int LayoutScrollbar::minimumThumbLength() const
{
LayoutScrollbarPart* partLayoutObject = m_parts.get(ThumbPart);
if (!partLayoutObject)
return 0;
partLayoutObject->layout();
return orientation() == HorizontalScrollbar ? partLayoutObject->size().width() : partLayoutObject->size().height();
}
void LayoutScrollbar::updateScrollbarParts(bool destroy) {
updateScrollbarPart(ScrollbarBGPart, destroy);
updateScrollbarPart(BackButtonStartPart, destroy);
updateScrollbarPart(ForwardButtonStartPart, destroy);
updateScrollbarPart(BackTrackPart, destroy);
updateScrollbarPart(ThumbPart, destroy);
updateScrollbarPart(ForwardTrackPart, destroy);
updateScrollbarPart(BackButtonEndPart, destroy);
updateScrollbarPart(ForwardButtonEndPart, destroy);
updateScrollbarPart(TrackBGPart, destroy);
if (destroy)
return;
// See if the scrollbar's thickness changed. If so, we need to mark our
// owning object as needing a layout.
bool isHorizontal = orientation() == HorizontalScrollbar;
int oldThickness = isHorizontal ? height() : width();
int newThickness = 0;
LayoutScrollbarPart* part = m_parts.get(ScrollbarBGPart);
if (part) {
part->layout();
newThickness =
(isHorizontal ? part->size().height() : part->size().width()).toInt();
}
if (newThickness != oldThickness) {
setFrameRect(
IntRect(location(), IntSize(isHorizontal ? width() : newThickness,
isHorizontal ? newThickness : height())));
if (LayoutBox* box = owningLayoutObjectWithinFrame()) {
if (box->isLayoutBlock())
toLayoutBlock(box)->notifyScrollbarThicknessChanged();
box->setChildNeedsLayout();
if (m_scrollableArea)
m_scrollableArea->setScrollCornerNeedsPaintInvalidation();
}
}
}