iOS Chromoting Client

remoting/ios/ui/host_view_controller.mm

+// Copyright 2014 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/ios/ui/host_view_controller.h"
+
+#include <OpenGLES/ES2/gl.h>
+
+#import "remoting/ios/data_store.h"
+
+namespace {
+
+// TODO (aboone) Some of the layout is not yet set in stone, so variables have
+// been used to possition and turn items on and off.  Evantually these should be
+// stabilized and removed.
+
+// Scrool speed multiplier for swiping
+const static int kMouseSensitivity = 2.5;
+
+// Scrool speed multiplier for mouse wheel
+const static int kMouseWheelSensitivity = 20;
+
+// Input Axis inversion
+// 1 for standard, -1 for inverted
+const static int kXAxisInversion = -1;
+const static int kYAxisInversion = -1;
+
+// Area the navigation bar consumes when visible in pixels
+const static int kTopMargin = 19;
+// Area the tool bar consumes when visible in pixels
+const static int kBottomMargin = 0;
+// Experimental value for bounding the maximum zoom ratio
+const static int kMaxZoomSize = 3;
+// Distance between Button in the Tool bar in pixels
+const static int kButtonSpacer = 15;
+
+#ifdef DEBUG
+// Some basic statistics.
+// The number of canvas updates received from the network.
+static uint32_t _applyCount = 0;
+// The number of frames drawn to the GL Context
+static uint32_t _frameCount = 0;
+// The number of frames that also required canvas updates to be drawn to the GL
+// Context.
+static uint32_t _drawCount = 0;
+#endif  // DEBUG
+}  // namespace
+
+@interface HostViewController (Private)
+- (void)setupGL;
+- (void)tearDownGL;
+- (void)bindTextureForIOS:(GLuint)glName;
+- (void)checkConnectStatus;
+- (void)doConnectToHostWithPin:(NSString*)hostPin
+                 createPairing:(BOOL)createPair;
+- (BOOL)convertTouchPointToMousePoint:(CGPoint)touchPoint
+                          targetPoint:(webrtc::DesktopVector&)desktopPoint;
+- (BOOL)convertMousePointToTouchPoint:(const webrtc::DesktopVector&)mousePoint
+                          targetPoint:(CGPoint&)touchPoint;
+- (void)logGLErrorCode:(NSString*)funcName;
+- (void)setFrameForControls;
+- (CGRect)getViewBounds;
+- (void)updateContentSize;
+- (void)updatePanVelocityShouldCancel:(bool)canceled;
+- (void)orientationChanged:(NSNotification*)note;
+- (webrtc::DesktopSize)getCurrentSize;
+- (void)panAndZoom:(CGPoint)translation scaleBy:(float)ratio;
++ (float)calculateScaleingDelta:(float)scale
+                           size:(float)size
+                       position:(float)position
+                         anchor:(float)anchor;
++ (int)calculatePositionDelta:(int)position
+                       length:(int)length
+                  translation:(int)translation
+                   scaleDelta:(int)scaleDelta
+                isAnchoredLow:(BOOL)isAnchoredLow
+               isAnchoredHigh:(BOOL)isAnchoredHigh;
++ (int)applyBoundsToFrameAxis:(float)position
+                        delta:(int)delta
+                   lowerBound:(int)lowerBound
+                   upperBound:(int)upperBound;
++ (int)calculateMousePosition:(int)nextPosition
+                  maxPosition:(int)maxPosition
+               centerPosition:(int)centerPosition
+                isAnchoredLow:(BOOL)isAnchoredLow
+               isAnchoredHigh:(BOOL)isAnchoredHigh;
+- (void)cancelVelocityWhenAtEdge;
+- (void)updateMousePositionAndAnchorsWithBounds:
+        (const webrtc::DesktopVector&)bounds
+                                    translation:(CGPoint)translation;
+- (BOOL)isPointInScene:(CGPoint)point;
+- (void)showToolbar:(BOOL)visible;
+@end
+
+@implementation HostViewController
+
+// Override UIViewController
+- (void)viewDidLoad {
+  [super viewDidLoad];
+
+  _context = [[EAGLContext alloc] initWithAPI:kEAGLRenderingAPIOpenGLES2];
+
+  DCHECK(_context);
+
+  GLKView* view = static_cast<GLKView*>(self.view);
+  view.context = _context;
+
+  [_keyEntryView setDelegate:self];
+
+  _controller = [[ClientController alloc] init];
+
+  _updateDisplayTimer =
+      [NSTimer scheduledTimerWithTimeInterval:0.4
+                                       target:self
+                                     selector:@selector(checkConnectStatus)
+                                     userInfo:nil
+                                      repeats:NO];
+  _mousePosition.set(0, 0);
+  _glBufferLock = [[NSLock alloc] init];
+  _glCursorLock = [[NSLock alloc] init];
+  _needCursorRedraw = NO;
+  _cursorDrawnToGL = webrtc::DesktopRect::MakeXYWH(0, 0, 0, 0);
+  _sizeChanged = YES;  // rgba
+  _frameSize.set(1, 1);
+  _scenePosition = GLKVector3Make(0, 0, 1);
+
+  [self updatePanVelocityShouldCancel:YES];
+
+  // [self updateContectSize] is implicit in this call, and required at this
+  // point
+  [self showToolbar:NO];
+
+  [self setupGL];
+
+  [_singleTapRecognizer requireGestureRecognizerToFail:_twoFingerTapRecognizer];
+  [_twoFingerTapRecognizer
+      requireGestureRecognizerToFail:_threeFingerTapRecognizer];
+  //[_pinchRecognizer requireGestureRecognizerToFail:_twoFingerTapRecognizer];
+  [_panRecognizer requireGestureRecognizerToFail:_singleTapRecognizer];
+  [_threeFingerPanRecognizer
+      requireGestureRecognizerToFail:_threeFingerTapRecognizer];
+  //[_pinchRecognizer requireGestureRecognizerToFail:_threeFingerPanRecognizer];
+
+  // Subscribe to changes in orientation
+  [[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
+  [[NSNotificationCenter defaultCenter]
+      addObserver:self
+         selector:@selector(orientationChanged:)
+             name:UIDeviceOrientationDidChangeNotification
+           object:[UIDevice currentDevice]];
+
+  [self.navigationController setNavigationBarHidden:YES animated:YES];
+
+  // We impliment UIBarPositioningDelegate to handle this class's delegate
+  [_viewToolbar setDelegate:self];
+  // Causes |_viewToolbar| to call |positionForBar| via it's delegate where we
+  // can inform it of it's relative position
+  [self setNeedsStatusBarAppearanceUpdate];
+}
+
+- (void)setupGL {
+  [EAGLContext setCurrentContext:_context];
+
+  _effect = [[GLKBaseEffect alloc] init];
+
+  [self logGLErrorCode:@"setupGL begin"];
+
+  // Create 2 textures in the array |_textureIds|
+  glGenTextures(2, _textureIds);
+
+  [self logGLErrorCode:@"setupGL init"];
+  // Initialize each texture
+  [self bindTextureForIOS:_textureIds[0]];
+  glBindTexture(GL_TEXTURE_2D, 0);
+
+  [self bindTextureForIOS:_textureIds[1]];
+  glBindTexture(GL_TEXTURE_2D, 0);
+
+  [self logGLErrorCode:@"setupGL textureComplete"];
+
+  // Texture 0 is the HOST Desktop layer, and will always replace what is in the
+  // draw context
