Add an option to enable single-touch A+B combo in iOS, closes #587

iOS/GBBackgroundView.m

@@ -332,6 +332,10 @@ static GB_key_mask_t angleToKeyMask(double angle)
         else if (CGPointSquaredDistance(point, _layout.selectLocation) <= buttonRadiusSquared) {
             mask |= GB_KEY_SELECT_MASK;
         }
+        else if ([[NSUserDefaults standardUserDefaults] boolForKey:@"GBEnableABCombo"] &&
+                 CGPointSquaredDistance(point, _layout.abComboLocation) <= buttonRadiusSquared) {
+            mask |= GB_KEY_A_MASK | GB_KEY_B_MASK;
+        }
         else if (!dpadHandled &&
                  fabs(point.x - _layout.dpadLocation.x) <= dpadRadius &&
                  fabs(point.y - _layout.dpadLocation.y) <= dpadRadius) {

iOS/GBHorizontalLayout.m

@@ -85,6 +85,9 @@
     self.bLocation = (CGPoint){self.bLocation.x + self.cutout, self.bLocation.y};
     self.startLocation = (CGPoint){self.startLocation.x + self.cutout, self.startLocation.y};
     self.selectLocation = (CGPoint){self.selectLocation.x + self.cutout, self.selectLocation.y};
+    self.abComboLocation = (CGPoint){(self.aLocation.x + self.bLocation.x) / 2,
+                                     (self.aLocation.y + self.bLocation.y) / 2};
+
     
     UIGraphicsBeginImageContextWithOptions(resolution, true, 1);
     [self drawBackground];

iOS/GBLayout.h

@@ -6,6 +6,7 @@
 @property (readonly) CGPoint dpadLocation;
 @property (readonly) CGPoint aLocation;
 @property (readonly) CGPoint bLocation;
+@property (readonly) CGPoint abComboLocation;
 @property (readonly) CGPoint startLocation;
 @property (readonly) CGPoint selectLocation;
 - (CGRect)viewRectForOrientation:(UIInterfaceOrientation)orientation;
@@ -19,6 +20,7 @@
 @property CGPoint dpadLocation;
 @property CGPoint aLocation;
 @property CGPoint bLocation;
+@property CGPoint abComboLocation;
 @property CGPoint startLocation;
 @property CGPoint selectLocation;
 @property (readonly) CGSize resolution;

iOS/GBSettingsViewController.m

@@ -321,6 +321,12 @@ static NSString const *typeLightTemp = @"typeLightTemp";
                 return @"Directional input is determined by the touch position.";
             },
         },
+        @{
+            @"items": @[
+                @{@"type": typeCheck, @"pref": @"GBEnableABCombo", @"title": @"Single-Touch A+B"},
+            ],
+            @"footer": @"Enable this option to allow pressing A+B by touching the space between the two buttons",
+        },
         @{
             @"header": @"Horizontal Swipe Behavior",
             @"items": @[

iOS/GBVerticalLayout.m

@@ -54,6 +54,8 @@
         round(buttonsCenter.y + buttonsDelta.height / 2)
     };
     
+    self.abComboLocation = buttonsCenter;
+    
     double controlsTop = self.dpadLocation.y - 80 * self.factor;
     double middleSpace = self.bLocation.x - buttonRadius - (self.dpadLocation.x + 80 * self.factor);