Collected all of the metric updating stuff into a single update() function. Far from optimal, but much better.

wintable/api.h

@@ -9,7 +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);
-	updateTableWidth(t);
+	update(t, TRUE);
 }
 
 HANDLER(apiHandlers)
@@ -21,8 +21,11 @@ HANDLER(apiHandlers)
 		// don't free the old font; see http://blogs.msdn.com/b/oldnewthing/archive/2008/09/12/8945692.aspx
 		t->font = (HFONT) wParam;
 		SendMessageW(t->header, WM_SETFONT, wParam, lParam);
-		// TODO how to properly handle LOWORD(lParam) != FALSE?
+		update(t, LOWORD(lParam) != FALSE);
-		// TODO depending on the result of the above, update table width to refresh t->headerHeight?
+		// TODO is this needed?
+		if (LOWORD(lParam) != FALSE)
+			// TODO check error
+			InvalidateRect(t->hwnd, NULL, TRUE);
 		*lResult = 0;
 		return TRUE;
 	case WM_GETFONT:
@@ -35,8 +38,8 @@ HANDLER(apiHandlers)
 	case tableSetRowCount:
 		rcp = (intptr_t *) lParam;
 		t->count = *rcp;
-		// TODO refresh table in this way?
+		// TODO shouldn't we just redraw everything?
-		updateTableWidth(t);
+		update(t, TRUE);
 		*lResult = 0;
 		return TRUE;
 	}

wintable/header.h

@@ -22,6 +22,9 @@ static void destroyHeader(struct table *t)
 		panic("error destroying Table header");
 }
 
+// to avoid weird bugs, the only functions allowed to call this one are the horizontal scroll functions
+// when we need to reposition the header in a situation other than a user-initiated scroll, we use a dummy scroll (hscrollby(t, 0))
+// see update() in update.h
 static void repositionHeader(struct table *t)
 {
 	RECT r;
@@ -58,40 +61,6 @@ static void headerAddColumn(struct table *t, WCHAR *name)
 		panic("error adding column to Table header");
 }
 
-// TODO make a better name for this?
-// TODO move to hscroll.h?
-// TODO organize this in general...
-// TODO because of this function's new extended functionality only hscrollto() is allowed to call repositionHeader()
-static void updateTableWidth(struct table *t)
-{
-	HDITEMW item;
-	intptr_t i;
-	RECT client;
-
-	t->width = 0;
-	// TODO count dividers?
-	// TODO use columnWidth()
-	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 updateTableWidth()");
-		t->width += item.cxy;
-	}
-
-	if (GetClientRect(t->hwnd, &client) == 0)
-		panic("error getting Table client rect in updateTableWidth()");
-	t->hpagesize = client.right - client.left;
-
-	// this part is critical: if we resize the columns to less than the client area width, then the following hscrollby() will make t->hscrollpos negative, which does very bad things
-	// note to self: do this regardless of whether the table width or the client area width was changed
-	if (t->hpagesize > t->width)
-		t->hpagesize = t->width;
-
-	// do a dummy scroll to update the horizontal scrollbar to use the new width
-	hscrollby(t, 0);
-}
-
 HANDLER(headerNotifyHandler)
 {
 	NMHDR *nmhdr = (NMHDR *) lParam;
@@ -100,10 +69,10 @@ HANDLER(headerNotifyHandler)
 		return FALSE;
 	if (nmhdr->code != HDN_ITEMCHANGED)
 		return FALSE;
-	updateTableWidth(t);
+	update(t, TRUE);
 	// TODO make more intelligent
+	// (TODO is it actually needed?)
 	InvalidateRect(t->hwnd, NULL, TRUE);
-	// TODO UpdateWindow()?
 	*lResult = 0;
 	return TRUE;
 }

wintable/main.h

@@ -103,6 +103,9 @@ struct table {
 // forward declaration (TODO needed?)
 static LRESULT notify(struct table *, UINT, intptr_t, intptr_t, uintptr_t);
 
+// necessary forward declaration
+static void update(struct table *, BOOL);
+
 #include "util.h"
 #include "coord.h"
 #include "scroll.h"
@@ -117,6 +120,7 @@ static LRESULT notify(struct table *, UINT, intptr_t, intptr_t, uintptr_t);
 #include "draw.h"
 #include "api.h"
 #include "accessibility.h"
+#include "update.h"
 
 static const handlerfunc handlers[] = {
 	eventHandlers,

wintable/resize.h

@@ -3,37 +3,18 @@
 // TODO why doesn't this trigger on first show?
 // TODO see if there's anything not metaphor related in the last bits of the scrollbar series
 // TODO rename this to boot
+// TODO merge with update.h?
 
