Added the support for vertical swipe direction.

MDCSwipeToChoose/Public/Options/MDCSwipeOptions.h

@@ -23,6 +23,7 @@
 //
 
 #import <UIKit/UIKit.h>
+#import "MDCSwipeDirection.h"
 
 @class MDCPanState;
 @class MDCSwipeResult;
@@ -81,6 +82,12 @@ typedef void (^MDCSwipeToChooseOnChosenBlock)(MDCSwipeResult *state);
  */
 @property (nonatomic, assign) CGFloat rotationFactor;
 
+/*!
+ * Contains the directions on which the swipe will be recognized
+ * Must be set using a OR operator (like MDCSwipeDirectionUp | MDCSwipeDirectionDown)
+ */
+@property (nonatomic, assign) MDCSwipeDirection allowedSwipeDirections;
+
 /*!
  * A callback to be executed when the view is panned. The block takes an instance of
  * `MDCPanState` as an argument. Use this `state` instance to determine the pan direction

MDCSwipeToChoose/Public/Options/MDCSwipeOptions.m

@@ -37,6 +37,7 @@ - (instancetype)init {
         _swipeCancelledAnimationOptions = UIViewAnimationOptionCurveEaseOut;
         _swipeAnimationDuration = 0.1;
         _swipeAnimationOptions = UIViewAnimationOptionCurveEaseIn;
+        _allowedSwipeDirections = MDCSwipeDirectionLeft | MDCSwipeDirectionRight;
         _rotationFactor = 3.f;
 
         _onChosen = [[self class] exitScreenOnChosenWithDuration:0.1

MDCSwipeToChoose/Public/State/MDCSwipeDirection.h

@@ -30,7 +30,9 @@
  * and a swipe to the right as positive.
  */
 typedef NS_ENUM(NSInteger, MDCSwipeDirection) {
-    MDCSwipeDirectionNone = 0,
-    MDCSwipeDirectionLeft,
-    MDCSwipeDirectionRight
+    MDCSwipeDirectionNone = 1,
+    MDCSwipeDirectionLeft = 2,
+    MDCSwipeDirectionRight = 4,
+    MDCSwipeDirectionUp = 8,
+    MDCSwipeDirectionDown = 16
 };

MDCSwipeToChoose/Public/Views/UIView+MDCSwipeToChoose.m

@@ -28,6 +28,8 @@
 #import "MDCGeometry.h"
 #import <objc/runtime.h>
 
+#define HAS_OPT(options, opt) ((options & opt) == opt)
+
 const void * const MDCSwipeOptionsKey = &MDCSwipeOptionsKey;
 const void * const MDCViewStateKey = &MDCViewStateKey;
 
@@ -114,6 +116,8 @@ - (void)mdc_setupPanGestureRecognizer {
 - (void)mdc_finalizePosition {
     MDCSwipeDirection direction = [self mdc_directionOfExceededThreshold];
     switch (direction) {
+        case MDCSwipeDirectionUp:
+        case MDCSwipeDirectionDown:
         case MDCSwipeDirectionRight:
         case MDCSwipeDirectionLeft: {
             CGPoint translation = MDCCGPointSubtract(self.center,
@@ -213,10 +217,16 @@ - (CGPoint)mdc_translationExceedingThreshold:(CGFloat)threshold
 }
 
 - (MDCSwipeDirection)mdc_directionOfExceededThreshold {
-    if (self.center.x > self.mdc_viewState.originalCenter.x + self.mdc_options.threshold) {
+    MDCSwipeDirection directions = [self mdc_options].allowedSwipeDirections;
+
+    if (HAS_OPT(directions, MDCSwipeDirectionRight) && self.center.x > self.mdc_viewState.originalCenter.x + self.mdc_options.threshold) {
         return MDCSwipeDirectionRight;
-    } else if (self.center.x < self.mdc_viewState.originalCenter.x - self.mdc_options.threshold) {
+    } else if (HAS_OPT(directions, MDCSwipeDirectionLeft) && self.center.x < self.mdc_viewState.originalCenter.x - self.mdc_options.threshold) {
         return MDCSwipeDirectionLeft;
+    } else if (HAS_OPT(directions, MDCSwipeDirectionUp) && self.center.y < self.mdc_viewState.originalCenter.y - self.mdc_options.threshold) {
+        return MDCSwipeDirectionUp;
+    } else if (HAS_OPT(directions, MDCSwipeDirectionDown) && self.center.y > self.mdc_viewState.originalCenter.y + self.mdc_options.threshold) {
+        return MDCSwipeDirectionDown;
     } else {
         return MDCSwipeDirectionNone;
     }