+  [_effect texture2d0].target = GLKTextureTarget2D;
+  [_effect texture2d0].name = _textureIds[0];
+  [_effect texture2d0].envMode = GLKTextureEnvModeReplace;
+  [_effect texture2d0].enabled = GL_TRUE;
+
+  // Texuture 1 is the Cursor layer, and is stamped on top of texture 0 as a
+  // transparent image
+  [_effect texture2d1].target = GLKTextureTarget2D;
+  [_effect texture2d1].name = _textureIds[1];
+  [_effect texture2d1].envMode = GLKTextureEnvModeDecal;
+  [_effect texture2d1].enabled = GL_TRUE;
+}
+
+// Override UIViewController
+- (void)viewDidUnload {
+  [super viewDidUnload];
+  [self tearDownGL];
+
+  if ([EAGLContext currentContext] == _context) {
+    [EAGLContext setCurrentContext:nil];
+  }
+  _context = nil;
+}
+
+- (void)tearDownGL {
+  [EAGLContext setCurrentContext:_context];
+  // Release 2 GL Textures
+  glDeleteTextures(2, _textureIds);
+}
+
+// Override UIViewController
+- (void)viewWillAppear:(BOOL)animated {
+  [super viewWillAppear:NO];
+
+  [self setFrameForControls];
+}
+
+// Override UIViewController
+- (void)viewWillDisappear:(BOOL)animated {
+  [super viewWillDisappear:NO];
+  NSArray* viewControllers = self.navigationController.viewControllers;
+  if (viewControllers.count > 1 &&
+      [viewControllers objectAtIndex:viewControllers.count - 2] == self) {
+    // View is disappearing because a new view controller was pushed onto the
+    // stack
+  } else if ([viewControllers indexOfObject:self] == NSNotFound) {
+    // View is disappearing because it was popped from the stack
+    [_controller disconnectFromHost];
+  }
+}
+
+// GL Binding Context requires some specific flags for the type of textures
+// being drawn
+- (void)bindTextureForIOS:(GLuint)glName {
+  glBindTexture(GL_TEXTURE_2D, glName);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+}
+
+// Callback from |_updateDisplayTimer|.  Occurs a short time after the form has
+// loaded.  Begin the connection to the host.
+- (void)checkConnectStatus {
+  if (_updateDisplayTimer) {
+    [_updateDisplayTimer invalidate];
+    _updateDisplayTimer = nil;
+  }
+
+  _bbiHostAndStatus.title = _host.hostName;
+  [_busyIndicator startAnimating];
+
+  NSString* authToken = [_authorization.parameters valueForKey:@"access_token"];
+
+  if (authToken == nil) {
+    authToken = [_authorization authorizationTokenKey];
+  }
+
+  [_controller connectToHost:[_authorization userEmail]
+                  authToken:authToken
+                   jabberId:_host.jabberId
+                     hostId:_host.hostId
+                  publicKey:_host.publicKey
+                   delegate:self];
+}
+
+// @protocol PinEntryViewControllerDelegate
+// Return the PIN input by User, indicate if the User should be prompted to
+// re-enter the pin in the future
+- (void)connectToHostWithPin:(NSString*)hostPin
+                shouldPrompt:(BOOL)shouldPrompt {
+  const HostPreferences* hostPrefs =
+      [[DataStore sharedStore] getHostForId:_host.hostId];
+  if (!hostPrefs) {
+    hostPrefs = [[DataStore sharedStore] createHost:_host.hostId];
+  }
+  if (hostPrefs) {
+    hostPrefs.hostPin = hostPin;
+    hostPrefs.askForPin = [NSNumber numberWithBool:shouldPrompt];
+    [[DataStore sharedStore] saveChanges];
+  }
+
+  [[_pinEntry presentingViewController] dismissViewControllerAnimated:NO
+                                                           completion:NULL];
+  _pinEntry = nil;
+
+  [self doConnectToHostWithPin:hostPin createPairing:!shouldPrompt];
+}
+
+// @protocol PinEntryViewControllerDelegate
+// Returns if the user canceled while entering their PIN
+- (void)cancelledConnectToHostWithPin {
+  [[_pinEntry presentingViewController] dismissViewControllerAnimated:NO
+                                                           completion:NULL];
+  _pinEntry = nil;
+
+  [self.navigationController popViewControllerAnimated:YES];
+}
+
+- (void)setHostDetails:(Host*)host
+         authorization:(GTMOAuth2Authentication*)authorization {
+  _host = host;
+  _authorization = authorization;
+}
+
+// Occurs after the user has entered thier PIN.  If Pairing is already
+// established, PIN entry may be skipped.
+- (void)doConnectToHostWithPin:(NSString*)hostPin
+                 createPairing:(BOOL)createPair {
+  [_controller authenticationResponse:hostPin createPair:createPair];
+}
+
+// Converts a point in the the CLIENT resolution to a similar point in the HOST
+// resolution.  Additionally, CLIENT resolution is expressed in float values
+// while HOST opperates in integer values.
+- (BOOL)convertTouchPointToMousePoint:(CGPoint)touchPoint
+                          targetPoint:(webrtc::DesktopVector&)mousePoint {
+  if (![self isPointInScene:touchPoint]) {
+    return NO;
+  }
+
+  // A touch location occurs in respect to the user's entire view surface.
+
+  // The GL Context is upside down from the User's perspective so flip it.
+  CGPoint glOrientedTouchPoint =
+      CGPointMake(touchPoint.x, _contentSize.height() - touchPoint.y);
+
+  // The GL surface generally is not at the same origination point as the touch,
+  // so translate by the scene's position.
+  CGPoint glOrientedPointInRespectToFrame =
+      CGPointMake(glOrientedTouchPoint.x - _scenePosition.x,
+                  glOrientedTouchPoint.y - _scenePosition.y);
+
+  // The perspective exists in relative to the CLIENT resoluation at 1:1, zoom
+  // our persepective so we are relative to the HOST at 1:1
+  CGPoint glOrientedPointInFrame =
+      CGPointMake(glOrientedPointInRespectToFrame.x / _scenePosition.z,
+                  glOrientedPointInRespectToFrame.y / _scenePosition.z);
+
+  // Finally, flip the perspective back over to the Users, but this time in
+  // respect to the HOST desktop.  Floor to ensure the result is always in
+  // frame.
+  CGPoint deskTopOrientedPointInFrame =
+      CGPointMake(floorf(glOrientedPointInFrame.x),
+                  floorf(_frameSize.height() - glOrientedPointInFrame.y));
+
+  // Convert from float to integer
+  mousePoint.set(deskTopOrientedPointInFrame.x, deskTopOrientedPointInFrame.y);
+
+  return CGRectContainsPoint(
+      CGRectMake(0, 0, _frameSize.width(), _frameSize.height()),
+      deskTopOrientedPointInFrame);
+}
+
+// Converts a point in the the HOST resolution to a similar point in the CLIENT
+// resolution.  Additionally, CLIENT resolution is expressed in float values
+// while HOST opperates in integer values.
+- (BOOL)convertMousePointToTouchPoint:(const webrtc::DesktopVector&)mousePoint
+                          targetPoint:(CGPoint&)touchPoint {
+
+  // A mouse point is in respect to the desktop frame.
