We can use XY slider objects as graphical representation of activity (state changes) on assigned audio process parameters. The XY slider can be activated with mouse point click-drag or any gesture control device such as joystick or sensors (via MCU and serial communication protocol) to output XY data.

[pictslider] object in Max/MSP. See pictslider help and [nodes] object.

Alternatively, you can create ‘similar’ XY slider (primitive) above in Pure Data using layer of [array] and [Hslider] object. Only mouse point steady-click is working for the [array] object as opposed to Hslider ‘jump on click’ setting. Therefore, you need to click your mouse over the array-hslider to input the XY data. However, you can use serial/MIDI data for continuous Y data feed to emulate the ‘drag’ motion.

The size and range of both array and Hslider need to be identically resized. See below setting.
More info on table and array: https://www.youtube.com/watch?v=gKsDZpIISQE

Quick solution for drag option with mouse; you may use [else/slider2d] object via ELSE external library for PD and explore the process behind it. Note that complex graphical object may affect your PD CPU load and performance (latency).

Another ‘long-learning-route’ option is to explore using [mousestate] object from cyclone library. You may want to explore this if you want to design complex GUI sonic motion-event gate/trigger such as spatial audio controller.