Implementation of principal-component color reduction.

ui/gfx/vector3d_f.h

 // Copyright (c) 2012 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.
 
 // Defines a simple float vector class.  This class is used to indicate a
 // distance in two dimensions between two points. Subtracting two points should
 // produce a vector, and adding a vector to a point produces the point at the
 // vector's distance from the original point.
 
 #ifndef UI_GFX_VECTOR3D_F_H_
@@ skipping 86 matching lines @@
   return result;
 }
 
 // Return the cross product of two vectors.
 inline Vector3dF CrossProduct(const Vector3dF& lhs, const Vector3dF& rhs) {
   Vector3dF result = lhs;
   result.Cross(rhs);
   return result;
 }
 
+// Return the dot product of two vectors with the second given as xyz.
+UI_EXPORT float DotProduct(const Vector3dF& lhs, float x, float y, float z);
+
 // Return the dot product of two vectors.
-UI_EXPORT float DotProduct(const Vector3dF& lhs, const Vector3dF& rhs);
+inline float DotProduct(const Vector3dF& lhs, const Vector3dF& rhs) {
+  return DotProduct(lhs, rhs.x(), rhs.y(), rhs.z());
+}
+
 
 // Return a vector that is |v| scaled by the given scale factors along each
 // axis.
 UI_EXPORT Vector3dF ScaleVector3d(const Vector3dF& v,
                                   float x_scale,
                                   float y_scale,
                                   float z_scale);
 
 // Return a vector that is |v| scaled by the given scale factor.
 inline Vector3dF ScaleVector3d(const Vector3dF& v, float scale) {
   return ScaleVector3d(v, scale, scale, scale);
 }
 
 }  // namespace gfx
 
 #endif // UI_GFX_VECTOR3D_F_H_