/// <inheritdoc/>
public override void Update()
{
int numVisibleEntries = MathEx.CeilToInt(height / (float)entryHeight) + 1;
numVisibleEntries = MathEx.Min(numVisibleEntries, entries.Count);
while (visibleEntries.Count < numVisibleEntries)
{
TEntry newEntry = new TEntry();
newEntry.Initialize(this);
newEntry.panel.SetHeight(entryHeight);
visibleEntries.Add(newEntry);
contentsDirty = true;
}
while (numVisibleEntries < visibleEntries.Count)
{
int lastIdx = visibleEntries.Count - 1;
visibleEntries[lastIdx].Destroy();
visibleEntries.RemoveAt(lastIdx);
contentsDirty = true;
}
if (scrollPct != scrollArea.VerticalScroll)
{
scrollPct = scrollArea.VerticalScroll;
contentsDirty = true;
}
if (contentsDirty)
{
int newHeight = entries.Count * entryHeight;
if (scrollToLatest)
{
if (totalHeight > height && scrollPct < 1.0f)
{
scrollToLatest = false;
}
}
else
{
if (totalHeight <= height || scrollPct >= 1.0f)
{
scrollToLatest = true;
}
}
totalHeight = newHeight;
int maxScrollOffset = MathEx.Max(0, totalHeight - height - 1);
float newScrollPct;
if (!scrollToLatest)
{
// Calculate the new scroll pct (which will be active after we change the top/bottom padding element
// sizes). If we use the existing scroll pct instead then the elements will lag one frame behind, which
// can be very noticeable on quickly updating lists.
newScrollPct = (scrollPct * scrollArea.Layout.Bounds.height) / totalHeight;
}
else
{
newScrollPct = 1.0f;
}
int startPos = MathEx.FloorToInt(newScrollPct * maxScrollOffset);
int startIndex = MathEx.FloorToInt(startPos / (float)entryHeight);
// Check if we're at the list bottom and the extra element is out of bounds
if ((startIndex + visibleEntries.Count) > entries.Count)
{
startIndex--; // Keep the extra element at the top always
}
topPadding.SetHeight(startIndex * entryHeight);
for (int i = 0; i < visibleEntries.Count; i++)
{
visibleEntries[i].UpdateContents(startIndex + i, entries[startIndex + i]);
}
int bottomPosition = MathEx.Min(totalHeight, (startIndex + visibleEntries.Count) * entryHeight);
bottomPadding.SetHeight(totalHeight - bottomPosition);
if (scrollToLatest)
{
if (newHeight <= height)
{
scrollArea.VerticalScroll = 0.0f;
}
else
{
scrollArea.VerticalScroll = 1.0f;
}
}
contentsDirty = false;
}
}