+
+  // Flip the perspective back over to the Users, in
+  // respect to the HOST desktop.
+  CGPoint deskTopOrientedPointInFrame =
+      CGPointMake(mousePoint.x(), _frameSize.height() - mousePoint.y());
+
+  // The perspective exists in relative to the CLIENT resoluation at 1:1, zoom
+  // our persepective so we are relative to the HOST at 1:1
+  CGPoint glOrientedPointInFrame =
+      CGPointMake(deskTopOrientedPointInFrame.x * _scenePosition.z,
+                  deskTopOrientedPointInFrame.y * _scenePosition.z);
+
+  // The GL surface generally is not at the same origination point as the touch,
+  // so translate by the scene's position.
+  CGPoint glOrientedPointInRespectToFrame =
+      CGPointMake(glOrientedPointInFrame.x + _scenePosition.x,
+                  glOrientedPointInFrame.y + _scenePosition.y);
+
+  // The GL Context is upside down from the User's perspective so flip it.
+  CGPoint glOrientedTouchPoint =
+      CGPointMake(glOrientedPointInRespectToFrame.x,
+                  _contentSize.height() - glOrientedPointInRespectToFrame.y);
+
+  // Convert from float to integer
+  touchPoint.x = floorf(glOrientedTouchPoint.x);
+  touchPoint.y = floorf(glOrientedTouchPoint.y);
+
+  return [self isPointInScene:touchPoint];
+}
+
+// Resize the view of the desktop - Zoon in/out.  This can occur during a Pan.
+- (IBAction)pinchGestureTriggered:(UIPinchGestureRecognizer*)sender {
+  if ([sender state] == UIGestureRecognizerStateChanged) {
+    [self panAndZoom:CGPointMake(0.0, 0.0) scaleBy:sender.scale];
+
+    sender.scale = 1.0;  // reset scale so next iteration is a relative ratio
+  }
+}
+
+// Left button click
+- (IBAction)tapGestureTriggered:(UITapGestureRecognizer*)sender {
+  if ([self isPointInScene:[sender locationInView:self.view]]) {
+    [Utility leftClickOn:_controller at:_mousePosition];
+  }
+}
+
+// Change position of scene.  This can occur during a pinch or longpress.
+// Or perform a Mouse Wheel Scroll
+- (IBAction)panGestureTriggered:(UIPanGestureRecognizer*)sender {
+  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)) {
+    _pinchRecognizer.enabled = NO;
+  }
+
+  if (!_pinchRecognizer.enabled) {
+    // Began with 2 touches, so this is a scrool event
+    translation.x *= kMouseWheelSensitivity;
+    translation.y *= kMouseWheelSensitivity;
+    [Utility mouseScroll:_controller
+                      at:_mousePosition
+                   delta:webrtc::DesktopVector(translation.x, translation.y)];
+  } else {
+    // Did not begin with 2 touches, pan event
+    if ([sender state] == UIGestureRecognizerStateChanged) {
+      CGPoint translation = [sender translationInView:self.view];
+
+      [self panAndZoom:translation scaleBy:1.0];
+
+    } else if ([sender state] == UIGestureRecognizerStateEnded) {
+      // After user removes their fingers from the screen, apply an acceleration
+      // effect
+      _panVelocity = [sender velocityInView:self.view];
+    }
+  }
+
+  // Finished the event chain
+  if (!([sender state] == UIGestureRecognizerStateBegan ||
+        [sender state] == UIGestureRecognizerStateChanged)) {
+    _pinchRecognizer.enabled = YES;
+  }
+
+  // Reset translation so next iteration is relative.
+  [sender setTranslation:CGPointZero inView:self.view];
+}
+
+// Click-Drag mouse operation.  This can occur during a Pan.
+- (IBAction)longPressGestureTriggered:(UILongPressGestureRecognizer*)sender {
+
+  if ([sender state] == UIGestureRecognizerStateBegan) {
+    [_controller mouseAction:_mousePosition
+                 wheelDelta:webrtc::DesktopVector(0, 0)
+                whichButton:1
+                 buttonDown:YES];
+  } else if (!([sender state] == UIGestureRecognizerStateBegan ||
+               [sender state] == UIGestureRecognizerStateChanged)) {
+    [_controller mouseAction:_mousePosition
+                 wheelDelta:webrtc::DesktopVector(0, 0)
+                whichButton:1
+                 buttonDown:NO];
+  }
+}
+
+// Right mouse button click
+- (IBAction)twoFingerTapGestureTriggered:(UITapGestureRecognizer*)sender {
+  if ([self isPointInScene:[sender locationInView:self.view]]) {
+    [Utility rightClickOn:_controller at:_mousePosition];
+  }
+}
+
+// Middle button click
+- (IBAction)threeFingerTapGestureTriggered:(UITapGestureRecognizer*)sender {
+
+  if ([self isPointInScene:[sender locationInView:self.view]]) {
+    [Utility middleClickOn:_controller at:_mousePosition];
+  }
+}
+
+// Show keyboard or navigation toolbar
+- (IBAction)threeFingerPanGestureTriggered:(UIPanGestureRecognizer*)sender {
+  if ([sender state] == UIGestureRecognizerStateChanged) {
+    CGPoint translation = [sender translationInView:self.view];
+    if (translation.y > 0) {
+      // Swiped down
+      [self.navigationController setNavigationBarHidden:NO animated:YES];
+    } else if (translation.y < 0) {
+      // Swiped up
+      [_keyEntryView becomeFirstResponder];
+    }
+    [sender setTranslation:CGPointZero inView:self.view];
+  }
+}
+
+// Do navigation 'back'
+- (IBAction)barBtnNavigationBackPressed:(id)sender {
+  [self.navigationController popViewControllerAnimated:YES];
+}
+
+// Display the keyboard
+- (IBAction)barBtnKeyboardPressed:(id)sender {
+  [_keyEntryView becomeFirstResponder];
+}
+
+// Display the navigation bar
+- (IBAction)barBtnToolBarHidePressed:(id)sender {
+  [self showToolbar:(_viewToolbar.frame.origin.y < 0)];  // Toolbar is either on
+                                                         // screen or off screen
+}
+
+// @protocol UIBarPositioningDelegate
+// Place the toolbar at the top of the screen
+- (UIBarPosition)positionForBar:(id<UIBarPositioning>)bar {
+  return UIBarPositionTopAttached;
+}
+
+// Override UIResponder
+// When any gesture beings, remove any acceleration effects currently being
+// applied.  Example, Panning view and let it shoot off into the distance, but
+// then I see a spot I'm interested in so I will touch to capture that locations
+// focus.
+- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)event {
+  [self updatePanVelocityShouldCancel:YES];
+  [super touchesBegan:touches withEvent:event];
+}
+
+// @protocol UIGestureRecognizerDelegate
+// Allow panning and zooming to occur simultaniously.
+// Allow panning and long press to occur simultaniously.
