| /* |
| * 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 "ViewportAnchor.h" |
| |
| #include "core/dom/ContainerNode.h" |
| #include "core/dom/Node.h" |
| #include "core/page/EventHandler.h" |
| #include "core/rendering/HitTestResult.h" |
| |
| using namespace WebCore; |
| |
| namespace WebKit { |
| |
| 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 | HitTestRequest::ConfusingAndOftenMisusedDisallowShadowContent).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 | HitTestRequest::ConfusingAndOftenMisusedDisallowShadowContent).innerNode(); |
| } |
| |
| while (node && node->boundingBox().isEmpty()) |
| node = node->parentNode(); |
| |
| return node; |
| } |
| |
| } // namespace |
| |
| ViewportAnchor::ViewportAnchor(EventHandler* eventHandler) |
| : m_eventHandler(eventHandler) { } |
| |
| void ViewportAnchor::setAnchor(const IntRect& viewRect, const FloatSize& anchorInViewCoords) |
| { |
| m_viewRect = viewRect; |
| m_anchorNode.clear(); |
| m_anchorNodeBounds = LayoutRect(); |
| m_anchorInNodeCoords = FloatSize(); |
| m_anchorInViewCoords = anchorInViewCoords; |
| |
| if (viewRect.isEmpty()) |
| return; |
| |
| // Preserve origins at the absolute screen origin |
| if (viewRect.location() == IntPoint::zero()) |
| return; |
| |
| FloatSize anchorOffset = viewRect.size(); |
| anchorOffset.scale(anchorInViewCoords.width(), anchorInViewCoords.height()); |
| const FloatPoint anchorPoint = FloatPoint(viewRect.location()) + anchorOffset; |
| |
| Node* node = findNonEmptyAnchorNode(flooredIntPoint(anchorPoint), viewRect, m_eventHandler); |
| if (!node) |
| return; |
| |
| m_anchorNode = node; |
| m_anchorNodeBounds = node->boundingBox(); |
| m_anchorInNodeCoords = anchorPoint - m_anchorNodeBounds.location(); |
| m_anchorInNodeCoords.scale(1.f / m_anchorNodeBounds.width(), 1.f / m_anchorNodeBounds.height()); |
| } |
| |
| IntPoint ViewportAnchor::computeOrigin(const IntSize& currentViewSize) const |
| { |
| if (!m_anchorNode || !m_anchorNode->inDocument()) |
| return m_viewRect.location(); |
| |
| const LayoutRect currentNodeBounds = m_anchorNode->boundingBox(); |
| if (m_anchorNodeBounds == currentNodeBounds) |
| return m_viewRect.location(); |
| |
| // Compute the new anchor point relative to the node position |
| FloatSize anchorOffsetFromNode = currentNodeBounds.size(); |
| anchorOffsetFromNode.scale(m_anchorInNodeCoords.width(), m_anchorInNodeCoords.height()); |
| FloatPoint anchorPoint = currentNodeBounds.location() + anchorOffsetFromNode; |
| |
| // Compute the new origin point relative to the new anchor point |
| FloatSize anchorOffsetFromOrigin = currentViewSize; |
| anchorOffsetFromOrigin.scale(m_anchorInViewCoords.width(), m_anchorInViewCoords.height()); |
| return flooredIntPoint(anchorPoint - anchorOffsetFromOrigin); |
| } |
| |
| } // namespace WebKit |