tools/debug-events: add ability to compress motion events

If --compress-motion-events is given (and stdout is a tty) reduce
the output printed to one line per repeated motion/axis/scroll sequence
(with a count). Example output:
 event6   POINTER_MOTION          108 +1.912s	 1.00/ -1.00 ( +1.00/ -1.00))
 event6   POINTER_BUTTON              +2.008s	BTN_LEFT (272) pressed, seat count: 1
 event6   POINTER_BUTTON              +2.074s	BTN_LEFT (272) released, seat count: 0
 event6   POINTER_MOTION           39 +5.249s	 0.00/  0.99 ( +0.00/ +1.00)
 event6   POINTER_BUTTON              +5.385s	BTN_LEFT (272) pressed, seat count: 1
 event6   POINTER_MOTION           66 +6.031s	-1.00/  0.00 ( -1.00/ +0.00)
 event6   POINTER_BUTTON              +6.401s	BTN_LEFT (272) released, seat count: 0

The event count (108, 39 and 66) is only printed for more than one event
in sequence so the output is otherwise identical (but 4 spaces wider
now)

If stdout is not a tty the event count is printed but no compression
happens since we rely on a ansi escape sequence for that. Could be fixed
by changing the current print statements to print a \n before the
current event instead of at the end of the current line.

This makes debugging events easier as button events and similar are no
longer obscured by pages of motion events in between.

Part-of: <https://gitlab.freedesktop.org/libinput/libinput/-/merge_requests/1041>

tools/libinput-debug-events.c

@@ -50,11 +50,13 @@ static struct tools_options options;
 static bool show_keycodes;
 static volatile sig_atomic_t stop = 0;
 static bool be_quiet = false;
+static bool compress_motion_events = false;
+static bool is_tty = false;
 
 #define printq(...) ({ if (!be_quiet)  printf(__VA_ARGS__); })
 
 static void
-print_event_header(struct libinput_event *ev)
+print_event_header(struct libinput_event *ev, size_t event_count)
 {
 	/* use for pointer value only, do not dereference */
 	static void *last_device = NULL;
@@ -173,6 +175,11 @@ print_event_header(struct libinput_event *ev)
 	       libinput_device_get_sysname(dev),
 	       type);
 
+	if (event_count > 1)
+		printq("%3zd ", event_count);
+	else
+		printq("    ");
+
 	last_device = dev;
 }
 
@@ -867,9 +874,14 @@ handle_and_print_events(struct libinput *li)
 {
 	int rc = -1;
 	struct libinput_event *ev;
+	static struct libinput_device *last_device = NULL;
+	static enum libinput_event_type last_event_type = LIBINPUT_EVENT_NONE;
+	static size_t event_repeat_count = 0;
+	static uint32_t last_log_serial = 0;
 
 	tools_dispatch(li);
 	while ((ev = libinput_get_event(li))) {
+		struct libinput_device *device = libinput_event_get_device(ev);
 		enum libinput_event_type type = libinput_event_get_type(ev);
 
 		if (type == LIBINPUT_EVENT_POINTER_AXIS) {
@@ -877,7 +889,34 @@ handle_and_print_events(struct libinput *li)
 			continue;
 		}
 
-		print_event_header(ev);
+		bool is_repeat = false;
+
+		switch (type) {
+		case LIBINPUT_EVENT_POINTER_MOTION:
+		case LIBINPUT_EVENT_POINTER_MOTION_ABSOLUTE:
+		case LIBINPUT_EVENT_POINTER_SCROLL_WHEEL:
+		case LIBINPUT_EVENT_POINTER_SCROLL_FINGER:
+		case LIBINPUT_EVENT_POINTER_SCROLL_CONTINUOUS:
+		case LIBINPUT_EVENT_TOUCH_MOTION:
+		case LIBINPUT_EVENT_TABLET_TOOL_AXIS:
+		case LIBINPUT_EVENT_GESTURE_PINCH_UPDATE:
+		case LIBINPUT_EVENT_GESTURE_SWIPE_UPDATE:
+			is_repeat = last_event_type == type && last_device == device && log_serial == last_log_serial;
+			break;
+		default:
+			break;
+		}
+
+		if (is_repeat) {
+			event_repeat_count++;
+			if (compress_motion_events)
+				printq("\e[1A");
+		} else {
+			event_repeat_count = 0;
+		}
+
+		if (type != LIBINPUT_EVENT_TOUCH_FRAME || !compress_motion_events)
+			print_event_header(ev, event_repeat_count + 1);
 