+// Pinch requires 2 touches, and long press requires a single touch, so they are
+// mutually exclusive regardless of if panning is the initiating guesture
+- (BOOL)gestureRecognizer:(UIGestureRecognizer*)gestureRecognizer
+    shouldRecognizeSimultaneouslyWithGestureRecognizer:
+        (UIGestureRecognizer*)otherGestureRecognizer {
+  if (gestureRecognizer == _pinchRecognizer ||
+      (gestureRecognizer == _panRecognizer)) {
+    if (otherGestureRecognizer == _pinchRecognizer ||
+        otherGestureRecognizer == _panRecognizer) {
+      return YES;
+    }
+  }
+
+  if (gestureRecognizer == _longPressRecognizer ||
+      gestureRecognizer == _panRecognizer) {
+    if (otherGestureRecognizer == _longPressRecognizer ||
+        otherGestureRecognizer == _panRecognizer) {
+      return YES;
+    }
+  }
+  return NO;
+}
+
+// @protocol ClientControllerDelegate
+// Prompt the user for their PIN if pairing has not already been established
+- (void)requestHostPin:(BOOL)pairingSupported {
+  BOOL requestPin = YES;
+  const HostPreferences* hostPrefs =
+      [[DataStore sharedStore] getHostForId:_host.hostId];
+  if (hostPrefs) {
+    requestPin = [hostPrefs.askForPin boolValue];
+    if (!requestPin) {
+      if (hostPrefs.hostPin == nil || hostPrefs.hostPin.length == 0) {
+        requestPin = YES;
+      }
+    }
+  }
+  if (requestPin == YES) {
+    _pinEntry = [[PinEntryViewController alloc] init];
+    if (_pinEntry) {
+      [_pinEntry setDelegate:self];
+      [_pinEntry setHostName:_host.hostName];
+      [_pinEntry setShouldPrompt:YES];
+      [_pinEntry setPairingSupported:pairingSupported];
+
+      [self presentViewController:_pinEntry animated:YES completion:nil];
+    }
+  } else {
+    [self doConnectToHostWithPin:hostPrefs.hostPin
+                   createPairing:pairingSupported];
+  }
+}
+
+// @protocol ClientControllerDelegate
+// Occurs when a connection to a HOST is established successfully
+- (void)connected {
+  [_busyIndicator stopAnimating];
+}
+
+// @protocol ClientControllerDelegate
+// Occurs when a connection to a HOST has failed
+- (void)connectionFailed:(NSString*)errorMessage {
+  [_busyIndicator stopAnimating];
+  NSString* errorMsg;
+  if ([_controller isConnected]) {
+    errorMsg = @"Lost Connection";
+  } else {
+    errorMsg = @"Unable to connect";
+  }
+  [Utility showAlert:errorMsg message:errorMessage];
+  [self.navigationController popViewControllerAnimated:YES];
+}
+
+// @protocol ClientControllerDelegate
+- (void)connectionStatus:(NSString*)statusMessage {
+  NSMutableString* hostStatus = [[NSMutableString alloc] init];
+  [hostStatus appendFormat:@"%@ - %@", _host.hostName, statusMessage];
+  _bbiHostAndStatus.title = hostStatus;
+}
+
+// @protocol ClientControllerDelegate
+// Copy the updated regions to a backing store to be consumed by the GL Context
+// on a different thread.  A region is stored in disjoint memory locations, and
+// must be transformed to a contiguous memory buffer for a GL Texture write.
+// /-----\
+// |  2-4|  This buffer is 5x3 bytes large, a region exists at bytes 2 to 4 and
+// |  7-9|  bytes 7 to 9.  The region is extracted to a new continguous buffer
+// |     |  of 6 bytes in length.
+// \-----/
+// More than 1 region may exist in the frame from each call, in which case a new
+// buffer is created for each region
+- (void)applyFrame:(const webrtc::DesktopSize&)size
+            stride:(NSInteger)stride
+              data:(uint8_t*)data
+           regions:(const std::vector<webrtc::DesktopRect>&)regions {
+
+#ifdef DEBUG
+  _applyCount++;
+#endif  // DEBUG
+
+  // The HOST can change resolution.  This always occurs on the first call to
+  // |applyFrame|
+  if (_frameSize.width() != size.width() ||
+      _frameSize.height() != size.height()) {
+    _frameSize.set(size.width(), size.height());
+
+    _scenePosition.x = 0;
+    _scenePosition.y = 0;
+
+    CGPoint ratios = [self pixelRatio];
+
+    float verticalPixelScaleRatio = 1;
+
+    // If the new resolution is larger then the old size, increase the zoom to
+    // fit the entire vertical height in the CLIENT resolution height.
+    if (_scenePosition.z < ratios.y) {
+      verticalPixelScaleRatio = 1 / _scenePosition.z;  // keep the current scale
+    } else {
+      verticalPixelScaleRatio =
+          ratios.y / _scenePosition.z;  // make scale small
+                                        // enough so it will
+                                        // fit vertical height
+    }
+
+    _isAnchorLeft = YES;
+    _isAnchorBottom = YES;
+    _isAnchorTop = YES;
+    _isAnchorRight = YES;
+
+    [self panAndZoom:CGPointMake(0.0, 0.0) scaleBy:verticalPixelScaleRatio];
+    _sizeChanged = YES;
+
+    webrtc::DesktopVector newMouseLocation;
+    if ([self convertTouchPointToMousePoint:
+                CGPointMake(_contentSize.width() / 2, _contentSize.height() / 2)
+                                targetPoint:newMouseLocation]) {
+      _mousePosition.set(newMouseLocation.x(), newMouseLocation.y());
+    }
+
+#if DEBUG
+    NSLog(@"resized frame:%d:%d scale:%f",
+          _frameSize.width(),
+          _frameSize.height(),
+          _scenePosition.z);
+#endif  // DEBUG
+  }
+
+  [_glBufferLock lock];  // going to make changes to |_glRegions|
+
+  uint32_t src_stride = stride;
+
+  for (uint32_t i = 0; i < regions.size(); i++) {
+    scoped_ptr<GLRegion> region(new GLRegion());
+
+    if (region.get()) {
+      webrtc::DesktopRect rect = regions.at(i);
+
+      webrtc::DesktopSize(rect.width(), rect.height());
+      region->offset.reset(new webrtc::DesktopVector(rect.left(), rect.top()));
+      region->image.reset(new webrtc::BasicDesktopFrame(
+          webrtc::DesktopSize(rect.width(), rect.height())));
+
+      if (region->image->data()) {
+        uint32_t bytes_per_row =
+            region->image->kBytesPerPixel * region->image->size().width();
+
+        uint32_t offset =
+            (src_stride * region->offset->y()) +                    // row
+            (region->offset->x() * region->image->kBytesPerPixel);  // column
+
+        uint8_t* src_buffer = data + offset;
+        uint8_t* dst_buffer = region->image->data();
+
+        // row by row copy
+        for (uint32_t j = 0; j < region->image->size().height(); j++) {
+          memcpy(dst_buffer, src_buffer, bytes_per_row);
+          dst_buffer += bytes_per_row;
+          src_buffer += src_stride;
+        }
+        _glRegions.push_back(region.release());
+      }
+    }
+  }
+  [_glBufferLock unlock];  // done makeing changes to |_glRegions|
+}
+
+// @protocol ClientControllerDelegate
+// Copy the delivered cursor to a backing store to be consumed by the GL Context
+// on a different thread.  Note only the most recent cursor is of importance,
+// discard the previous cursor.
