Add configurable button map to tappings

The previously hardcoded button map for tapping is 1/2/3 to LRM. But the
middle button is a common feature on the desktop (used for paste, most
prominently) and three-finger tapping is almost impossible to do reliably on
some touchpads (e.g. the T440 has a recognition rate of ~1 in 5).

Left and right buttons have a prominent physical position (either softbuttons
or physical buttons) so make the tap order configurable. Those that require
middle buttons reliably can use the [software] buttons for left/right and
2-finger tap for a middle button.

https://bugs.freedesktop.org/show_bug.cgi?id=96962

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

src/evdev-mt-touchpad-tap.c

@@ -934,6 +934,25 @@ tp_tap_config_get_default(struct libinput_device *device)
 	return tp_tap_default(evdev);
 }
 
+static enum libinput_config_status
+tp_tap_config_set_map(struct libinput_device *device,
+		      enum libinput_config_tap_button_map map)
+{
+	return LIBINPUT_CONFIG_STATUS_UNSUPPORTED;
+}
+
+static enum libinput_config_tap_button_map
+tp_tap_config_get_map(struct libinput_device *device)
+{
+	return LIBINPUT_CONFIG_TAP_MAP_LRM;
+}
+
+static enum libinput_config_tap_button_map
+tp_tap_config_get_default_map(struct libinput_device *device)
+{
+	return LIBINPUT_CONFIG_TAP_MAP_LRM;
+}
+
 static enum libinput_config_status
 tp_tap_config_set_drag_enabled(struct libinput_device *device,
 			       enum libinput_config_drag_state enabled)
@@ -1017,6 +1036,9 @@ tp_init_tap(struct tp_dispatch *tp)
 	tp->tap.config.set_enabled = tp_tap_config_set_enabled;
 	tp->tap.config.get_enabled = tp_tap_config_is_enabled;
 	tp->tap.config.get_default = tp_tap_config_get_default;
+	tp->tap.config.set_map = tp_tap_config_set_map;
+	tp->tap.config.get_map = tp_tap_config_get_map;
+	tp->tap.config.get_default_map = tp_tap_config_get_default_map;
 	tp->tap.config.set_drag_enabled = tp_tap_config_set_drag_enabled;
 	tp->tap.config.get_drag_enabled = tp_tap_config_get_drag_enabled;
 	tp->tap.config.get_default_drag_enabled = tp_tap_config_get_default_drag_enabled;

src/libinput-private.h

@@ -164,6 +164,11 @@ struct libinput_device_config_tap {
 	enum libinput_config_tap_state (*get_enabled)(struct libinput_device *device);
 	enum libinput_config_tap_state (*get_default)(struct libinput_device *device);
 
+	enum libinput_config_status (*set_map)(struct libinput_device *device,
+						   enum libinput_config_tap_button_map map);
+	enum libinput_config_tap_button_map (*get_map)(struct libinput_device *device);
+	enum libinput_config_tap_button_map (*get_default_map)(struct libinput_device *device);
+
 	enum libinput_config_status (*set_drag_enabled)(struct libinput_device *device,
 							enum libinput_config_drag_state);
 	enum libinput_config_drag_state (*get_drag_enabled)(struct libinput_device *device);

src/libinput.c

@@ -3351,6 +3351,42 @@ libinput_device_config_tap_get_default_enabled(struct libinput_device *device)
 	return device->config.tap->get_default(device);
 }
 
