/*
* 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/rendering/RenderVTTCue.h"
#include "core/html/track/vtt/VTTCue.h"
#include "core/rendering/LayoutRectRecorder.h"
#include "core/rendering/RenderView.h"
namespace WebCore {
RenderVTTCue::RenderVTTCue(VTTCueBox* element)
: RenderBlockFlow(element)
, m_cue(element->getCue())
{
}
void RenderVTTCue::layout()
{
LayoutRectRecorder recorder(*this);
RenderBlockFlow::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;
LayoutStateMaintainer statePusher(*this, locationOffset());
if (m_cue->snapToLines())
repositionCueSnapToLinesSet();
else
repositionCueSnapToLinesNotSet();
}
bool RenderVTTCue::findFirstLineBox(InlineFlowBox*& firstLineBox)
{
if (firstChild()->isRenderInline())
firstLineBox = toRenderInline(firstChild())->firstLineBox();
else
return false;
return true;
}
bool RenderVTTCue::initializeLayoutParameters(InlineFlowBox* firstLineBox, LayoutUnit& step, LayoutUnit& position)
{
ASSERT(firstChild());
RenderBlock* parentBlock = containingBlock();
// 1. Horizontal: Let step be the height of the first line box in boxes.
// Vertical: Let step be the width of the first line box in boxes.
step = m_cue->getWritingDirection() == VTTCue::Horizontal ? firstLineBox->height() : firstLineBox->width();
// 2. If step is zero, then jump to the step labeled done positioning below.
if (!step)
return false;
// 3. Let line position be the text track cue computed line position.
int linePosition = m_cue->calculateComputedLinePosition();
// 4. Vertical Growing Left: Add one to line position then negate it.
if (m_cue->getWritingDirection() == VTTCue::VerticalGrowingLeft)
linePosition = -(linePosition + 1);
// 5. Let position be the result of multiplying step and line position.
position = step * linePosition;
// 6. Vertical Growing Left: Decrease position by the width of the
// bounding box of the boxes in boxes, then increase position by step.
if (m_cue->getWritingDirection() == VTTCue::VerticalGrowingLeft) {
position -= width();
position += step;
}
// 7. If line position is less than zero...
if (linePosition < 0) {
// Horizontal / Vertical: ... then increase position by the
// height / width of the video's rendering area ...
position += m_cue->getWritingDirection() == VTTCue::Horizontal ? parentBlock->height() : parentBlock->width();
// ... and negate step.
step = -step;
}
return true;
}
void RenderVTTCue::placeBoxInDefaultPosition(LayoutUnit position, bool& switched)
{
// 8. Move all boxes in boxes ...
if (m_cue->getWritingDirection() == VTTCue::Horizontal) {
// Horizontal: ... down by the distance given by position
setY(y() + position);
} else {
// Vertical: ... right by the distance given by position
setX(x() + position);
}
// 9. Default: Remember the position of all the boxes in boxes as their
// default position.
// FIXME: Why the direct conversion between float and LayoutUnit? crbug.com/350474
m_fallbackPosition = FloatPoint(location());
// 10. Let switched be false.
switched = false;
}
bool RenderVTTCue::isOutside() const
{
return !containingBlock()->absoluteBoundingBoxRect().contains(absoluteContentBox());
}
bool RenderVTTCue::isOverlapping() const
{
for (RenderObject* box = previousSibling(); box; box = box->previousSibling()) {
IntRect boxRect = box->absoluteBoundingBoxRect();
if (absoluteBoundingBoxRect().intersects(boxRect))
return true;
}
return false;
}
bool RenderVTTCue::shouldSwitchDirection(InlineFlowBox* firstLineBox, LayoutUnit step) const
{
LayoutUnit top = y();
LayoutUnit left = x();
LayoutUnit bottom = top + firstLineBox->height();
LayoutUnit right = left + firstLineBox->width();
// 12. Horizontal: If step is negative and the top of the first line
// box in boxes is now above the top of the video's rendering area,
// or if step is positive and the bottom of the first line box in
// boxes is now below the bottom of the video's rendering area, jump
// to the step labeled switch direction.
LayoutUnit parentHeight = containingBlock()->height();
if (m_cue->getWritingDirection() == VTTCue::Horizontal && ((step < 0 && top < 0) || (step > 0 && bottom > parentHeight)))
return true;
// 12. Vertical: If step is negative and the left edge of the first line
// box in boxes is now to the left of the left edge of the video's
// rendering area, or if step is positive and the right edge of the
// first line box in boxes is now to the right of the right edge of
// the video's rendering area, jump to the step labeled switch direction.
LayoutUnit parentWidth = containingBlock()->width();
if (m_cue->getWritingDirection() != VTTCue::Horizontal && ((step < 0 && left < 0) || (step > 0 && right > parentWidth)))
return true;
return false;
}
void RenderVTTCue::moveBoxesByStep(LayoutUnit step)
{
// 13. Horizontal: Move all the boxes in boxes down by the distance
// given by step. (If step is negative, then this will actually
// result in an upwards movement of the boxes in absolute terms.)
if (m_cue->getWritingDirection() == VTTCue::Horizontal)
setY(y() + step);
// 13. Vertical: Move all the boxes in boxes right by the distance
// given by step. (If step is negative, then this will actually
// result in a leftwards movement of the boxes in absolute terms.)
else
setX(x() + step);
}
bool RenderVTTCue::switchDirection(bool& switched, LayoutUnit& step)
{
// 15. Switch direction: Move all the boxes in boxes back to their
// default position as determined in the step above labeled default.
setX(m_fallbackPosition.x());
setY(m_fallbackPosition.y());
// 16. If switched is true, jump to the step labeled done
// positioning below.
if (switched)
return false;
// 17. Negate step.
step = -step;
// 18. Set switched to true.
switched = true;
return true;
}
void RenderVTTCue::repositionCueSnapToLinesSet()
{
InlineFlowBox* firstLineBox;
LayoutUnit step;
LayoutUnit position;
if (!findFirstLineBox(firstLineBox))
return;
if (!initializeLayoutParameters(firstLineBox, step, position))
return;
bool switched;
placeBoxInDefaultPosition(position, switched);
// 11. Step loop: If none of the boxes in boxes would overlap any of the boxes
// in output and all the boxes in output are within the video's rendering area
// then jump to the step labeled done positioning.
while (isOutside() || isOverlapping()) {
if (!shouldSwitchDirection(firstLineBox, step)) {
// 13. Move all the boxes in boxes ...
// 14. Jump back to the step labeled step loop.
moveBoxesByStep(step);
} else if (!switchDirection(switched, step)) {
break;
}
// 19. Jump back to the step labeled step loop.
}
// Acommodate extra top and bottom padding, border or margin.
// Note: this is supported only for internal UA styling, not through the cue selector.
if (hasInlineDirectionBordersPaddingOrMargin()) {
IntRect containerRect = containingBlock()->absoluteBoundingBoxRect();
IntRect cueRect = absoluteBoundingBoxRect();
int topOverflow = cueRect.y() - containerRect.y();
int bottomOverflow = containerRect.y() + containerRect.height() - cueRect.y() - cueRect.height();
int adjustment = 0;
if (topOverflow < 0)
adjustment = -topOverflow;
else if (bottomOverflow < 0)
adjustment = bottomOverflow;
if (adjustment)
setY(y() + adjustment);
}
}
void RenderVTTCue::repositionCueSnapToLinesNotSet()
{
// FIXME: Implement overlapping detection when snap-to-lines is not set. http://wkb.ug/84296
}
} // namespace WebCore