Low perfomace while generating legend

[liuar]

A customer who has a map with 700+ layers. Currently each layer sends request to generate legend even if it’s hidden or disabled. The legend should be generated on demand to improve performance.

Expect: The legend generated dynamically, so the map author could improve the performace by well organized groups.

1. For the layers which are not displayed in the legend, browser should not send requests to generate legend images. 2. If the user expand a group, then the request will be sent out to generate the legend images for the layers in that group. 3. If a layer's legend image is requested, browser will not send requests unless the legend image has been changed due to the scale changing.

[zspitzer]

simply having some basic caching for legend images would really help here

[liuar]

Replying to zspitzer:

simply having some basic caching for legend images would really help here

Thanks for your reply. Caching is a good way to resolve such kind fo problems. But for this case, we cannot use cache. For example, if we cached a legend image of a layer, the image will not change during the layer's scale changing. I would like to add a flag in layer item: iconWasRequested to mark if the legend image has been requested. The flag will be set to false while the layer's scale changed.

[tomfukushima]

Shows a problem with the patch

[tomfukushima]

I tried out the patch but found the error that is shown in the attached (extra white box in legend.gif) image. Are you able to reproduce? What I did was open the Sheboygan sample and zoomed in until the themed parcel layer showed up.

[liuar]

Replying to tomfukushima:

I tried out the patch but found the error that is shown in the attached (extra white box in legend.gif) image. Are you able to reproduce? What I did was open the Sheboygan sample and zoomed in until the themed parcel layer showed up.

I can reproduce that. Howerver, it's reproducible in previous revision either.

[tomfukushima]

Right that is some new behavior with the fix to #800. Submitting this patch: r4056.

[brucedechant]

Submitted to sandbox/adsk/2.1 r4369