[PATCH libinput 06/10] Add a pointer acceleration API

[Hans de Goede]

Hi,

On 09/19/2014 07:44 AM, Peter Hutterer wrote:
> Only exposes one knob - speed, normalized to a [-1, 1] range with 0 being the
> neutral "this is what we think is normal" speed. -1 and 1 reflect the
> slowest/fastest reasonable speed on this device.
> 
> Note: with this API we commit to having any pointer accelerating as a true
> gliding scale. We cannot map the [-1,1] range into a discrete set of steps
> as we do not communicate to the caller whether a specific value has changed
> the acceleration. Without that, a caller may assume that acceleration has
> changed even when it is not visible to the user.
> 
> Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>

Looks good:

Reviewed-by: Hans de Goede <hdegoede at redhat.com>

Regards,

Hans

> ---
>  src/libinput-private.h |  9 ++++++++
>  src/libinput.c         | 40 ++++++++++++++++++++++++++++++++++
>  src/libinput.h         | 59 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 108 insertions(+)
> 
> diff --git a/src/libinput-private.h b/src/libinput-private.h
> index cf03c03..614e8e1 100644
> --- a/src/libinput-private.h
> +++ b/src/libinput-private.h
> @@ -109,10 +109,19 @@ struct libinput_device_config_send_events {
>  	enum libinput_config_send_events_mode (*get_default_mode)(struct libinput_device *device);
>  };
>  
> +struct libinput_device_config_accel {
> +	int (*available)(struct libinput_device *device);
> +	enum libinput_config_status (*set_speed)(struct libinput_device *device,
> +						 double speed);
> +	double (*get_speed)(struct libinput_device *device);
> +	double (*get_default_speed)(struct libinput_device *device);
> +};
> +
>  struct libinput_device_config {
>  	struct libinput_device_config_tap *tap;
>  	struct libinput_device_config_calibration *calibration;
>  	struct libinput_device_config_send_events *sendevents;
> +	struct libinput_device_config_accel *accel;
>  };
>  
>  struct libinput_device {
> diff --git a/src/libinput.c b/src/libinput.c
> index 14f0257..18f3496 100644
> --- a/src/libinput.c
> +++ b/src/libinput.c
> @@ -1388,3 +1388,43 @@ libinput_device_config_send_events_get_default_mode(struct libinput_device *devi
>  {
>  	return LIBINPUT_CONFIG_SEND_EVENTS_ENABLED;
>  }
> +
> +
> +LIBINPUT_EXPORT int
> +libinput_device_config_accel_is_available(struct libinput_device *device)
> +{
> +	return device->config.accel ?
> +		device->config.accel->available(device) : 0;
> +}
> +
> +LIBINPUT_EXPORT enum libinput_config_status
> +libinput_device_config_accel_set_speed(struct libinput_device *device,
> +				       double speed)
> +{
> +	if (!libinput_device_config_accel_is_available(device))
> +		return LIBINPUT_CONFIG_STATUS_UNSUPPORTED;
> +
> +	if (speed < -1.0 || speed > 1.0)
> +		return LIBINPUT_CONFIG_STATUS_INVALID;
> +
> +	return device->config.accel->set_speed(device, speed);
> +}
> +
> +LIBINPUT_EXPORT double
> +libinput_device_config_accel_get_speed(struct libinput_device *device)
> +{
> +	if (!libinput_device_config_accel_is_available(device))
> +		return 0;
> +
> +	return device->config.accel->get_speed(device);
> +}
> +
> +LIBINPUT_EXPORT double
> +libinput_device_config_accel_get_default_speed(struct libinput_device *device)
> +{
> +	if (!libinput_device_config_accel_is_available(device))
> +		return 0;
> +
> +	return device->config.accel->get_default_speed(device);
> +}
> +
> diff --git a/src/libinput.h b/src/libinput.h
> index 806e1ab..83e3b37 100644
> --- a/src/libinput.h
> +++ b/src/libinput.h
> @@ -1783,6 +1783,65 @@ libinput_device_config_send_events_get_mode(struct libinput_device *device);
>  enum libinput_config_send_events_mode
>  libinput_device_config_send_events_get_default_mode(struct libinput_device *device);
>  
> +/**
> + * @ingroup config
> + *
> + * Check if a device uses libinput-internal pointer-acceleration.
> + *
> + * @param device The device to configure
> + *
> + * @return 0 if the device is not accelerated, nonzero if it is accelerated
> + */
> +int
> +libinput_device_config_accel_is_available(struct libinput_device *device);
> +
> +/**
> + * @ingroup config
> + *
> + * Set the pointer acceleration speed of this pointer device within a range
> + * of [-1, 1], where 0 is the default acceleration for this device, -1 is
> + * the slowest acceleration and 1 is the maximum acceleration available on
> + * this device. The actual pointer acceleration mechanism is
> + * implementation-dependent, as is the number of steps available within the
> + * range. libinput picks the semantically closest acceleration step if the
> + * requested value does not match a discreet setting.
> + *
> + * @param device The device to configure
> + * @param speed The normalized speed, in a range of [-1, 1]
> + *
> + * @return A config status code
> + */
> +enum libinput_config_status
> +libinput_device_config_accel_set_speed(struct libinput_device *device,
> +				       double speed);
> +
> +/**
> + * @ingroup config
> + *
> + * Get the current pointer acceleration setting for this pointer device. The
> + * returned value is normalized to a range of [-1, 1].
> + * See libinput_device_config_accel_set_speed() for details.
> + *
> + * @param device The device to configure
> + *
> + * @return The current speed, range -1 to 1
> + */
> +double
> +libinput_device_config_accel_get_speed(struct libinput_device *device);
> +
> +/**
> + * @ingroup config
> + *
> + * Return the default speed setting for this device, normalized to a range
> + * of [-1, 1].
> + * See libinput_device_config_accel_set_speed() for details.
> + *
> + * @param device The device to configure
> + * @return The default speed setting for this device.
> + */
> +double
> +libinput_device_config_accel_get_default_speed(struct libinput_device *device);
> +
>  #ifdef __cplusplus
>  }
>  #endif
>