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// Copyright 2014 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.
#ifndef UI_GFX_GEOMETRY_SCROLL_OFFSET_H_
#define UI_GFX_GEOMETRY_SCROLL_OFFSET_H_
#include <iosfwd>
#include <string>
#include "ui/gfx/geometry/safe_integer_conversions.h"
#include "ui/gfx/geometry/vector2d.h"
#include "ui/gfx/gfx_export.h"
namespace gfx {
// TODO(szager): Reconcile terminology with blink. An 'offset' here corresponds
// to a 'position' in blink. In blink, 'offset' means something else. See
// third_party/WebKit/Source/core/layout/README.md for more information.
class GFX_EXPORT ScrollOffset {
public:
ScrollOffset() : x_(0), y_(0) {}
ScrollOffset(float x, float y) : x_(x), y_(y) {}
explicit ScrollOffset(const Vector2dF& v) : x_(v.x()), y_(v.y()) {}
explicit ScrollOffset(const Vector2d& v) : x_(v.x()), y_(v.y()) {}
float x() const { return x_; }
void set_x(float x) { x_ = x; }
float y() const { return y_; }
void set_y(float y) { y_ = y; }
// True if both components are 0.
bool IsZero() const {
return x_ == 0 && y_ == 0;
}
// Add the components of the |other| ScrollOffset to the current ScrollOffset.
void Add(const ScrollOffset& other) {
x_ += other.x_;
y_ += other.y_;
}
// Subtract the components of the |other| ScrollOffset from the current
// ScrollOffset.
void Subtract(const ScrollOffset& other) {
x_ -= other.x_;
y_ -= other.y_;
}
Vector2dF DeltaFrom(const ScrollOffset& v) const {
return Vector2dF(x_ - v.x(), y_ - v.y());
}
void operator+=(const ScrollOffset& other) { Add(other); }
void operator-=(const ScrollOffset& other) { Subtract(other); }
void SetToMin(const ScrollOffset& other) {
x_ = x_ <= other.x_ ? x_ : other.x_;
y_ = y_ <= other.y_ ? y_ : other.y_;
}
void SetToMax(const ScrollOffset& other) {
x_ = x_ >= other.x_ ? x_ : other.x_;
y_ = y_ >= other.y_ ? y_ : other.y_;
}
void Scale(float scale) { Scale(scale, scale); }
void Scale(float x_scale, float y_scale) {
x_ *= x_scale;
y_ *= y_scale;
}
std::string ToString() const;
private:
float x_;
float y_;
};
inline bool operator==(const ScrollOffset& lhs, const ScrollOffset& rhs) {
return lhs.x() == rhs.x() && lhs.y() == rhs.y();
}
inline bool operator!=(const ScrollOffset& lhs, const ScrollOffset& rhs) {
return lhs.x() != rhs.x() || lhs.y() != rhs.y();
}
inline ScrollOffset operator-(const ScrollOffset& v) {
return ScrollOffset(-v.x(), -v.y());
}
inline ScrollOffset operator+(const ScrollOffset& lhs,
const ScrollOffset& rhs) {
ScrollOffset result = lhs;
result.Add(rhs);
return result;
}
inline ScrollOffset operator-(const ScrollOffset& lhs,
const ScrollOffset& rhs) {
ScrollOffset result = lhs;
result.Add(-rhs);
return result;
}
inline Vector2d ScrollOffsetToFlooredVector2d(const ScrollOffset& v) {
return Vector2d(ToFlooredInt(v.x()), ToFlooredInt(v.y()));
}
inline Vector2dF ScrollOffsetToVector2dF(const ScrollOffset& v) {
return Vector2dF(v.x(), v.y());
}
inline ScrollOffset ScrollOffsetWithDelta(const ScrollOffset& offset,
const Vector2dF& delta) {
return ScrollOffset(offset.x() + delta.x(),
offset.y() + delta.y());
}
// This is declared here for use in gtest-based unit tests but is defined in
// the //ui/gfx:test_support target. Depend on that to use this in your unit
// test. This should not be used in production code - call ToString() instead.
void PrintTo(const ScrollOffset& scroll_offset, ::std::ostream* os);
} // namespace gfx
#endif // UI_GFX_GEOMETRY_SCROLL_OFFSET_H_