Add zwp-tablet-unstable-v2 client support

This allows wlroots based compositors to properly use graphic tablets
with the wayland backend.
This should be a decent quality of life improvement when working on
tablet related features.

6 files changed, 960 insertions, 1 deletions

diff --git a/backend/meson.build b/backend/meson.build
index ca85ad31..574d4f74 100644
--- a/backend/meson.build
+++ b/backend/meson.build
@@ -28,6 +28,7 @@ backend_files = files(
 	'wayland/backend.c',
 	'wayland/output.c',
 	'wayland/wl_seat.c',
+	'wayland/tablet_v2.c',
 )
 
 backend_deps = [
diff --git a/backend/wayland/backend.c b/backend/wayland/backend.c
index c2762c4a..b1d08568 100644
--- a/backend/wayland/backend.c
+++ b/backend/wayland/backend.c
@@ -19,6 +19,11 @@
 #include "xdg-decoration-unstable-v1-client-protocol.h"
 #include "pointer-gestures-unstable-v1-client-protocol.h"
 #include "xdg-shell-client-protocol.h"
+#include "tablet-unstable-v2-client-protocol.h"
+
+struct wlr_wl_tablet_seat *wlr_wl_add_tablet_seat(
+		struct zwp_tablet_manager_v2 *manager,
+		struct wl_seat *seat, struct wlr_wl_backend *backend);
 
 struct wlr_wl_backend *get_wl_backend_from_backend(struct wlr_backend *backend) {
 	assert(wlr_backend_is_wl(backend));
@@ -81,6 +86,9 @@ static void registry_global(void *data, struct wl_registry *registry,
 	} else if (strcmp(iface, zwp_pointer_gestures_v1_interface.name) == 0) {
 		wl->zwp_pointer_gestures_v1 = wl_registry_bind(registry, name,
 			&zwp_pointer_gestures_v1_interface, 1);
+	} else if (strcmp(iface, zwp_tablet_manager_v2_interface.name) == 0) {
+		wl->tablet_manager = wl_registry_bind(registry, name,
+			&zwp_tablet_manager_v2_interface, 1);
 	}
 }
 
@@ -109,6 +117,11 @@ static bool backend_start(struct wlr_backend *backend) {
 		create_wl_keyboard(wl->keyboard, wl);
 	}
 
+	if (wl->tablet_manager && wl->seat) {
+		wlr_wl_add_tablet_seat(wl->tablet_manager,
+			wl->seat, wl);
+	}
+
 	for (size_t i = 0; i < wl->requested_outputs; ++i) {
 		wlr_wl_output_create(&wl->backend);
 	}
diff --git a/backend/wayland/tablet_v2.c b/backend/wayland/tablet_v2.c
new file mode 100644
index 00000000..10a6d84d
--- /dev/null
+++ b/backend/wayland/tablet_v2.c
@@ -0,0 +1,941 @@
+#ifndef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 200809L
+#endif
+
+#include <wayland-util.h>
+#include <assert.h>
+#include <math.h>
+#include <stdlib.h>
+#include <string.h>
+#include <wlr/interfaces/wlr_tablet_pad.h>
+#include <wlr/interfaces/wlr_tablet_tool.h>
+#include <wlr/types/wlr_input_device.h>
+#include <wlr/interfaces/wlr_input_device.h>
+
+#include "util/signal.h"
+#include "wlr/util/log.h"
+#include "tablet-unstable-v2-client-protocol.h"
+
+#include <backend/wayland.h>
+
+struct wlr_wl_tablet_seat {
+	struct zwp_tablet_seat_v2 *tablet_seat;
+	struct wl_list tablets;
+	struct wl_list tools;
+//	struct wl_list pads; // wlr_wl_tablet_pad::link
+};
+
+struct wlr_wl_tablet_tool {
+	/* static */
+	struct zwp_tablet_tool_v2 *tool;
+	struct wlr_tablet_tool wlr_tool;
+
+	/* semi-static */
+	struct wlr_wl_input_device *tablet;
+	double pre_x, pre_y;
+
+	/* per frame */
+	double x, y;
+
+	double pressure;
+	double distance;
+	double tilt_x, tilt_y;
+	double rotation;
+	double slider;
+	double wheel_delta;
+
+	bool is_in;
+	bool is_out;
+
+	bool is_up;
+	bool is_down;
+};
+
+struct wlr_wl_tablet_pad_ring {
+	struct wl_list link; // wlr_wl_tablet_pad_group::rings
+	/* static */
+	struct zwp_tablet_pad_ring_v2 *ring;
+	struct wlr_wl_tablet_pad_group *group;
+	size_t index;
+
+	/* per frame */
+	enum wlr_tablet_pad_ring_source source;
+	double angle;
+	bool stopped;
+};
+
+struct wlr_wl_tablet_pad_strip {
+	struct wl_list link; // wlr_wl_tablet_pad_group::strips
+	struct zwp_tablet_pad_strip_v2 *strip;
+	struct wlr_wl_tablet_pad_group *group;
+	size_t index;
+
+	enum wlr_tablet_pad_strip_source source;
+	double position;
+	bool stopped;
+};
+
+struct wlr_wl_tablet_pad_group {
+	struct zwp_tablet_pad_group_v2 *pad_group;
+	struct wlr_tablet_pad *pad;
+	unsigned int mode;
+
+	struct wlr_tablet_pad_group group;
+
+	struct wl_list rings; // wlr_wl_tablet_pad_ring::link
+	struct wl_list strips; // wlr_wl_tablet_pad_strips::link
+};
+
+static uint32_t get_current_time_msec(void) {
+	struct timespec now;
+	clock_gettime(CLOCK_MONOTONIC, &now);
