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ios/chrome/browser/ui/side_swipe/side_swipe_navigation_view.mm

Index: ios/chrome/browser/ui/side_swipe/side_swipe_navigation_view.mm
diff --git a/ios/chrome/browser/ui/side_swipe/side_swipe_navigation_view.mm b/ios/chrome/browser/ui/side_swipe/side_swipe_navigation_view.mm
new file mode 100644
index 0000000000000000000000000000000000000000..24dbefc133527e548c280c500346c74102ad9402
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+++ b/ios/chrome/browser/ui/side_swipe/side_swipe_navigation_view.mm
@@ -0,0 +1,424 @@
+// Copyright 2015 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.
+
+#import "ios/chrome/browser/ui/side_swipe/side_swipe_navigation_view.h"
+
+#include <cmath>
+
+#include "base/logging.h"
+#include "base/mac/objc_property_releaser.h"
+#include "base/mac/scoped_nsobject.h"
+#include "base/metrics/user_metrics.h"
+#include "base/metrics/user_metrics_action.h"
+#import "ios/chrome/browser/ui/side_swipe/side_swipe_util.h"
+#import "ios/chrome/browser/ui/side_swipe_gesture_recognizer.h"
+#include "ios/chrome/browser/ui/ui_util.h"
+#import "ios/chrome/browser/ui/uikit_ui_util.h"
+#import "ios/chrome/common/material_timing.h"
+
+namespace {
+
+enum class SwipeType { CHANGE_TABS, NAVIGATION };
+
+typedef struct {
+  CGFloat min;
+  CGFloat max;
+} FloatRange;
+
+CGFloat MapValueToRange(FloatRange from, FloatRange to, CGFloat value) {
+  DCHECK(from.min < from.max);
+  if (value <= from.min)
+    return to.min;
+  if (value >= from.max)
+    return to.max;
+  const CGFloat fromDst = from.max - from.min;
+  const CGFloat toDst = to.max - to.min;
+  return to.min + ((value - from.min) / fromDst) * toDst;
+}
+
+// The portion of the screen width a swipe must travel after which a navigation
+// should be initiated.
+const CGFloat kSwipeThreshold = 0.53;
+
+// Convert the velocity (which is measured in points per second) to points per
+// |kSwipeVelocityFraction| of a second.
+const CGFloat kSwipeVelocityFraction = 0.1;
+
+// Distance after which the arrow should animate in.
+const CGFloat kArrowThreshold = 32;
+
+// Duration of the snapping animation when the selection bubble animates.
+const CGFloat kSelectionSnappingAnimationDuration = 0.2;
+
+// Size of the selection circle.
+const CGFloat kSelectionSize = 64.0;
+
+// Start scale of the selection circle.
+const CGFloat kSelectionDownScale = 0.1875;
+
+// The final scale of the selection bubble when the threshold is met.
+const CGFloat kSelectionAnimationScale = 23;
+
+// The duration of the animations played when the threshold is met.
+const CGFloat kSelectionAnimationDuration = 0.5;
+}
+
+@interface SideSwipeNavigationView () {
+ @private
+
+  // The back or forward sprite image.
+  base::scoped_nsobject<UIImageView> arrowView_;
+
+  // The selection bubble.
+  CAShapeLayer* selectionCircleLayer_;
+
+  // If |NO| this is an edge gesture and navigation isn't possible. Don't show
+  // arrows and bubbles and don't allow navigate.
+  BOOL canNavigate_;
+
+  // If |YES| arrowView_ is directionnal and must be rotated 180 degreed for the
+  // forward panes.
+  BOOL rotateForward_;
+
+  base::mac::ObjCPropertyReleaser _propertyReleaser_SideSwipeNavigationView;
+}
+// Returns a newly allocated and configured selection circle shape.
+- (CAShapeLayer*)newSelectionCircleLayer;
+// Pushes the touch towards the edge because it's difficult to touch the very
+// edge of the screen (touches tend to sit near x ~ 4).
