chromium/ui/gfx/geometry/axis_transform2d.h

// Copyright 2017 The Chromium Authors
// 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 <optional>

#include "base/check_op.h"
#include "ui/gfx/geometry/clamp_float_geometry.h"
#include "ui/gfx/geometry/geometry_export.h"
#include "ui/gfx/geometry/rect_f.h"
#include "ui/gfx/geometry/vector2d_f.h"

namespace gfx {

struct DecomposedTransform;

// This class implements the subset of 2D linear transforms that only
// translation and uniform scaling are allowed.
// Internally this is stored as a vector for pre-scale, and another vector
// for post-translation. The class constructor and member accessor follows
// the same convention, but a scalar scale factor is also accepted.
//
// Results of the *Map* methods are clamped with ClampFloatGeometry().
// See the definition of the function for details.
//
class GEOMETRY_EXPORT AxisTransform2d { … };

inline AxisTransform2d PreScaleAxisTransform2d(const AxisTransform2d& t,
                                               float scale) { … }

inline AxisTransform2d PostScaleAxisTransform2d(const AxisTransform2d& t,
                                                float scale) { … }

inline AxisTransform2d PreTranslateAxisTransform2d(
    const AxisTransform2d& t,
    const Vector2dF& translation) { … }

inline AxisTransform2d PostTranslateAxisTransform2d(
    const AxisTransform2d& t,
    const Vector2dF& translation) { … }

inline AxisTransform2d ConcatAxisTransform2d(const AxisTransform2d& post,
                                             const AxisTransform2d& pre) { … }

inline AxisTransform2d InvertAxisTransform2d(const AxisTransform2d& t) { … }

// 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_