+	return now.tv_nsec / (1000 * 1000) + now.tv_sec * 1000;
+}
+
+struct wlr_wl_tablet_seat *wlr_wl_add_tablet_seat(
+		struct zwp_tablet_manager_v2 *manager,
+		struct wl_seat *seat, struct wlr_wl_backend *backend);
+
+static void handle_tablet_pad_ring_source(void *data,
+		struct zwp_tablet_pad_ring_v2 *zwp_tablet_pad_ring_v2,
+		uint32_t source) {
+	struct wlr_wl_tablet_pad_ring *ring = data;
+	ring->source = source;
+}
+
+static void handle_tablet_pad_ring_angle(void *data,
+		struct zwp_tablet_pad_ring_v2 *zwp_tablet_pad_ring_v2,
+		wl_fixed_t degrees) {
+	struct wlr_wl_tablet_pad_ring *ring = data;
+	ring->angle = wl_fixed_to_double(degrees);
+}
+
+static void handle_tablet_pad_ring_stop(void *data,
+		struct zwp_tablet_pad_ring_v2 *zwp_tablet_pad_ring_v2) {
+	struct wlr_wl_tablet_pad_ring *ring = data;
+	ring->stopped = true;
+}
+
+static void handle_tablet_pad_ring_frame(void *data,
+		struct zwp_tablet_pad_ring_v2 *zwp_tablet_pad_ring_v2,
+		uint32_t time) {
+	struct wlr_wl_tablet_pad_ring *ring = data;
+
+	struct wlr_event_tablet_pad_ring evt = {
+		.time_msec = time,
+		.source = ring->source,
+		.ring = ring->index,
+		.position = ring->angle,
+		.mode = ring->group->mode,
+	};
+
+	if (ring->angle >= 0) {
+		wlr_signal_emit_safe(&ring->group->pad->events.ring, &evt);
+	}
+	if (ring->stopped) {
+		evt.position = -1;
+		wlr_signal_emit_safe(&ring->group->pad->events.ring, &evt);
+	}
+
+	ring->angle = -1;
+	ring->stopped = false;
+	ring->source = 0;
+}
+
+static const struct zwp_tablet_pad_ring_v2_listener tablet_pad_ring_listener = {
+	.source = handle_tablet_pad_ring_source,
+	.angle = handle_tablet_pad_ring_angle,
+	.stop = handle_tablet_pad_ring_stop,
+	.frame = handle_tablet_pad_ring_frame,
+};
+
+static void handle_tablet_pad_strip_source(void *data,
+		struct zwp_tablet_pad_strip_v2 *zwp_tablet_pad_strip_v2,
+		uint32_t source) {
+	struct wlr_wl_tablet_pad_strip *strip = data;
+	strip->source = source;
+}
+
+static void handle_tablet_pad_strip_position(void *data,
+		struct zwp_tablet_pad_strip_v2 *zwp_tablet_pad_strip_v2,
+		uint32_t position) {
+	struct wlr_wl_tablet_pad_strip *strip = data;
+	strip->position = (double) position / 65536.0;
+}
+
+static void handle_tablet_pad_strip_stop(void *data,
+		struct zwp_tablet_pad_strip_v2 *zwp_tablet_pad_strip_v2) {
+	struct wlr_wl_tablet_pad_strip *strip = data;
+	strip->stopped = true;
+}
+
+static void handle_tablet_pad_strip_frame(void *data,
+		struct zwp_tablet_pad_strip_v2 *zwp_tablet_pad_strip_v2,
+		uint32_t time) {
+	struct wlr_wl_tablet_pad_strip *strip = data;
+
+	struct wlr_event_tablet_pad_strip evt = {
+		.time_msec = time,
+		.source = strip->source,
+		.strip = strip->index,
+		.position = strip->position,
+		.mode = strip->group->mode,
+	};
+
+	if (strip->position >= 0) {
+		wlr_signal_emit_safe(&strip->group->pad->events.strip, &evt);
+	}
+	if (strip->stopped) {
+		evt.position = -1;
+		wlr_signal_emit_safe(&strip->group->pad->events.strip, &evt);
+	}
+
+	strip->position = -1;
+	strip->stopped = false;
+	strip->source = 0;
+}
+
+static const struct zwp_tablet_pad_strip_v2_listener tablet_pad_strip_listener = {
+	.source = handle_tablet_pad_strip_source,
+	.position = handle_tablet_pad_strip_position,
+	.stop = handle_tablet_pad_strip_stop,
+	.frame = handle_tablet_pad_strip_frame,
+};
+
+static void handle_tablet_pad_group_buttons(void *data,
+		struct zwp_tablet_pad_group_v2 *pad_group,
+		struct wl_array *buttons) {
+	struct wlr_wl_tablet_pad_group *group = data;
+
+	group->group.buttons = calloc(1, buttons->size);
+	if (!group->group.buttons) {
+		// FIXME: Add actual error handling
+		return;
+	}
+
+	group->group.button_count = buttons->size / sizeof(int);
+	memcpy(group->group.buttons, buttons->data, buttons->size);
+}
+
+static void handle_tablet_pad_group_modes(void *data,
+		struct zwp_tablet_pad_group_v2 *pad_group, uint32_t modes) {
+	struct wlr_wl_tablet_pad_group *group = data;
+
+	group->group.mode_count = modes;
+}
+
+static void handle_tablet_pad_group_ring(void *data,
+		struct zwp_tablet_pad_group_v2 *pad_group,
+		struct zwp_tablet_pad_ring_v2 *ring) {
+	struct wlr_wl_tablet_pad_group *group = data;
+	struct wlr_wl_tablet_pad_ring *tablet_ring =
+		calloc(1, sizeof(struct wlr_wl_tablet_pad_ring));
+	if (!tablet_ring) {
+		zwp_tablet_pad_ring_v2_destroy(ring);