 		switch (type) {
 		case LIBINPUT_EVENT_NONE:
@@ -914,9 +953,12 @@ handle_and_print_events(struct libinput *li)
 		case LIBINPUT_EVENT_TOUCH_MOTION:
 		case LIBINPUT_EVENT_TOUCH_UP:
 		case LIBINPUT_EVENT_TOUCH_CANCEL:
-		case LIBINPUT_EVENT_TOUCH_FRAME:
 			print_touch_event(ev);
 			break;
+		case LIBINPUT_EVENT_TOUCH_FRAME:
+			if (!compress_motion_events)
+				print_touch_event(ev);
+			break;
 		case LIBINPUT_EVENT_GESTURE_SWIPE_BEGIN:
 			print_gesture_event_without_coords(ev);
 			break;
@@ -979,6 +1021,11 @@ handle_and_print_events(struct libinput *li)
 			break;
 		}
 
+		last_device = device;
+		if (type != LIBINPUT_EVENT_TOUCH_FRAME)
+			last_event_type = type;
+		last_log_serial = log_serial;
+
 		libinput_event_destroy(ev);
 		rc = 0;
 	}
@@ -1040,6 +1087,8 @@ main(int argc, char **argv)
 
 	tools_init_options(&options);
 
+	is_tty = isatty(STDOUT_FILENO);
+
 	while (1) {
 		int c;
 		int option_index = 0;
@@ -1050,6 +1099,7 @@ main(int argc, char **argv)
 			OPT_VERBOSE,
 			OPT_SHOW_KEYCODES,
 			OPT_QUIET,
+			OPT_COMPRESS_MOTION_EVENTS,
 		};
 		static struct option opts[] = {
 			CONFIGURATION_OPTIONS,
@@ -1060,6 +1110,7 @@ main(int argc, char **argv)
 			{ "grab",                      no_argument,       0, OPT_GRAB },
 			{ "verbose",                   no_argument,       0, OPT_VERBOSE },
 			{ "quiet",                     no_argument,       0, OPT_QUIET },
+			{ "compress-motion-events",    no_argument,       0, OPT_COMPRESS_MOTION_EVENTS },
 			{ 0, 0, 0, 0}
 		};
 
@@ -1108,6 +1159,10 @@ main(int argc, char **argv)
 		case OPT_VERBOSE:
 			verbose = true;
 			break;
+		case OPT_COMPRESS_MOTION_EVENTS:
+			/* We compress by using ansi escape sequences */
+			compress_motion_events = is_tty;
+			break;
 		default:
 			if (tools_parse_option(c, optarg, &options) != 0) {
 				usage();

tools/shared.c

@@ -45,6 +45,7 @@
 #include "util-strings.h"
 
 static uint32_t dispatch_counter = 0;
+uint32_t log_serial = 0;
 
 void
 tools_dispatch(struct libinput *libinput)
@@ -94,6 +95,8 @@ log_handler(struct libinput *li,
 
 	if (is_tty)
 		printf(ANSI_NORMAL);
+
+	log_serial++;
 }
 
 void

tools/shared.h

@@ -32,6 +32,8 @@
 
 #define EXIT_INVALID_USAGE 2
 
+extern uint32_t log_serial;
+
 enum configuration_options {
 	OPT_TAP_ENABLE = 256,
 	OPT_TAP_DISABLE,