ui/gfx/geometry/scroll_offset.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_SCROLL_OFFSET_H_
   6 #define UI_GFX_GEOMETRY_SCROLL_OFFSET_H_
   7
   8 #include <iosfwd>
   9 #include <string>
  10
  11 #include "ui/gfx/geometry/safe_integer_conversions.h"
  12 #include "ui/gfx/geometry/vector2d.h"
  13 #include "ui/gfx/gfx_export.h"
  14
  15 namespace gfx {
  16
  17 class GFX_EXPORT ScrollOffset {
  18  public:
  19   ScrollOffset() : x_(0), y_(0) {}
  20   ScrollOffset(double x, double y) : x_(x), y_(y) {}
  21   explicit ScrollOffset(const Vector2dF& v) : x_(v.x()), y_(v.y()) {}
  22   explicit ScrollOffset(const Vector2d& v) : x_(v.x()), y_(v.y()) {}
  23
  24   double x() const { return x_; }
  25   void set_x(double x) { x_ = x; }
  26
  27   double y() const { return y_; }
  28   void set_y(double y) { y_ = y; }
  29
  30   // True if both components are 0.
  31   bool IsZero() const {
  32     return x_ == 0 && y_ == 0;
  33   }
  34
  35   // Add the components of the |other| ScrollOffset to the current ScrollOffset.
  36   void Add(const ScrollOffset& other) {
  37     x_ += other.x_;
  38     y_ += other.y_;
  39   }
  40
  41   // Subtract the components of the |other| ScrollOffset from the current
  42   // ScrollOffset.
  43   void Subtract(const ScrollOffset& other) {
  44     x_ -= other.x_;
  45     y_ -= other.y_;
  46   }
  47
  48   Vector2dF DeltaFrom(const ScrollOffset& v) const {
  49     return Vector2dF(x_ - v.x(), y_ - v.y());
  50   }
  51
  52   void operator+=(const ScrollOffset& other) { Add(other); }
  53   void operator-=(const ScrollOffset& other) { Subtract(other); }
  54
  55   void SetToMin(const ScrollOffset& other) {
  56     x_ = x_ <= other.x_ ? x_ : other.x_;
  57     y_ = y_ <= other.y_ ? y_ : other.y_;
  58   }
  59
  60   void SetToMax(const ScrollOffset& other) {
  61     x_ = x_ >= other.x_ ? x_ : other.x_;
  62     y_ = y_ >= other.y_ ? y_ : other.y_;
  63   }
  64
  65   void Scale(double scale) { Scale(scale, scale); }
  66   void Scale(double x_scale, double y_scale) {
  67     x_ *= x_scale;
  68     y_ *= y_scale;
  69   }
  70
  71   std::string ToString() const;
  72
  73  private:
  74   double x_;
  75   double y_;
  76 };
  77
  78 inline bool operator==(const ScrollOffset& lhs, const ScrollOffset& rhs) {
  79   return lhs.x() == rhs.x() && lhs.y() == rhs.y();
  80 }
  81
  82 inline bool operator!=(const ScrollOffset& lhs, const ScrollOffset& rhs) {
  83   return lhs.x() != rhs.x() || lhs.y() != rhs.y();
  84 }
  85
  86 inline ScrollOffset operator-(const ScrollOffset& v) {
  87   return ScrollOffset(-v.x(), -v.y());
  88 }
  89
  90 inline ScrollOffset operator+(const ScrollOffset& lhs,
  91                               const ScrollOffset& rhs) {
  92   ScrollOffset result = lhs;
  93   result.Add(rhs);
  94   return result;
  95 }
  96
  97 inline ScrollOffset operator-(const ScrollOffset& lhs,
  98                               const ScrollOffset& rhs) {
  99   ScrollOffset result = lhs;
 100   result.Add(-rhs);
 101   return result;
 102 }
 103
 104 inline Vector2d ScrollOffsetToFlooredVector2d(const ScrollOffset& v) {
 105   return Vector2d(ToFlooredInt(v.x()), ToFlooredInt(v.y()));
 106 }
 107
 108 inline Vector2dF ScrollOffsetToVector2dF(const ScrollOffset& v) {
 109   return Vector2dF(v.x(), v.y());
 110 }
 111
 112 inline ScrollOffset ScrollOffsetWithDelta(const ScrollOffset& offset,
 113                                           const Vector2dF& delta) {
 114   return ScrollOffset(offset.x() + delta.x(),
 115                       offset.y() + delta.y());
 116 }
 117
 118 // This is declared here for use in gtest-based unit tests but is defined in
 119 // the gfx_test_support target. Depend on that to use this in your unit test.
 120 // This should not be used in production code - call ToString() instead.
 121 void PrintTo(const ScrollOffset& scroll_offset, ::std::ostream* os);
 122
 123 }  // namespace gfx
 124
 125 #endif  // UI_GFX_GEOMETRY_SCROLL_OFFSET_H_