ui/gfx/geometry/cubic_bezier.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_GFX_GEOMETRY_CUBIC_BEZIER_H_
   6 #define UI_GFX_GEOMETRY_CUBIC_BEZIER_H_
   7
   8 #include "base/macros.h"
   9 #include "ui/gfx/gfx_export.h"
  10
  11 namespace gfx {
  12
  13 class GFX_EXPORT CubicBezier {
  14  public:
  15   CubicBezier(double x1, double y1, double x2, double y2);
  16   ~CubicBezier();
  17
  18   // Returns an approximation of y at the given x.
  19   double Solve(double x) const;
  20
  21   // Returns an approximation of dy/dx at the given x.
  22   double Slope(double x) const;
  23
  24   // Sets |min| and |max| to the bezier's minimum and maximium y values in the
  25   // interval [0, 1].
  26   void Range(double* min, double* max) const;
  27
  28  private:
  29   void InitGradients();
  30
  31   double x1_;
  32   double y1_;
  33   double x2_;
  34   double y2_;
  35
  36   double start_gradient_;
  37   double end_gradient_;
  38
  39   DISALLOW_ASSIGN(CubicBezier);
  40 };
  41
  42 }  // namespace gfx
  43
  44 #endif  // UI_GFX_GEOMETRY_CUBIC_BEZIER_H_