From 134e15691d8ed1e3cf33e336c484228306079962 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jesu=CC=81s=20A=2E=20A=CC=81lvarez?= <zydeco@namedfork.net>
Date: Fri, 18 Nov 2016 22:12:56 +0100
Subject: [PATCH] support multi-touch mouse-down, resolves #2

---
 Mini vMac/TrackPad.m | 75 ++++++++++++++++++++++++++++++--------------
 1 file changed, 51 insertions(+), 24 deletions(-)

diff --git a/Mini vMac/TrackPad.m b/Mini vMac/TrackPad.m
index f5c373b..64104d3 100644
--- a/Mini vMac/TrackPad.m	
+++ b/Mini vMac/TrackPad.m	
@@ -19,7 +19,8 @@
     NSTimeInterval previousClickTime, previousTouchTime;
     CGFloat touchDistanceThreshold;
     CGPoint previousTouchLoc;
-    BOOL click, drag;
+    BOOL shouldClick;
+    BOOL isDragging;
     NSMutableSet *currentTouches;
 }
 
@@ -28,58 +29,84 @@
         touchTimeThreshold = 0.25;
         touchDistanceThreshold = 16;
         currentTouches = [NSMutableSet setWithCapacity:4];
+        self.multipleTouchEnabled = YES;
     }
     return self;
 }
 
-- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
-    click = YES;
-    CGPoint touchLoc = [touches.anyObject locationInView:self];
-    if ((event.timestamp - previousTouchTime < touchTimeThreshold) &&
-        fabs(previousTouchLoc.x - touchLoc.x) < touchDistanceThreshold &&
-        fabs(previousTouchLoc.y - touchLoc.y) < touchDistanceThreshold) {
-        drag = YES;
-        [[AppDelegate sharedEmulator] setMouseButton:YES];
+- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
+    [currentTouches unionSet:touches];
+    if (currentTouches.count == 1) {
+        [self firstTouchBegan:touches.anyObject withEvent:event];
+    } else {
+        [self startDragging];
     }
-    previousTouchTime = event.timestamp;
-    previousTouchLoc = touchLoc;
 }
 
-- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
-    CGPoint touchLoc = [touches.anyObject locationInView:self];
-    CGPoint locDiff = touchLoc;
-    locDiff.x -= previousTouchLoc.x;
-    locDiff.y -= previousTouchLoc.y;
+- (void)firstTouchBegan:(UITouch *)touch withEvent:(UIEvent *)event {
+    CGPoint touchLoc = [touch locationInView:self];
+    if (!isDragging && (event.timestamp - previousTouchTime < touchTimeThreshold) &&
+        fabs(previousTouchLoc.x - touchLoc.x) < touchDistanceThreshold &&
+        fabs(previousTouchLoc.y - touchLoc.y) < touchDistanceThreshold) {
+        [self startDragging];
+    }
+}
+
+- (void)touchesMoved:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
+    UITouch *touch = touches.anyObject;
+    CGPoint touchLoc = [touch locationInView:self];
+    previousTouchLoc = [touch previousLocationInView:self];
     // acceleration
+    CGPoint locDiff = CGPointMake(touchLoc.x - previousTouchLoc.x, touchLoc.y - previousTouchLoc.y);
     NSTimeInterval timeDiff = 100 * (event.timestamp - previousTouchTime);
     NSTimeInterval accel = TRACKPAD_ACCEL_N / (TRACKPAD_ACCEL_T + ((timeDiff * timeDiff)/TRACKPAD_ACCEL_D));
     locDiff.x *= accel;
     locDiff.y *= accel;
-    click = NO;
+    shouldClick = NO;
     [[AppDelegate sharedEmulator] moveMouseX:locDiff.x Y:locDiff.y];
     previousTouchTime = event.timestamp;
     previousTouchLoc = touchLoc;
 }
 
-- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event {
+- (void)touchesEnded:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
+    [currentTouches minusSet:touches];
+    if (currentTouches.count > 0) {
+        return;
+    }
     CGPoint touchLoc = [touches.anyObject locationInView:self];
-    if (click && (event.timestamp - previousTouchTime < touchTimeThreshold)) {
+    if (shouldClick && (event.timestamp - previousTouchTime < touchTimeThreshold)) {
         [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(mouseClick) object:nil];
         [NSObject cancelPreviousPerformRequestsWithTarget:self selector:@selector(mouseUp) object:nil];
         [self performSelector:@selector(mouseClick) withObject:nil afterDelay:touchTimeThreshold];
     }
-    click = NO;
-    if (drag) {
-        [[AppDelegate sharedEmulator] setMouseButton:NO];
-        drag = NO;
+    shouldClick = NO;
+    if (isDragging) {
+        [self stopDragging];
     }
     
     previousTouchLoc = touchLoc;
     previousTouchTime = event.timestamp;
 }
 
+- (void)touchesCancelled:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
+    [currentTouches minusSet:touches];
+    [self stopDragging];
+}
+
+- (void)startDragging {
+    isDragging = YES;
+    shouldClick = NO;
+    [[AppDelegate sharedEmulator] setMouseButton:YES];
+}
+
+- (void)stopDragging {
+    isDragging = NO;
+    shouldClick = NO;
+    [[AppDelegate sharedEmulator] setMouseButton:NO];
+}
+
 - (void)mouseClick {
-    if (drag) {
+    if (isDragging) {
         return;
     }
     [[AppDelegate sharedEmulator] setMouseButton:YES];