NS_IMETHODIMP
nsListBoxBodyFrame::ScrollToIndex(PRInt32 aRowIndex)
{
if (( aRowIndex < 0 ) || (mRowHeight == 0))
return NS_OK;
PRInt32 newIndex = aRowIndex;
PRInt32 delta = mCurrentIndex > newIndex ? mCurrentIndex - newIndex : newIndex - mCurrentIndex;
PRBool up = newIndex < mCurrentIndex;
// Check to be sure we're not scrolling off the bottom of the tree
PRInt32 lastPageTopRow = GetRowCount() - (GetAvailableHeight() / mRowHeight);
if (lastPageTopRow < 0)
lastPageTopRow = 0;
if (aRowIndex > lastPageTopRow)
return NS_OK;
mCurrentIndex = newIndex;
// Since we're going to flush anyway, we need to not do this off an event
DoInternalPositionChangedSync(up, delta);
// This change has to happen immediately.
// Flush any pending reflow commands.
// XXXbz why, exactly?
mContent->GetDocument()->FlushPendingNotifications(Flush_Layout);
return NS_OK;
}
nsresult
nsListBoxBodyFrame::InternalPositionChangedCallback()
{
nsListScrollSmoother* smoother = GetSmoother();
if (smoother->mDelta == 0)
return NS_OK;
mCurrentIndex += smoother->mDelta;
if (mCurrentIndex < 0)
mCurrentIndex = 0;
return DoInternalPositionChangedSync(smoother->mDelta < 0,
smoother->mDelta < 0 ?
-smoother->mDelta : smoother->mDelta);
}
nsresult
nsListBoxBodyFrame::EnsureIndexIsVisible(PRInt32 aRowIndex)
{
if (aRowIndex < 0)
return NS_ERROR_ILLEGAL_VALUE;
PRInt32 rows = 0;
if (mRowHeight)
rows = GetAvailableHeight()/mRowHeight;
if (rows <= 0)
rows = 1;
PRInt32 bottomIndex = mCurrentIndex + rows;
// if row is visible, ignore
if (mCurrentIndex <= aRowIndex && aRowIndex < bottomIndex)
return NS_OK;
PRInt32 delta;
bool up = aRowIndex < mCurrentIndex;
if (up) {
delta = mCurrentIndex - aRowIndex;
mCurrentIndex = aRowIndex;
}
else {
// Check to be sure we're not scrolling off the bottom of the tree
if (aRowIndex >= GetRowCount())
return NS_ERROR_ILLEGAL_VALUE;
// Bring it just into view.
delta = 1 + (aRowIndex-bottomIndex);
mCurrentIndex += delta;
}
// Safe to not go off an event here, since this is coming from the
// box object.
DoInternalPositionChangedSync(up, delta);
return NS_OK;
}
