[9fans] draw blanking

[erik quanstrom <quanstro@quanstro.net>]

i noticed (and this is fairly obvious from the code), that
draw blanking will never happen if the cursor is being
redrawn.  such as if it is near the tail of catclock.

a fix to the proc-style mouse is below.

also, i noticed that for non-vga machines, it's not possible
to set the blanktime.  it seems that a little reorganization
would be beneficial.

- erik

/n/dump/2013/0416/sys/src/9/port/devmouse.c:33,38 - ../port/devmouse.c:33,39
  {
  	Lock;
  	Mousestate;
+ 	int	active;
  	int	redraw;		/* update cursor on screen */
  	Rendez	redrawr;	/* wait for cursor screen updates */
  	ulong	lastcounter;	/* value when /dev/mouse read */
/n/dump/2013/0416/sys/src/9/port/devmouse.c:515,527 - ../port/devmouse.c:516,528
  	while(waserror())
  		;
  	for(;;){
+ 		drawactive(mouse.active);
+ 		mouse.active = 0;
+
  		if(mouse.redraw){
  			mouse.redraw = 0;
  			cursoroff();
  			cursoron();
- 			drawactive(1);
- 		} else {
- 			drawactive(0);
  		}
  		tsleep(&mouse.redrawr, shouldredraw, 0, 20*1000);
  	}
/n/dump/2013/0416/sys/src/9/port/devmouse.c:562,568 - ../port/devmouse.c:563,570
  void
  mousetrack(int dx, int dy, int b, int msec)
  {
- 	int x, y, lastb;
+ 	int lastb;
+ 	Point xy;

  	if(gscreen==nil)
  		return;
/n/dump/2013/0416/sys/src/9/port/devmouse.c:571,590 - ../port/devmouse.c:573,595
  		dx = scale(dx);
  		dy = scale(dy);
  	}
- 	x = mouse.xy.x + dx;
- 	y = mouse.xy.y + dy;
+ 	xy.x = mouse.xy.x + dx;
+ 	xy.y = mouse.xy.y + dy;

- 	if(x < gscreen->clipr.min.x)
- 		x = gscreen->clipr.min.x;
- 	if(x >= gscreen->clipr.max.x)
- 		x = gscreen->clipr.max.x;
- 	if(y < gscreen->clipr.min.y)
- 		y = gscreen->clipr.min.y;
- 	if(y >= gscreen->clipr.max.y)
- 		y = gscreen->clipr.max.y;
+ 	if(xy.x < gscreen->clipr.min.x)
+ 		xy.x = gscreen->clipr.min.x;
+ 	if(xy.x >= gscreen->clipr.max.x)
+ 		xy.x = gscreen->clipr.max.x;
+ 	if(xy.y < gscreen->clipr.min.y)
+ 		xy.y = gscreen->clipr.min.y;
+ 	if(xy.y >= gscreen->clipr.max.y)
+ 		xy.y = gscreen->clipr.max.y;

  	lastb = mouse.buttons;
- 	mouse.xy = Pt(x, y);
+ 	if(!eqpt(xy, mouse.xy)){
+ 		mouse.active = 1;
+ 		mouse.xy = xy;
+ 	}
  	mouse.buttons = b|kbdbuttons;
  	mouse.counter++;
  	mouse.msec = msec;
/n/dump/2013/0416/sys/src/9/port/devmouse.c:594,599 - ../port/devmouse.c:599,605
  	 * queue any more events until a reader polls the mouse.
  	 */
  	if(!mouse.qfull && lastb != b) {	/* add to ring */
+ 		mouse.active = 1;
  		mouse.queue[mouse.wi] = mouse.Mousestate;
  		if(++mouse.wi == nelem(mouse.queue))
  			mouse.wi = 0;