sway: add bindgesture command

Co-authored-by: Michael Weiser <michael.weiser@gmx.de>

include/gesture.h

@@ -0,0 +1,104 @@
+#ifndef _SWAY_GESTURE_H
+#define _SWAY_GESTURE_H
+
+#include <stdbool.h>
+#include <stdint.h>
+
+/**
+ * A gesture type used in binding.
+ */
+enum gesture_type {
+	GESTURE_TYPE_NONE = 0,
+	GESTURE_TYPE_HOLD,
+	GESTURE_TYPE_PINCH,
+	GESTURE_TYPE_SWIPE,
+};
+
+// Turns single type enum value to constant string representation.
+const char *gesture_type_string(enum gesture_type direction);
+
+// Value to use to accept any finger count
+extern const uint8_t GESTURE_FINGERS_ANY;
+
+/**
+ * A gesture direction used in binding.
+ */
+enum gesture_direction {
+	GESTURE_DIRECTION_NONE = 0,
+	// Directions based on delta x and y
+	GESTURE_DIRECTION_UP = 1 << 0,
+	GESTURE_DIRECTION_DOWN = 1 << 1,
+	GESTURE_DIRECTION_LEFT = 1 << 2,
+	GESTURE_DIRECTION_RIGHT = 1 << 3,
+	// Directions based on scale
+	GESTURE_DIRECTION_INWARD = 1 << 4,
+	GESTURE_DIRECTION_OUTWARD = 1 << 5,
+	// Directions based on rotation
+	GESTURE_DIRECTION_CLOCKWISE = 1 << 6,
+	GESTURE_DIRECTION_COUNTERCLOCKWISE = 1 << 7,
+};
+
+// Turns single direction enum value to constant string representation.
+const char *gesture_direction_string(enum gesture_direction direction);
+
+/**
+ * Struct representing a pointer gesture
+ */
+struct gesture {
+	enum gesture_type type;
+	uint8_t fingers;
+	uint32_t directions;
+};
+
+/**
+ * Parses gesture from <gesture>[:<fingers>][:<directions>] string.
+ *
+ * Return NULL on success, otherwise error message string
+ */
+char *gesture_parse(const char *input, struct gesture *output);
+
+// Turns gesture into string representation
+char *gesture_to_string(struct gesture *gesture);
+
+// Check if gesture is of certain type and finger count.
+bool gesture_check(struct gesture *target,
+		enum gesture_type type, uint8_t fingers);
+
+// Check if a gesture target/binding is match by other gesture/input
+bool gesture_match(struct gesture *target,
+		struct gesture *to_match, bool exact);
+
+// Returns true if gesture are exactly the same
+bool gesture_equal(struct gesture *a, struct gesture *b);
+
+// Compare distance between two matched target gestures.
+int8_t gesture_compare(struct gesture *a, struct gesture *b);
+
+// Small helper struct to track gestures over time
+struct gesture_tracker {
+	enum gesture_type type;
+	uint8_t fingers;
+	double dx, dy;
+	double scale;
+	double rotation;
+};
+
+// Begin gesture tracking
+void gesture_tracker_begin(struct gesture_tracker *tracker,
+		enum gesture_type type, uint8_t fingers);
+
+// Check if the provides type is currently being tracked
+bool gesture_tracker_check(struct gesture_tracker *tracker,
+		enum gesture_type type);
+
+// Update gesture track with new data point
+void gesture_tracker_update(struct gesture_tracker *tracker, double dx,
+		double dy, double scale, double rotation);
+
+// Reset tracker
+void gesture_tracker_cancel(struct gesture_tracker *tracker);
+
+// Reset tracker and return gesture tracked
+struct gesture *gesture_tracker_end(struct gesture_tracker *tracker);
+
+#endif