Implement <video controls> dodging for text track layout

Source/core/layout/LayoutVTTCue.cpp

 /*
  * Copyright (C) 2012 Victor Carbune (victor@rosedu.org)
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. 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.
  *
  * 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
  * 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 "core/layout/LayoutVTTCue.h"
 
+#include "core/html/shadow/MediaControls.h"
 #include "core/html/track/vtt/VTTCue.h"
 #include "core/layout/LayoutInline.h"
 #include "core/layout/LayoutState.h"
 
 namespace blink {
 
 LayoutVTTCue::LayoutVTTCue(VTTCueBox* element)
     : LayoutBlockFlow(element)
     , m_cue(element->getCue())
 {
 }
 
 class SnapToLinesLayouter {
     STACK_ALLOCATED();
 public:
-    SnapToLinesLayouter(LayoutVTTCue& cueBox, float linePosition)
+    SnapToLinesLayouter(LayoutVTTCue& cueBox, const IntRect& controlsRect, float linePosition)
         : m_cueBox(cueBox)
+        , m_controlsRect(controlsRect)
         , m_linePosition(linePosition)
     {
     }
 
     void layout();
 
 private:
     bool isOutside() const;
     bool isOverlapping() const;
     LayoutUnit computeInitialPositionAdjustment(LayoutUnit&) const;
     bool shouldSwitchDirection(InlineFlowBox*, LayoutUnit) const;
 
     void moveBoxesBy(LayoutUnit distance)
     {
         m_cueBox.setLogicalTop(m_cueBox.logicalTop() + distance);
     }
 
     InlineFlowBox* findFirstLineBox() const;
 
     LayoutPoint m_specifiedPosition;
     LayoutVTTCue& m_cueBox;
+    IntRect m_controlsRect;
     float m_linePosition;
 };
 
 InlineFlowBox* SnapToLinesLayouter::findFirstLineBox() const
 {
     if (!m_cueBox.firstChild()->isLayoutInline())
         return nullptr;
     return toLayoutInline(m_cueBox.firstChild())->firstLineBox();
 }
 
@@ skipping 32 matching lines @@
     return position;
 }
 
 bool SnapToLinesLayouter::isOutside() const
 {
     return !m_cueBox.containingBlock()->absoluteBoundingBoxRect().contains(m_cueBox.absoluteContentBox());
 }
 
 bool SnapToLinesLayouter::isOverlapping() const
 {
+    IntRect cueBoxRect = m_cueBox.absoluteBoundingBoxRect();
     for (LayoutObject* box = m_cueBox.previousSibling(); box; box = box->previousSibling()) {
         IntRect boxRect = box->absoluteBoundingBoxRect();
 
-        if (m_cueBox.absoluteBoundingBoxRect().intersects(boxRect))
+        if (cueBoxRect.intersects(boxRect))
             return true;
     }
 
+    if (cueBoxRect.intersects(m_controlsRect))
+        return true;
+
     return false;
 }
 
 bool SnapToLinesLayouter::shouldSwitchDirection(InlineFlowBox* firstLineBox, LayoutUnit step) const
 {
     // 21. Horizontal: If step is negative and the top of the first line box in
     // boxes is now above the top of the title area, or if step is positive and
     // the bottom of the first line box in boxes is now below the bottom of the
     // title area, jump to the step labeled switch direction.
     // Vertical: If step is negative and the left edge of the first line
@@ skipping 174 matching lines @@
     // longer necessary, since cues having the region parameter set do not have
     // any positioning parameters. Also, in this case, the regions themselves
     // have positioning information.
     if (!m_cue->regionId().isEmpty())
         return;
 
     ASSERT(firstChild());
 
     LayoutState state(*this, locationOffset());
 
+    // Determine the area covered by the media controls, if any. If the controls
+    // are present, they are the next sibling of the text track container, which
+    // is our parent. (LayoutMedia ensures that the media controls are laid out
+    // before text tracks, so that the layout is up-to-date here.)
+    ASSERT(parent()->node()->isTextTrackContainer());
+    IntRect controlsRect;
+    if (LayoutObject* parentSibling = parent()->nextSibling()) {
+        // Only a part of the media controls is used for overlap avoidance.
+        MediaControls* controls = toMediaControls(parentSibling->node());
+        if (LayoutObject* controlsLayout = controls->layoutObjectForTextTrackLayout())
+            controlsRect = controlsLayout->absoluteBoundingBoxRect();
+    }
+
     // http://dev.w3.org/html5/webvtt/#dfn-apply-webvtt-cue-settings - step 13.
     if (m_cue->snapToLines()) {
-        SnapToLinesLayouter(*this, m_cue->calculateComputedLinePosition()).layout();
+        SnapToLinesLayouter(*this, controlsRect, m_cue->calculateComputedLinePosition()).layout();
 
         adjustForTopAndBottomMarginBorderAndPadding();
     } else {
         repositionCueSnapToLinesNotSet();
     }
 }
 
 } // namespace blink
-