third_party/WebKit/Source/platform/geometry/TransformState.h

/*
 * Copyright (C) 2011 Apple Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
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 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE COMPUTER, INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE COMPUTER, INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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#ifndef TransformState_h
#define TransformState_h

#include "platform/geometry/FloatPoint.h"
#include "platform/geometry/FloatQuad.h"
#include "platform/geometry/IntSize.h"
#include "platform/geometry/LayoutSize.h"
#include "platform/transforms/AffineTransform.h"
#include "platform/transforms/TransformationMatrix.h"
#include "wtf/Allocator.h"
#include <memory>

namespace blink {

class PLATFORM_EXPORT TransformState {
  STACK_ALLOCATED();

 public:
  enum TransformDirection {
    ApplyTransformDirection,
    UnapplyInverseTransformDirection
  };
  enum TransformAccumulation { FlattenTransform, AccumulateTransform };

  TransformState(TransformDirection mappingDirection,
                 const FloatPoint& p,
                 const FloatQuad& quad)
      : m_lastPlanarPoint(p),
        m_lastPlanarQuad(quad),
        m_accumulatingTransform(false),
        m_forceAccumulatingTransform(false),
        m_mapPoint(true),
        m_mapQuad(true),
        m_direction(mappingDirection) {}

  TransformState(TransformDirection mappingDirection, const FloatPoint& p)
      : m_lastPlanarPoint(p),
        m_accumulatingTransform(false),
        m_forceAccumulatingTransform(false),
        m_mapPoint(true),
        m_mapQuad(false),
        m_direction(mappingDirection) {}

  TransformState(TransformDirection mappingDirection, const FloatQuad& quad)
      : m_lastPlanarQuad(quad),
        m_accumulatingTransform(false),
        m_forceAccumulatingTransform(false),
        m_mapPoint(false),
        m_mapQuad(true),
        m_direction(mappingDirection) {}

  // Accumulate a transform but don't map any points directly.
  TransformState(TransformDirection mappingDirection)
      : m_accumulatedTransform(TransformationMatrix::create()),
        m_accumulatingTransform(true),
        m_forceAccumulatingTransform(true),
        m_mapPoint(false),
        m_mapQuad(false),
        m_direction(mappingDirection) {}

  TransformState(const TransformState& other) { *this = other; }

  TransformState& operator=(const TransformState&);

  void setQuad(const FloatQuad& quad) {
    // FIXME: this assumes that the quad being added is in the coordinate system
    // of the current state.  This breaks if we're simultaneously mapping a
    // point.  https://bugs.webkit.org/show_bug.cgi?id=106680
    ASSERT(!m_mapPoint);
    m_accumulatedOffset = LayoutSize();
    m_lastPlanarQuad = quad;
  }

  void move(LayoutUnit x,
            LayoutUnit y,
            TransformAccumulation accumulate = FlattenTransform) {
    move(LayoutSize(x, y), accumulate);
  }

  void move(const LayoutSize&, TransformAccumulation = FlattenTransform);
  void move(const IntSize& size,
            TransformAccumulation accumulate = FlattenTransform) {
    move(LayoutSize(size), accumulate);
  }
  void applyTransform(const AffineTransform& transformFromContainer,
                      TransformAccumulation = FlattenTransform,
                      bool* wasClamped = 0);
  void applyTransform(const TransformationMatrix& transformFromContainer,
                      TransformAccumulation = FlattenTransform,
                      bool* wasClamped = 0);
  void flatten(bool* wasClamped = 0);

  // Return the coords of the point or quad in the last flattened layer
  FloatPoint lastPlanarPoint() const { return m_lastPlanarPoint; }
  FloatQuad lastPlanarQuad() const { return m_lastPlanarQuad; }

  // Return the point or quad mapped through the current transform
  FloatPoint mappedPoint(bool* wasClamped = 0) const;
  FloatQuad mappedQuad(bool* wasClamped = 0) const;

  // Return the accumulated transform.
  const TransformationMatrix& accumulatedTransform() const;

 private:
  void translateTransform(const LayoutSize&);
  void translateMappedCoordinates(const LayoutSize&);
  void flattenWithTransform(const TransformationMatrix&, bool* wasClamped);
  void applyAccumulatedOffset();

  FloatPoint m_lastPlanarPoint;
  FloatQuad m_lastPlanarQuad;

  // We only allocate the transform if we need to
  std::unique_ptr<TransformationMatrix> m_accumulatedTransform;
  LayoutSize m_accumulatedOffset;
  bool m_accumulatingTransform;
  bool m_forceAccumulatingTransform;
  bool m_mapPoint, m_mapQuad;
  TransformDirection m_direction;
};

}  // namespace blink

#endif  // TransformState_h