How can I stop a function so it can restart again?

[lucas vidgen]

Hi,

I have this function:

function startAnimation() {
 
        lastVertex = 0;
        k=0;
        i = 0;
      step = 5; 
      tick = 10; 
      stepnum=0;
      speed = "";
        eol=poly.Distance();
        map.setCenter(poly.getVertex(0),16);
        map.addOverlay(new GMarker(poly.getVertex(0),G_START_ICON));
        map.addOverlay(new GMarker(poly.getVertex(poly.getVertexCount()-1),G_END_ICON));
        if (supportsCanvas) {
          marker = new ELabel(poly.getVertex(0), '<canvas id="carcanvas" width="32" height="32"><\/canvas>',null,new GSize(-16,16));
            map.addOverlay(marker);
          canvas = document.getElementById("carcanvas").getContext('2d');
          var p0 = poly.getVertex(0);
            var p1 = poly.getVertex(1);
          angle = bearing(p0,p1);
          plotcar();
        } else {
          marker = new GMarker(poly.getVertex(0),{icon:car});
          map.addOverlay(marker);
        }
        poly2 = new GPolyline([poly.getVertex(0), poly.getVertex(1), poly.getVertex(2)], 0,0);
//        map.addOverlay(poly2);
 
        setTimeout("animate(0)",2000);  // Allow time for the initial map display
 
}

that is fired by this button:

<input type="button" onclick="startAnimation()" value="Show Bus Route 1" style="width:120px; height:24px; text-align:center">

but if you click the button again, the original function continues working while the second one executes.

If you want to see it in action, it's here

Is there some way that that button click can say "stop the first one and start the next one"?

thanks for your help.

[JKing]

Try creating a reset function that will return all values to their starting position. Then call this reset function at the start of your startAnimation function.

[lucas vidgen]

thanks, JKing

but assuming that those variables would just be the global variables and without the var part, it would look like this:

function reSet() { 
lastVertex = 0;
        k=1;
        i = 0;
      step = 5; 
      tick = 10; 
      stepnum=1;
      speed = "";
      }

which doesn't seem to do anything. Or were you talking about something else?

[JKing]

Well when I tried the example you gave it appears as if the bus tries to run its route starting from where ever it left off last. What I was thinking is that you need to reposition the bus to the start and then run its route or alternatively and more complexly find where the bus is on its route if it has already been activated and continue on from the last point.

[lucas vidgen]

totally.

but how? There's not some sort of "clear everything" command?

[JKing]

clearOverlays()?

[lucas vidgen]

assuming you would call that like this:

onclick="startAnimation();clearOverlays()"

it doesn't appear to do anything

Here's what I figure (because I obviously didn't write the code myself):

If you let the bus run til the end of its course then click the button again, it runs smoothly - the map pans correctly and you can see the angle of the bus moving as if it were on the road, but it stays in the same spot.

So it looks like all the other functions are reinitiating, just not the one that actually moves the bus.

Now, if you look at it on IE7 (or some other browser that doesn't support canvases) you can see that if you let the bus get to the end and then click the button, the original bus will stay at the end but a second bus appears and it follows the route fine.

but if you click halfway though the route, the second bus appears and they both try to run the course which makes for weirdness.

So what all that tells me is that I'm looking for:
1)a way to cancel the function with the onclick, and
2)a way to reset the canvas position if canvases are supoorted.

which doesn't help me at all, but it may mean something to you...

[JKing]

Sorry I should have elaborated. Not sure what version of the google maps api you are using but with a quick scan through version 2 documentation I noticed there is a clearOverlays function.

Try adding it to the start of your function.

map.clearOverlays();
 

[lucas vidgen]

closer... have a look here:
http://xelawho.com/map/moving3.htm

at least now we get two buses, weird and shaky as they are... but the second one is following the bearings of the first, which says to me that the original function is still operating...

[lucas vidgen]

what about return; ?

doesn't that do something like abort?