SDL module: added unset gadget code

include-lib/sdl-lib.l1h

@@ -69,6 +69,7 @@
 	(set string s free_all_gadgetsstr@sdl "free_all_gadgets")
     (set string s set_window_titlestr@sdl "sdl_set_window_title")
     (set string s set_gadget_menustr@sdl "set_gadget_menu")
+    (set string s unset_gadgetstr@sdl "unset_gadget")
     (set int64 1 open@sdl 0)
     (set int64 1 quit@sdl 1)
     (set int64 1 update@sdl 2)
@@ -130,6 +131,7 @@
 	(set int64 1 free_all_gadgets@sdl 59)
     (set int64 1 set_window_title@sdl 60)
     (set int64 1 set_gadget_menu@sdl 61)
+    (set int64 1 unset_gadget@sdl 62)
     // call arguments
     (set int64 1 width@sdl 0)
     (set int64 1 height@sdl 0)
@@ -206,6 +208,7 @@
 	(2 mod@sdl free_all_gadgets@sdl free_all_gadgetsstr@sdladdr intr0)
     (2 mod@sdl set_window_title@sdl set_window_titlestr@sdladdr intr0)
     (2 mod@sdl set_gadget_menu@sdl set_gadget_menustr@sdladdr intr0)
+    (2 mod@sdl unset_gadget@sdl unset_gadgetstr@sdladdr intr0)
     (width@sdl stpushi)
     (height@sdl stpushi)
     (bit@sdl stpushi)
@@ -417,3 +420,6 @@
 (sdl_set_window_title func)
     (3 mod@sdl set_window_title@sdl 0 intr0)
 (funcend)
+(sdl_unset_gadget func)
+    (3 mod@sdl unset_gadget@sdl 0 intr0)
+(funcend)

vm/modules/sdl-2.0/gui.c

@@ -7520,3 +7520,40 @@ U1 *free_all_gadgets (U1 *sp, U1 *sp_top, U1 *sp_bottom, U1 *data)
 
 	return (sp);
 }
+
+U1 *unset_gadget (U1 *sp, U1 *sp_top, U1 *sp_bottom, U1 *data)
+{
+    // this just unsets a gadget from the gadgets list.
+    // You have to blank it out by overpainting it by the window background color!
+
+	S8 gadget_index ALIGN;
+
+	sp = stpopi ((U1 *) &gadget_index, sp, sp_top);
+    if (sp == NULL)
+    {
+ 	   printf ("unset_gadet: error missing gadget index!\n");
+       return (NULL);
+    }
+
+	if (! screen[screennum].gadget)
+    {
+        printf ("unset_gadget: error gadget list not allocated!\n");
+        return (NULL);
+    }
+
+    if (gadget_index >= screen[screennum].gadgets)
+    {
+        printf ("unset_gadget error gadget index out of range!\n");
+        return (NULL);
+    }
+
+    if (! screen[screennum].font_ttf.font)
+    {
+        printf ("unset_gadget: error no ttf font loaded!\n");
+        return (NULL);
+    }
+
+    free_gadget (screennum, gadget_index);
+
+    return (sp);
+}