Initial commit: ACE-Step UI - Open source music generation interface

server/audio-editor/keys.js

@@ -0,0 +1,89 @@
+(function( w, d, PKAE ) {
+	'use strict';
+	
+	function KeyHandler () {
+		var q = this;
+		
+		q.keyMap          = {}; // holds a map of all the active keys
+		q.callbacks       = {}; // callbacks for when a key combintation becomes active
+		q.singleCallbacks = {}; // callbacks to the 'keypress' event - not required
+
+		q.addCallback = function (callback_name, callback_function, keys) {
+			q.callbacks[ callback_name ] = {
+				keys : keys,
+				callback : callback_function
+			};
+		};
+		q.addSingleCallback = function (callback_name, callback_function, key) {
+			q.singleCallbacks[ callback_name ] = {
+				key : key,
+				callback : callback_function
+			};
+		};
+		q.removeCallback = function ( callback_name ) {
+			q.callbacks[ callback_name ] = null;
+		};
+		
+		d.addEventListener ('keydown', function ( e ) {
+			var keyCode = e.keyCode;
+
+			q.keyDown (keyCode, e);
+		});
+
+		q.keyDown = function (keyCode, e ) {
+			q.keyMap[keyCode] = 1;
+
+			for (var key in q.callbacks) {
+				var group = q.callbacks[key];
+				if (!group) continue;
+				
+				var l = group.keys.length;
+				var all_ok = true;
+				while (l-- > 0) {
+					if (!q.keyMap[group.keys[l]])
+					{
+						all_ok = false;
+						break;
+					}
+				}
+
+				all_ok && group.callback && group.callback ( keyCode, q.keyMap, e );
+			}			
+		};
+
+		q.keyUp = function ( keyCode ) {
+			q.keyMap[keyCode] = 0;
+		};
+
+		q.keyPress = function ( keyCode, e ) {
+			for (var key in q.singleCallbacks) {
+				var group = q.singleCallbacks[key];
+				if (!group) continue;
+				
+				if (group.key === keyCode)
+					group.callback && group.callback ( e );
+			}
+		};
+
+		d.addEventListener ('keyup', function ( e ) {
+			var keyCode = e.keyCode;
+			q.keyUp (keyCode);
+		});
+
+		d.addEventListener ('keypress', function ( e ) {
+			var keyCode = e.keyCode;
+
+			q.keyPress (keyCode, e);
+		});
+
+		w.addEventListener ('blur', function ( e ) {
+			q.keyMap = {};
+		}, false);
+		d.addEventListener ('contextmenu', function( e ) {
+			e.preventDefault();
+		}, false);
+	};
+	
+	PKAE._deps.keyhandler = KeyHandler;
+
+})( window, document, PKAudioEditor  );