NS_IMETHODIMP
nsListBoxBodyFrame::PositionChanged(nsScrollbarFrame* aScrollbar, PRInt32 aOldIndex, PRInt32& aNewIndex)
{
if (mScrolling || mRowHeight == 0)
return NS_OK;
nscoord oldTwipIndex, newTwipIndex;
oldTwipIndex = mCurrentIndex*mRowHeight;
newTwipIndex = nsPresContext::CSSPixelsToAppUnits(aNewIndex);
PRInt32 twipDelta = newTwipIndex > oldTwipIndex ? newTwipIndex - oldTwipIndex : oldTwipIndex - newTwipIndex;
PRInt32 rowDelta = twipDelta / mRowHeight;
PRInt32 remainder = twipDelta % mRowHeight;
if (remainder > (mRowHeight/2))
rowDelta++;
if (rowDelta == 0)
return NS_OK;
// update the position to be row based.
PRInt32 newIndex = newTwipIndex > oldTwipIndex ? mCurrentIndex + rowDelta : mCurrentIndex - rowDelta;
//aNewIndex = newIndex*mRowHeight/mOnePixel;
nsListScrollSmoother* smoother = GetSmoother();
// if we can't scroll the rows in time then start a timer. We will eat
// events until the user stops moving and the timer stops.
if (smoother->IsRunning() || rowDelta*mTimePerRow > USER_TIME_THRESHOLD) {
smoother->Stop();
smoother->mDelta = newTwipIndex > oldTwipIndex ? rowDelta : -rowDelta;
smoother->Start();
return NS_OK;
}
smoother->Stop();
mCurrentIndex = newIndex;
smoother->mDelta = 0;
if (mCurrentIndex < 0) {
mCurrentIndex = 0;
return NS_OK;
}
return InternalPositionChanged(newTwipIndex < oldTwipIndex, rowDelta);
}
NS_IMETHODIMP
nsListBoxBodyFrame::VisibilityChanged(nsISupports* aScrollbar, PRBool aVisible)
{
PRInt32 lastPageTopRow = GetRowCount() - (GetAvailableHeight() / mRowHeight);
if (lastPageTopRow < 0)
lastPageTopRow = 0;
PRInt32 delta = mCurrentIndex - lastPageTopRow;
if (delta > 0) {
mCurrentIndex = lastPageTopRow;
InternalPositionChanged(PR_TRUE, delta);
}
return NS_OK;
}
NS_IMETHODIMP
nsListBoxBodyFrame::ScrollbarButtonPressed(nsScrollbarFrame* aScrollbar, PRInt32 aOldIndex, PRInt32 aNewIndex)
{
if (aOldIndex == aNewIndex)
return NS_OK;
if (aNewIndex < aOldIndex)
mCurrentIndex--;
else mCurrentIndex++;
if (mCurrentIndex < 0) {
mCurrentIndex = 0;
return NS_OK;
}
InternalPositionChanged(aNewIndex < aOldIndex, 1);
return NS_OK;
}
NS_IMETHODIMP
nsListBoxBodyFrame::VisibilityChanged(bool aVisible)
{
if (mRowHeight == 0)
return NS_OK;
PRInt32 lastPageTopRow = GetRowCount() - (GetAvailableHeight() / mRowHeight);
if (lastPageTopRow < 0)
lastPageTopRow = 0;
PRInt32 delta = mCurrentIndex - lastPageTopRow;
if (delta > 0) {
mCurrentIndex = lastPageTopRow;
InternalPositionChanged(true, delta);
}
return NS_OK;
}