Open Bug 1906977 Opened 5 months ago Updated 4 months ago

Pen pointer without tilt support still reports tiltX=1 and tiltY=1

Categories

(Core :: Widget: Gtk, defect, P3)

Product:
Core
Component:
Widget: Gtk
Version:
Firefox 127
Type:
defect

Tracking

()

Status:
UNCONFIRMED

People

(Reporter: denilsonsa, Unassigned, NeedInfo)

References

(Blocks 1 open bug)

Details

Steps to reproduce:

Context:

  • Firefox nightly 130.0a1 (2024-07-09) (64-bit)
  • Manjaro Linux on x86_64
  • KDE/Plasma with X11
  • [056a:0016] Wacom Co., Ltd CTE-640 [Graphire4 (6x8)] using the default kernel drivers.

AFAIK, this is the tilt support for Wacom tablets:

  • Bamboo, Graphire: basic models, no tilt support.
  • Intuos, Intuos Pro, Cintiq: professional models, with tilt support.

(As a side note, very few Wacom pens support twist/rotation.)

I don't know about tilt support on tablets from other brands, nor for devices such as Microsoft Surface or even the iPad.

Steps to reproduce:

  1. Open one of the following pages:
  2. Use the pen.

Actual results:

This Wacom tablet does not support pen tilt. And yet Firefox reports tiltX=1 and tiltY=1.

(Side note: twist=0 is working as expected, reporting zero for this device.)

Expected results:

Since tilt is not supported, we expect tiltX=0 and tiltY=0. As per Pointer Events specifications:

For hardware and platforms that do not report tilt, the value MUST be 0.
…
For hardware and platforms that do not report tilt, the value MUST be 0.
…
For hardware and platforms that do not report twist, the value MUST be 0.

I've also tested on Google Chrome on this same system. This bug is NOT present in Chrome, it seems exclusive to Firefox.

Semi-related: bug 1822714

Component: Untriaged → Widget: Gtk
Priority: -- → P3
Product: Firefox → Core

While testing bug 1906974 on a Microsoft Surface device, I found something.

The Surface pen supports tilt for the pen tip, but NOT for the pen eraser. Chrome handles it correctly: the pen tip shows tiltX and tiltY values, and the eraser shows those values as zero.

In Firefox, however, the eraser tiltX and tiltY values seem unchanged (i.e. leftover) from the pen tip value. In other words:

  1. Use Firefox (or Chrome) on Microsoft Surface.
  2. Touch the pen tip on the screen. Observe the tiltX and tiltY values changing.
  3. Flip the pen around, and touch (or press hard) the eraser on the screen.
  4. Since the eraser doesn't have tilt support, Chrome correctly shows tilt as zero, but Firefox shows tilt as the last tilt values from the pen tip. Oops!

Untested: twist. I don't have access to any pen with twist/rotation, and I can't test that.

Flags: needinfo?(stransky)
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