color: Clarify default behaviors

ui/gfx/icc_profile.cc

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "ui/gfx/icc_profile.h"
 
 #include <list>
 
 #include "base/containers/mru_cache.h"
 #include "base/lazy_instance.h"
@@ skipping 90 matching lines @@
 
 #if !defined(OS_WIN) && !defined(OS_MACOSX) && !defined(USE_X11)
 // static
 ICCProfile ICCProfile::FromBestMonitor() {
   return ICCProfile();
 }
 #endif
 
 // static
 ICCProfile ICCProfile::FromColorSpace(const gfx::ColorSpace& color_space) {
-  if (color_space == gfx::ColorSpace())
+  if (!color_space.IsValid())
     return ICCProfile();
 
   // If |color_space| was created from an ICC profile, retrieve that exact
   // profile.
-  if (color_space.icc_profile_id_) {
-    Cache& cache = g_cache.Get();
-    base::AutoLock lock(cache.lock);
-    auto found = cache.id_to_icc_profile_mru.Get(color_space.icc_profile_id_);
-    if (found != cache.id_to_icc_profile_mru.end())
-      return found->second;
+  ICCProfile result;
+  if (FromId(color_space.icc_profile_id_, false, &result)) {
+    return result;
   }
 
   // Otherwise, construct an ICC profile based on the best approximated
   // primaries and matrix.
   SkMatrix44 to_XYZD50_matrix;
   color_space.GetPrimaryMatrix(&to_XYZD50_matrix);
   SkColorSpaceTransferFn fn;
   if (!color_space.GetTransferFunction(&fn)) {
     DLOG(ERROR) << "Failed to get ColorSpace transfer function for ICCProfile.";
     return ICCProfile();
   }
-
   sk_sp<SkData> data = SkICC::WriteToICC(fn, to_XYZD50_matrix);
   if (!data) {
     DLOG(ERROR) << "Failed to create SkICC.";
     return ICCProfile();
   }
-
-  // gfx::ColorTransform assumes that this will return an empty profile for any
-  // color space that was not constructed from an ICC profile.
-  // TODO(ccameron): Fix this assumption.
-  // return FromData(data->data(), data->size());
-  return ICCProfile();
+  return FromData(data->data(), data->size());
 }
 
 const std::vector<char>& ICCProfile::GetData() const {
   return data_;
 }
 
 const ColorSpace& ICCProfile::GetColorSpace() const {
   // Move this ICC profile to the most recently used end of the cache,
   // inserting if needed.
   if (id_) {
     Cache& cache = g_cache.Get();
     base::AutoLock lock(cache.lock);
     auto found = cache.id_to_icc_profile_mru.Get(id_);
     if (found == cache.id_to_icc_profile_mru.end())
       found = cache.id_to_icc_profile_mru.Put(id_, *this);
   }
   return color_space_;
 }
 
+// static
+bool ICCProfile::FromId(uint64_t id,
+                        bool only_if_needed,
+                        ICCProfile* icc_profile) {
+  if (!id)
+    return false;
+
+  Cache& cache = g_cache.Get();
+  base::AutoLock lock(cache.lock);
+
+  auto found = cache.id_to_icc_profile_mru.Get(id);
+  if (found == cache.id_to_icc_profile_mru.end())
+    return false;
+
+  const ICCProfile& found_icc_profile = found->second;
+  if (found_icc_profile.color_space_is_accurate_ && only_if_needed)
+    return false;
+
+  *icc_profile = found_icc_profile;
+  return true;
+}
+
 void ICCProfile::ComputeColorSpaceAndCache() {
   if (!id_)
     return;
 
   // If this already exists in the cache, just update its |color_space_|.
   {
     Cache& cache = g_cache.Get();
     base::AutoLock lock(cache.lock);
     auto found = cache.id_to_icc_profile_mru.Get(id_);
     if (found != cache.id_to_icc_profile_mru.end()) {
       color_space_ = found->second.color_space_;
       return;
     }
   }
 