+- (CGPoint)adjustPointToEdge:(CGPoint)point;
+@end
+
+@implementation SideSwipeNavigationView
+
+@synthesize targetView = targetView_;
+
+- (instancetype)initWithFrame:(CGRect)frame
+                withDirection:(UISwipeGestureRecognizerDirection)direction
+                  canNavigate:(BOOL)canNavigate
+                        image:(UIImage*)image
+                rotateForward:(BOOL)rotateForward {
+  self = [super initWithFrame:frame];
+  if (self) {
+    _propertyReleaser_SideSwipeNavigationView.Init(
+        self, [SideSwipeNavigationView class]);
+    self.backgroundColor = [UIColor colorWithWhite:90.0 / 256 alpha:1.0];
+
+    canNavigate_ = canNavigate;
+    rotateForward_ = rotateForward;
+    if (canNavigate) {
+      image = [image imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
+      const CGRect imageSize = CGRectMake(0, 0, 24, 24);
+      arrowView_.reset([[UIImageView alloc] initWithImage:image]);
+      [arrowView_ setTintColor:[UIColor whiteColor]];
+      selectionCircleLayer_ = [self newSelectionCircleLayer];
+      [arrowView_ setFrame:imageSize];
+    }
+
+    UIImage* shadowImage =
+        [UIImage imageNamed:@"side_swipe_navigation_content_shadow"];
+    CGRect borderFrame =
+        CGRectMake(0, 0, shadowImage.size.width, self.frame.size.height);
+    base::scoped_nsobject<UIImageView> border(
+        [[UIImageView alloc] initWithFrame:borderFrame]);
+    [border setImage:shadowImage];
+    [self addSubview:border];
+    if (direction == UISwipeGestureRecognizerDirectionRight) {
+      borderFrame.origin.x = frame.size.width - shadowImage.size.width;
+      [border setFrame:borderFrame];
+      [border setAutoresizingMask:UIViewAutoresizingFlexibleLeftMargin];
+    } else {
+      [border setTransform:CGAffineTransformMakeRotation(M_PI)];
+      [border setAutoresizingMask:UIViewAutoresizingFlexibleRightMargin];
+    }
+
+    [self.layer addSublayer:selectionCircleLayer_];
+    [self setClipsToBounds:YES];
+    [self addSubview:arrowView_];
+  }
+  return self;
+}
+
+- (CGPoint)adjustPointToEdge:(CGPoint)currentPoint {
+  CGFloat width = CGRectGetWidth(self.targetView.bounds);
+  CGFloat half = floor(width / 2);
+  CGFloat padding = floor(std::abs(currentPoint.x - half) / half);
+
+  // Push towards the edges.
+  if (currentPoint.x > half)
+    currentPoint.x += padding;
+  else
+    currentPoint.x -= padding;
+
+  // But don't go past the edges.
+  if (currentPoint.x < 0)
+    currentPoint.x = 0;
+  else if (currentPoint.x > width)
+    currentPoint.x = width;
+
+  return currentPoint;
+}
+
+- (void)updateFrameAndAnimateContents:(CGFloat)distance
+                           forGesture:(SideSwipeGestureRecognizer*)gesture {
+  CGFloat width = CGRectGetWidth(self.targetView.bounds);
+
+  // Immediately set frame size.
+  CGRect frame = self.frame;
+  if (gesture.direction == UISwipeGestureRecognizerDirectionRight) {
+    frame.size.width = self.targetView.frame.origin.x;
+    frame.origin.x = 0;
+  } else {
+    frame.origin.x = self.targetView.frame.origin.x + width;
+    frame.size.width = width - frame.origin.x;
+  }
+  [self setFrame:frame];
+
+  // Move |selectionCircleLayer_| without animations.
+  CGRect bounds = self.bounds;
+  CGPoint center = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds));
+  [arrowView_ setCenter:AlignPointToPixel(center)];
+  [CATransaction begin];
+  [CATransaction setDisableActions:YES];
+  [selectionCircleLayer_ setPosition:center];
+  [CATransaction commit];
+
+  CGFloat rotationStart = -M_PI_2;
+  CGFloat rotationEnd = 0;
+  if (gesture.direction == UISwipeGestureRecognizerDirectionLeft) {
+    if (rotateForward_) {
+      rotationStart = M_PI * 1.5;
+      rotationEnd = M_PI;
+    } else {
+      rotationStart = M_PI * 0.5;
+      rotationEnd = 0;
+    }
+  }
+  CGAffineTransform rotation = CGAffineTransformMakeRotation(MapValueToRange(
+      {0, kArrowThreshold}, {rotationStart, rotationEnd}, distance));
+  CGFloat scale = MapValueToRange({0, kArrowThreshold}, {0, 1}, distance);
+  [arrowView_ setTransform:CGAffineTransformScale(rotation, scale, scale)];
+
+  // Animate selection bubbles dpending on distance.
+  [UIView beginAnimations:@"transform" context:NULL];
+  [UIView setAnimationDuration:kSelectionSnappingAnimationDuration];
+  if (distance < (width * kSwipeThreshold)) {
+    // Scale selection down.