+LIBINPUT_EXPORT enum libinput_config_status
+libinput_device_config_tap_set_button_map(struct libinput_device *device,
+					    enum libinput_config_tap_button_map map)
+{
+	switch (map) {
+	case LIBINPUT_CONFIG_TAP_MAP_LRM:
+	case LIBINPUT_CONFIG_TAP_MAP_LMR:
+		break;
+	default:
+		return LIBINPUT_CONFIG_STATUS_INVALID;
+	}
+
+	if (libinput_device_config_tap_get_finger_count(device) == 0)
+		return LIBINPUT_CONFIG_STATUS_UNSUPPORTED;
+
+	return device->config.tap->set_map(device, map);
+}
+
+LIBINPUT_EXPORT enum libinput_config_tap_button_map
+libinput_device_config_tap_get_button_map(struct libinput_device *device)
+{
+	if (libinput_device_config_tap_get_finger_count(device) == 0)
+		return LIBINPUT_CONFIG_TAP_MAP_LRM;
+
+	return device->config.tap->get_map(device);
+}
+
+LIBINPUT_EXPORT enum libinput_config_tap_button_map
+libinput_device_config_tap_get_default_button_map(struct libinput_device *device)
+{
+	if (libinput_device_config_tap_get_finger_count(device) == 0)
+		return LIBINPUT_CONFIG_TAP_MAP_LRM;
+
+	return device->config.tap->get_default_map(device);
+}
+
 LIBINPUT_EXPORT enum libinput_config_status
 libinput_device_config_tap_set_drag_enabled(struct libinput_device *device,
 					    enum libinput_config_drag_state enable)

src/libinput.h

@@ -3771,6 +3771,88 @@ libinput_device_config_tap_get_enabled(struct libinput_device *device);
 enum libinput_config_tap_state
 libinput_device_config_tap_get_default_enabled(struct libinput_device *device);
 
+/**
+ * @ingroup config
+ */
+enum libinput_config_tap_button_map {
+	/** 1/2/3 finger tap maps to left/right/middle */
+	LIBINPUT_CONFIG_TAP_MAP_LRM,
+	/** 1/2/3 finger tap maps to left/middle/right*/
+	LIBINPUT_CONFIG_TAP_MAP_LMR,
+};
+
+/**
+ * @ingroup config
+ *
+ * Set the finger number to button number mapping for tap-to-click. The
+ * default mapping on most devices is to have a 1, 2 and 3 finger tap to map
+ * to the left, right and middle button, respectively.
+ * A device may permit changing the button mapping but disallow specific
+ * maps. In this case @ref LIBINPUT_CONFIG_STATUS_UNSUPPORTED is returned,
+ * the caller is expected to handle this case correctly.
+ *
+ * Changing the button mapping may not take effect immediately,
+ * the device may wait until it is in a neutral state before applying any
+ * changes.
+ *
+ * The mapping may be changed when tap-to-click is disabled. The new mapping
+ * takes effect when tap-to-click is enabled in the future.
+ *
+ * @note It is an application bug to call this function for devices where
+ * libinput_device_config_tap_get_finger_count() returns 0.
+ *
+ * @param device The device to configure
+ * @param map The new finger-to-button number mapping
+ * @return A config status code. Changing the order on a device that does not
+ * support tapping always fails with @ref LIBINPUT_CONFIG_STATUS_UNSUPPORTED.
+ *
+ * @see libinput_device_config_tap_get_button_map
+ * @see libinput_device_config_tap_get_default_button_map
+ */
+enum libinput_config_status
+libinput_device_config_tap_set_button_map(struct libinput_device *device,
+					    enum libinput_config_tap_button_map map);
+
+/**
+ * @ingroup config
+ *
+ * Get the finger number to button number mapping for tap-to-click.
+ *
+ * The return value for a device that does not support tapping is always
+ * @ref LIBINPUT_CONFIG_TAP_MAP_LRM.
+ *
+ * @note It is an application bug to call this function for devices where
+ * libinput_device_config_tap_get_finger_count() returns 0.
+ *
+ * @param device The device to configure
+ * @return The current finger-to-button number mapping
+ *
+ * @see libinput_device_config_tap_set_button_map
+ * @see libinput_device_config_tap_get_default_button_map
+ */
+enum libinput_config_tap_button_map
+libinput_device_config_tap_get_button_map(struct libinput_device *device);
+
+/**
+ * @ingroup config
+ *
+ * Get the default finger number to button number mapping for tap-to-click.
+ *
+ * The return value for a device that does not support tapping is always
+ * @ref LIBINPUT_CONFIG_TAP_MAP_LRM.
+ *
+ * @note It is an application bug to call this function for devices where
+ * libinput_device_config_tap_get_finger_count() returns 0.
+ *
+ * @param device The device to configure
+ * @return The current finger-to-button number mapping
+ *
+ * @see libinput_device_config_tap_set_button_map
+ * @see libinput_device_config_tap_get_default_button_map
+ */
+enum libinput_config_tap_button_map
+libinput_device_config_tap_get_default_button_map(struct libinput_device *device);
+
 /**
  * @ingroup config
  *

