Revert "strip down SkICC.cpp"

This reverts commit eab50eb9c6117c2a9d0e5648f89cebbb4dbd9d30
and this tiny bit of e61b969a07ba3ebe9e47e61381ad16c5d2c549a2:

    https://skia-review.googlesource.com/c/skia/+/127122/3/tests/ICCTest.cpp

Change-Id: I4306e5118a4e5eb88c05078186a28bd443fd76f7
Reviewed-on: https://skia-review.googlesource.com/127305
Reviewed-by: Mike Klein <mtklein@chromium.org>
Commit-Queue: Mike Klein <mtklein@chromium.org>

1 files changed, 89 insertions, 17 deletions

diff --git a/include/core/SkICC.h b/include/core/SkICC.h
index 9d2ada347e..8c5ec566b7 100644
--- a/include/core/SkICC.h
+++ b/include/core/SkICC.h
@@ -12,26 +12,98 @@
 #include "SkRefCnt.h"
 
 struct SkColorSpaceTransferFn;
+class SkColorSpace;
+class SkData;
+class SkMatrix44;
 
-SK_API sk_sp<SkData> SkWriteICCProfile(const SkColorSpaceTransferFn&, const float toXYZD50[9]);
+class SK_API SkICC : public SkRefCnt {
+public:
 
-namespace SkICC {
-    static inline sk_sp<SkData> WriteToICC(const SkColorSpaceTransferFn& fn,
-                                           const SkMatrix44& toXYZD50) {
-        if (toXYZD50.get(3,0) == 0 && toXYZD50.get(3,1) == 0 && toXYZD50.get(3,2) == 0 &&
-            toXYZD50.get(3,3) == 1 &&
-            toXYZD50.get(0,3) == 0 && toXYZD50.get(1,3) == 0 && toXYZD50.get(2,3) == 0) {
+    /**
+     *  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);
 
-            float m33[9];
-            for (int r = 0; r < 3; r++)
-            for (int c = 0; c < 3; c++) {
-                m33[3*r+c] = toXYZD50.get(r,c);
-            }
-            return SkWriteICCProfile(fn, m33);
+    /**
+     *  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;
+
+    /**
+     *  Please do not call this unless isNumericalTransferFn() has been called and it
+     *  fails.  SkColorSpaceTransferFn is the preferred representation.
+     *
+     *  If it is not possible to represent the R, G, and B transfer functions numerically
+     *  and it is still necessary to get the transfer function, this will return the
+     *  transfer functions as three tables (R, G, and B).
+     *
+     *  If possible, this will return tables of the same length as they were specified in
+     *  the ICC profile.  This means that the lengths of the three tables are not
+     *  guaranteed to be the same.  If the ICC representation was not a table, the length
+     *  will be chosen arbitrarily.
+     *
+     *  The lengths of the tables are all guaranteed to be at least 2.  Entries in the
+     *  tables are guaranteed to be in [0, 1].
+     *
+     *  This API may be deleted in favor of a numerical approximation of the raw data.
+     *
+     *  This function may fail, indicating that the ICC profile does not have transfer
+     *  functions.
+     */
+    struct Channel {
+        // Byte offset of the start of the table in |fStorage|
+        size_t fOffset;
+        int    fCount;
+    };
+    struct Tables {
+        Channel fRed;
+        Channel fGreen;
+        Channel fBlue;
+
+        const float* red() {
+            return (const float*) (fStorage->bytes() + fRed.fOffset);
+        }
+        const float* green() {
+            return (const float*) (fStorage->bytes() + fGreen.fOffset);
         }
-        return nullptr;
-    }
-}
+        const float* blue() {
+            return (const float*) (fStorage->bytes() + fBlue.fOffset);
+        }
+
+        sk_sp<SkData> fStorage;
+    };
+    bool rawTransferFnData(Tables* tables) 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;
+
+    friend class ICCTest;
+};
 
-#endif//SkICC_DEFINED
+#endif