backends/x11: Touch support

Closes #1749

backend/x11/input_device.c

@@ -11,6 +11,7 @@
 #include <wlr/interfaces/wlr_input_device.h>
 #include <wlr/interfaces/wlr_keyboard.h>
 #include <wlr/interfaces/wlr_pointer.h>
+#include <wlr/interfaces/wlr_touch.h>
 #include <wlr/util/log.h>
 
 #include "backend/x11.h"
@@ -66,6 +67,51 @@ static void send_pointer_position_event(struct wlr_x11_output *output,
 	wlr_signal_emit_safe(&output->pointer.events.frame, &output->pointer);
 }
 
+static void send_touch_down_event(struct wlr_x11_output *output,
+		int16_t x, int16_t y, int32_t touch_id, xcb_timestamp_t time) {
+	struct wlr_event_touch_down ev = {
+		.device = &output->touch_dev,
+		.time_msec = time,
+		.x = (double)x / output->wlr_output.width,
+		.y = (double)y / output->wlr_output.height,
+		.touch_id = touch_id,
+	};
+	wlr_signal_emit_safe(&output->touch.events.down, &ev);
+}
+
+static void send_touch_motion_event(struct wlr_x11_output *output,
+		int16_t x, int16_t y, int32_t touch_id, xcb_timestamp_t time) {
+	struct wlr_event_touch_motion ev = {
+		.device = &output->touch_dev,
+		.time_msec = time,
+		.x = (double)x / output->wlr_output.width,
+		.y = (double)y / output->wlr_output.height,
+		.touch_id = touch_id,
+	};
+	wlr_signal_emit_safe(&output->touch.events.motion, &ev);
+}
+
+static void send_touch_up_event(struct wlr_x11_output *output,
+		int32_t touch_id, xcb_timestamp_t time) {
+	struct wlr_event_touch_up ev = {
+		.device = &output->touch_dev,
+		.time_msec = time,
+		.touch_id = touch_id,
+	};
+	wlr_signal_emit_safe(&output->touch.events.up, &ev);
+}
+
+static struct wlr_x11_touchpoint* get_touchpoint_from_x11_touch_id(struct wlr_x11_output *output,
+		uint32_t id) {
+	struct wlr_x11_touchpoint *touchpoint;
+	wl_list_for_each(touchpoint, &output->touchpoints, link) {
+		if (touchpoint->x11_id == id) {
+			return touchpoint;
+		}
+	}
+	return NULL;
+}
+
 void handle_x11_xinput_event(struct wlr_x11_backend *x11,
 		xcb_ge_generic_event_t *event) {
 	struct wlr_x11_output *output;
@@ -194,6 +240,70 @@ void handle_x11_xinput_event(struct wlr_x11_backend *x11,
 		}
 		break;
 	}
+	case XCB_INPUT_TOUCH_BEGIN: {
+		xcb_input_touch_begin_event_t *ev = (xcb_input_touch_begin_event_t *)event;
+
+		output = get_x11_output_from_window_id(x11, ev->event);
+		if (!output) {
+			return;
+		}
+
+		int32_t id = 0;
+		if (!wl_list_empty(&output->touchpoints)) {
+			struct wlr_x11_touchpoint *last_touchpoint = wl_container_of(
+				output->touchpoints.next, last_touchpoint, link);
+			id = last_touchpoint->wayland_id + 1;
+		}
+
+		struct wlr_x11_touchpoint *touchpoint = calloc(1, sizeof(struct wlr_x11_touchpoint));
+		touchpoint->x11_id = ev->detail;
+		touchpoint->wayland_id = id;
+		wl_list_init(&touchpoint->link);
+		wl_list_insert(&output->touchpoints, &touchpoint->link);
+
+		send_touch_down_event(output, ev->event_x >> 16,
+			ev->event_y >> 16, touchpoint->wayland_id, ev->time);
+		x11->time = ev->time;
+		break;
+	}
+	case XCB_INPUT_TOUCH_END: {
+		xcb_input_touch_end_event_t *ev = (xcb_input_touch_end_event_t *)event;
+
+		output = get_x11_output_from_window_id(x11, ev->event);
+		if (!output) {
+			return;
+		}
+
+		struct wlr_x11_touchpoint *touchpoint = get_touchpoint_from_x11_touch_id(output, ev->detail);
+		if (!touchpoint) {
+			return;
+		}
+
+		send_touch_up_event(output, touchpoint->wayland_id, ev->time);
+		x11->time = ev->time;
+
+		wl_list_remove(&touchpoint->link);
+		free(touchpoint);
+		break;
+	}
+	case XCB_INPUT_TOUCH_UPDATE: {
+		xcb_input_touch_update_event_t *ev = (xcb_input_touch_update_event_t *)event;
+
+		output = get_x11_output_from_window_id(x11, ev->event);
+		if (!output) {
+			return;
+		}
+
+		struct wlr_x11_touchpoint *touchpoint = get_touchpoint_from_x11_touch_id(output, ev->detail);
+		if (!touchpoint) {
+			return;
+		}
+
+		send_touch_motion_event(output, ev->event_x >> 16,
+			ev->event_y >> 16, touchpoint->wayland_id, ev->time);
+		x11->time = ev->time;
+		break;
+	}
 	}
 }
 
