Looking for Help with setting up a LrDevelopController.addAdjustmentChangeObserver

Question

So I am trying to send some current develop settings to my Stream deck using the SDK and am looking for the right way to obtain the values whenever the Develop Tab is opened, a new photo is selected, or adjustments have been made. From the docs the AdjustmentChangeObserver in the LrDevelopController should provide a lot of that information, but when I set it up like below, I do not see any traces in my log, assuming it's not being called:myObserver = {}

-- Function to monitor slider changes
local function adjustmentChangeObserverCallback(propertyName, newValue)
    logger:trace("Adjustment changed: " .. tostring(propertyName) .. " = " .. tostring(newValue))

-- Callback function is triggered when an adjustment changes
    if propertyName and newValue then
        -- Log the property name and its new value
        logger:trace("Adjustment changed: " .. propertyName .. " = " .. tostring(newValue))

-- Example: Perform some action when exposure changes
        if propertyName == "Exposure" then
            logger:trace("Exposure changed to: " .. tostring(newValue))
            -- Add any additional logic here, e.g., sending data via socket
        end
    end
end

LrTasks.startAsyncTask (function ()
    LrFunctionContext.callWithContext ("adjustmentObserver", function (context)
        LrDevelopController.addAdjustmentChangeObserver (context, myObserver, adjustmentChangeObserverCallback)

while _G.running do 
            LrTasks.sleep (1) 
        end
        end)
    end)Any idea what I am doing wrong here?I also did not find which values are being passed by the function, the documentation is a bit sparse on this function.  thank you!Wolfgang

johnrellis · Accepted Answer

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The following script works with my Debugging Toolkit:

LrFunctionContext.postAsyncTaskWithContext ("", function (context)
    LrApplicationView.switchToModule ("develop")
    Debug.logn ("Registering observer")
    LrDevelopController.addAdjustmentChangeObserver (context, {"Hello"},
        function (...) Debug.lognpp ("Change", {...}) end)
    Debug.logn ("Registered")
    LrTasks.sleep (30)
    Debug.logn ("Stopping")
    end)

Some notes:

1. addAdjustmentChangeObserver() must be called while the Develop module is active -- otherwise it is ignored.

2. If the user switches away from the Develop module and then back, the change observer will still be called.

3. It's easy to miss, but the documentation provides the signature of the observer function:

3. callback

( function( observer ) ) Function that will be called.

The observer function takes one argument, the "observer" object that was passed to addAdjustmentChangeObserver(). The setting being changed and its new value are not passed. My test script above verifies this by logging all the arguments passed to the function.

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