feat($swipe): Refactor swipe logic from ngSwipe to $swipe service.

This new service is used by the ngSwipeLeft/Right directives, and by the
separate ngCarousel and swipe-to-delete directives which are under
development.

1 files changed, 16 insertions, 78 deletions

diff --git a/src/ngMobile/directive/ngSwipe.js b/src/ngMobile/directive/ngSwipe.js
index 6de7aa57..e68e45da 100644
--- a/src/ngMobile/directive/ngSwipe.js
+++ b/src/ngMobile/directive/ngSwipe.js
@@ -55,36 +55,20 @@
  */
 
 function makeSwipeDirective(directiveName, direction) {
-  ngMobile.directive(directiveName, ['$parse', function($parse) {
+  ngMobile.directive(directiveName, ['$parse', '$swipe', function($parse, $swipe) {
     // The maximum vertical delta for a swipe should be less than 75px.
     var MAX_VERTICAL_DISTANCE = 75;
     // Vertical distance should not be more than a fraction of the horizontal distance.
     var MAX_VERTICAL_RATIO = 0.3;
     // At least a 30px lateral motion is necessary for a swipe.
     var MIN_HORIZONTAL_DISTANCE = 30;
-    // The total distance in any direction before we make the call on swipe vs. scroll.
-    var MOVE_BUFFER_RADIUS = 10;
-
-    function getCoordinates(event) {
-      var touches = event.touches && event.touches.length ? event.touches : [event];
-      var e = (event.changedTouches && event.changedTouches[0]) ||
-          (event.originalEvent && event.originalEvent.changedTouches &&
-              event.originalEvent.changedTouches[0]) ||
-          touches[0].originalEvent || touches[0];
-
-      return {
-        x: e.clientX,
-        y: e.clientY
-      };
-    }
 
     return function(scope, element, attr) {
       var swipeHandler = $parse(attr[directiveName]);
+
       var startCoords, valid;
-      var totalX, totalY;
-      var lastX, lastY;
 
-      function validSwipe(event) {
+      function validSwipe(coords) {
         // Check that it's within the coordinates.
         // Absolute vertical distance must be within tolerances.
         // Horizontal distance, we take the current X - the starting X.
@@ -94,7 +78,6 @@ function makeSwipeDirective(directiveName, direction) {
         // illegal ones a negative delta.
         // Therefore this delta must be positive, and larger than the minimum.
         if (!startCoords) return false;
-        var coords = getCoordinates(event);
         var deltaY = Math.abs(coords.y - startCoords.y);
         var deltaX = (coords.x - startCoords.x) * direction;
         return valid && // Short circuit for already-invalidated swipes.
@@ -104,65 +87,20 @@ function makeSwipeDirective(directiveName, direction) {
             deltaY / deltaX < MAX_VERTICAL_RATIO;
       }
 
-      element.bind('touchstart mousedown', function(event) {
-        startCoords = getCoordinates(event);
-        valid = true;
-        totalX = 0;
-        totalY = 0;
-        lastX = startCoords.x;
-        lastY = startCoords.y;
-      });
-
-      element.bind('touchcancel', function(event) {
-        valid = false;
-      });
-
-      element.bind('touchmove mousemove', function(event) {
-        if (!valid) return;
-
-        // Android will send a touchcancel if it thinks we're starting to scroll.
-        // So when the total distance (+ or - or both) exceeds 10px in either direction,
-        // we either:
-        // - On totalX > totalY, we send preventDefault() and treat this as a swipe.
-        // - On totalY > totalX, we let the browser handle it as a scroll.
-
-        // Invalidate a touch while it's in progress if it strays too far away vertically.
-        // We don't want a scroll down and back up while drifting sideways to be a swipe just
-        // because you happened to end up vertically close in the end.
-        if (!startCoords) return;
-        var coords = getCoordinates(event);
-
-        if (Math.abs(coords.y - startCoords.y) > MAX_VERTICAL_DISTANCE) {
+      $swipe.bind(element, {
+        'start': function(coords) {
+          startCoords = coords;
+          valid = true;
+        },
+        'cancel': function() {
           valid = false;
-          return;
-        }
-
-        totalX += Math.abs(coords.x - lastX);
-        totalY += Math.abs(coords.y - lastY);
-
-        lastX = coords.x;
-        lastY = coords.y;
-
-        if (totalX < MOVE_BUFFER_RADIUS && totalY < MOVE_BUFFER_RADIUS) {
-          return;
-        }
-
-        // One of totalX or totalY has exceeded the buffer, so decide on swipe vs. scroll.
-        if (totalY > totalX) {
-          valid = false;
-          return;
-        } else {
-          event.preventDefault();
-        }
-      });
-
-      element.bind('touchend mouseup', function(event) {
-        if (validSwipe(event)) {
-          // Prevent this swipe from bubbling up to any other elements with ngSwipes.
-          event.stopPropagation();
-          scope.$apply(function() {
-            swipeHandler(scope, {$event:event});
-          });
+        },
+        'end': function(coords) {
+          if (validSwipe(coords)) {
+            scope.$apply(function() {
+              swipeHandler(scope);
+            });
+          }
         }
       });
     };