 HANDLER(resizeHandler)
 {
 	WINDOWPOS *wp;
-	RECT client;
-	intptr_t height;
 
 	if (uMsg != WM_WINDOWPOSCHANGED)
 		return FALSE;
 	wp = (WINDOWPOS *) lParam;
 	if ((wp->flags & SWP_NOSIZE) != 0)
 		return FALSE;
-
+	update(t, TRUE);
-	// TODO does wp store the window rect or the client rect?
-	if (GetClientRect(t->hwnd, &client) == 0)
-		panic("error getting Table client rect in resizeHandler()");
-	// TODO do this after calling updateTableWidth() (which calls repositionHeader()?)?
-	client.top += t->headerHeight;
-
-	// update the width...
-	// this will call repositionHeader(); there's a good reason... (see comments)
-	// TODO when I clean that mess up, remove this comment
-	updateTableWidth(t);
-
-	// ...and the height
-	// TODO find out if order matters
-	height = client.bottom - client.top;
-	t->vpagesize = height / rowht(t);
-	// do a dummy scroll to reflect those changes
-	vscrollby(t, 0);
-
 	*lResult = 0;
 	return TRUE;
 }

wintable/test.c

@@ -117,7 +117,8 @@ int main(int argc, char *argv[])
 	INITCOMMONCONTROLSEX icc;
 	WNDCLASSW wc;
 
-	mkbitmap();
+	if (argc != 1)
+		msgfont = TRUE;
 	ZeroMemory(&icc, sizeof (INITCOMMONCONTROLSEX));
 	icc.dwSize = sizeof (INITCOMMONCONTROLSEX);
 	icc.dwICC = ICC_LISTVIEW_CLASSES;

wintable/update.h

@@ -0,0 +1,44 @@
+// 8 january 2015
+
+// Whenever a number of things in the Table changes, the update() function needs to be called to update any metrics and scrolling positions.
+// The control font changing is the big one, as that comes with a flag that decides whether or not to redraw everything. We'll need to respect that here.
+
+// TODO actually use redraw here
+static void update(struct table *t, int redraw)
+{
+	RECT client;
+	intptr_t i;
+	intptr_t height;
+
+	// before we do anything we need the client rect
+	if (GetClientRect(t->hwnd, &client) == 0)
+		panic("error getting Table client rect in update()");
+
+	// the first step is to figure out how wide the whole table is
+	// TODO count dividers?
+	t->width = 0;
+	for (i = 0; i < t->nColumns; i++)
+		t->width += columnWidth(t, i);
+
+	// now we need to figure out how much of the width of the table can be seen at once
+	t->hpagesize = client.right - client.left;
+	// this part is critical: if we resize the columns to less than the client area width, then the following hscrollby() will make t->hscrollpos negative, which does very bad things
+	// we do this regardless of which of the two has changed, just to be safe
+	if (t->hpagesize > t->width)
+		t->hpagesize = t->width;
+
+	// now we do a dummy horizontal scroll to apply the new width and horizontal page size
+	// this will also reposition and resize the header (the latter in case the font changed), which will be important for the next step
+	hscrollby(t, 0);
+
+	// now that we have the new height of the header, we can fix up vertical scrolling
+	// so let's take the header height away from the client area
+	client.top += t->headerHeight;
+	// and update our page size appropriately
+	height = client.bottom - client.top;
+	t->vpagesize = height / rowht(t);
+	// and do a dummy vertical scroll to apply that
+	vscrollby(t, 0);
+
+	// TODO invalidate /everything/?
+}