[PATCH] Wheelmouse support for zvtterm

[Richard Hult <rhult hem2 passagen se>]

I have made a small patch that makes gnome-terminal and other apps that
use zvtterm support scrollwheel mice. I'm not a guru so it might be
totally off. At least it works for me ;)

Feel free to commit it or throw it away, or even better, please make it
work the right way if it's wrong :)

Richard

Index: zvtterm.c
===================================================================
RCS file: /cvs/gnome/gnome-libs/zvt/zvtterm.c,v
retrieving revision 1.95
diff -u -r1.95 zvtterm.c
--- zvtterm.c	1999/03/09 05:00:23	1.95
+++ zvtterm.c	1999/03/09 22:57:41
@@ -91,6 +91,7 @@
 static void zvt_term_fix_scrollbar (ZvtTerm *term);
 static void vtx_unrender_selection (struct _vtx *vx);
 static void zvt_term_scroll (ZvtTerm *term, int n);
+static void zvt_term_scroll_by_lines (ZvtTerm *term, int n);
 
 
 /* transparent terminal prototypes */
@@ -1363,6 +1364,19 @@
 			NULL, NULL, 0);
       }
     break;
+
+    /* Handle scrollwheel mice. These are most commonly configured (at
+     * least when using XFree86), to transform the wheel movement into
+     * button 4 (up) and 5 (down) events. 12 lines matches gtk+ scrollbar
+     * scrollwheel mouse behaviour.
+     */
+  case 4:
+    zvt_term_scroll_by_lines (term, -12);
+    break;
+
+  case 5:
+    zvt_term_scroll_by_lines (term, 12);
+    break;
   }
   return FALSE;
 }
@@ -1390,6 +1404,11 @@
   x = x/term->charwidth;
   y = y/term->charheight + vx->vt.scrollbackoffset;
 
+  /* ignore wheel mice buttons (4 and 5) */
+  /* otherwise they affect the selection */
+  if (event->button == 4 || event->button == 5)
+    return FALSE;
+
   /* report mouse to terminal */
   if (!(event->state & GDK_SHIFT_MASK))
     if (vt_report_button(&vx->vt, 0, event->state, x, y))
@@ -1738,6 +1757,30 @@
       n > 0 ? MIN(new_value, term->adjustment->upper- term->adjustment->page_size) :
       MAX(new_value, term->adjustment->lower));
 }
+
+static void
+zvt_term_scroll_by_lines (ZvtTerm *term, int n)
+{
+  gfloat new_value = 0;
+
+  if (n > 0)
+    {
+      new_value = MIN(term->adjustment->value + n, term->adjustment->upper - n);
+    }
+  else if (n < 0)
+    {
+      new_value = MAX(term->adjustment->value + n, term->adjustment->lower);
+    }
+  else
+    {
+      return;
+    }
+
+  gtk_adjustment_set_value (
+      term->adjustment,
+      new_value); 
+}
+
 
 /*
  * Keyboard input callback