4 files changed, 46 insertions, 5 deletions
diff --git a/wintable/new/hscroll.h b/wintable/new/hscroll.h
index a2534b5..1560490 100644
--- a/wintable/new/hscroll.h
+++ b/wintable/new/hscroll.h
@@ -13,6 +13,7 @@ static struct scrollParams hscrollParams(struct table *t)
 	p.length = t->width;
 	p.scale = 1;
 	p.post = repositionHeader;
+	p.wheelCarry = &(t->hwheelCarry);
 	return p;
 }
 
diff --git a/wintable/new/main.c b/wintable/new/main.c
index 0482d04..00bc5fb 100644
--- a/wintable/new/main.c
+++ b/wintable/new/main.c
@@ -62,6 +62,8 @@ struct table {
 	intptr_t count;
 	intptr_t vscrollpos;		// in rows
 	intptr_t vpagesize;		// in rows
+	int hwheelCarry;
+	int vwheelCarry;
 };
 
 #include "util.h"
diff --git a/wintable/new/scroll.h b/wintable/new/scroll.h
index 81b49c5..1f333a8 100644
--- a/wintable/new/scroll.h
+++ b/wintable/new/scroll.h
@@ -6,6 +6,7 @@ struct scrollParams {
 	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)
@@ -104,3 +105,26 @@ static void scroll(struct table *t, int which, struct scrollParams *p, WPARAM wP
 	}
 	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);
+}
diff --git a/wintable/new/vscroll.h b/wintable/new/vscroll.h
index bcab488..a1dc4c4 100644
--- a/wintable/new/vscroll.h
+++ b/wintable/new/vscroll.h
@@ -13,6 +13,7 @@ static struct scrollParams vscrollParams(struct table *t)
 	p.length = t->count;
 	p.scale = rowht(t);
 	p.post = NULL;
+	p.wheelCarry = &(t->vwheelCarry);
 	return p;
 }
 
@@ -40,12 +41,25 @@ static void vscroll(struct table *t, WPARAM wParam, LPARAM lParam)
 	scroll(t, SB_VERT, &p, wParam, lParam);
 }
 
+static void vwheelscroll(struct table *t, WPARAM wParam, LPARAM lParam)
+{
+	struct scrollParams p;
+
+	p = vscrollParams(t);
+	wheelscroll(t, SB_VERT, &p, wParam, lParam);
+}
+
 // TODO WM_MOUSEWHEEL
 HANDLER(vscrollHandler)
 {
-	if (uMsg != WM_VSCROLL)
-		return FALSE;
-	vscroll(t, wParam, lParam);
-	*lResult = 0;
-	return TRUE;
+	switch (uMsg) {
+	case WM_VSCROLL:
+		vscroll(t, wParam, lParam);
+		*lResult = 0;
+		return TRUE;
+	case WM_MOUSEWHEEL:
+		vwheelscroll(t, wParam, lParam);
+		// TODO what to return?
+	}
+	return FALSE;
 }