input/tablet: add a config option to set pen as relative input

Closes swaywm#4139.

include/sway/commands.h

@@ -257,6 +257,7 @@ sway_cmd input_cmd_scroll_button;
 sway_cmd input_cmd_scroll_method;
 sway_cmd input_cmd_tap;
 sway_cmd input_cmd_tap_button_map;
+sway_cmd input_cmd_tool_mode;
 sway_cmd input_cmd_xkb_capslock;
 sway_cmd input_cmd_xkb_file;
 sway_cmd input_cmd_xkb_layout;

include/sway/config.h

@@ -11,8 +11,10 @@
 #include "list.h"
 #include "swaynag.h"
 #include "tree/container.h"
+#include "sway/input/tablet.h"
 #include "sway/tree/root.h"
 #include "wlr-layer-shell-unstable-v1-protocol.h"
+#include "wlr/types/wlr_tablet_tool.h"
 
 // TODO: Refactor this shit
 
@@ -116,6 +118,11 @@ enum input_config_mapped_to {
 	MAPPED_TO_REGION,
 };
 
+struct input_config_tool {
+	enum wlr_tablet_tool_type type;
+	enum sway_tablet_tool_mode mode;
+};
+
 /**
  * options for input devices
  */
@@ -160,6 +167,8 @@ struct input_config {
 	char *mapped_to_output;
 	struct wlr_box *mapped_to_region;
 
+	list_t *tools;
+
 	bool capturable;
 	struct wlr_box region;
 };

include/sway/input/tablet.h

@@ -11,11 +11,17 @@ struct sway_tablet {
 	struct wlr_tablet_v2_tablet *tablet_v2;
 };
 
+enum sway_tablet_tool_mode {
+	SWAY_TABLET_TOOL_MODE_ABSOLUTE,
+	SWAY_TABLET_TOOL_MODE_RELATIVE,
+};
+
 struct sway_tablet_tool {
 	struct sway_seat *seat;
 	struct sway_tablet *tablet;
 	struct wlr_tablet_v2_tablet_tool *tablet_v2_tool;
 
+	enum sway_tablet_tool_mode mode;
 	double tilt_x, tilt_y;
 
 	struct wl_listener set_cursor;

sway/commands/input.c

@@ -29,6 +29,7 @@ static struct cmd_handler input_handlers[] = {
 	{ "scroll_method", input_cmd_scroll_method },
 	{ "tap", input_cmd_tap },
 	{ "tap_button_map", input_cmd_tap_button_map },
+	{ "tool_mode", input_cmd_tool_mode },
 	{ "xkb_file", input_cmd_xkb_file },
 	{ "xkb_layout", input_cmd_xkb_layout },
 	{ "xkb_model", input_cmd_xkb_model },

sway/commands/input/tool_mode.c

@@ -0,0 +1,73 @@
+#include <strings.h>
+#include "sway/commands.h"
+#include "sway/config.h"
+
+static void set_tool_mode(struct input_config *ic,
+		enum wlr_tablet_tool_type type, enum sway_tablet_tool_mode mode) {
+	for (int i = 0; i < ic->tools->length; i++) {
+		struct input_config_tool *tool = ic->tools->items[i];
+		if (tool->type == type) {
+			tool->mode = mode;
+			return;
+		}
+	}
+
+	struct input_config_tool *tool = calloc(1, sizeof(*tool));
+	if (tool) {
+		tool->type = type;
+		tool->mode = mode;
+		list_add(ic->tools, tool);
+	}
+}
+
+struct cmd_results *input_cmd_tool_mode(int argc, char **argv) {
+	struct cmd_results *error;
+	if ((error = checkarg(argc, "tool_mode", EXPECTED_AT_LEAST, 2))) {
+		return error;
+	}
+
+	struct input_config *ic = config->handler_context.input_config;
+	if (!ic) {
+		return cmd_results_new(CMD_FAILURE, "No input device defined.");
+	}
+
+	enum sway_tablet_tool_mode tool_mode;
+	if (!strcasecmp(argv[1], "absolute")) {
+		tool_mode = SWAY_TABLET_TOOL_MODE_ABSOLUTE;
+	} else if (!strcasecmp(argv[1], "relative")) {
+		tool_mode = SWAY_TABLET_TOOL_MODE_RELATIVE;
+	} else {
+		goto invalid_command;
+	}
+
+	if (!strcasecmp(argv[0], "*")) {
+		set_tool_mode(ic, WLR_TABLET_TOOL_TYPE_PEN, tool_mode);
+		set_tool_mode(ic, WLR_TABLET_TOOL_TYPE_ERASER, tool_mode);
+		set_tool_mode(ic, WLR_TABLET_TOOL_TYPE_BRUSH, tool_mode);
+		set_tool_mode(ic, WLR_TABLET_TOOL_TYPE_PENCIL, tool_mode);
+		set_tool_mode(ic, WLR_TABLET_TOOL_TYPE_AIRBRUSH, tool_mode);
+	} else {
+		enum wlr_tablet_tool_type tool_type;
+		if (!strcasecmp(argv[0], "pen")) {
+			tool_type = WLR_TABLET_TOOL_TYPE_PEN;
+		} else if (!strcasecmp(argv[0], "eraser")) {
+			tool_type = WLR_TABLET_TOOL_TYPE_ERASER;
+		} else if (!strcasecmp(argv[0], "brush")) {
+			tool_type = WLR_TABLET_TOOL_TYPE_BRUSH;
+		} else if (!strcasecmp(argv[0], "pencil")) {
+			tool_type = WLR_TABLET_TOOL_TYPE_PENCIL;
+		} else if (!strcasecmp(argv[0], "airbrush")) {
+			tool_type = WLR_TABLET_TOOL_TYPE_AIRBRUSH;
+		} else {
+			goto invalid_command;
+		}
+
+		set_tool_mode(ic, tool_type, tool_mode);
+	}
+
+	return cmd_results_new(CMD_SUCCESS, NULL);
+
+invalid_command:
+	return cmd_results_new(CMD_INVALID,
+		"Expected 'tool_mode <tool> <absolute|relative>'");
+}