src/libinput.sym

@@ -274,3 +274,9 @@ LIBINPUT_1.4 {
 	libinput_tablet_pad_mode_group_set_user_data;
 	libinput_tablet_pad_mode_group_unref;
 } LIBINPUT_1.3;
+
+LIBINPUT_1.5 {
+	libinput_device_config_tap_get_button_map;
+	libinput_device_config_tap_get_default_button_map;
+	libinput_device_config_tap_set_button_map;
+} LIBINPUT_1.4;

tools/shared.c

@@ -45,6 +45,7 @@ enum options {
 	OPT_VERBOSE,
 	OPT_TAP_ENABLE,
 	OPT_TAP_DISABLE,
+	OPT_TAP_MAP,
 	OPT_DRAG_ENABLE,
 	OPT_DRAG_DISABLE,
 	OPT_DRAG_LOCK_ENABLE,
@@ -101,6 +102,7 @@ tools_usage()
 	       "--set-scroll-button=BTN_MIDDLE ... set the button to the given button code\n"
 	       "--set-profile=[adaptive|flat].... set pointer acceleration profile\n"
 	       "--set-speed=<value>.... set pointer acceleration speed\n"
+	       "--set-tap-map=[lrm|lmr] ... set button mapping for tapping\n"
 	       "\n"
 	       "These options apply to all applicable devices, if a feature\n"
 	       "is not explicitly specified it is left at each device's default.\n"
@@ -121,6 +123,7 @@ tools_init_context(struct tools_context *context)
 
 	memset(options, 0, sizeof(*options));
 	options->tapping = -1;
+	options->tap_map = -1;
 	options->drag = -1;
 	options->drag_lock = -1;
 	options->natural_scroll = -1;
@@ -168,6 +171,7 @@ tools_parse_args(int argc, char **argv, struct tools_context *context)
 			{ "set-scroll-method", 1, 0, OPT_SCROLL_METHOD },
 			{ "set-scroll-button", 1, 0, OPT_SCROLL_BUTTON },
 			{ "set-profile", 1, 0, OPT_PROFILE },
+			{ "set-tap-map", 1, 0, OPT_TAP_MAP },
 			{ "speed", 1, 0, OPT_SPEED },
 			{ 0, 0, 0, 0}
 		};
@@ -206,6 +210,20 @@ tools_parse_args(int argc, char **argv, struct tools_context *context)
 		case OPT_TAP_DISABLE:
 			options->tapping = 0;
 			break;
+		case OPT_TAP_MAP:
+			if (!optarg) {
+				tools_usage();
+				return 1;
+			}
+			if (streq(optarg, "lrm")) {
+				options->tap_map = LIBINPUT_CONFIG_TAP_MAP_LRM;
+			} else if (streq(optarg, "lmr")) {
+				options->tap_map = LIBINPUT_CONFIG_TAP_MAP_LMR;
+			} else {
+				tools_usage();
+				return 1;
+			}
+			break;
 		case OPT_DRAG_ENABLE:
 			options->drag = 1;
 			break;
@@ -451,6 +469,9 @@ tools_device_apply_config(struct libinput_device *device,
 {
 	if (options->tapping != -1)
 		libinput_device_config_tap_set_enabled(device, options->tapping);
+	if (options->tap_map != -1)
+		libinput_device_config_tap_set_button_map(device,
+							  options->tap_map);
 	if (options->drag != -1)
 		libinput_device_config_tap_set_drag_enabled(device,
 							    options->drag);

tools/shared.h

@@ -46,6 +46,7 @@ struct tools_options {
 	int middlebutton;
 	enum libinput_config_click_method click_method;
 	enum libinput_config_scroll_method scroll_method;
+	enum libinput_config_tap_button_map tap_map;
 	int scroll_button;
 	double speed;
 	int dwt;