+		return;
+	}
+	tablet_ring->index = group->pad->ring_count++;
+	tablet_ring->group = group;
+	zwp_tablet_pad_ring_v2_add_listener(ring, &tablet_pad_ring_listener, 
+		tablet_ring);
+
+	group->group.rings = realloc(group->group.rings,
+		++group->group.ring_count * sizeof(unsigned int));
+	group->group.rings[group->group.ring_count - 1] =
+		tablet_ring->index;
+}
+
+static void handle_tablet_pad_group_strip(void *data,
+		struct zwp_tablet_pad_group_v2 *pad_group,
+		struct zwp_tablet_pad_strip_v2 *strip) {
+	struct wlr_wl_tablet_pad_group *group = data;
+	struct wlr_wl_tablet_pad_strip *tablet_strip =
+		calloc(1, sizeof(struct wlr_wl_tablet_pad_strip));
+	if (!tablet_strip) {
+		zwp_tablet_pad_strip_v2_destroy(strip);
+		return;
+	}
+	tablet_strip->index = group->pad->strip_count++;
+	tablet_strip->group = group;
+	zwp_tablet_pad_strip_v2_add_listener(strip, &tablet_pad_strip_listener, 
+		tablet_strip);
+
+	group->group.strips = realloc(group->group.strips,
+		++group->group.strip_count * sizeof(unsigned int));
+	group->group.strips[group->group.strip_count - 1] =
+		tablet_strip->index;
+}
+
+static void handle_tablet_pad_group_done(void *data,
+		struct zwp_tablet_pad_group_v2 *pad_group) {
+	/* Empty for now */
+}
+
+static void handle_tablet_pad_group_mode_switch(void *data,
+		struct zwp_tablet_pad_group_v2 *pad_group,
+		uint32_t time, uint32_t serial, uint32_t mode) {
+	struct wlr_wl_tablet_pad_group *group = data;
+	group->mode = mode;
+}
+
+/* This isn't in the listener, but keep the naming scheme around since the
+ * other removed functions work like this, and pad sub-resources are just a bit
+ * special */
+static void handle_tablet_pad_group_removed(
+		struct wlr_wl_tablet_pad_group *group) {
+
+	/* No need to remove the ::link on strips rings as long as we do *not*
+	 * wl_list_remove on the wl_groups ring/strip attributes here */
+	struct wlr_wl_tablet_pad_ring *ring, *tmp_ring;
+	wl_list_for_each_safe(ring, tmp_ring, &group->rings, link) {
+		zwp_tablet_pad_ring_v2_destroy(ring->ring);
+		free(ring);
+	}
+
+	struct wlr_wl_tablet_pad_strip *strip, *tmp_strip;
+	wl_list_for_each_safe(strip, tmp_strip, &group->strips, link) {
+		zwp_tablet_pad_strip_v2_destroy(strip->strip);
+		free(strip);
+	}
+
+	zwp_tablet_pad_group_v2_destroy(group->pad_group);
+
+	/* While I'm pretty sure we have control over this as well, it's
+	 * outside the scope of a single function, so better be safe than
+	 * sorry */
+	wl_list_remove(&group->group.link);
+	free(group);
+}
+
+static const struct zwp_tablet_pad_group_v2_listener tablet_pad_group_listener = {
+	.buttons = handle_tablet_pad_group_buttons,
+	.modes = handle_tablet_pad_group_modes,
+	.ring = handle_tablet_pad_group_ring,
+	.strip = handle_tablet_pad_group_strip,
+	.done = handle_tablet_pad_group_done,
+	.mode_switch = handle_tablet_pad_group_mode_switch,
+};
+
+static void handle_tablet_pad_group(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad,
+		struct zwp_tablet_pad_group_v2 *pad_group) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet_pad *pad = dev->wlr_input_device.tablet_pad;
+
+	struct wlr_wl_tablet_pad_group *group =
+		calloc(1, sizeof(struct wlr_wl_tablet_pad_group));
+	if (!group) {
+		zwp_tablet_pad_group_v2_destroy(pad_group);
+		return;
+	}
+	group->pad_group = pad_group;
+	group->pad = pad;
+
+	wl_list_init(&group->rings);
+	wl_list_init(&group->strips);
+
+	zwp_tablet_pad_group_v2_add_listener(pad_group,
+		&tablet_pad_group_listener, group);
+
+	wl_list_insert(&pad->groups, &group->group.link);
+}
+
+static void handle_tablet_pad_path(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2,
+		const char *path) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet_pad *tablet_pad = dev->wlr_input_device.tablet_pad;
+
+	wlr_list_push(&tablet_pad->paths, strdup(path));
+}
+
+static void handle_tablet_pad_buttons(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2,
+		uint32_t buttons) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet_pad *tablet_pad = dev->wlr_input_device.tablet_pad;
+
+	tablet_pad->button_count = buttons;
+}
+
+static void handle_tablet_pad_button(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2,
+		uint32_t time, uint32_t button, uint32_t state) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet_pad *tablet_pad = dev->wlr_input_device.tablet_pad;
