This changes the API in various ways, and updates the backends for this.
Overall, this is a massive simplification of the API, as most future backends
can't support the previously-offered API.
This also removes the testautomation pen code (not only did these interfaces
change completely, it also did something no other test did: mock the internal
API), and replaces testpen.c with a different implementation (the existing
code was fine, it was just easier to start from scratch than update it).
It was intended to make the API easier to use, but various automatic garbage collection all had flaws, and making the application periodically clean up temporary memory added cognitive load to using the API, and in many cases was it was difficult to restructure threaded code to handle this.
So, we're largely going back to the original system, where the API returns allocated results and you free them.
In addition, to solve the problems we originally wanted temporary memory for:
* Short strings with a finite count, like device names, get stored in a per-thread string pool.
* Events continue to use temporary memory internally, which is cleaned up on the next event processing cycle.
This patch adds an API for querying pressure-
sensitive pens, cf. SDL_pen.h:
- Enumerate all pens
- Get pen capabilities, names, GUIDs
- Distinguishes pens and erasers
- Distinguish attached and detached pens
- Pressure and tilt support
- Rotation, distance, throttle wheel support
(throttle wheel untested)
- Pen type and meta-information reporting
(partially tested)
Pen event reporting:
- Three new event structures: PenTip, PenMotion, and
PenButton
- Report location with sub-pixel precision
- Include axis and button status, is-eraser flag
Internal pen tracker, intended to be independent
of platform APIs, cf. SDL_pen_c.h:
- Track known pens
- Handle pen hotplugging
Automatic test:
- testautomation_pen.c
Other features:
- XInput2 implementation, incl. hotplugging
- Wayland implementation, incl. hotplugging
- Backward compatibility: pen events default to
emulating pens with mouse ID SDL_PEN_MOUSEID
- Can be toggled via SDL_HINT_PEN_NOT_MOUSE
- Test/demo program (testpen)
- Wacom pen feature identification by pen ID
Acknowledgements:
- Ping Cheng (Wacom) provided extensive feedback
on Wacom pen features and detection so that
hopefully untested Wacom devices have a
realistic chance of working out of the box.
