[OpenLayers-Dev] ticket 2593 in OpenLayers 2.10

[Marc Pfister]

Bart van den Eijnden (OSGIS) wrote:

> are you sure?
>
> http://trac.openlayers.org/changeset/10675
>
> reads:
>
>if ((OpenLayers.Util.indexOf(this.layer.SUPPORTED_TRANSITIONS,
>this.layer.transitionEffect) != -1) ||  this.layer.singleTile) {
>
>and singleTile is true.

This will turn on the transitions in a generic sense, but the actual transitions of the backbuffered image don't occur until line 535:

 533	        // if the ratio is not the same as it was last time (i.e. we are
 534	        // zooming), then we need to adjust the backBuffer tile
 535	        if (ratio != this.lastRatio) {
 536	            if (this.layer.transitionEffect == 'resize') {
 537	                // In this case, we can just immediately resize the
 538	                // backBufferTile.

If you are zooming, your transitionEffect should be empty and the backbuffering skipped.

If you're panning and not zooming, then you jump to line 572:


 568	            // default effect is just to leave the existing tile
 569	            // until the new one loads if this is a singleTile and
 570	            // there was no change in resolution.  Otherwise we
 571	            // don't bother to show the backBufferTile at all
 572	            if (this.layer.singleTile) {
 573	                this.backBufferTile.show();
 574	            } else {
 575	                this.backBufferTile.hide();
 576	            }

The singleTile layer will backbuffer in panning, maintaining the visual continuity of the panned layer.

Since your problem occurs in the zoom, can you set a breakpoint in the block around line 539 and see if it trips?

- Marc