+
+	struct wlr_event_tablet_pad_button evt = {
+		.time_msec = time,
+		.button = button,
+		.state = state,
+		.mode = 0,
+		.group = 0,
+	};
+
+	wlr_signal_emit_safe(&tablet_pad->events.button, &evt);
+}
+
+static void handle_tablet_pad_done(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2) {
+	struct wlr_wl_input_device *dev = data;
+
+	wlr_signal_emit_safe(&dev->backend->backend.events.new_input,
+		&dev->wlr_input_device);
+}
+
+static void handle_tablet_pad_enter(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2,
+		uint32_t serial, struct zwp_tablet_v2 *tablet_p,
+		struct wl_surface *surface) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet_pad *tablet_pad = dev->wlr_input_device.tablet_pad;
+	struct wlr_wl_input_device *tab_dev = zwp_tablet_v2_get_user_data(tablet_p);
+	struct wlr_input_device *tablet = &tab_dev->wlr_input_device;
+	wlr_log(WLR_DEBUG, "Tablet: %p\n", tablet);
+
+	wlr_signal_emit_safe(&tablet_pad->events.attach_tablet, tablet);
+}
+
+static void handle_tablet_pad_leave(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2,
+		uint32_t serial, struct wl_surface *surface) {
+	/* Empty. Probably staying that way, unless we want to create/destroy
+	 * tablet on enter/leave events (ehh) */
+}
+
+static void handle_tablet_pad_removed(void *data,
+		struct zwp_tablet_pad_v2 *zwp_tablet_pad_v2) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet_pad *tablet_pad = dev->wlr_input_device.tablet_pad;
+
+	/* This doesn't free anything, but emits the destroy signal */
+	wlr_input_device_destroy(&dev->wlr_input_device);
+	/* This is a bit ugly, but we need to remove it from our list */
+	wl_list_remove(&dev->wlr_input_device.link);
+
+	struct wlr_wl_tablet_pad_group *group, *it;
+	wl_list_for_each_safe(group, it, &tablet_pad->groups, group.link) {
+		handle_tablet_pad_group_removed(group);
+	}
+
+	/* This frees */
+	wlr_tablet_pad_destroy(tablet_pad);
+	zwp_tablet_pad_v2_destroy(dev->resource);
+	free(dev);
+}
+
+static const struct zwp_tablet_pad_v2_listener tablet_pad_listener = {
+	.group = handle_tablet_pad_group,
+	.path = handle_tablet_pad_path,
+	.buttons = handle_tablet_pad_buttons,
+	.button = handle_tablet_pad_button,
+	.done = handle_tablet_pad_done,
+	.enter = handle_tablet_pad_enter,
+	.leave = handle_tablet_pad_leave,
+	.removed = handle_tablet_pad_removed,
+};
+
+static void handle_pad_added(void *data,
+		struct zwp_tablet_seat_v2 *zwp_tablet_seat_v2,
+		struct zwp_tablet_pad_v2 *id) {
+	wlr_log(WLR_DEBUG, "New tablet pad");
+	struct wlr_wl_backend *backend = data;
+	struct wlr_wl_input_device *dev = create_wl_input_device(
+		backend, WLR_INPUT_DEVICE_TABLET_PAD);
+	if (!dev) {
+		/* This leaks a couple of server-sent resource ids. iirc this
+		 * shouldn't ever be a problem, but it isn't exactly nice
+		 * either. */
+		zwp_tablet_pad_v2_destroy(id);
+		return;
+	}
+
+	dev->resource = id;
+	struct wlr_input_device *wlr_dev = &dev->wlr_input_device;
+	wlr_dev->tablet_pad = calloc(1, sizeof(*wlr_dev->tablet_pad));
+
+	if (!wlr_dev->tablet_pad) {
+		/* This leaks a couple of server-sent resource ids. iirc this
+		 * shouldn't ever be a problem, but it isn't exactly nice
+		 * either. */
+		free(dev);
+		zwp_tablet_pad_v2_destroy(id);
+		return;
+	}
+	wlr_tablet_pad_init(wlr_dev->tablet_pad, NULL);
+	zwp_tablet_pad_v2_add_listener(id, &tablet_pad_listener, dev);
+}
+
+static void handle_tablet_tool_done(void *data,
+		struct zwp_tablet_tool_v2 *id) {
+	/* empty */
+}
+static enum wlr_tablet_tool_type tablet_type_to_wlr_type(enum zwp_tablet_tool_v2_type type) {
+
+	switch(type) {
+	case ZWP_TABLET_TOOL_V2_TYPE_PEN:
+		return WLR_TABLET_TOOL_TYPE_PEN;
+	case ZWP_TABLET_TOOL_V2_TYPE_ERASER:
+		return WLR_TABLET_TOOL_TYPE_ERASER;
+	case ZWP_TABLET_TOOL_V2_TYPE_BRUSH:
+		return WLR_TABLET_TOOL_TYPE_BRUSH;
+	case ZWP_TABLET_TOOL_V2_TYPE_PENCIL:
+		return WLR_TABLET_TOOL_TYPE_PENCIL;
+	case ZWP_TABLET_TOOL_V2_TYPE_AIRBRUSH:
+		return WLR_TABLET_TOOL_TYPE_AIRBRUSH;
+	case ZWP_TABLET_TOOL_V2_TYPE_MOUSE:
+		return WLR_TABLET_TOOL_TYPE_MOUSE;
+	case ZWP_TABLET_TOOL_V2_TYPE_LENS:
+		return WLR_TABLET_TOOL_TYPE_LENS;
+	default:
+		break;
+	}
+
+	assert(false && "Unreachable");
+}
+
+static void handle_tablet_tool_type(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t tool_type) {