sway/config/input.c

@@ -40,6 +40,7 @@ struct input_config *new_input_config(const char* identifier) {
 	input->xkb_numlock = INT_MIN;
 	input->xkb_capslock = INT_MIN;
 	input->xkb_file_is_set = false;
+	input->tools = create_list();
 
 	return input;
 }
@@ -153,6 +154,23 @@ void merge_input_config(struct input_config *dst, struct input_config *src) {
 		memcpy(dst->calibration_matrix.matrix, src->calibration_matrix.matrix,
 			sizeof(src->calibration_matrix.matrix));
 	}
+	for (int i = 0; i < src->tools->length; i++) {
+		struct input_config_tool *src_tool = src->tools->items[i];
+		for (int j = 0; j < dst->tools->length; j++) {
+			struct input_config_tool *dst_tool = dst->tools->items[i];
+			if (src_tool->type == dst_tool->type) {
+				dst_tool->mode = src_tool->mode;
+				goto outer;
+			}
+		}
+
+		struct input_config_tool *dst_tool = malloc(sizeof(*dst_tool));
+		memcpy(dst_tool, src_tool, sizeof(*dst_tool));
+		list_add(dst->tools, dst_tool);
+
+		outer:
+		continue;
+	}
 }
 
 static bool validate_xkb_merge(struct input_config *dest,
@@ -358,6 +376,7 @@ void free_input_config(struct input_config *ic) {
 	free(ic->mapped_from_region);
 	free(ic->mapped_to_output);
 	free(ic->mapped_to_region);
+	list_free_items_and_destroy(ic->tools);
 	free(ic);
 }
 

sway/input/cursor.c

@@ -566,14 +566,14 @@ static void handle_tablet_tool_position(struct sway_cursor *cursor,
 			ic->mapped_from_region, &x, &y);
 	}
 
-	switch (tool->tablet_v2_tool->wlr_tool->type) {
-	case WLR_TABLET_TOOL_TYPE_LENS:
-	case WLR_TABLET_TOOL_TYPE_MOUSE:
-		wlr_cursor_move(cursor->cursor, input_device->wlr_device, dx, dy);
-		break;
-	default:
+	switch (tool->mode) {
+	case SWAY_TABLET_TOOL_MODE_ABSOLUTE:
 		wlr_cursor_warp_absolute(cursor->cursor, input_device->wlr_device,
 			change_x ? x : NAN, change_y ? y : NAN);
+		break;
+	case SWAY_TABLET_TOOL_MODE_RELATIVE:
+		wlr_cursor_move(cursor->cursor, input_device->wlr_device, dx, dy);
+		break;
 	}
 
 	double sx, sy;

sway/input/tablet.c

@@ -140,6 +140,28 @@ void sway_tablet_tool_configure(struct sway_tablet *tablet,
 		return;
 	}
 
+	switch (wlr_tool->type) {
+	case WLR_TABLET_TOOL_TYPE_LENS:
+	case WLR_TABLET_TOOL_TYPE_MOUSE:
+		tool->mode = SWAY_TABLET_TOOL_MODE_RELATIVE;
+		break;
+	default:
+		tool->mode = SWAY_TABLET_TOOL_MODE_ABSOLUTE;
+
+		struct input_config *ic = input_device_get_config(
+			tablet->seat_device->input_device);
+		if (!ic) {
+			break;
+		}
+
+		for (int i = 0; i < ic->tools->length; i++) {
+			struct input_config_tool *tool_config = ic->tools->items[i];
+			if (tool_config->type == wlr_tool->type) {
+				tool->mode = tool_config->mode;
+			}
+		}
+	}
+
 	tool->seat = tablet->seat_device->sway_seat;
 	tool->tablet = tablet;
 	tool->tablet_v2_tool =

sway/meson.build

@@ -167,6 +167,7 @@ sway_sources = files(
 	'commands/input/scroll_method.c',
 	'commands/input/tap.c',
 	'commands/input/tap_button_map.c',
+	'commands/input/tool_mode.c',
 	'commands/input/xkb_capslock.c',
 	'commands/input/xkb_file.c',
 	'commands/input/xkb_layout.c',

sway/sway-input.5.scd

@@ -94,6 +94,17 @@ The following commands may only be used in the configuration file.
 *input* <identifier> xkb_numlock enabled|disabled
 	Initially enables or disables NumLock on startup, the default is disabled.
 
+## TABLET CONFIGURATION
+
+*input* <identifier> tool_mode <tool> <absolute|relative>
+	Sets whether movement of a tablet tool should be treated as absolute or
+	relative; the default is absolute.
+
+	Valid values for _\<tool\>_ are currently "pen", "eraser", "brush",
+	"pencil", "airbrush", and the wildcard _\*_, which matches all tools.
+
+	Mouse and lens tools ignore this setting and are always treated as relative.
+
 ## MAPPING CONFIGURATION
 
 *input* <identifier> map_to_output <identifier>