsupported ICC profile file")
+