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/*
* Copyright (C) 2013 Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met:
*
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above
* copyright notice, this list of conditions and the following disclaimer
* in the documentation and/or other materials provided with the
* distribution.
* * Neither the name of Google Inc. nor the names of its
* contributors may be used to endorse or promote products derived from
* this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "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 THE COPYRIGHT
* OWNER 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 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "web/ViewportAnchor.h"
#include "core/dom/ContainerNode.h"
#include "core/dom/Node.h"
#include "core/frame/FrameView.h"
#include "core/page/EventHandler.h"
#include "core/rendering/HitTestResult.h"
namespace blink {
namespace {
static const float viewportAnchorRelativeEpsilon = 0.1f;
static const int viewportToNodeMaxRelativeArea = 2;
template <typename RectType>
int area(const RectType& rect) {
return rect.width() * rect.height();
}
Node* findNonEmptyAnchorNode(const IntPoint& point, const IntRect& viewRect, EventHandler* eventHandler)
{
Node* node = eventHandler->hitTestResultAtPoint(point, HitTestRequest::ReadOnly | HitTestRequest::Active).innerNode();
// If the node bounding box is sufficiently large, make a single attempt to
// find a smaller node; the larger the node bounds, the greater the
// variability under resize.
const int maxNodeArea = area(viewRect) * viewportToNodeMaxRelativeArea;
if (node && area(node->boundingBox()) > maxNodeArea) {
IntSize pointOffset = viewRect.size();
pointOffset.scale(viewportAnchorRelativeEpsilon);
node = eventHandler->hitTestResultAtPoint(point + pointOffset, HitTestRequest::ReadOnly | HitTestRequest::Active).innerNode();
}
while (node && node->boundingBox().isEmpty())
node = node->parentNode();
return node;
}
void moveToEncloseRect(IntRect& outer, const FloatRect& inner)
{
IntPoint minimumPosition = ceiledIntPoint(inner.location() + inner.size() - FloatSize(outer.size()));
IntPoint maximumPosition = flooredIntPoint(inner.location());
IntPoint outerOrigin = outer.location();
outerOrigin = outerOrigin.expandedTo(minimumPosition);
outerOrigin = outerOrigin.shrunkTo(maximumPosition);
outer.setLocation(outerOrigin);
}
void moveIntoRect(FloatRect& inner, const IntRect& outer)
{
FloatPoint minimumPosition = FloatPoint(outer.location());
FloatPoint maximumPosition = minimumPosition + outer.size() - inner.size();
// Adjust maximumPosition to the nearest lower integer because
// PinchViewport::maximumScrollPosition() does the same.
// The value of minumumPosition is already adjusted since it is
// constructed from an integer point.
maximumPosition = flooredIntPoint(maximumPosition);
FloatPoint innerOrigin = inner.location();
innerOrigin = innerOrigin.expandedTo(minimumPosition);
innerOrigin = innerOrigin.shrunkTo(maximumPosition);
inner.setLocation(innerOrigin);
}
} // namespace
ViewportAnchor::ViewportAnchor(EventHandler* eventHandler)
: m_eventHandler(eventHandler) { }
void ViewportAnchor::setAnchor(const IntRect& outerViewRect, const IntRect& innerViewRect,
const FloatSize& anchorInInnerViewCoords)
{
// Preserve the inner viewport position in document in case we won't find the anchor
m_pinchViewportInDocument = innerViewRect.location();
m_anchorNode.clear();
m_anchorNodeBounds = LayoutRect();
m_anchorInNodeCoords = FloatSize();
m_anchorInInnerViewCoords = anchorInInnerViewCoords;
m_normalizedPinchViewportOffset = FloatSize();
if (innerViewRect.isEmpty())
return;
// Preserve origins at the absolute screen origin
if (innerViewRect.location() == IntPoint::zero())
return;
// Inner rectangle should be within the outer one.
ASSERT(outerViewRect.contains(innerViewRect));
// Outer rectangle is used as a scale, we need positive width and height.
ASSERT(!outerViewRect.isEmpty());
m_normalizedPinchViewportOffset = innerViewRect.location() - outerViewRect.location();
// Normalize by the size of the outer rect
m_normalizedPinchViewportOffset.scale(1.0 / outerViewRect.width(), 1.0 / outerViewRect.height());
FloatSize anchorOffset = innerViewRect.size();
anchorOffset.scale(anchorInInnerViewCoords.width(), anchorInInnerViewCoords.height());
const FloatPoint anchorPoint = FloatPoint(innerViewRect.location()) + anchorOffset;
Node* node = findNonEmptyAnchorNode(flooredIntPoint(anchorPoint), innerViewRect, m_eventHandler);
if (!node)
return;
m_anchorNode = node;
m_anchorNodeBounds = node->boundingBox();
m_anchorInNodeCoords = anchorPoint - FloatPoint(m_anchorNodeBounds.location());
m_anchorInNodeCoords.scale(1.f / m_anchorNodeBounds.width(), 1.f / m_anchorNodeBounds.height());
}
void ViewportAnchor::computeOrigins(const FrameView& frameView, const FloatSize& innerSize,
IntPoint& mainFrameOffset, FloatPoint& pinchViewportOffset) const
{
IntSize outerSize = frameView.visibleContentRect().size();
// Compute the viewport origins in CSS pixels relative to the document.
FloatSize absPinchViewportOffset = m_normalizedPinchViewportOffset;
absPinchViewportOffset.scale(outerSize.width(), outerSize.height());
FloatPoint innerOrigin = getInnerOrigin(innerSize);
FloatPoint outerOrigin = innerOrigin - absPinchViewportOffset;
IntRect outerRect = IntRect(flooredIntPoint(outerOrigin), outerSize);
FloatRect innerRect = FloatRect(innerOrigin, innerSize);
moveToEncloseRect(outerRect, innerRect);
outerRect.setLocation(frameView.adjustScrollPositionWithinRange(outerRect.location()));
moveIntoRect(innerRect, outerRect);
mainFrameOffset = outerRect.location();
pinchViewportOffset = FloatPoint(innerRect.location() - outerRect.location());
}
FloatPoint ViewportAnchor::getInnerOrigin(const FloatSize& innerSize) const
{
if (!m_anchorNode || !m_anchorNode->inDocument())
return m_pinchViewportInDocument;
const LayoutRect currentNodeBounds = m_anchorNode->boundingBox();
if (m_anchorNodeBounds == currentNodeBounds)
return m_pinchViewportInDocument;
// Compute the new anchor point relative to the node position
FloatSize anchorOffsetFromNode(currentNodeBounds.size());
anchorOffsetFromNode.scale(m_anchorInNodeCoords.width(), m_anchorInNodeCoords.height());
FloatPoint anchorPoint = FloatPoint(currentNodeBounds.location()) + anchorOffsetFromNode;
// Compute the new origin point relative to the new anchor point
FloatSize anchorOffsetFromOrigin = innerSize;
anchorOffsetFromOrigin.scale(m_anchorInInnerViewCoords.width(), m_anchorInInnerViewCoords.height());
return anchorPoint - anchorOffsetFromOrigin;
}
} // namespace blink
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