void LayoutVTTCue::layout()
{
LayoutBlockFlow::layout();
// If WebVTT Regions are used, the regular WebVTT layout algorithm is no
// 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, controlsRect, m_cue->calculateComputedLinePosition()).layout();
adjustForTopAndBottomMarginBorderAndPadding();
} else {
repositionCueSnapToLinesNotSet();
}
}
IntRect LayoutVTTCue::computeControlsRect() const {
// 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.)
DCHECK(parent()->node()->isTextTrackContainer());
LayoutObject* controlsContainer = parent()->nextSibling();
if (!controlsContainer)
return IntRect();
// Only a part of the media controls is used for overlap avoidance.
MediaControls* controls = toMediaControls(controlsContainer->node());
LayoutObject* controlsLayout = controls->layoutObjectForTextTrackLayout();
// The (second part of the) following is mostly defensive - in general
// there should be a LayoutBox representing the part of the controls that
// are relevant for overlap avoidance. (The controls pseudo elements are
// generally reachable from outside the shadow tree though, hence the
// "mostly".)
if (!controlsLayout || !controlsLayout->isBox())
return IntRect();
// Assume that the controls container are positioned in the same relative
// position as the text track container. (LayoutMedia::layout ensures this.)
return contentBoxRelativeToAncestor(toLayoutBox(*controlsLayout),
toLayoutBox(*controlsContainer));
}