project for a (works on my devices) demo

headers/input/touch/touch_controller_L1_builder.h

@@ -0,0 +1,20 @@
+#pragma once
+
+#include "touch_data.h"
+
+/* yes int instead of uint */
+void TC_L1_builder_set_tracking_id( int64_t tracking_id);
+
+void TC_L1_builder_set_position_x( uint64_t x_coord);
+
+void TC_L1_builder_set_position_y( uint64_t y_coord);
+
+void TC_L1_builder_set_major_axis( uint64_t width);
+
+void TC_L1_builder_set_approaching_major_axis( uint64_t width);
+
+void TC_L1_builder_set_slot_number( uint64_t number);
+
+void TC_L1_builder_copy_tracked_events( touch_event ***store, uint8_t *count);
+
+void TC_L1_builder_destroy_copy( touch_event **store, uint8_t count);

headers/input/touch/touch_controller_L2.h

@@ -0,0 +1,9 @@
+#include "touch_data.h"
+
+touch_coordinates* TC_L2_getAABB( touch_event **events, uint8_t count);
+
+float TC_L2_get_width( touch_event **events, uint8_t count);
+
+float TC_L2_get_angle( touch_event **events, uint8_t count);
+
+touch_coordinates* TC_L2_get_midpoint( touch_event **events, uint8_t count);

headers/input/touch/touch_controller_L3.h

@@ -0,0 +1,13 @@
+#pragma once
+
+#include "touch_controller_L2.h"
+
+void TC_L3_get_position_deltas(
+	touch_event **previous, uint8_t previous_count, 
+	touch_event **current, uint8_t current_count, 
+	touch_coordinates **deltas, uint8_t *count
+);
+
+float TC_L3_get_angle_delta( float previous_angle, float current_angle);
+
+touch_coordinates* TC_L3_get_midpoint_delta( touch_coordinates previous, touch_coordinates current);

headers/input/touch/touch_controller_L3_deltas_compute.h

@@ -0,0 +1,22 @@
+#pragma once
+
+#include <stdint.h>
+
+typedef struct {
+	uint8_t state; /* entered unchanged exited */
+	uint8_t old_index;
+	uint8_t new_index;
+	uint64_t tracking_id;
+} tracked_delta;
+
+/* could also resort to TRANSIENT / PERSISTENT */
+static const uint8_t TRACKED_DELTA_ENTERED = 0;
+static const uint8_t TRACKED_DELTA_UNCHANGED = 1;
+static const uint8_t TRACKED_DELTA_EXITED = 2;
+
+
+void touch_events_sorted_ids_deltas( 
+	tracked_delta **endbuffer, uint16_t *endcount, 
+	uint64_t *previous_ids, uint8_t previous_count, 
+	uint64_t *current_ids, uint8_t current_count
+);

headers/input/touch/touch_data.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <stdint.h>
+
+typedef struct {
+	int64_t x;	/* touch horizontal center */
+	int64_t y;	/* touch vertical center */
+} touch_coordinates;
+
+/* using ultrawide ints (narrowing later) */
+typedef struct {
+	uint64_t slot_number;
+	uint64_t tracking_id;	/* this increases with each new touch */
+	touch_coordinates position;
+	/* ignoring ABS_MT_TOUCH_MAJOR 
+		and ABS_MT_WIDTH_MAJOR 
+	*/
+} touch_event;
+
+touch_event* touch_event_new();
+
+void touch_event_copy( touch_event *dst, touch_event *src);
+
+touch_coordinates* new_touch_coordinates_buffer( uint8_t count);
+
+void free_touch_coordinates_buffer( touch_coordinates* buffer);
+
+void touch_events_array_copy( touch_event ***dst, touch_event **src, uint8_t count);
+
+void free_touch_events_array( touch_event **buffer, uint8_t count);

headers/input/touch/two_fingers_simultaneous.event

@@ -0,0 +1,21 @@
+ABS_MT_TRACKING_ID [UNIQUE ID OF INITIATED CONTACT] 100
+ABS_MT_POSITION_X [CENTER X TOUCH POSITION] 288
+ABS_MT_POSITION_Y [CENTER Y TOUCH POSITION] 1028
+ABS_MT_TOUCH_MAJOR [MAJOR AXIS OF TOUCH ELLIPSE] 40
+ABS_MT_WIDTH_MAJOR [MINOR AXIS OF APPROACHING ELLIPSE] 40
+
+ABS_MT_SLOT [MULTITOUCH SLOT MODIFIED] 1
+ABS_MT_TRACKING_ID [UNIQUE ID OF INITIATED CONTACT] 101
+ABS_MT_POSITION_X [CENTER X TOUCH POSITION] 866
+ABS_MT_POSITION_Y [CENTER Y TOUCH POSITION] 660
+ABS_MT_TOUCH_MAJOR [MAJOR AXIS OF TOUCH ELLIPSE] 49
+ABS_MT_WIDTH_MAJOR [MINOR AXIS OF APPROACHING ELLIPSE] 49
+TOUCH EVENT BEGIN
+separator for 0 : 0
+
+ABS_MT_SLOT [MULTITOUCH SLOT MODIFIED] 0
+ABS_MT_TRACKING_ID [UNIQUE ID OF INITIATED CONTACT] -1
+ABS_MT_SLOT [MULTITOUCH SLOT MODIFIED] 1
+ABS_MT_TRACKING_ID [UNIQUE ID OF INITIATED CONTACT] -1
+TOUCH EVENT END
+separator for 0 : 0