+	struct wlr_wl_tablet_tool *tool = data;
+
+	tool->wlr_tool.type = tablet_type_to_wlr_type(tool_type);
+}
+
+static void handle_tablet_tool_serial(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t high, uint32_t low) {
+	struct wlr_wl_tablet_tool *tool = data;
+
+	tool->wlr_tool.hardware_serial =
+		((uint64_t) high) << 32 | (uint64_t) low;
+}
+
+static void handle_tablet_tool_id_wacom(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t high, uint32_t low) {
+	struct wlr_wl_tablet_tool *tool = data;
+
+	tool->wlr_tool.hardware_wacom =
+		((uint64_t) high) << 32 | (uint64_t) low;
+}
+
+static void handle_tablet_tool_capability(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t capability) {
+	struct wlr_wl_tablet_tool *tool = data;
+
+	enum zwp_tablet_tool_v2_capability cap = capability;
+	
+	switch(cap) {
+	case ZWP_TABLET_TOOL_V2_CAPABILITY_TILT:
+		tool->wlr_tool.tilt = true;
+		break;
+	case ZWP_TABLET_TOOL_V2_CAPABILITY_PRESSURE:
+		tool->wlr_tool.pressure = true;
+		break;
+	case ZWP_TABLET_TOOL_V2_CAPABILITY_DISTANCE:
+		tool->wlr_tool.distance = true;
+		break;
+	case ZWP_TABLET_TOOL_V2_CAPABILITY_ROTATION:
+		tool->wlr_tool.rotation = true;
+		break;
+	case ZWP_TABLET_TOOL_V2_CAPABILITY_SLIDER:
+		tool->wlr_tool.slider = true;
+		break;
+	case ZWP_TABLET_TOOL_V2_CAPABILITY_WHEEL:
+		tool->wlr_tool.wheel = true;
+		break;
+	}
+}
+
+static void handle_tablet_tool_proximity_in(void *data,
+		struct zwp_tablet_tool_v2 *id, uint32_t serial,
+		struct zwp_tablet_v2 *tablet_id,
+		struct wl_surface *surface) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->is_in = true;
+	tool->tablet = zwp_tablet_v2_get_user_data(tablet_id);
+}
+
+static void handle_tablet_tool_proximity_out(void *data,
+		struct zwp_tablet_tool_v2 *id) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->is_out = true;
+}
+
+static void handle_tablet_tool_down(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		unsigned int serial) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->is_down = true;
+}
+
+static void handle_tablet_tool_up(void *data,
+		struct zwp_tablet_tool_v2 *id) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->is_up = true;
+}
+
+static void handle_tablet_tool_motion(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		wl_fixed_t x, wl_fixed_t y) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->x = wl_fixed_to_double(x);
+	tool->y = wl_fixed_to_double(y);
+}
+
+static void handle_tablet_tool_pressure(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t pressure) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->pressure = (double) pressure / 65535.0;
+}
+
+static void handle_tablet_tool_distance(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t distance) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->distance = (double) distance / 65535.0;
+}
+
+static void handle_tablet_tool_tilt(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		wl_fixed_t x, wl_fixed_t y) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->tilt_x = wl_fixed_to_double(x);
+	tool->tilt_y = wl_fixed_to_double(y);
+}
+
+static void handle_tablet_tool_rotation(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		wl_fixed_t rotation) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->rotation = wl_fixed_to_double(rotation);
+}
+
+static void handle_tablet_tool_slider(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		int slider) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->slider = (double) slider / 65535.0;;
+}
+
+// TODO: This looks wrong :/
+static void handle_tablet_tool_wheel(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		wl_fixed_t degree, int clicks) {
+	struct wlr_wl_tablet_tool *tool = data;
+	tool->wheel_delta = wl_fixed_to_double(degree);
+}
+
+static void handle_tablet_tool_button(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t serial, uint32_t button, uint32_t state) {
+	struct wlr_wl_tablet_tool *tool = data;
+	struct wlr_tablet *tablet = tool->tablet->wlr_input_device.tablet;
+
+	struct wlr_event_tablet_tool_button evt = {
+		.device = &tool->tablet->wlr_input_device,
+		.tool = &tool->wlr_tool,
+		.time_msec = get_current_time_msec(),
+		.button = button,
+		.state = state == ZWP_TABLET_TOOL_V2_BUTTON_STATE_RELEASED ?