+- (void)applyCursor:(const webrtc::DesktopSize&)size
+            hotspot:(const webrtc::DesktopVector&)hotspot
+         cursorData:(uint8_t*)data {
+
+  [_glCursorLock lock];  // going to make changes to |_cursor|
+
+  // MouseCursor takes ownership of DesktopFrame
+  _cursor.reset(
+      new webrtc::MouseCursor(new webrtc::BasicDesktopFrame(size), hotspot));
+
+  if (_cursor->image().data()) {
+    memcpy(_cursor->image().data(),
+           data,
+           size.width() * size.height() * _cursor->image().kBytesPerPixel);
+
+    _needCursorRedraw = YES;
+  } else {
+    _cursor.reset();
+    _needCursorRedraw = NO;
+  }
+
+  [_glCursorLock unlock];  // done makeing changes to |_cursor|
+}
+
+// @protocol GLKViewDelegate
+// There is quite a few gotchas involved in working with this function.  For
+// sanity purposes, I've just assumed calls to the function are on a different
+// thread which I've termed GL Context.  Any varibles consumed by this function
+// should be thread safe.
+//
+// Clear Screen, update desktop, update cursor, define possition, and finally
+// present
+//
+// In general, avoid expensive work in this function to maximize frame rate.
+- (void)glkView:(GLKView*)view drawInRect:(CGRect)rect {
+
+  [self updatePanVelocityShouldCancel:NO];
+
+  // Clear to black, to give the background color
+  glClearColor(0.0, 0.0, 0.0, 1.0);
+  glClear(GL_COLOR_BUFFER_BIT);
+
+  [self logGLErrorCode:@"drawInRect bindBuffer"];
+
+  if (_glRegions.size() > 0 || _sizeChanged) {
+#ifdef DEBUG
+    _drawCount++;
+#endif  // DEBUG
+
+    if (_sizeChanged) {
+      // Update desktop is done by regions.  But for the first call and when the
+      // size changes (from the HOST changing desktop resoluation) we have to
+      // reinitialize the textures.
+      [self bindTextureForIOS:_textureIds[0]];
+
+      glTexImage2D(GL_TEXTURE_2D,
+                   0,
+                   GL_RGBA,
+                   _frameSize.width(),
+                   _frameSize.height(),
+                   0,
+                   GL_RGBA,
+                   GL_UNSIGNED_BYTE,
+                   NULL);
+
+      glBindTexture(GL_TEXTURE_2D, 0);
+
+      [self bindTextureForIOS:_textureIds[1]];
+
+      glTexImage2D(GL_TEXTURE_2D,
+                   0,
+                   GL_RGBA,
+                   _frameSize.width(),
+                   _frameSize.height(),
+                   0,
+                   GL_RGBA,
+                   GL_UNSIGNED_BYTE,
+                   NULL);
+
+      glBindTexture(GL_TEXTURE_2D, 0);
+
+      [self logGLErrorCode:@"drawInRect glTexImage2D"];
+      _sizeChanged = NO;
+    }
+
+    [self bindTextureForIOS:_textureIds[0]];
+
+    [_glBufferLock lock];  // going to make changes to |_glRegions|
+
+    for (uint32_t i = 0; i < _glRegions.size(); i++) {
+
+      GLRegion* region = _glRegions[i];
+
+      // |data| is properly ordered by |applyFrame|
+      glTexSubImage2D(GL_TEXTURE_2D,
+                      0,
+                      region->offset->x(),
+                      region->offset->y(),
+                      region->image->size().width(),
+                      region->image->size().height(),
+                      GL_RGBA,
+                      GL_UNSIGNED_BYTE,
+                      region->image->data());
+
+      [self logGLErrorCode:@"drawInRect glTexSubImage2D"];
+    }
+
+    _glRegions.clear();
+
+    [_glBufferLock unlock];  // done makeing changes to |_glRegions|
+
+    // release bind - be nice
+    glBindTexture(GL_TEXTURE_2D, 0);
+  }
+
+  // When the cursor needs to be redraw in a different spot then we must clear
+  // the previous area.
+  if (_cursor.get() != NULL &&
+      (_needCursorRedraw == YES ||
+       _cursorDrawnToGL.left() != _mousePosition.x() - _cursor->hotspot().x() ||
+       _cursorDrawnToGL.top() != _mousePosition.y() - _cursor->hotspot().y())) {
+
+    [_glCursorLock lock];  // going to make changes to |_cursor|
+    [self bindTextureForIOS:_textureIds[1]];
+
+    if (_cursorDrawnToGL.width() > 0 && _cursorDrawnToGL.height() > 0) {
+      webrtc::BasicDesktopFrame transparentCursor(_cursorDrawnToGL.size());
+
+      if (transparentCursor.data() != NULL) {
+        CHECK(transparentCursor.kBytesPerPixel ==
+              _cursor->image().kBytesPerPixel);
+        memset(transparentCursor.data(),
+               0,
+               transparentCursor.stride() * transparentCursor.size().height());
+
+        glTexSubImage2D(GL_TEXTURE_2D,
+                        0,
+                        _cursorDrawnToGL.left(),
+                        _cursorDrawnToGL.top(),
+                        _cursorDrawnToGL.width(),
+                        _cursorDrawnToGL.height(),
+                        GL_RGBA,
+                        GL_UNSIGNED_BYTE,
+                        transparentCursor.data());
+
+        // there is no longer any cursor drawn to screen
+        _cursorDrawnToGL = webrtc::DesktopRect::MakeXYWH(0, 0, 0, 0);
+      }
+    }
+
+    if (_cursor.get() != NULL) {
+
+      CGRect screen =
+          CGRectMake(0.0, 0.0, _frameSize.width(), _frameSize.height());
+      CGRect cursor = CGRectMake(_mousePosition.x() - _cursor->hotspot().x(),
+                                 _mousePosition.y() - _cursor->hotspot().y(),
+                                 _cursor->image().size().width(),
+                                 _cursor->image().size().height());
+
+      if (CGRectContainsRect(screen, cursor)) {
+        _cursorDrawnToGL = webrtc::DesktopRect::MakeXYWH(cursor.origin.x,
+                                                         cursor.origin.y,
+                                                         cursor.size.width,
+                                                         cursor.size.height);
+
+        glTexSubImage2D(GL_TEXTURE_2D,
+                        0,
+                        _cursorDrawnToGL.left(),
+                        _cursorDrawnToGL.top(),
+                        _cursorDrawnToGL.width(),
+                        _cursorDrawnToGL.height(),
+                        GL_RGBA,
+                        GL_UNSIGNED_BYTE,
+                        _cursor->image().data());
+
+      } else if (CGRectIntersectsRect(screen, rect)) {
+        // Some of the cursor falls off screen, need to clip it
+        CGRect intersection = CGRectIntersection(screen, cursor);
+        _cursorDrawnToGL =
+            webrtc::DesktopRect::MakeXYWH(intersection.origin.x,
+                                          intersection.origin.y,
+                                          intersection.size.width,
+                                          intersection.size.height);
+
+        webrtc::BasicDesktopFrame partialCursor(webrtc::DesktopSize(
+            _cursorDrawnToGL.width(), _cursorDrawnToGL.height()));
+
+        if (partialCursor.data()) {
+          CHECK(partialCursor.kBytesPerPixel ==
+                _cursor->image().kBytesPerPixel);
+
+          uint32_t src_stride = _cursor->image().stride();
+          uint32_t dst_stride = partialCursor.stride();
+
+          uint8_t* source = _cursor->image().data();
+          source +=
+              (static_cast<int32_t>(cursor.origin.y) - _cursorDrawnToGL.top()) *
+              src_stride;
+          source += (static_cast<int32_t>(cursor.origin.x) -
+                     _cursorDrawnToGL.left()) *
+                    _cursor->image().kBytesPerPixel;
+          uint8_t* dst = partialCursor.data();
