drag parameter to user data field like in console

Helper

On 28/03/2017 at 02:26, xxxxxxxx wrote:

I'm trying to do something cheeky here, wondering if its possible.
I want to make a python tag which performs an action on an object's parameters, but the user can define which parameter it is performed on by just dragging the parameter into a user data field;
exactly like how we can drag a parameter or object into our python scripts or console.
I thought I could do this with a string field but it doesn't let me, link field doesn't either.

What makes the console input field so special, is there any way this could be done?
cheers!

Helper

On 29/03/2017 at 05:23, xxxxxxxx wrote:

Hi,

The Console input is an edit text that processes the drag and drop events for parameters. Same for the Script Manager except it's a multi-line edit text.

You can create a String user data that uses the Multi-Line String Interface in Python mode (Check PYTHON in Details tab). The Multi-Line String GUI accepts dragged parameters.
In code, DESC_CUSTOMGUI would be set to CUSTOMGUI_STRINGMULTI and DR_MULTILINE_PYTHON to 1.

Then in the Python tag you can evaluate a dynamically built expression string generated with the String user data that contains the parameter ID.
Here's some code:

import c4d
  
def main() :
    obj = op.GetObject()
  
    data = obj[c4d.ID_USERDATA,1]
    
    # Evaluates the parameter ID string
    # Returns a list of integers for the description levels
    paramID = eval(data)
    print paramID
    
    # Builds the expression obj[ID]
    expr = "obj" + data
    paramValue = eval(expr)
    print paramValue

Helper

On 30/03/2017 at 11:39, xxxxxxxx wrote:

Hey thank you that works great!
I can now get the value of the dragged in parameter.
But, if you wanted to set the evaluated parameter, how would you proceed?

Helper

On 31/03/2017 at 07:25, xxxxxxxx wrote:

Originally posted by xxxxxxxx

But, if you wanted to set the evaluated parameter, how would you proceed?

You can set the evaluated parameter with obj ->SetParameter( id, data, flags ).
SetParameter() needs a complete DescID (with the DescLevel dtype filled) to effectively set a parameter.
To get a full DescID, the best solution is to use Description.CheckDescID() (function added in R18).

Here's some code:

import c4d
  
def main() :
    obj = op.GetObject()
  
    data = obj[c4d.ID_USERDATA,1]
    param = eval(data)
  
    desc = obj.GetDescription(c4d.DESCFLAGS_DESC_0)
    if desc is None:
        return
    
    partialID = c4d.DescID()
    for level in param:
        partialID.PushId(c4d.DescLevel(level))
    
    completeID = desc.CheckDescID(partialID, [obj])
    if completeID is None:
        return
    
    obj.SetParameter(completeID, 100, c4d.DESCFLAGS_SET_0)

Helper

On 31/03/2017 at 11:19, xxxxxxxx wrote:

This really exciting, it works perfectly.
I don't quite grasp whats happening with all this ID stuff, I need to read up on it!
Thanks again!