1 files changed, 130 insertions, 0 deletions
diff --git a/wintable/scroll.h b/wintable/scroll.h
new file mode 100644
index 0000000..1f333a8
--- /dev/null
+++ b/wintable/scroll.h
@@ -0,0 +1,130 @@
+// 9 december 2014
+
+struct scrollParams {
+	intptr_t *pos;
+	intptr_t pagesize;
+	intptr_t length;
+	intptr_t scale;
+	void (*post)(struct table *);
+	int *wheelCarry;
+};
+
+static void scrollto(struct table *t, int which, struct scrollParams *p, intptr_t pos)
+{
+	RECT scrollArea;
+	SCROLLINFO si;
+	intptr_t xamount, yamount;
+
+	if (pos < 0)
+		pos = 0;
+	if (pos > p->length - p->pagesize)
+		pos = p->length - p->pagesize;
+
+	// we don't want to scroll the header
+	if (GetClientRect(t->hwnd, &scrollArea) == 0)
+		panic("error getting Table client rect for scrollto()");
+	scrollArea.top += t->headerHeight;
+
+	// negative because ScrollWindowEx() is "backwards"
+	xamount = -(pos - *(p->pos)) * p->scale;
+	yamount = 0;
+	if (which == SB_VERT) {
+		yamount = xamount;
+		xamount = 0;
+	}
+
+	if (ScrollWindowEx(t->hwnd, xamount, yamount,
+		&scrollArea, &scrollArea, NULL, NULL,
+		SW_ERASE | SW_INVALIDATE) == ERROR)
+;// TODO failure case ignored for now; see https://bugs.winehq.org/show_bug.cgi?id=37706
+//		panic("error scrolling Table");
+	// TODO call UpdateWindow()?
+
+	*(p->pos) = pos;
+
+	// now commit our new scrollbar setup...
+	ZeroMemory(&si, sizeof (SCROLLINFO));
+	si.cbSize = sizeof (SCROLLINFO);
+	si.fMask = SIF_PAGE | SIF_POS | SIF_RANGE;
+	si.nPage = p->pagesize;
+	si.nMin = 0;
+	si.nMax = p->length - 1;		// endpoint inclusive
+	si.nPos = *(p->pos);
+	SetScrollInfo(t->hwnd, which, &si, TRUE);
+
+	if (p->post != NULL)
+		(*(p->post))(t);
+}
+
+static void scrollby(struct table *t, int which, struct scrollParams *p, intptr_t delta)
+{
+	scrollto(t, which, p, *(p->pos) + delta);
+}
+
+static void scroll(struct table *t, int which, struct scrollParams *p, WPARAM wParam, LPARAM lParam)
+{
+	intptr_t pos;
+	SCROLLINFO si;
+
+	pos = *(p->pos);
+	switch (LOWORD(wParam)) {
+	case SB_LEFT:			// also SB_TOP
+		pos = 0;
+		break;
+	case SB_RIGHT:		// also SB_BOTTOM
+		pos = p->length - p->pagesize;
+		break;
+	case SB_LINELEFT:		// also SB_LINEUP
+		pos--;
+		break;
+	case SB_LINERIGHT:		// also SB_LINEDOWN
+		pos++;
+		break;
+	case SB_PAGELEFT:		// also SB_PAGEUP
+		pos -= p->pagesize;
+		break;
+	case SB_PAGERIGHT:	// also SB_PAGEDOWN
+		pos += p->pagesize;
+		break;
+	case SB_THUMBPOSITION:
+		ZeroMemory(&si, sizeof (SCROLLINFO));
+		si.cbSize = sizeof (SCROLLINFO);
+		si.fMask = SIF_POS;
+		if (GetScrollInfo(t->hwnd, which, &si) == 0)
+			panic("error getting thumb position for scroll() in Table");
+		pos = si.nPos;
+		break;
+	case SB_THUMBTRACK:
+		ZeroMemory(&si, sizeof (SCROLLINFO));
+		si.cbSize = sizeof (SCROLLINFO);
+		si.fMask = SIF_TRACKPOS;
+		if (GetScrollInfo(t->hwnd, which, &si) == 0)
+			panic("error getting thumb track position for scroll() in Table");
+		pos = si.nTrackPos;
+		break;
+	}
+	scrollto(t, which, p, pos);
+}
+
+static void wheelscroll(struct table *t, int which, struct scrollParams *p, WPARAM wParam, LPARAM lParam)
+{
+	int delta;
+	int lines;
+	UINT scrollAmount;
+
+	delta = GET_WHEEL_DELTA_WPARAM(wParam);
+	// TODO make a note of what the appropriate hscroll constant is
+	if (SystemParametersInfoW(SPI_GETWHEELSCROLLLINES, 0, &scrollAmount, 0) == 0)
+		// TODO use scrollAmount == 3 instead?
+		panic("error getting wheel scroll amount in wheelscroll()");
+	if (scrollAmount == WHEEL_PAGESCROLL)
+		scrollAmount = p->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 += *(p->wheelCarry);
+	lines = delta * ((int) scrollAmount) / WHEEL_DELTA;
+	*(p->wheelCarry) = delta - lines * WHEEL_DELTA / ((int) scrollAmount);
+	scrollby(t, which, p, -lines);
+}