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From: jromine@GREMLIN.NRTC.NORTHROP.COM (John Romine)
Newsgroups: comp.windows.x
Subject: Re: Flaky cursor on color Sun
Message-ID: <22539.549222138@gremlin.nrtc.northrop.com>
Date: Thu, 28-May-87 17:18:06 EDT
Article-I.D.: gremlin.22539.549222138
Posted: Thu May 28 17:18:06 1987
Date-Received: Sat, 30-May-87 09:11:31 EDT
References: <1610@kontron.UUCP>
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
Lines: 93


    on a Sun 3/260 color system...  whenever the mouse cursor gets very
    near the left edge of the screen, I get "mouse droppings" (leftover
    images of the cursor) along the this edge.

Yes, I had this problem too (on 3/280 and 3/160 color systems).  The problem
is when the mouse is accelerated, it can end up at an invalid location.

Below is a context diff of the fix I installed.  Note, this doesn't totally
cure the problem, it just stops it from happening most of the time.  Also,
you will probably want to slow down the mouse acceleration using "xset m";
doing that also causes the problem to occur less often.

John Romine
Northrop Research and Technology Center
jromine@gremlin.nrtc.northrop.com
213/544-5219


*** /tmp/,RCSt1a04028	Thu May 28 10:26:21 1987
--- events.c	Fri Apr 17 17:53:48 1987
***************
*** 74,81 ****
  extern int vsdev;
  extern DEVICE *CurrentDevice;
  
! int sunthreshold = 0;
! int sunaccel = 0;
  
  #ifdef	RAW_KBD
  extern unsigned state_mask;
--- 74,81 ----
  extern int vsdev;
  extern DEVICE *CurrentDevice;
  
! int sunthreshold = 1;			/* was 0 /JLR */
! int sunaccel = 1;			/* was 0 /JLR */
  
  #ifdef	RAW_KBD
  extern unsigned state_mask;
***************
*** 326,340 ****
  		int dy = Xevent.vse_y - CurrentDevice->mouse->y;
  
  		if (sunthreshold <= (dx > 0 ? dx : -dx) + (dy > 0 ? dy : -dy)) {
! 			Xevent.vse_x = CurrentDevice->mouse->x + dx * sunaccel;
! 			Xevent.vse_y = CurrentDevice->mouse->y + dy * sunaccel;
! 		}
! 	
  	    }
- 	    SetCursorPosition((vsCursor *) &Xevent);	/* XXX - tacky */
  	}
  
! 	Xevent.vse_key;
  
  	if (Xevent.vse_type == VSE_MMOTION) {
  	    register vsBox *b = CurrentDevice->mbox;
--- 326,360 ----
  		int dy = Xevent.vse_y - CurrentDevice->mouse->y;
  
  		if (sunthreshold <= (dx > 0 ? dx : -dx) + (dy > 0 ? dy : -dy)) {
! 		    register short new_x, new_y;	/* 09Apr87/JLR */
! 
! 		    new_x = CurrentDevice->mouse->x + dx * sunaccel;
! 		    new_y = CurrentDevice->mouse->y + dy * sunaccel;
! 
! 		    /* keep cursor on screen - 09Apr98/JLR */
! 		    /* this should check against cursor->... see cursor.c */
! 		    if (new_x >= CurrentDevice->width)	/* cursor->xmax */
! 			Xevent.vse_x = CurrentDevice->width - 1;
! 		    else if (new_x < 0)			/* cursor->xmin */
! 			Xevent.vse_x = 0;
! 		    else
! 			Xevent.vse_x = (unsigned short) new_x;
! 
! 		    if (new_y >= CurrentDevice->height)	/* cursor->ymax */
! 			Xevent.vse_y = CurrentDevice->height - 1;
! 		    else if (new_y < 0)			/* cursor->ymin */
! 			Xevent.vse_y = 0;
! 		    else
! 			Xevent.vse_y = (unsigned short) new_y;
!     		}
! #ifdef	notdef
! 	fprintf (stderr, "\nMOTION: %d, %d\n", Xevent.vse_x, Xevent.vse_y);
! #endif	notdef
! 	    SetCursorPosition((vsCursor *) &Xevent);/* XXX - tacky */
  	    }
  	}
  
! 	Xevent.vse_key;					/* EH? */
  
  	if (Xevent.vse_type == VSE_MMOTION) {
  	    register vsBox *b = CurrentDevice->mbox;