[Remoting iOS] Basic viewport manipulation support

remoting/client/ios/client_gestures.mm

 // Copyright 2017 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #if !defined(__has_feature) || !__has_feature(objc_arc)
 #error "This file requires ARC support."
 #endif
 
 #import "remoting/client/ios/client_gestures.h"
 
 @implementation ClientGestures
 
-- (id)initWithView:(UIView*)view {
+- (instancetype)initWithView:(UIView*)view
+                    viewport:(remoting::DesktopViewport*)vp {
+  _view = view;
+  _viewport = vp;
+
   _inputScheme = HostInputSchemeTouch;
 
   _longPressRecognizer = [[UILongPressGestureRecognizer alloc]
       initWithTarget:self
               action:@selector(longPressGestureTriggered:)];
   _longPressRecognizer.delegate = self;
   [view addGestureRecognizer:_longPressRecognizer];
 
   _panRecognizer = [[UIPanGestureRecognizer alloc]
       initWithTarget:self
@@ skipping 68 matching lines @@
 // Integreation with the original implementation will be done with the app
 // is able to run to the point of interaction and debugging can happen.
 // I would prefer to leave this here rather than deleting because it is close
 // to the implementation that will be used client gestures integration.
 // This is a new class that was derived from the original source which had
 // the implementation mixed in with the host controller and was a huge mess.
 
 // Resize the view of the desktop - Zoom in/out.  This can occur during a Pan.
 - (IBAction)pinchGestureTriggered:(UIPinchGestureRecognizer*)sender {
   // LOG_TRACE(INFO) << "pinchGestureTriggered";
-  // if ([sender state] == UIGestureRecognizerStateChanged) {
-  //   [self applySceneChange:CGPointMake(0.0, 0.0) scaleBy:sender.scale];
-  //
-  //   sender.scale = 1.0;  // reset scale so next iteration is a relative ratio
-  // }
+  if ([sender state] == UIGestureRecognizerStateChanged) {
+    CGPoint pivot = [sender locationInView:_view];

[Yuwei, 2017/05/03 05:52:35]

I'm planning on creating a new C++ class to be shared with Android to handle
touch events, so eventually these code may be moved to that class and this class
may just become a pure adapter.

[nicholss, 2017/05/03 15:33:50]

Note this class is copy/paste from the original bad code. 

+    _viewport->ScaleDesktop(pivot.x, pivot.y, sender.scale);
+
+    sender.scale = 1.0;  // reset scale so next iteration is a relative ratio
+  }
 }
 
 - (IBAction)tapGestureTriggered:(UITapGestureRecognizer*)sender {
   // LOG_TRACE(INFO) << "tapGestureTriggered";
   // CGPoint touchPoint = [sender locationInView:self.view];
   // if ([_scene containsTouchPoint:touchPoint]) {
   //   if (_inputScheme == HostInputSchemeTouch) {
   //     [_scene setMouseLocationFromLocationInView:touchPoint];
   //     _circle.expandedRadius = 11.0f;
   //     [_circle doExpandingAnimationAtLocation:[_scene mouseLocationInView]];
   //   }
   //   [Utility leftClickOn:_clientToHostProxy at:_scene.mousePosition];
   // }
 }
 
 // Change position of scene.  This can occur during a pinch or long press.
 // Or perform a Mouse Wheel Scroll.
+// TODO(yuweih): The comment above doesn't seem right. Non-panning gestures
+//     should be moved out of this method.
 - (IBAction)panGestureTriggered:(UIPanGestureRecognizer*)sender {
+  // TODO(yuweih): Need deceleration animation, probably in another class.
+  if ([sender state] == UIGestureRecognizerStateChanged &&
+      [sender numberOfTouches] == 1) {
+    CGPoint translation = [sender translationInView:_view];
+    _viewport->MoveDesktop(translation.x, translation.y);
+
+    // Reset translation so next iteration is relative
+    [sender setTranslation:CGPointZero inView:_view];
+  }
+
   // LOG_TRACE(INFO) << "panGestureTriggered";
   //   CGPoint translation = [sender translationInView:self.view];
   //   // If we start with 2 touches, and the pinch gesture is not in progress
   //   yet,
   //   // then disable it, so mouse scrolling and zoom do not occur at the same
   //   // time.
   //   if ([sender numberOfTouches] == 2 &&
   //       [sender state] == UIGestureRecognizerStateBegan &&
   //       !(_pinchRecognizer.state == UIGestureRecognizerStateBegan ||
   //         _pinchRecognizer.state == UIGestureRecognizerStateChanged)) {
@@ skipping 195 matching lines @@
       otherGestureRecognizer == _edgeGesture) {
     return YES;
   }
   // TODO(nicholss): If we return NO here, it dismisses the other reconizers.
   // As we add more types of reconizers, they need to be accounted for in the
   // above logic.
   return NO;
 }
 
 @end