+  color_space_is_accurate_ = true;
+  SkMatrix44 to_XYZD50_matrix;
+  SkColorSpaceTransferFn fn;
+  sk_sp<SkICC> sk_icc = SkICC::Make(data_.data(), data_.size());
+  if (sk_icc) {
+    if (!sk_icc->toXYZD50(&to_XYZD50_matrix)) {
+      // Just say that the primaries were the sRGB primaries if we can't
+      // extract them.
+      gfx::ColorSpace::CreateSRGB().GetPrimaryMatrix(&to_XYZD50_matrix);
+      color_space_is_accurate_ = false;
+      DLOG(ERROR) << "Unable to handle ICCProfile primaries.";
+    }
+    if (!sk_icc->isNumericalTransferFn(&fn)) {
+      // Just say that the transfer function was sRGB if we cannot read it.
+      // TODO(ccameron): Use a least squares approximation of the transfer
+      // function when it is not numerical.
+      gfx::ColorSpace::CreateSRGB().GetTransferFunction(&fn);
+      color_space_is_accurate_ = false;
+      DLOG(ERROR) << "Unable to handle ICCProfile transfer function.";
+    }
+  } else {
+    gfx::ColorSpace::CreateSRGB().GetPrimaryMatrix(&to_XYZD50_matrix);
+    gfx::ColorSpace::CreateSRGB().GetTransferFunction(&fn);
+    color_space_is_accurate_ = false;
+    DLOG(ERROR) << "Unable parse ICCProfile.";
+  }
+
   // Compute the color space.
-  color_space_ = gfx::ColorSpace(
-      ColorSpace::PrimaryID::CUSTOM, ColorSpace::TransferID::CUSTOM,
-      ColorSpace::MatrixID::RGB, ColorSpace::RangeID::FULL);
+  color_space_ = gfx::ColorSpace::CreateCustom(to_XYZD50_matrix, fn);
   color_space_.icc_profile_id_ = id_;
   color_space_.icc_profile_sk_color_space_ =
       SkColorSpace::MakeICC(data_.data(), data_.size());
 
-  sk_sp<SkICC> sk_icc = SkICC::Make(data_.data(), data_.size());
-  if (sk_icc) {
-    bool result;
-    SkMatrix44 to_XYZD50_matrix;
-    result = sk_icc->toXYZD50(&to_XYZD50_matrix);
-    if (result) {
-      for (int row = 0; row < 3; ++row) {
-        for (int col = 0; col < 3; ++col) {
-          color_space_.custom_primary_matrix_[3 * row + col] =
-              to_XYZD50_matrix.get(row, col);
-        }
-      }
-    } else {
-      // Just say that the primaries were the sRGB primaries if we can't
-      // extract them.
-      color_space_.primaries_ = ColorSpace::PrimaryID::BT709;
-      DLOG(ERROR) << "Unable to handle ICCProfile primaries.";
-    }
-    SkColorSpaceTransferFn fn;
-    result = sk_icc->isNumericalTransferFn(&fn);
-    if (result) {
-      color_space_.custom_transfer_params_[0] = fn.fA;
-      color_space_.custom_transfer_params_[1] = fn.fB;
-      color_space_.custom_transfer_params_[2] = fn.fC;
-      color_space_.custom_transfer_params_[3] = fn.fD;
-      color_space_.custom_transfer_params_[4] = fn.fE;
-      color_space_.custom_transfer_params_[5] = fn.fF;
-      color_space_.custom_transfer_params_[6] = fn.fG;
-    } else {
-      // Just say that the transfer function was sRGB if we cannot read it.
-      // TODO(ccameron): Use a least squares approximation of the transfer
-      // function when it is not numerical.
-      color_space_.transfer_ = ColorSpace::TransferID::IEC61966_2_1;
-      DLOG(ERROR) << "Unable to handle ICCProfile transfer function.";
-    }
-  }
-
   // Add to the cache.
   {
     Cache& cache = g_cache.Get();
     base::AutoLock lock(cache.lock);
     cache.id_to_icc_profile_mru.Put(id_, *this);
   }
 }
 
 // static
 bool ICCProfile::IsValidProfileLength(size_t length) {
   return length >= kMinProfileLength && length <= kMaxProfileLength;
 }
 
 }  // namespace gfx