+			WLR_BUTTON_RELEASED : WLR_BUTTON_PRESSED,
+	};
+
+	wlr_signal_emit_safe(&tablet->events.button, &evt);
+}
+
+static void clear_tablet_tool_values(struct wlr_wl_tablet_tool *tool) {
+	tool->is_out = tool->is_in = false;
+	tool->is_up = tool->is_down = false;
+	tool->x = tool->y = NAN;
+	tool->pressure = NAN;
+	tool->distance = NAN;
+	tool->tilt_x = tool->tilt_y = NAN;
+	tool->rotation = NAN;
+	tool->slider = NAN;
+	tool->wheel_delta = NAN;
+}
+
+static void handle_tablet_tool_frame(void *data,
+		struct zwp_tablet_tool_v2 *id,
+		uint32_t time) {
+	struct wlr_wl_tablet_tool *tool = data;
+	if (tool->is_out && tool->is_in) {
+		/* we got a tablet tool coming in and out of proximity before
+		 * we could process it. Just ignore anything it did */
+		goto clear_values;
+	}
+	struct wlr_tablet *tablet = tool->tablet->wlr_input_device.tablet;
+
+	if (tool->is_in) {
+		struct wlr_event_tablet_tool_proximity evt = {
+			.device = &tool->tablet->wlr_input_device,
+			.tool = &tool->wlr_tool,
+			.time_msec = time,
+			.x = tool->x,
+			.y = tool->y,
+			.state = WLR_TABLET_TOOL_PROXIMITY_IN,
+		};
+	
+		wlr_signal_emit_safe(&tablet->events.proximity, &evt);
+	}
+
+	{
+		struct wlr_event_tablet_tool_axis evt = {
+			.device = &tool->tablet->wlr_input_device,
+			.tool = &tool->wlr_tool,
+			.time_msec = time,
+			.updated_axes = 0,
+		};
+
+		if (!isnan(tool->x) && !tool->is_in) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_X;
+			evt.x = tool->x;
+		}
+
+		if (!isnan(tool->y) && !tool->is_in) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_Y;
+			evt.y = tool->y;
+		}
+
+		if (!isnan(tool->pressure)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_PRESSURE;
+			evt.pressure = tool->pressure;
+		}
+
+		if (!isnan(tool->distance)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_DISTANCE;
+			evt.distance = tool->distance;
+		}
+
+		if (!isnan(tool->tilt_x)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_TILT_X;
+			evt.tilt_x = tool->tilt_x;
+		}
+
+		if (!isnan(tool->tilt_y)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_TILT_Y;
+			evt.tilt_y = tool->tilt_y;
+		}
+
+		if (!isnan(tool->rotation)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_ROTATION;
+			evt.rotation = tool->rotation;
+		}
+
+		if (!isnan(tool->slider)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_SLIDER;
+			evt.slider = tool->slider;
+		}
+
+		if (!isnan(tool->wheel_delta)) {
+			evt.updated_axes |= WLR_TABLET_TOOL_AXIS_WHEEL;
+			evt.wheel_delta = tool->wheel_delta;
+		}
+
+		if (evt.updated_axes) {
+			wlr_signal_emit_safe(&tablet->events.proximity, &evt);
+		}
+	}
+
+	/* This will always send down then up if we got both.
+	 * Maybe we should send them right away, in case we get up then both in
+	 * series?
