Source/WebCore/platform/graphics/transforms/TransformState.cpp

/*
 * 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,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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#include "config.h"
#include "TransformState.h"

#include <wtf/PassOwnPtr.h>

namespace WebCore {

TransformState& TransformState::operator=(const TransformState& other)
{
    m_mapPoint = other.m_mapPoint;
    m_mapQuad = other.m_mapQuad;
    if (m_mapPoint)
        m_lastPlanarPoint = other.m_lastPlanarPoint;
    if (m_mapQuad)
        m_lastPlanarQuad = other.m_lastPlanarQuad;
    m_accumulatingTransform = other.m_accumulatingTransform;
    m_direction = other.m_direction;
    
    m_accumulatedTransform.clear();

    if (other.m_accumulatedTransform)
        m_accumulatedTransform = adoptPtr(new TransformationMatrix(*other.m_accumulatedTransform));
        
    return *this;
}

void TransformState::move(LayoutUnit x, LayoutUnit y, TransformAccumulation accumulate)
{
    if (m_accumulatingTransform && m_accumulatedTransform) {
        // If we're accumulating into an existing transform, apply the translation.
        if (m_direction == ApplyTransformDirection)
            m_accumulatedTransform->translateRight(x, y);
        else
            m_accumulatedTransform->translate(x, y);
        
        // Then flatten if necessary.
        if (accumulate == FlattenTransform)
            flatten();
    } else {
        // Just move the point and, optionally, the quad.
        if (m_direction == UnapplyInverseTransformDirection) {
            x = -x;
            y = -y;
        }
        if (m_mapPoint)
            m_lastPlanarPoint.move(x, y);
        if (m_mapQuad)
            m_lastPlanarQuad.move(x, y);
    }
    m_accumulatingTransform = accumulate == AccumulateTransform;
}

// FIXME: We transform AffineTransform to TransformationMatrix. This is rather inefficient.
void TransformState::applyTransform(const AffineTransform& transformFromContainer, TransformAccumulation accumulate, bool* wasClamped)
{
    applyTransform(transformFromContainer.toTransformationMatrix(), accumulate, wasClamped);
}

void TransformState::applyTransform(const TransformationMatrix& transformFromContainer, TransformAccumulation accumulate, bool* wasClamped)
{
    if (wasClamped)
        *wasClamped = false;

    // If we have an accumulated transform from last time, multiply in this transform
    if (m_accumulatedTransform) {
        if (m_direction == ApplyTransformDirection)
            m_accumulatedTransform = adoptPtr(new TransformationMatrix(transformFromContainer * *m_accumulatedTransform));
        else
            m_accumulatedTransform->multiply(transformFromContainer);
    } else if (accumulate == AccumulateTransform) {
        // Make one if we started to accumulate
        m_accumulatedTransform = adoptPtr(new TransformationMatrix(transformFromContainer));
    }
    
    if (accumulate == FlattenTransform) {
        const TransformationMatrix* finalTransform = m_accumulatedTransform ? m_accumulatedTransform.get() : &transformFromContainer;
        flattenWithTransform(*finalTransform, wasClamped);
    }
    m_accumulatingTransform = accumulate == AccumulateTransform;
}

void TransformState::flatten(bool* wasClamped)
{
    if (wasClamped)
        *wasClamped = false;

    if (!m_accumulatedTransform) {
        m_accumulatingTransform = false;
        return;
    }
    
    flattenWithTransform(*m_accumulatedTransform, wasClamped);
}

FloatPoint TransformState::mappedPoint(bool* wasClamped) const
{
    if (wasClamped)
        *wasClamped = false;

    if (!m_accumulatedTransform)
        return m_lastPlanarPoint;

    if (m_direction == ApplyTransformDirection)
        return m_accumulatedTransform->mapPoint(m_lastPlanarPoint);

    return m_accumulatedTransform->inverse().projectPoint(m_lastPlanarPoint, wasClamped);
}

FloatQuad TransformState::mappedQuad(bool* wasClamped) const
{
    if (wasClamped)
        *wasClamped = false;

    if (!m_accumulatedTransform)
        return m_lastPlanarQuad;

    if (m_direction == ApplyTransformDirection)
        return m_accumulatedTransform->mapQuad(m_lastPlanarQuad);

    return m_accumulatedTransform->inverse().projectQuad(m_lastPlanarQuad, wasClamped);
}

void TransformState::flattenWithTransform(const TransformationMatrix& t, bool* wasClamped)
{
    if (m_direction == ApplyTransformDirection) {
        if (m_mapPoint)
            m_lastPlanarPoint = t.mapPoint(m_lastPlanarPoint);
        if (m_mapQuad)
            m_lastPlanarQuad = t.mapQuad(m_lastPlanarQuad);
    } else {
        TransformationMatrix inverseTransform = t.inverse();
        if (m_mapPoint)
            m_lastPlanarPoint = inverseTransform.projectPoint(m_lastPlanarPoint);
        if (m_mapQuad)
            m_lastPlanarQuad = inverseTransform.projectQuad(m_lastPlanarQuad, wasClamped);
    }

    // We could throw away m_accumulatedTransform if we wanted to here, but that
    // would cause thrash when traversing hierarchies with alternating
    // preserve-3d and flat elements.
    if (m_accumulatedTransform)
        m_accumulatedTransform->makeIdentity();
    m_accumulatingTransform = false;
}

} // namespace WebCore