fPreviousBounds
fPreviousBounds = Bounds();
BRect fPreviousBounds;
_InvalidateCanvas(currentBounds | fPreviousBounds);
fPreviousBounds = currentBounds;
BRect fPreviousBounds;
&& Bounds().Width() > fPreviousBounds.Width()) {
scroll.x = std::max(fPreviousBounds.Width() - Bounds().Width(),
&& Bounds().Height() > fPreviousBounds.Height()) {
scroll.y = std::max(fPreviousBounds.Height() - Bounds().Height(),
fPreviousBounds = Bounds();
fPreviousBounds = Bounds();
BRect fPreviousBounds;