color: Clarify default behaviors

ui/gfx/color_space.cc

Index: ui/gfx/color_space.cc
diff --git a/ui/gfx/color_space.cc b/ui/gfx/color_space.cc
index 0f5a42b601841ca529d42c456df504512c708914..f526b0ac4715f39684763b6259a3a15b6ecde046 100644
--- a/ui/gfx/color_space.cc
+++ b/ui/gfx/color_space.cc
@@ -15,31 +15,77 @@
 
 namespace gfx {
 
-ColorSpace::PrimaryID ColorSpace::PrimaryIDFromInt(int primary_id) {
-  if (primary_id < 0 || primary_id > static_cast<int>(PrimaryID::LAST))
-    return PrimaryID::UNKNOWN;
-  if (primary_id > static_cast<int>(PrimaryID::LAST_STANDARD_VALUE) &&
-      primary_id < 1000)
-    return PrimaryID::UNKNOWN;
-  return static_cast<PrimaryID>(primary_id);
-}
+// static
+ColorSpace ColorSpace::CreateVideo(int video_primary,
+                                   int video_transfer,
+                                   int video_matrix,
+                                   RangeID range_id) {
+  ColorSpace result;
+
+  int first_primary = static_cast<int>(PrimaryID::FIRST_VIDEO_VALUE);
+  int last_primary = static_cast<int>(PrimaryID::LAST_VIDEO_VALUE);
+  if (video_primary < 0 || video_primary > last_primary - first_primary) {
+    result.primaries_ = PrimaryID::BT709;
+  } else {
+    result.primaries_ = static_cast<PrimaryID>(video_primary + first_primary);
+  }
+
+  int first_transfer = static_cast<int>(TransferID::FIRST_VIDEO_VALUE);
+  int last_transfer = static_cast<int>(TransferID::LAST_VIDEO_VALUE);
+  if (video_transfer < 0 || video_transfer > last_transfer - first_transfer) {
+    result.transfer_ = TransferID::BT709;
+  } else {
+    result.transfer_ = static_cast<TransferID>(video_transfer + first_transfer);
+  }
+
+  int first_matrix = static_cast<int>(MatrixID::FIRST_VIDEO_VALUE);
+  int last_matrix = static_cast<int>(MatrixID::LAST_VIDEO_VALUE);
+  if (video_matrix < 0 || video_matrix > last_matrix - first_matrix) {
+    result.matrix_ = MatrixID::BT709;
+  } else {
+    result.matrix_ = static_cast<MatrixID>(video_matrix + first_matrix);
+  }
 
-ColorSpace::TransferID ColorSpace::TransferIDFromInt(int transfer_id) {
-  if (transfer_id < 0 || transfer_id > static_cast<int>(TransferID::LAST))
-    return TransferID::UNKNOWN;
-  if (transfer_id > static_cast<int>(TransferID::LAST_STANDARD_VALUE) &&
-      transfer_id < 1000)
-    return TransferID::UNKNOWN;
-  return static_cast<TransferID>(transfer_id);
+  result.range_ = range_id;
+  return result;
 }
 
-ColorSpace::MatrixID ColorSpace::MatrixIDFromInt(int matrix_id) {
-  if (matrix_id < 0 || matrix_id > static_cast<int>(MatrixID::LAST))
-    return MatrixID::UNKNOWN;
-  if (matrix_id > static_cast<int>(MatrixID::LAST_STANDARD_VALUE) &&
-      matrix_id < 1000)
-    return MatrixID::UNKNOWN;
-  return static_cast<MatrixID>(matrix_id);
+void ColorSpace::GetVideoParameters(int* video_primary,
+                                    int* video_transfer,
+                                    int* video_matrix,
+                                    bool* full_range) {
+  int first_primary = static_cast<int>(PrimaryID::FIRST_VIDEO_VALUE);
+  int last_primary = static_cast<int>(PrimaryID::LAST_VIDEO_VALUE);
+  *video_primary = static_cast<int>(primaries_) - first_primary;
+  if (*video_primary < 0 || *video_primary > last_primary - first_primary) {
+    *video_primary = static_cast<int>(PrimaryID::BT709) - first_primary;
+  }
+
+  int first_transfer = static_cast<int>(TransferID::FIRST_VIDEO_VALUE);
+  int last_transfer = static_cast<int>(TransferID::LAST_VIDEO_VALUE);
+  *video_transfer = static_cast<int>(transfer_) - first_transfer;
+  if (*video_transfer < 0 || *video_transfer > last_transfer - first_transfer) {
+    *video_transfer = static_cast<int>(TransferID::BT709) - first_transfer;
+  }
+
+  int first_matrix = static_cast<int>(MatrixID::FIRST_VIDEO_VALUE);
+  int last_matrix = static_cast<int>(MatrixID::LAST_VIDEO_VALUE);
+  *video_matrix = static_cast<int>(matrix_) - first_matrix;
+  if (*video_matrix < 0 || *video_matrix > last_matrix - first_matrix) {
+    *video_matrix = static_cast<int>(MatrixID::BT709) - first_matrix;
+  }
+
+  switch (range_) {
+    case RangeID::FULL:
+      *full_range = true;
+      break;
+    case RangeID::UNSPECIFIED:
+    case RangeID::LIMITED:
+    case RangeID::DERIVED:
+    case RangeID::INVALID:
+      *full_range = false;
+      break;
+  }
 }
 
