static void wheelscroll(struct table *t, WPARAM wParam)
{
int delta;
int lines;
UINT scrollAmount;
delta = GET_WHEEL_DELTA_WPARAM(wParam);
if (SystemParametersInfoW(SPI_GETWHEELSCROLLLINES, 0, &scrollAmount, 0) == 0)
abort();
if (scrollAmount == WHEEL_PAGESCROLL)
scrollAmount = t->pagesize;
if (scrollAmount == 0) // no mouse wheel scrolling (or t->pagesize == 0)
return;
// the rest of this is basically http://blogs.msdn.com/b/oldnewthing/archive/2003/08/07/54615.aspx and http://blogs.msdn.com/b/oldnewthing/archive/2003/08/11/54624.aspx
// see those pages for information on subtleties
delta += t->wheelCarry;
lines = delta * ((int) scrollAmount) / WHEEL_DELTA;
t->wheelCarry = delta - lines * WHEEL_DELTA / ((int) scrollAmount);
vscrollby(t, -lines);
}
void areaUpdateScroll(uiArea *a)
{
// use a no-op scroll to simulate scrolling
hscrollby(a, 0);
vscrollby(a, 0);
}