@@ -221,6 +331,14 @@ const struct wlr_pointer_impl pointer_impl = {
 	.destroy = pointer_destroy,
 };
 
+static void touch_destroy(struct wlr_touch *wlr_touch) {
+	// Don't free the touch, it's on the stack
+}
+
+const struct wlr_touch_impl touch_impl = {
+	.destroy = touch_destroy,
+};
+
 void update_x11_pointer_position(struct wlr_x11_output *output,
 		xcb_timestamp_t time) {
 	struct wlr_x11_backend *x11 = output->x11;

backend/x11/output.c

@@ -9,6 +9,7 @@
 
 #include <wlr/interfaces/wlr_output.h>
 #include <wlr/interfaces/wlr_pointer.h>
+#include <wlr/interfaces/wlr_touch.h>
 #include <wlr/util/log.h>
 
 #include "backend/x11.h"
@@ -80,6 +81,7 @@ static void output_destroy(struct wlr_output *wlr_output) {
 	struct wlr_x11_backend *x11 = output->x11;
 
 	wlr_input_device_destroy(&output->pointer_dev);
+	wlr_input_device_destroy(&output->touch_dev);
 
 	wl_list_remove(&output->link);
 	wl_event_source_remove(output->frame_timer);
@@ -167,7 +169,10 @@ struct wlr_output *wlr_x11_output_create(struct wlr_backend *backend) {
 			XCB_INPUT_XI_EVENT_MASK_BUTTON_RELEASE |
 			XCB_INPUT_XI_EVENT_MASK_MOTION |
 			XCB_INPUT_XI_EVENT_MASK_ENTER |
-			XCB_INPUT_XI_EVENT_MASK_LEAVE,
+			XCB_INPUT_XI_EVENT_MASK_LEAVE |
+			XCB_INPUT_XI_EVENT_MASK_TOUCH_BEGIN |
+			XCB_INPUT_XI_EVENT_MASK_TOUCH_END |
+			XCB_INPUT_XI_EVENT_MASK_TOUCH_UPDATE,
 	};
 	xcb_input_xi_select_events(x11->xcb, output->win, 1, &xinput_mask.head);
 
@@ -201,8 +206,16 @@ struct wlr_output *wlr_x11_output_create(struct wlr_backend *backend) {
 	output->pointer_dev.pointer = &output->pointer;
 	output->pointer_dev.output_name = strdup(wlr_output->name);
 
+	wlr_input_device_init(&output->touch_dev, WLR_INPUT_DEVICE_TOUCH,
+		&input_device_impl, "X11 touch", 0, 0);
+	wlr_touch_init(&output->touch, &touch_impl);
+	output->touch_dev.touch = &output->touch;
+	output->touch_dev.output_name = strdup(wlr_output->name);
+	wl_list_init(&output->touchpoints);
+
 	wlr_signal_emit_safe(&x11->backend.events.new_output, wlr_output);
 	wlr_signal_emit_safe(&x11->backend.events.new_input, &output->pointer_dev);
+	wlr_signal_emit_safe(&x11->backend.events.new_input, &output->touch_dev);
 
 	return wlr_output;
 }

include/backend/x11.h

@@ -31,12 +31,22 @@ struct wlr_x11_output {
 	struct wlr_pointer pointer;
 	struct wlr_input_device pointer_dev;
 
+	struct wlr_touch touch;
+	struct wlr_input_device touch_dev;
+	struct wl_list touchpoints; // wlr_x11_touchpoint::link
+
 	struct wl_event_source *frame_timer;
 	int frame_delay;
 
 	bool cursor_hidden;
 };
 
+struct wlr_x11_touchpoint {
+	uint32_t x11_id;
+	int wayland_id;
+	struct wl_list link; // wlr_x11_output::touch_points
+};
+
 struct wlr_x11_backend {
 	struct wlr_backend backend;
 	struct wl_display *wl_display;
@@ -79,6 +89,7 @@ struct wlr_x11_output *get_x11_output_from_window_id(
 
 extern const struct wlr_keyboard_impl keyboard_impl;
 extern const struct wlr_pointer_impl pointer_impl;
+extern const struct wlr_touch_impl touch_impl;
 extern const struct wlr_input_device_impl input_device_impl;
 
 void handle_x11_xinput_event(struct wlr_x11_backend *x11,