Is GoView.DocScale available to client script?

GoDiagram (6 and previous)
1

Hello all,
I’m using GoDiagram Web and am attempting to place a slider control on my page that will allow the user to zoom the image rendered in my GoView in and out as they move the indicator on the slider. I’ve successfully hooked this up, rescaling the diagram via calls to goZoom when the user moves the slider. This works nicely and is done without postback as NoPost=“true” on my GoView.
I have also overridden mouse wheel functionality in a similar fashion. When the user uses the mouse wheel within the boundaries of my GoView, the image displayed by the GoView zooms in and out via calls to goZoom. Again, since NoPost=“true”, this is done nicely without postback.
Unfortunately, I cannot figure out how to update my slider control in response to zoom changes made via the mouse wheel without postback. I can update my slider’s value via client script, however, I need the GoView DocScale value in order to do so.
Is it possible to access or calculate the DocScale of a GoView via client side script? I thought this information might be accessible via the object returned from goFindView or that I might be able to return a GoPartInfo from the GoView that exposes this property. This however does not seem possible (perhaps I missed something?). It also does not seem possible to return a value from an overloaded GoViewDataRenderer.HandleClientRequest method.

Perhaps I'm stuck with trying postback and an MS AJAX UpdatePanel to hide the flickers?
Any suggestions appreciated.
Thanks,
John
2

It’s true that implementing a GoViewDataRenderer.HandleClientRequest is meant for handling “events” in a general sense, not for returning “values”.

The way to pass that information from the server to the client is to override the GoViewDataRenderer.Render method. Demo1 has an example of this, passing the GoView.Selection.Count and information about the type of the primary selection.

3

Thanks Jake. Overriding GoViewDataRenderer.Render and implementing goOnLoad client side has solved my problem.

This seems to be the case, but can you confirm that goOnLoad acts as a callback and will not be fired until the image has been reloaded? Before finding the goOnLoad method I was having syncronization issues client side, as the slider would be updated prior to image reload.
Thanks,
John