[OpenLayers-Users] wms untiled 'busy loading' message or image

[Erik Uzureau]

Dear Benoit et tous,

I'm actually working on getting reliable loadstart/loadend messages
going in a sandbox that I've been working on for the past couple of
weeks.

I'm hoping to write tests today and have a patch ready and hopefully
integrated by the end of the week.

Once in (cross fingers), all layers derived of Grid.js will correctly
fire "loadstart", "loadend" and "tileloaded" events. Similar to your
implementation below, there will be a new property on the grid layer
called numLoadingTiles, which can be used to implement a progress bar.

Keep an eye out for it,
Erik




On 7/10/07, Benoit Myard <myardbenoit at gmail.com> wrote:
> // Here is the code:
>
> OpenLayers.Control.LoadMonitor = OpenLayers.Class.create();
> OpenLayers.Control.LoadMonitor.prototype =
>   OpenLayers.Class.inherit( OpenLayers.Control, {
>
>     div: null,
>     counter: 0,
>
>     activate: function() {
>       var img = OpenLayers.Util.getImagesLocation() + "loading.gif";
>       var size = new OpenLayers.Size(40, 40);
>       var dim = OpenLayers.Element.getDimensions(this.map.viewPortDiv);
>       var pos = new OpenLayers.Pixel((dim.width - size.w) / 2,
>                                     (dim.height - size.h) / 2);
>
>       this.div = OpenLayers.Util.createDiv("LoadMonitor", pos, size, img);
>       this.div.style.zIndex = 1000;
>
>       this.map.viewPortDiv.appendChild(this.div);
>     },
>
>     deactivate: function() {
>       if (this.div) {
>         this.div.style.display = "none";
>         this.div = null;
>       }
>     },
>
>     draw: function() {
>       this.activate();
>     },
>
>     monitor: function(layer) {
>       layer.events.register('loadstart', this, this.start);
>       layer.events.register('loadcancel', this, this.end);
>       layer.events.register('loadend', this, this.end);
>     },
>
>     start: function(layer) {
>       this.counter++
>       if (this.counter > 0 && this.div)
>         this.div.style.display = "block";
>     },
>
>     end: function(layer) {
>       if (this.counter > 0)
>           this.counter--;
>       if (this.counter == 0 && this.div)
>         this.div.style.display = "none";
>     },
>
>     CLASS_NAME: "OpenLayers.Control.LoadMonitor"
> });
>
> // And here is an example:
>
> var map = new OpenLayers.Map(...);
>
> var monitor = new ExpWeb.Control.LoadMonitor();
> map.addControl(monitor);
>
> var layer = new OpenLayers.Layer.WMS(...);
> monitor.monitor(layer);
> map.addLayer(layer);
>
> It's not automated because I had to have the ability to choose which
> layer to monitor. Also, for some reason, events are somewhat strange.
> Add breakpoints in start() and end() if you use FireBug and note
> events triggered. Any idea ?
>
> Cheers.
>
> --
> Benoit Myard
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