+
+          for (uint32_t y = 0; y < _cursorDrawnToGL.height(); y++) {
+            memcpy(dst, source, dst_stride);
+            source += src_stride;
+            dst += dst_stride;
+          }
+
+          glTexSubImage2D(GL_TEXTURE_2D,
+                          0,
+                          _cursorDrawnToGL.left(),
+                          _cursorDrawnToGL.top(),
+                          _cursorDrawnToGL.width(),
+                          _cursorDrawnToGL.height(),
+                          GL_RGBA,
+                          GL_UNSIGNED_BYTE,
+                          partialCursor.data());
+        }
+      }
+    }
+
+    glBindTexture(GL_TEXTURE_2D, 0);
+    [_glCursorLock unlock];  // done makeing changes to |_cursor|
+
+    _needCursorRedraw = NO;
+    [self logGLErrorCode:@"drawInRect mouseDrawComplete"];
+  }
+
+  // The scene is the entire CLIENT screen
+  GLKMatrix4 projectionMatrix = GLKMatrix4MakeOrtho(
+      0.0, _contentSize.width(), 0.0, _contentSize.height(), 1.0, -1.0);
+  [_effect transform].projectionMatrix = projectionMatrix;
+
+  // Start by using the entire scene
+  GLKMatrix4 modelMatrix = GLKMatrix4Identity;
+
+  // Position scene according to any panning or bounds
+  modelMatrix = GLKMatrix4Translate(
+      modelMatrix, _scenePosition.x, _scenePosition.y + kBottomMargin, 0.0);
+
+  webrtc::DesktopSize currentSize = [self getCurrentSize];
+  CGPoint ratios = [self pixelRatio];
+
+  // Apply zoom
+  modelMatrix = GLKMatrix4Scale(
+      modelMatrix,
+      _scenePosition.z / ratios.x,
+      _scenePosition.z / ratios.y *
+          (1.0 -
+           (static_cast<float>(kTopMargin + _toolbarHeight + kBottomMargin) /
+            static_cast<float>(currentSize.height()))),
+      1.0);
+
+  // We are directly above the sceen and looking down.
+  GLKMatrix4 viewMatrix = GLKMatrix4MakeLookAt(
+      0.0, 0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 1.0, 0.0);  // center view
+
+  [_effect transform].modelviewMatrix =
+      GLKMatrix4Multiply(viewMatrix, modelMatrix);
+
+  [_effect prepareToDraw];
+
+  [self logGLErrorCode:@"drawInRect prepareToDrawComplete"];
+
+  glEnableVertexAttribArray(GLKVertexAttribPosition);
+  glEnableVertexAttribArray(GLKVertexAttribTexCoord0);
+  glEnableVertexAttribArray(GLKVertexAttribTexCoord1);
+
+  // Define our scene space
+  glVertexAttribPointer(GLKVertexAttribPosition,
+                        2,
+                        GL_FLOAT,
+                        GL_FALSE,
+                        sizeof(TexturedVertex),
+                        &(_quad.bl.geometryVertex));
+  // Define the desktop plane
+  glVertexAttribPointer(GLKVertexAttribTexCoord0,
+                        2,
+                        GL_FLOAT,
+                        GL_FALSE,
+                        sizeof(TexturedVertex),
+                        &(_quad.bl.textureVertex));
+  // Define the cursor plane
+  glVertexAttribPointer(GLKVertexAttribTexCoord1,
+                        2,
+                        GL_FLOAT,
+                        GL_FALSE,
+                        sizeof(TexturedVertex),
+                        &(_quad.bl.textureVertex));
+
+  // Draw!
+  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
+
+  [self logGLErrorCode:@"drawInRect exit"];
+
+#ifdef DEBUG
+  _frameCount++;
+
+  if (_frameCount % 150 == 0) {
+    NSLog(@"@drawInRect drawCount:%d ApplyCount%d", _drawCount, _applyCount);
+  }
+#endif  // DEBUG
+}
+
+// Sometimes its necessary to read gl errors.  This is called in various places
+// while working in the GL Context
+- (void)logGLErrorCode:(NSString*)funcName {
+  GLenum errorCode = 1;
+
+  while (errorCode != 0) {
+    errorCode = glGetError();  // I don't know why this is returning an error
+                               // ont he first call to this function, but if I
+                               // don't read it, then stuff doesn't work...
+#if DEBUG
+    if (errorCode != 0) {
+      NSLog(@"glerror in %@: %X", funcName, errorCode);
+    }
+#endif  // DEBUG
+  }
+}
+
+// Position busy spinner in the middle of the frame
+- (void)setFrameForControls {
+  CGRect mainFrameForSpinner = self.view.frame;
+  CGRect spinnerFrame = _busyIndicator.frame;
+  spinnerFrame.origin.x =
+      (mainFrameForSpinner.size.width / 2) - (spinnerFrame.size.width / 2);
+  spinnerFrame.origin.y =
+      (mainFrameForSpinner.size.height / 2) - (spinnerFrame.size.height / 2);
+  _busyIndicator.frame = spinnerFrame;
+}
+
+// @protocol KeyInputDelegate
+// Send keyboard input to HOST
+- (void)keyboardActionKeyCode:(uint32_t)keyPressed isKeyDown:(BOOL)keyDown {
+  [_controller keyboardAction:keyPressed keyDown:keyDown];
+}
+
+// Return the client resolution in User's perspective
+- (CGRect)getViewBounds {
+  CGRect curBounds = self.view.bounds;
+  if ((curBounds.size.height > curBounds.size.width) &&
+      [Utility isInLandscapeMode]) {
+    float width = curBounds.size.height;
+    curBounds.size.height = curBounds.size.width;
+    curBounds.size.width = width;
+  }
+  return curBounds;
+}
+
+// Update the CLIENT resoluation and draw scene size, account for margins
+- (void)updateContentSize {
+
+  CGRect viewBounds = [self getViewBounds];
+
+  viewBounds.size.height -= (kTopMargin + _toolbarHeight + kBottomMargin);
+
+  _contentSize.set(viewBounds.size.width, viewBounds.size.height);
+
+  TexturedQuad newQuad;
+  newQuad.bl.geometryVertex = CGPointMake(0.0, 0.0);
+  newQuad.br.geometryVertex = CGPointMake(_contentSize.width(), 0.0);
+  newQuad.tl.geometryVertex = CGPointMake(0.0, _contentSize.height());
+  newQuad.tr.geometryVertex =
+      CGPointMake(_contentSize.width(), _contentSize.height());
+
+  newQuad.bl.textureVertex = CGPointMake(0.0, 1.0);
+  newQuad.br.textureVertex = CGPointMake(1.0, 1.0);
+  newQuad.tl.textureVertex = CGPointMake(0.0, 0.0);
+  newQuad.tr.textureVertex = CGPointMake(1.0, 0.0);
+
+  _quad = newQuad;
+}
+
+// Update the scene acceleration vector
+- (void)updatePanVelocityShouldCancel:(bool)canceled {
+
+  if (canceled) {
+    _panVelocity = CGPointMake(0.0, 0.0);
+  }
+
+  BOOL inMotion = ((_panVelocity.x != 0.0) || (_panVelocity.y != 0.0));
+
+  _singleTapRecognizer.enabled = !inMotion;
+  _longPressRecognizer.enabled = !inMotion;
+
+  if (inMotion) {
+
+    uint32_t divisor = 50 / _scenePosition.z;
+    float reducer = .95;
+
+    if (_panVelocity.x != 0.0 && ABS(_panVelocity.x) < divisor) {
+      _panVelocity = CGPointMake(0.0, _panVelocity.y);
+    }
+
+    if (_panVelocity.y != 0.0 && ABS(_panVelocity.y) < divisor) {
+      _panVelocity = CGPointMake(_panVelocity.x, 0.0);
+    }
+
+    [self panAndZoom:CGPointMake(_panVelocity.x / divisor,
+                                 _panVelocity.y / divisor)
+             scaleBy:1.0];
+
+    _panVelocity =
+        CGPointMake(_panVelocity.x * reducer, _panVelocity.y * reducer);
+  }
+}
+
+// Callback from NSNotificationCenter when the User changes orientation
+- (void)orientationChanged:(NSNotification*)note {
+  [self updateContentSize];
+  [self panAndZoom:CGPointMake(0.0, 0.0) scaleBy:1.0];
+}
+
+// Returns the number of pixels displayed per device pixel when the scaleing is
+// such that the entire frame would fit perfectly in content.  Note the ratios
+// are different for width and height, some people have multiple monitors, some
+// have 16:9 or 4:3 while iPad is always single screen, but different iOS
+// devices have different resoluations.
