WIP: Skia support library for ICC tasks

As a starting point, this would be mostly trivial to implement using
SkColorSpace.

This also would give us the flexibility to begin to move all of
the ICC related code from SkColorSpace to SkICC.

What are the advantages of moving this away from SkColorSpace?
(1) A long term goal (once Chrome uses SkCodec), might be to
move SkColorSpace::MakeICC() out of the public API.  That way,
we can guarantee that we can draw to/from *any* SkColorSpace.
(2) Keeps SkColorSpace separate from ICC-specific representations
like SkColorSpaceTransferFn etc.

BUG=skia:

Change-Id: Iddeb9903221fb57fbfc01218d8641c928b4a5165
Reviewed-on: https://skia-review.googlesource.com/5676
Commit-Queue: Matt Sarett <msarett@google.com>
Reviewed-by: Brian Osman <brianosman@google.com>
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 73 insertions, 0 deletions

diff --git a/include/core/SkICC.h b/include/core/SkICC.h
new file mode 100644
index 0000000000..3780498df9
--- /dev/null
+++ b/include/core/SkICC.h
@@ -0,0 +1,73 @@
+/*
+ * Copyright 2016 Google Inc.
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+#ifndef SkICC_DEFINED
+#define SkICC_DEFINED
+
+#include "SkRefCnt.h"
+
+struct SkColorSpaceTransferFn;
+class SkColorSpace;
+class SkData;
+class SkMatrix44;
+
+class SK_API SkICC : public SkRefCnt {
+public:
+
+    /**
+     *  Parse an ICC profile.
+     *
+     *  Returns nullptr if the data is not a valid ICC profile or if the profile
+     *  input space is not RGB.
+     */
+    static sk_sp<SkICC> Make(const void*, size_t);
+
+    /**
+     *  If the gamut can be represented as transformation into XYZ D50, returns
+     *  true and sets the proper values in |toXYZD50|.
+     *
+     *  If not, returns false.  This indicates that the ICC data is too complex
+     *  to isolate a simple gamut transformation.
+     */
+    bool toXYZD50(SkMatrix44* toXYZD50) const;
+
+    /**
+     *  If the transfer function can be represented as coefficients to the standard
+     *  equation, returns true and sets |fn| to the proper values.
+     *
+     *  If not, returns false.  This indicates one of the following:
+     *  (1) The R, G, and B transfer functions are not the same.
+     *  (2) The transfer function is represented as a table that we have not managed
+     *      to match to a standard curve.
+     *  (3) The ICC data is too complex to isolate a single transfer function.
+     */
+    bool isNumericalTransferFn(SkColorSpaceTransferFn* fn) const;
+
+    /**
+     *  If the transfer function can be approximated as coefficients to the standard
+     *  equation, returns true and sets |fn| to the proper values.
+     *
+     *  If not, returns false.  This indicates one of the following:
+     *  (1) The R, G, and B transfer functions are not the same.
+     *  (2) The transfer function is represented as a table that is not increasing with
+     *      end points at zero and one.
+     *  (3) The ICC data is too complex to isolate a single transfer function.
+     */
+    bool approximateNumericalTransferFn(SkColorSpaceTransferFn* fn) const;
+
+    /**
+     *  Write an ICC profile with transfer function |fn| and gamut |toXYZD50|.
+     */
+    static sk_sp<SkData> WriteToICC(const SkColorSpaceTransferFn& fn, const SkMatrix44& toXYZD50);
+
+private:
+    SkICC(sk_sp<SkColorSpace> colorSpace);
+
+    sk_sp<SkColorSpace> fColorSpace;
+};
+
+#endif