+	 * Downside: Here we have the frame time, if we sent right away, we
+	 * need to generate the time */
+	if (tool->is_down) {
+		struct wlr_event_tablet_tool_tip evt = {
+			.device = &tool->tablet->wlr_input_device,
+			.tool = &tool->wlr_tool,
+			.time_msec = time,
+			.x = tool->x,
+			.y = tool->y,
+			.state = WLR_TABLET_TOOL_TIP_DOWN,
+		};
+	
+		wlr_signal_emit_safe(&tablet->events.tip, &evt);
+	}
+
+	if (tool->is_up) {
+		struct wlr_event_tablet_tool_tip evt = {
+			.device = &tool->tablet->wlr_input_device,
+			.tool = &tool->wlr_tool,
+			.time_msec = time,
+			.x = tool->x,
+			.y = tool->y,
+			.state = WLR_TABLET_TOOL_TIP_UP,
+		};
+	
+		wlr_signal_emit_safe(&tablet->events.tip, &evt);
+	}
+
+	if (tool->is_out) {
+		struct wlr_event_tablet_tool_proximity evt = {
+			.device = &tool->tablet->wlr_input_device,
+			.tool = &tool->wlr_tool,
+			.time_msec = time,
+			.x = tool->x,
+			.y = tool->y,
+			.state = WLR_TABLET_TOOL_PROXIMITY_OUT,
+		};
+	
+		wlr_signal_emit_safe(&tablet->events.proximity, &evt);
+	}
+
+clear_values:
+	clear_tablet_tool_values(tool);
+}
+
+static void handle_tablet_tool_removed(void *data,
+		struct zwp_tablet_tool_v2 *id) {
+	struct wlr_wl_tablet_tool *tool = data;
+
+	zwp_tablet_tool_v2_destroy(tool->tool);
+	wlr_signal_emit_safe(&tool->wlr_tool.events.destroy, &tool->wlr_tool);
+	free(tool);
+}
+
+static const struct zwp_tablet_tool_v2_listener tablet_tool_listener = {
+	.removed = handle_tablet_tool_removed,
+	.done = handle_tablet_tool_done,
+	.type = handle_tablet_tool_type,
+	.hardware_serial = handle_tablet_tool_serial,
+	.hardware_id_wacom = handle_tablet_tool_id_wacom,
+	.capability = handle_tablet_tool_capability,
+
+	.proximity_in = handle_tablet_tool_proximity_in,
+	.proximity_out = handle_tablet_tool_proximity_out,
+	.down = handle_tablet_tool_down,
+	.up = handle_tablet_tool_up,
+
+	.motion = handle_tablet_tool_motion,
+	.pressure = handle_tablet_tool_pressure,
+	.distance = handle_tablet_tool_distance,
+	.tilt = handle_tablet_tool_tilt,
+	.rotation = handle_tablet_tool_rotation,
+	.slider = handle_tablet_tool_slider,
+	.wheel = handle_tablet_tool_wheel,
+	.button = handle_tablet_tool_button,
+	.frame = handle_tablet_tool_frame,
+};
+
+static void handle_tool_added(void *data,
+		struct zwp_tablet_seat_v2 *zwp_tablet_seat_v2,
+		struct zwp_tablet_tool_v2 *id) {
+	wlr_log(WLR_DEBUG, "New tablet tool");
+	struct wlr_wl_tablet_tool *tool = calloc(1, sizeof(*tool));
+	if (!tool) {
+		zwp_tablet_tool_v2_destroy(id);
+		return;
+	}
+	tool->tool = id;
+	clear_tablet_tool_values(tool);
+	wl_signal_init(&tool->wlr_tool.events.destroy);
+	zwp_tablet_tool_v2_add_listener(id, &tablet_tool_listener, tool);
+}
+
+static void handle_tablet_name(void *data, struct zwp_tablet_v2 *zwp_tablet_v2,
+		const char *name) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet *tablet = dev->wlr_input_device.tablet;
+	tablet->name = strdup(name);
+}
+
+static void handle_tablet_id(void *data, struct zwp_tablet_v2 *zwp_tablet_v2,
+		uint32_t vid, uint32_t pid) {
+	struct wlr_wl_input_device *dev = data;
+	dev->wlr_input_device.vendor = vid;
+	dev->wlr_input_device.product = pid;
+}
+
+static void handle_tablet_path(void *data, struct zwp_tablet_v2 *zwp_tablet_v2,
+		const char *path) {
+	struct wlr_wl_input_device *dev = data;
+	struct wlr_tablet *tablet = dev->wlr_input_device.tablet;
+
+	wlr_list_push(&tablet->paths, strdup(path));
+}
+
+static void handle_tablet_done(void *data, struct zwp_tablet_v2 *zwp_tablet_v2) {
+	struct wlr_wl_input_device *dev = data;
+
+	wlr_signal_emit_safe(&dev->backend->backend.events.new_input,
+		&dev->wlr_input_device);
+}
+
+static void handle_tablet_removed(void *data,
+		struct zwp_tablet_v2 *zwp_tablet_v2) {
+	struct wlr_wl_input_device *dev = data;
+
+	/* This doesn't free anything, but emits the destroy signal */
+	wlr_input_device_destroy(&dev->wlr_input_device);
+	/* This is a bit ugly, but we need to remove it from our list */