+- (CGPoint)pixelRatio {
+
+  CGPoint r = CGPointMake(static_cast<float>(_contentSize.width()) /
+                              static_cast<float>(_frameSize.width()),
+                          static_cast<float>(_contentSize.height()) /
+                              static_cast<float>(_frameSize.height()));
+  return r;
+}
+
+// Return the FrameSize in persepective of the CLIENT resolution
+- (webrtc::DesktopSize)getCurrentSize {
+  webrtc::DesktopSize r(_frameSize.width() * _scenePosition.z,
+                        _frameSize.height() * _scenePosition.z);
+  return r;
+}
+
+// Applies translation and zoom originateing from |touch|.  Translation is
+// bounded to screen edges.  Zooming is bounded on the lower side to the maximun
+// of width and height, and on the upper side by a constant, experimentally
+// chosen.
+- (void)panAndZoom:(CGPoint)translation scaleBy:(float)ratio {
+
+  CGPoint ratios = [self pixelRatio];
+
+  // New Scaleing factor bounded by a min and max
+  float resultScale = _scenePosition.z * ratio;
+  float scaleUpperBound = kMaxZoomSize;
+  float scaleLowerBound = MIN(ratios.x, ratios.y);
+
+  if (resultScale < scaleLowerBound) {
+    resultScale = scaleLowerBound;
+  } else if (resultScale > scaleUpperBound) {
+    resultScale = scaleUpperBound;
+  }
+
+  // The GL perspective is upside down in relation to the User's view, so flip
+  // the translation
+  translation.y = -translation.y;
+
+  // These could be user options, but just using constants for now.
+  translation.x =
+      translation.x * kXAxisInversion * (1 / (ratios.x * kMouseSensitivity));
+  translation.y =
+      translation.y * kYAxisInversion * (1 / (ratios.y * kMouseSensitivity));
+
+  CGPoint delta = CGPointMake(0, 0);
+  CGPoint scaleDelta = CGPointMake(0, 0);
+
+  webrtc::DesktopSize currentSize = [self getCurrentSize];
+
+  // When bounded on the top or right, this point is where the scene must be
+  // positioned given its current deminsions
+  webrtc::DesktopVector bounds(_contentSize.width() - currentSize.width(),
+                               _contentSize.height() - currentSize.height());
+
+  // There are rounding errors in the scope of this function, see the butterfly
+  // effect.  In successsive calls, the resulting position isn't always exactly
+  // the calculated position. If we know we are Anchored, then go ahead and
+  // reposition it to the values above.
+  if (_isAnchorRight) {
+    _scenePosition =
+        GLKVector3Make(bounds.x(), _scenePosition.y, _scenePosition.z);
+  }
+
+  if (_isAnchorTop) {
+    _scenePosition =
+        GLKVector3Make(_scenePosition.x, bounds.y(), _scenePosition.z);
+  }
+
+  if (_scenePosition.z != resultScale) {
+
+    // When scaling the scene, the origination of scaleing is the mouse's
+    // location.  But when the frame is anchored, adjust the origination to the
+    // anchor point.
+
+    CGPoint mousePositionInClientResolution;
+    [self convertMousePointToTouchPoint:_mousePosition
+                            targetPoint:mousePositionInClientResolution];
+
+    if (_isAnchorLeft) {
+      mousePositionInClientResolution.x = 0;
+    } else if (_isAnchorRight) {
+      mousePositionInClientResolution.x = _contentSize.width();
+    }
+
+    if (_isAnchorTop) {
+      mousePositionInClientResolution.y = _contentSize.height();
+    } else if (_isAnchorBottom) {
+      mousePositionInClientResolution.y = 0;
+    }
+
+    scaleDelta.x -= [HostViewController
+        calculateScaleingDelta:ratio
+                          size:currentSize.width()
+                      position:_scenePosition.x
+                        anchor:mousePositionInClientResolution.x];
+
+    scaleDelta.y -= [HostViewController
+        calculateScaleingDelta:ratio
+                          size:currentSize.height()
+                      position:_scenePosition.y
+                        anchor:mousePositionInClientResolution.y];
+  }
+
+  delta.x = [HostViewController
+      calculatePositionDelta:_scenePosition.x
+                      length:_contentSize.width() - currentSize.width()
+                 translation:translation.x
+                  scaleDelta:scaleDelta.x
+               isAnchoredLow:_isAnchorLeft
+              isAnchoredHigh:_isAnchorRight];
+
+  delta.y = [HostViewController
+      calculatePositionDelta:_scenePosition.y
+                      length:_contentSize.height() - currentSize.height()
+                 translation:translation.y
+                  scaleDelta:scaleDelta.y
+               isAnchoredLow:_isAnchorBottom
+              isAnchoredHigh:_isAnchorTop];
+
+  delta.x = [HostViewController applyBoundsToFrameAxis:_scenePosition.x
+                                                 delta:delta.x
+                                            lowerBound:bounds.x() + scaleDelta.x
+                                            upperBound:0];
+
+  delta.y = [HostViewController applyBoundsToFrameAxis:_scenePosition.y
+                                                 delta:delta.y
+                                            lowerBound:bounds.y() + scaleDelta.y
+                                            upperBound:0];
+
+  BOOL isLeftAndRightAnchored = _isAnchorLeft && _isAnchorRight;
+  BOOL isTopAndBottomAnchored = _isAnchorTop && _isAnchorBottom;
+
+  [self updateMousePositionAndAnchorsWithBounds:bounds translation:translation];
+
+  // If both anchors were lost, then keep the one that is easier to predict
+  if (isLeftAndRightAnchored && !_isAnchorLeft && !_isAnchorRight) {
+    delta.x = -_scenePosition.x;
+    _isAnchorLeft = YES;
+  }
+
+  // If both anchors were lost, then keep the one that is easier to predict
+  if (isTopAndBottomAnchored && !_isAnchorTop && !_isAnchorBottom) {
+    delta.y = -_scenePosition.y;
+    _isAnchorBottom = YES;
+  }
+
+  // FINALLY, update the scene's position
+  _scenePosition = GLKVector3Make(
+      _scenePosition.x + delta.x, _scenePosition.y + delta.y, resultScale);
+
+  // Notify HOST that the mouse moved
+  [Utility moveMouse:_controller at:_mousePosition];
+}
+
+// When zoom is changed the scene is also translated to keep the
+// origination point (the spot the user is touching) at the same place in the
+// User's perspective.