 ColorSpace::ColorSpace() {}
@@ -60,12 +106,6 @@ ColorSpace::ColorSpace(PrimaryID primaries,
       matrix_(matrix),
       range_(range) {}
 
-ColorSpace::ColorSpace(int primaries, int transfer, int matrix, RangeID range)
-    : primaries_(PrimaryIDFromInt(primaries)),
-      transfer_(TransferIDFromInt(transfer)),
-      matrix_(MatrixIDFromInt(matrix)),
-      range_(range) {}
-
 ColorSpace::ColorSpace(const ColorSpace& other)
     : primaries_(other.primaries_),
       transfer_(other.transfer_),
@@ -82,11 +122,11 @@ ColorSpace::ColorSpace(const ColorSpace& other)
            sizeof(custom_primary_matrix_));
   }
 }
-
 ColorSpace::~ColorSpace() = default;
 
 bool ColorSpace::IsValid() const {
-  return *this != gfx::ColorSpace();
+  return primaries_ != PrimaryID::INVALID && transfer_ != TransferID::INVALID &&
+         matrix_ != MatrixID::INVALID && range_ != RangeID::INVALID;
 }
 
 // static
@@ -197,10 +237,8 @@ sk_sp<SkColorSpace> ColorSpace::ToSkColorSpace() const {
     return icc_profile_sk_color_space_;
 
   // Unspecified color spaces correspond to the null SkColorSpace.
-  if (primaries_ == PrimaryID::UNSPECIFIED ||
-      transfer_ == TransferID::UNSPECIFIED) {
+  if (!IsValid())
     return nullptr;
-  }
 
   // Handle only full-range RGB spaces.
   if (matrix_ != MatrixID::RGB) {
@@ -249,10 +287,13 @@ void ColorSpace::GetPrimaryMatrix(SkMatrix44* to_XYZD50) const {
       to_XYZD50->set3x3RowMajorf(custom_primary_matrix_);
       return;
 
+    case ColorSpace::PrimaryID::INVALID:
+      to_XYZD50->setIdentity();
+      return;
+
     case ColorSpace::PrimaryID::RESERVED0:
     case ColorSpace::PrimaryID::RESERVED:
     case ColorSpace::PrimaryID::UNSPECIFIED:
-    case ColorSpace::PrimaryID::UNKNOWN:
     case ColorSpace::PrimaryID::BT709:
       // BT709 is our default case. Put it after the switch just
       // in case we somehow get an id which is not listed in the switch.
@@ -417,8 +458,6 @@ bool ColorSpace::GetTransferFunction(SkColorSpaceTransferFn* fn) const {
     case ColorSpace::TransferID::RESERVED0:
     case ColorSpace::TransferID::RESERVED:
     case ColorSpace::TransferID::UNSPECIFIED:
-    case ColorSpace::TransferID::UNKNOWN:
-    // All unknown values default to BT709
     case ColorSpace::TransferID::BT709:
     case ColorSpace::TransferID::SMPTE170M:
     case ColorSpace::TransferID::BT2020_10:
@@ -458,6 +497,7 @@ bool ColorSpace::GetTransferFunction(SkColorSpaceTransferFn* fn) const {
     case ColorSpace::TransferID::LOG_SQRT:
     case ColorSpace::TransferID::SMPTEST2084:
     case ColorSpace::TransferID::SMPTEST2084_NON_HDR:
+    case ColorSpace::TransferID::INVALID:
       break;
   }
 
@@ -476,13 +516,13 @@ void ColorSpace::GetTransferMatrix(SkMatrix44* matrix) const {
   float Kb = 0;
   switch (matrix_) {
     case ColorSpace::MatrixID::RGB:
+    case ColorSpace::MatrixID::INVALID:
       matrix->setIdentity();
       return;
 
     case ColorSpace::MatrixID::BT709:
     case ColorSpace::MatrixID::UNSPECIFIED:
     case ColorSpace::MatrixID::RESERVED:
-    case ColorSpace::MatrixID::UNKNOWN:
       Kr = 0.2126f;
       Kb = 0.0722f;
       break;
@@ -563,6 +603,7 @@ void ColorSpace::GetRangeAdjustMatrix(SkMatrix44* matrix) const {
   switch (range_) {
     case RangeID::FULL:
     case RangeID::UNSPECIFIED:
+    case RangeID::INVALID:
       matrix->setIdentity();
       return;
 
@@ -572,6 +613,7 @@ void ColorSpace::GetRangeAdjustMatrix(SkMatrix44* matrix) const {
   }
   switch (matrix_) {
     case MatrixID::RGB:
+    case MatrixID::INVALID:
     case MatrixID::YCOCG:
       matrix->setScale(255.0f/219.0f, 255.0f/219.0f, 255.0f/219.0f);
       matrix->postTranslate(-16.0f/219.0f, -16.0f/219.0f, -16.0f/219.0f);
@@ -587,7 +629,6 @@ void ColorSpace::GetRangeAdjustMatrix(SkMatrix44* matrix) const {
     case MatrixID::BT2020_NCL:
     case MatrixID::BT2020_CL:
     case MatrixID::YDZDX:
-    case MatrixID::UNKNOWN:
       matrix->setScale(255.0f/219.0f, 255.0f/224.0f, 255.0f/224.0f);
       matrix->postTranslate(-16.0f/219.0f, -15.5f/224.0f, -15.5f/224.0f);
       break;