From 60ddf397e389f25f0a038548d9c808c83d815ba7 Mon Sep 17 00:00:00 2001
From: phillbush <phillbush@cock.li>
Date: Sat, 13 Feb 2021 20:36:55 -0300
Subject: [PATCH] add support for mouse scrolling (#26)

---
 xmenu.1 |  1 -
 xmenu.c | 93 ++++++++++++++++++++++++++++++++++++++++-----------------
 xmenu.h |  1 +
 3 files changed, 66 insertions(+), 29 deletions(-)

diff --git a/xmenu.1 b/xmenu.1
index 82a6ebb..7b14eea 100644
--- a/xmenu.1
+++ b/xmenu.1
@@ -190,7 +190,6 @@ or
 .BR "\(dqright\(dq" ,
 text is aligned to the left, center, or right of the menu, respectively.
 By default, text is aligned to the left.
-
 .SH EXAMPLES
 The following script illustrates the use of
 .BR xmenu .
diff --git a/xmenu.c b/xmenu.c
index 8658a9d..afb4301 100644
--- a/xmenu.c
+++ b/xmenu.c
@@ -1129,17 +1129,37 @@ itemcycle(struct Menu *currmenu, int direction)
 	return item;
 }
 
+/* check if button is used to scroll */
+static int
+isscrollbutton(unsigned int button)
+{
+	if (button == Button4 || button == Button5)
+		return 1;
+	return 0;
+}
+
 /* check if button is used to open a item on click */
 static int
 isclickbutton(unsigned int button)
 {
-	if (button == Button1)
+	if (button == Button1 || button == Button2)
 		return 1;
 	if (!rflag && button == Button3)
 		return 1;
 	return 0;
 }
 
+/* warp pointer to center of selected item */
+static void
+warppointer(struct Menu *menu, struct Item *item)
+{
+	if (menu == NULL || item == NULL)
+		return;
+	if (menu->selected) {
+		XWarpPointer(dpy, None, menu->win, 0, 0, 0, 0, menu->w / 2, item->y + item->h / 2);
+	}
+}
+
 /* append buf into text */
 static int
 append(char *text, char *buf, size_t textsize, size_t buflen)
@@ -1240,6 +1260,7 @@ run(struct Menu *currmenu)
 	KeySym ksym;
 	Status status;
 	XEvent ev;
+	int warped = 0;
 	int action;
 	int len;
 	int i;
@@ -1256,38 +1277,50 @@ run(struct Menu *currmenu)
 				action = ACTION_DRAW;
 			break;
 		case MotionNotify:
-			menu = getmenu(currmenu, ev.xbutton.window);
-			item = getitem(menu, ev.xbutton.y);
-			if (menu == NULL || item == NULL || previtem == item)
-				break;
-			previtem = item;
-			select = menu->selected = item;
-			if (item->submenu != NULL) {
-				currmenu = item->submenu;
-				select = NULL;
-			} else {
-				currmenu = menu;
+			if (!warped) {
+				menu = getmenu(currmenu, ev.xbutton.window);
+				item = getitem(menu, ev.xbutton.y);
+				if (menu == NULL || item == NULL || previtem == item)
+					break;
+				previtem = item;
+				select = menu->selected = item;
+				if (item->submenu != NULL) {
+					currmenu = item->submenu;
+					select = NULL;
+				} else {
+					currmenu = menu;
+				}
+				action = ACTION_CLEAR | ACTION_SELECT | ACTION_MAP | ACTION_DRAW;
 			}
-			action = ACTION_CLEAR | ACTION_SELECT | ACTION_MAP | ACTION_DRAW;
+			warped = 0;
 			break;
 		case ButtonRelease:
-			if (!isclickbutton(ev.xbutton.button))
-				break;
-			menu = getmenu(currmenu, ev.xbutton.window);
-			item = getitem(menu, ev.xbutton.y);
-			if (menu == NULL || item == NULL)
-				break;
+			if (isscrollbutton(ev.xbutton.button)) {
+				if (ev.xbutton.button == Button4)
+					select = itemcycle(currmenu, ITEMPREV);
+				else
+					select = itemcycle(currmenu, ITEMNEXT);
+				action = ACTION_CLEAR | ACTION_SELECT | ACTION_DRAW | ACTION_WARP;
+			} else if (isclickbutton(ev.xbutton.button)) {
+				menu = getmenu(currmenu, ev.xbutton.window);
+				item = getitem(menu, ev.xbutton.y);
+				if (menu == NULL || item == NULL)
+					break;
 enteritem:
-			if (item->label == NULL)
-				break;  /* ignore separators */
-			if (item->submenu != NULL) {
-				currmenu = item->submenu;
-			} else {
-				printf("%s\n", item->output);
-				return;
+				if (item->label == NULL)
+					break;  /* ignore separators */
+				if (item->submenu != NULL) {
+					currmenu = item->submenu;
+				} else {
+					printf("%s\n", item->output);
+					return;
+				}
+				select = currmenu->list;
+				action = ACTION_CLEAR | ACTION_SELECT | ACTION_MAP | ACTION_DRAW;
+				if (ev.xbutton.button == Button2) {
+					action |= ACTION_WARP;
+				}
 			}
-			select = currmenu->list;
-			action = ACTION_CLEAR | ACTION_SELECT | ACTION_MAP | ACTION_DRAW;
 			break;
 		case ButtonPress:
 			menu = getmenu(currmenu, ev.xbutton.window);
@@ -1419,6 +1452,10 @@ append:
 			mapmenu(currmenu);
 		if (action & ACTION_DRAW)
 			drawmenus(currmenu);
+		if (action & ACTION_WARP) {
+			warppointer(currmenu, select);
+			warped = 1;
+		}
 	}
 }
 
diff --git a/xmenu.h b/xmenu.h
index b5f1556..5e369a2 100644
--- a/xmenu.h
+++ b/xmenu.h
@@ -6,6 +6,7 @@
 #define ACTION_SELECT 1<<1      /* select item */
 #define ACTION_MAP    1<<2      /* remap menu windows */
 #define ACTION_DRAW   1<<3      /* redraw menu windows */
+#define ACTION_WARP   1<<4      /* warp the pointer */
 
 /* enum for keyboard menu navigation */
 enum { ITEMPREV, ITEMNEXT, ITEMFIRST, ITEMLAST };