Started readding hscroll code; just recomputeHScroll() for now.

wintable/new/api.h

@@ -9,6 +9,7 @@ static void addColumn(struct table *t, WPARAM wParam, LPARAM lParam)
 	if (t->columnTypes[t->nColumns - 1] >= nTableColumnTypes)
 		panic("invalid column type passed to tableAddColumn");
 	headerAddColumn(t, (WCHAR *) lParam);
+	recomputeHScroll(t);
 }
 
 HANDLER(apiHandlers)

wintable/new/header.h

@@ -61,6 +61,8 @@ HANDLER(headerNotifyHandler)
 		return FALSE;
 	if (nmhdr->code != HDN_ITEMCHANGED)
 		return FALSE;
+	// TODO should this be last?
+	recomputeHScroll(t);
 	// TODO make more intelligent
 	InvalidateRect(t->hwnd, NULL, TRUE);
 	// TODO UpdateWindow()?

wintable/new/hscroll.h

@@ -0,0 +1,44 @@
+// 9 december 2014
+
+static void hscrollto(struct table *t, intptr_t pos)
+{
+	// TODO
+}
+
+static void hscrollby(struct table *t, intptr_t delta)
+{
+	// TODO
+}
+
+static void hscroll(struct table *t, WPARAM wParam, LPARAM lParam)
+{
+	// TODO
+}
+
+static void recomputeHScroll(struct table *t)
+{
+	SCROLLINFO si;
+	HDITEMW item;
+	intptr_t i, width;
+	RECT r;
+
+	width = 0;
+	// TODO count dividers?
+	for (i = 0; i < t->nColumns; i++) {
+		ZeroMemory(&item, sizeof (HDITEMW));
+		item.mask = HDI_WIDTH;
+		if (SendMessageW(t->header, HDM_GETITEM, (WPARAM) i, (LPARAM) (&item)) == FALSE)
+			panic("error getting Table column width for recomputeHScroll()");
+		width += item.cxy;
+	}
+	if (GetClientRect(t->hwnd, &r) == 0)
+		panic("error getting Table client rect for recomputeHScroll()");
+	ZeroMemory(&si, sizeof (SCROLLINFO));
+	si.cbSize = sizeof (SCROLLINFO);
+	si.fMask = SIF_PAGE | SIF_RANGE;
+	si.nPage = r.right - r.left;
+	si.nMin = 0;
+	si.nMax = width - 1;		// endpoint inclusive
+	SetScrollInfo(t->hwnd, SB_HORZ, &si, TRUE);
+	// TODO what happens if the above call renders the current scroll position moot?
+}

wintable/new/main.c

@@ -57,6 +57,7 @@ struct table {
 #include "util.h"
 #include "coord.h"
 #include "events.h"
+#include "hscroll.h"
 #include "header.h"
 #include "children.h"
 #include "resize.h"

wintable/new/resize.h

@@ -14,6 +14,7 @@ HANDLER(resizeHandler)
 	if ((wp->flags & SWP_NOSIZE) != 0)
 		return FALSE;
 	repositionHeader(t);
+	recomputeHScroll(t);
 	*lResult = 0;
 	return TRUE;
 }