++ (float)calculateScaleingDelta:(float)scale
+                           size:(float)size
+                       position:(float)position
+                         anchor:(float)anchor {
+
+  float newSize = size * scale;
+
+  float scaleXBy = fabs(position - anchor) / newSize;
+
+  float delta = (newSize - size) * scaleXBy;
+
+  return delta;
+}
+
+// Determine overall |_scenePosition| Delta for an axis
++ (int)calculatePositionDelta:(int)position
+                       length:(int)length
+                  translation:(int)translation
+                   scaleDelta:(int)scaleDelta
+                isAnchoredLow:(BOOL)isAnchoredLow
+               isAnchoredHigh:(BOOL)isAnchoredHigh {
+
+  if (isAnchoredLow && isAnchoredHigh) {
+    // center the view
+    return (length / 2) - position;
+  } else if (isAnchoredLow) {
+    return 0;
+  } else if (isAnchoredHigh) {
+    return scaleDelta;
+  } else {
+
+    return translation + scaleDelta;
+  }
+}
+
+// |position + delta| is snapped to the bounds, return the delta in respect to
+// the bounding.
++ (int)applyBoundsToFrameAxis:(float)position
+                        delta:(int)delta
+                   lowerBound:(int)lowerBound
+                   upperBound:(int)upperBound {
+  int result = position + delta;
+
+  if (lowerBound < upperBound) {  // the view is larger than the bounds
+    if (result > upperBound) {
+      result = upperBound;
+    } else if (result < lowerBound) {
+      result = lowerBound;
+    }
+  } else {  // the view is smaller than the bounds
+    if (result < upperBound) {
+      result = upperBound;
+    } else if (result > lowerBound) {
+      result = lowerBound;
+    }
+  }
+  return result - position;
+}
+
+// Return |nextPosition| when it is anchored and still in the respective 1/2 of
+// the screen.  When |nextPosition| is outside scene's edge, snap to edge.
+// Otherwise return |centerPosition|
++ (int)calculateMousePosition:(int)nextPosition
+                  maxPosition:(int)maxPosition
+               centerPosition:(int)centerPosition
+                isAnchoredLow:(BOOL)isAnchoredLow
+               isAnchoredHigh:(BOOL)isAnchoredHigh {
+
+  if (nextPosition < 0) {
+    return 0;
+  }
+  if (nextPosition > maxPosition - 1) {
+    return maxPosition - 1;
+  }
+
+  if ((isAnchoredLow && nextPosition <= centerPosition) ||
+      (isAnchoredHigh && nextPosition >= centerPosition)) {
+    return nextPosition;
+  }
+
+  return centerPosition;
+}
+
+// If the mouse is at an edge, remove any existing velocity from vector
+- (void)cancelVelocityWhenAtEdge {
+  if (_panVelocity.x != 0.0) {
+    if (_mousePosition.x() == 0 ||
+        _mousePosition.x() == _frameSize.width() - 1) {
+      _panVelocity = CGPointMake(0.0, _panVelocity.y);
+    }
+  }
+
+  if (_panVelocity.y != 0.0) {
+    if (_mousePosition.y() == 0 ||
+        _mousePosition.y() == _frameSize.height() - 1) {
+      _panVelocity = CGPointMake(_panVelocity.x, 0.0);
+    }
+  }
+}
+
+// Mouse is tracked in the prespective of the HOST desktop, but the projection
+// to the user is in the prespective of the CLIENT resolution.  Find the HOST
+// position that is the center of the current CLIENT view.  If the mouse is in
+// the half of the CLIENT screen that is closest to an anchor, then move the
+// mouse, otherwise the mouse should be centered.
+- (void)updateMousePositionAndAnchorsWithBounds:
+        (const webrtc::DesktopVector&)bounds
+                                    translation:(CGPoint)translation {
+  webrtc::DesktopVector centerMouseLocation;
+  [self convertTouchPointToMousePoint:CGPointMake(_contentSize.width() / 2,
+                                                  _contentSize.height() / 2)
+                          targetPoint:centerMouseLocation];
+
+  webrtc::DesktopVector predictedMousePosition(
+      _mousePosition.x() - translation.x, _mousePosition.y() + translation.y);
+
+  _mousePosition
+      .set([HostViewController calculateMousePosition:predictedMousePosition.x()
+                                          maxPosition:_frameSize.width()
+                                       centerPosition:centerMouseLocation.x()
+                                        isAnchoredLow:_isAnchorLeft
+                                       isAnchoredHigh:_isAnchorRight],
+           [HostViewController calculateMousePosition:predictedMousePosition.y()
+                                          maxPosition:_frameSize.height()
+                                       centerPosition:centerMouseLocation.y()
+                                        isAnchoredLow:_isAnchorTop
+                                       isAnchoredHigh:_isAnchorBottom]);
+  [self cancelVelocityWhenAtEdge];
+
+  _isAnchorLeft = (bounds.x() >= 0) ||
+                  ((_scenePosition.x) == 0 &&
+                   predictedMousePosition.x() < centerMouseLocation.x());
+
+  _isAnchorRight = (bounds.x() >= 0) ||
+                   (_scenePosition.x == bounds.x() &&
+                    predictedMousePosition.x() > centerMouseLocation.x());
+  _isAnchorTop = (bounds.y() >= 0) ||
+                 (_scenePosition.y == bounds.y() &&
+                  predictedMousePosition.y() < centerMouseLocation.y());
+  _isAnchorBottom = (bounds.y() >= 0) ||
+                    ((_scenePosition.y) == 0 &&
+                     predictedMousePosition.y() > centerMouseLocation.y());
+}
+
+- (BOOL)isPointInScene:(CGPoint)point {
+  CGRect frame = CGRectMake(0,
+                            kTopMargin + _toolbarHeight,
+                            _contentSize.width(),
+                            _contentSize.height());
+  return CGRectContainsPoint(frame, point);
+}
+
+// Animate the toolbar moving on or offscreen
+- (void)showToolbar:(BOOL)visible {
+  if (visible && (_viewToolbar.frame.origin.y >= 0)) {
+    return;
+  }
+
+  CGRect frame = [_viewToolbar frame];
+  frame.origin.y = -frame.size.height;
+  int newToolbarHeight = 0;
+
+  if (visible) {
+    frame.origin.y = 20;
+    newToolbarHeight = 40;
+  }
+
+  _toolbarHeight = newToolbarHeight;
+
+  [UIView animateWithDuration:0.5
+                   animations:^{ [_viewToolbar setFrame:frame]; }
+                   completion:^(BOOL finished) {
+                                   // Nothing to do for now
+                               }];
+
+  [self updateContentSize];
+  [self panAndZoom:CGPointMake(0.0, 0.0) scaleBy:1.0];
+}
+@end