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// Copyright (c) 2017 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_AXIS_TRANSFORM2D_H_
#define UI_GFX_GEOMETRY_AXIS_TRANSFORM2D_H_
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/vector2d_f.h"
#include "ui/gfx/gfx_export.h"
namespace gfx {
// This class implements the subset of 2D linear transforms that only
// translation and uniform scaling are allowed.
// Internally this is stored as a scalar pre-scale factor, and a vector
// for post-translation. The class constructor and member accessor follows
// the same convention.
class GFX_EXPORT AxisTransform2d {
public:
constexpr AxisTransform2d() = default;
constexpr AxisTransform2d(float scale, const Vector2dF& translation)
: scale_(scale), translation_(translation) {}
bool operator==(const AxisTransform2d& other) const {
return scale_ == other.scale_ && translation_ == other.translation_;
}
bool operator!=(const AxisTransform2d& other) const {
return !(*this == other);
}
void PreScale(float scale) { scale_ *= scale; }
void PostScale(float scale) {
scale_ *= scale;
translation_.Scale(scale);
}
void PreTranslate(const Vector2dF& translation) {
translation_ += ScaleVector2d(translation, scale_);
}
void PostTranslate(const Vector2dF& translation) {
translation_ += translation;
}
void PreConcat(const AxisTransform2d& pre) {
PreTranslate(pre.translation_);
PreScale(pre.scale_);
}
void PostConcat(const AxisTransform2d& post) {
PostScale(post.scale_);
PostTranslate(post.translation_);
}
void Invert() {
DCHECK(scale_);
scale_ = 1.f / scale_;
translation_.Scale(-scale_);
}
PointF MapPoint(const PointF& p) const {
return ScalePoint(p, scale_) + translation_;
}
PointF InverseMapPoint(const PointF& p) const {
return ScalePoint(p - translation_, 1.f / scale_);
}
RectF MapRect(const RectF& r) const {
DCHECK(scale_ >= 0.f);
return ScaleRect(r, scale_) + translation_;
}
RectF InverseMapRect(const RectF& r) const {
DCHECK(scale_ > 0.f);
return ScaleRect(r - translation_, 1.f / scale_);
}
float scale() const { return scale_; }
const Vector2dF& translation() const { return translation_; }
std::string ToString() const;
private:
// Scale is applied before translation, i.e.
// this->Transform(p) == scale_ * p + translation_
float scale_ = 1.f;
Vector2dF translation_;
};
static inline AxisTransform2d PreScaleAxisTransform2d(const AxisTransform2d& t,
float scale) {
AxisTransform2d result(t);
result.PreScale(scale);
return result;
}
static inline AxisTransform2d PostScaleAxisTransform2d(const AxisTransform2d& t,
float scale) {
AxisTransform2d result(t);
result.PostScale(scale);
return result;
}
static inline AxisTransform2d PreTranslateAxisTransform2d(
const AxisTransform2d& t,
const Vector2dF& translation) {
AxisTransform2d result(t);
result.PreTranslate(translation);
return result;
}
static inline AxisTransform2d PostTranslateAxisTransform2d(
const AxisTransform2d& t,
const Vector2dF& translation) {
AxisTransform2d result(t);
result.PostTranslate(translation);
return result;
}
static inline AxisTransform2d ConcatAxisTransform2d(
const AxisTransform2d& post,
const AxisTransform2d& pre) {
AxisTransform2d result(post);
result.PreConcat(pre);
return result;
}
static inline AxisTransform2d InvertAxisTransform2d(const AxisTransform2d& t) {
AxisTransform2d result = t;
result.Invert();
return result;
}
// 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 AxisTransform2d&, ::std::ostream* os);
} // namespace gfx
#endif // UI_GFX_GEOMETRY_AXIS_TRANSFORM2D_H_