A European patent filing reveals Apple's work on possibly adding a new 'Slide' gesture to Apple Pencil in future. This would compliment the current 'Double Tap' gesture introduced with Apple Pencil 2.
Apple notes in their patent filing that there's a need for an iPad to have faster, more efficient methods and interfaces for user interface manipulation. Such methods and interfaces optionally complement or replace conventional methods for manipulating user interfaces. Such methods and interfaces reduce the number, extent, and/or nature of the inputs from a user and produce a more efficient human-machine interface.
In Apple's patent FIG. 21E below we see an extended Apple Pencil Menu that has added the "Slide Gesture." FIG. 21N is an example of a slide gesture used to "Decrease Thickness." In FIG. 21V we see an example of a slide gesture used to "Increase Opacity."
Like most inventions, Apple doesn't want to limit the new gesture applying only to an iPad. Apple notes that in some embodiments, the electronic device is a desktop computer. In some embodiments, the electronic device is portable (e.g., a notebook computer, tablet computer, or handheld device). In some embodiments, the electronic device is a personal electronic device (e.g., a wearable electronic device, such as a watch). In some embodiments, the electronic device has a touchpad. In some embodiments, the electronic device has a touch-sensitive display or "touch screen."
Of course, Windows has merged touch with pen use whereas Apple's VPs of hardware and marketing have recently stated that this isn't going to happen for Apple devices. Yet their patent keeps the door open, which is wise.
Apple has been working on this the new 'Slide' gesture since 2018. In January of this year Apple's patent application 20200012358 surfaced describing a "Slide" gesture as seen in patent figure 7 below.
To review Apple's larger and lengthy patent describing this new Slide gesture, review the Scribd documents provided for you below covering the patent description and patent figures.
The series of patent figures below relating to the possible future 'Slide' gesture begins with FIG. 21E.
Considering that this is a patent application, the timing of such a product to market is unknown at this time.