Cache dst LUTs in SkColorSpaceXform

This is only useful in the rare case that the dst does not
fall into one of our main paths.

But it's a good optimization, since this does happen,
and typically, the dst won't change.

ColorCodecBench z620 --nonstd --xform_only
Without Patch 511us
With Patch    348us

BUG=skia:

GOLD_TRYBOT_URL= https://gold.skia.org/search?issue=3400

Change-Id: Ibf68d9ce7072680465662922f4aa15630545e3d6
Reviewed-on: https://skia-review.googlesource.com/3400
Reviewed-by: Mike Klein <mtklein@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>
Commit-Queue: Matt Sarett <msarett@google.com>

1 files changed, 18 insertions, 0 deletions

diff --git a/src/core/SkColorSpace.cpp b/src/core/SkColorSpace.cpp
index bdef5b3b75..b956c7fe3e 100644
--- a/src/core/SkColorSpace.cpp
+++ b/src/core/SkColorSpace.cpp
@@ -8,6 +8,7 @@
 #include "SkColorSpace.h"
 #include "SkColorSpace_Base.h"
 #include "SkColorSpacePriv.h"
+#include "SkColorSpaceXform_Base.h"
 #include "SkOnce.h"
 #include "SkPoint3.h"
 
@@ -319,6 +320,23 @@ const SkMatrix44& SkColorSpace_Base::fromXYZD50() const {
     return fFromXYZD50;
 }
 
+void SkColorSpace_Base::toDstGammaTables(const uint8_t* tables[3], sk_sp<SkData>* storage,
+                                         int numTables) const {
+    fToDstGammaOnce([this, numTables] {
+        const bool gammasAreMatching = numTables <= 1;
+        fDstStorage =
+                SkData::MakeUninitialized(numTables * SkColorSpaceXform_Base::kDstGammaTableSize);
+        SkColorSpaceXform_Base::BuildDstGammaTables(fToDstGammaTables,
+                                                    (uint8_t*) fDstStorage->writable_data(), this,
+                                                    gammasAreMatching);
+    });
+
+    *storage = fDstStorage;
+    tables[0] = fToDstGammaTables[0];
+    tables[1] = fToDstGammaTables[1];
+    tables[2] = fToDstGammaTables[2];
+}
+
 ///////////////////////////////////////////////////////////////////////////////////////////////////
 
 enum Version {