Re: [pointerevents] Stylus eraser: should it be a new pointerType instead of a button state?

> == Stylus eraser: should it be a new pointerType instead of a button state? ==

I would say yes. As Mustaq pointed out there’s “Eraser Mode” and “Erasing Action”. Eraser Mode signals the UI to switch to an erasing tool and/or show an eraser cursor. Erasing Action performs an erase stroke.

Flipping to the eraser end, or pressing the erase side switch, activates Eraser Mode. At the lowest level, USB HID has an Invert bit usage (not a switch usage) to indicate Erase Mode. Using the tail transducer, or pressing the eraser side switch sets this bit. Using this bit to set a pointerType to Eraser would be a great way to indicate Eraser Mode.

Drawing (tip pressure > 0) while in Eraser Mode performs an Eraser Action. In PE this is currently Buttons==32 and the erase mode vs erase action are inseparable. So there’s no way to indicate (tool setting or cursor shape) that erasing will occur (erasing mode).

If there was a pointerType eraser there’s no need for button = 32. Button 1 for an eraser pointerType would do an erase action and is consistent with allowing other button presses while hovering (1 + 4, 1 + 8).

A note about hover switches:
Side switches can be used to changes modes or to target (click on things). Mode changes while hovering (such as switching to eraser mode) are fine because there’s no need for high precision. If a side switch is set to a targeting action (such as right click) it is difficult for the user to precisely target because pressing a side switch while hovering often results in unintended lateral stylus movement. Microsoft’s solution was to make the right click button a modifier instead of an action, so you have to press the button and also press the tip to execute a right click. This makes right click targeting more precise. The Wacom control panel gives a choice, immediately act on a side switch or force it to be combined with the tip. Linux also gives this choice. Chrome immediately acts on side switches (a side switch set to right click acts immediately when pressed).
"A change of perception is worth 80 IQ points." -- Alan Kay

Received on Friday, 26 August 2016 18:18:59 UTC