+	wl_list_remove(&dev->wlr_input_device.link);
+
+	zwp_tablet_v2_destroy(dev->resource);
+	free(dev);
+}
+
+static const struct zwp_tablet_v2_listener tablet_listener = {
+	.name = handle_tablet_name,
+	.id = handle_tablet_id,
+	.path = handle_tablet_path,
+	.done = handle_tablet_done,
+	.removed = handle_tablet_removed,
+};
+
+static void handle_tab_added(void *data,
+		struct zwp_tablet_seat_v2 *zwp_tablet_seat_v2,
+		struct zwp_tablet_v2 *id) {
+	wlr_log(WLR_DEBUG, "New tablet");
+	struct wlr_wl_backend *backend = data;
+	struct wlr_wl_input_device *dev = create_wl_input_device(
+		backend, WLR_INPUT_DEVICE_TABLET_TOOL);
+	dev->resource = id;
+
+	if (!dev) {
+		zwp_tablet_v2_destroy(id);
+		return;
+	}
+	struct wlr_input_device *wlr_dev = &dev->wlr_input_device;
+	wlr_dev->tablet = calloc(1, sizeof(*wlr_dev->tablet));
+
+	if (!wlr_dev->tablet) {
+		zwp_tablet_v2_destroy(id);
+		return;
+	}
+	zwp_tablet_v2_set_user_data(id, wlr_dev->tablet);
+	wlr_tablet_init(wlr_dev->tablet, NULL);
+	zwp_tablet_v2_add_listener(id, &tablet_listener, dev);
+}
+
+static const struct zwp_tablet_seat_v2_listener tablet_seat_listener = {
+	.tablet_added = handle_tab_added,
+	.tool_added = handle_tool_added,
+	.pad_added = handle_pad_added,
+};
+
+struct wlr_wl_tablet_seat *wlr_wl_add_tablet_seat(
+		struct zwp_tablet_manager_v2 *manager,
+		struct wl_seat *seat, struct wlr_wl_backend *backend) {
+	struct wlr_wl_tablet_seat *ret =
+		calloc(1, sizeof(struct wlr_wl_tablet_seat));
+
+	if (!(ret->tablet_seat =
+			zwp_tablet_manager_v2_get_tablet_seat(manager, seat))) {
+		free(ret);
+		return NULL;
+	}
+
+	zwp_tablet_seat_v2_add_listener(ret->tablet_seat,
+		&tablet_seat_listener, backend);
+
+	wl_list_init(&ret->tablets);
+	wl_list_init(&ret->tools);
+	//wl_list_init(&ret->pads);
+
+	return ret;
+}
diff --git a/backend/wayland/wl_seat.c b/backend/wayland/wl_seat.c
index 96c083ed..dd498153 100644
--- a/backend/wayland/wl_seat.c
+++ b/backend/wayland/wl_seat.c
@@ -303,7 +303,7 @@ bool wlr_input_device_is_wl(struct wlr_input_device *dev) {
 	return dev->impl == &input_device_impl;
 }
 
-static struct wlr_wl_input_device *create_wl_input_device(
+struct wlr_wl_input_device *create_wl_input_device(
 		struct wlr_wl_backend *backend, enum wlr_input_device_type type) {
 	struct wlr_wl_input_device *dev =
 		calloc(1, sizeof(struct wlr_wl_input_device));
diff --git a/include/backend/wayland.h b/include/backend/wayland.h
index e25aba43..f46e6c75 100644
--- a/include/backend/wayland.h
+++ b/include/backend/wayland.h
@@ -38,6 +38,7 @@ struct wlr_wl_backend {
 	struct wl_pointer *pointer;
 	struct wl_keyboard *keyboard;
 	struct wlr_wl_pointer *current_pointer;
+	struct zwp_tablet_manager_v2 *tablet_manager;
 	char *seat_name;
 };
 
@@ -92,6 +93,8 @@ void update_wl_output_cursor(struct wlr_wl_output *output);
 struct wlr_wl_pointer *pointer_get_wl(struct wlr_pointer *wlr_pointer);
 void create_wl_pointer(struct wl_pointer *wl_pointer, struct wlr_wl_output *output);
 void create_wl_keyboard(struct wl_keyboard *wl_keyboard, struct wlr_wl_backend *wl);
+struct wlr_wl_input_device *create_wl_input_device(
+	struct wlr_wl_backend *backend, enum wlr_input_device_type type);
 
 extern const struct wl_seat_listener seat_listener;
 
diff --git a/protocol/meson.build b/protocol/meson.build
index b7a0241e..25694010 100644
--- a/protocol/meson.build
+++ b/protocol/meson.build
@@ -46,6 +46,7 @@ client_protocols = [
 	[wl_protocol_dir, 'unstable/pointer-constraints/pointer-constraints-unstable-v1.xml'],
 	[wl_protocol_dir, 'unstable/pointer-gestures/pointer-gestures-unstable-v1.xml'],
 	[wl_protocol_dir, 'unstable/relative-pointer/relative-pointer-unstable-v1.xml'],
+	[wl_protocol_dir, 'unstable/tablet/tablet-unstable-v2.xml'],
 	[wl_protocol_dir, 'unstable/text-input/text-input-unstable-v3.xml'],
 	[wl_protocol_dir, 'unstable/xdg-decoration/xdg-decoration-unstable-v1.xml'],
 	[wl_protocol_dir, 'unstable/xdg-shell/xdg-shell-unstable-v6.xml'],