+    selectionCircleLayer_.transform =
+        CATransform3DMakeScale(kSelectionDownScale, kSelectionDownScale, 1);
+    selectionCircleLayer_.opacity = 0;
+    [arrowView_ setAlpha:MapValueToRange({0, 64}, {0, 1}, distance)];
+    [arrowView_ setTintColor:[UIColor whiteColor]];
+  } else {
+    selectionCircleLayer_.transform = CATransform3DMakeScale(1, 1, 1);
+    selectionCircleLayer_.opacity = 0.75;
+    [arrowView_ setAlpha:1];
+    [arrowView_ setTintColor:self.backgroundColor];
+  }
+  [UIView commitAnimations];
+}
+
+- (void)explodeSelection:(void (^)(void))block {
+  [CATransaction begin];
+  [CATransaction setCompletionBlock:^{
+    // Note that the animations below may complete at slightly different times
+    // resulting in frame(s) between animation completion and the transaction's
+    // completion handler that show the original state. To avoid this flicker,
+    // the animations use a fillMode forward and are not removed until the
+    // transaction completion handler is executed.
+    [selectionCircleLayer_ removeAnimationForKey:@"opacity"];
+    [selectionCircleLayer_ removeAnimationForKey:@"transform"];
+    [selectionCircleLayer_ setOpacity:0];
+    [arrowView_ setAlpha:0];
+    self.backgroundColor = [UIColor whiteColor];
+    block();
+
+  }];
+
+  CAMediaTimingFunction* timing =
+      ios::material::TimingFunction(ios::material::CurveEaseInOut);
+  CABasicAnimation* scaleAnimation =
+      [CABasicAnimation animationWithKeyPath:@"transform"];
+  scaleAnimation.fromValue =
+      [NSValue valueWithCATransform3D:CATransform3DIdentity];
+  scaleAnimation.toValue =
+      [NSValue valueWithCATransform3D:CATransform3DMakeScale(
+                                          kSelectionAnimationScale,
+                                          kSelectionAnimationScale, 1)];
+  scaleAnimation.timingFunction = timing;
+  scaleAnimation.duration = kSelectionAnimationDuration;
+  scaleAnimation.fillMode = kCAFillModeForwards;
+  scaleAnimation.removedOnCompletion = NO;
+  [selectionCircleLayer_ addAnimation:scaleAnimation forKey:@"transform"];
+
+  CABasicAnimation* opacityAnimation =
+      [CABasicAnimation animationWithKeyPath:@"opacity"];
+  opacityAnimation.fromValue = @(selectionCircleLayer_.opacity);
+  opacityAnimation.toValue = @(1);
+  opacityAnimation.timingFunction = timing;
+  opacityAnimation.duration = kSelectionAnimationDuration;
+  opacityAnimation.fillMode = kCAFillModeForwards;
+  opacityAnimation.removedOnCompletion = NO;
+  [selectionCircleLayer_ addAnimation:opacityAnimation forKey:@"opacity"];
+
+  CABasicAnimation* positionAnimation =
+      [CABasicAnimation animationWithKeyPath:@"position"];
+  positionAnimation.fromValue =
+      [NSValue valueWithCGPoint:selectionCircleLayer_.position];
+
+  CGPoint finalPosition = CGPointMake([self.targetView superview].center.x,
+                                      selectionCircleLayer_.position.y);
+  positionAnimation.toValue = [NSValue valueWithCGPoint:finalPosition];
+  positionAnimation.timingFunction = timing;
+  positionAnimation.duration = kSelectionAnimationDuration;
+  positionAnimation.fillMode = kCAFillModeForwards;
+  positionAnimation.removedOnCompletion = NO;
+  [selectionCircleLayer_ addAnimation:positionAnimation forKey:@"position"];
+  [CATransaction commit];
+
+  [arrowView_ setAlpha:1];
+  [arrowView_ setTintColor:self.backgroundColor];
+  [UIView animateWithDuration:kSelectionAnimationDuration
+                   animations:^{
+                     [arrowView_ setAlpha:0];
+                   }];
+}
+
+- (void)handleHorizontalPan:(SideSwipeGestureRecognizer*)gesture
+     onOverThresholdCompletion:(void (^)(void))onOverThresholdCompletion
+    onUnderThresholdCompletion:(void (^)(void))onUnderThresholdCompletion {
+  CGPoint currentPoint = [gesture locationInView:gesture.view];
+  CGPoint velocityPoint = [gesture velocityInView:gesture.view];
+  currentPoint.x -= gesture.swipeOffset;
+
+  // Push point to edge.
+  currentPoint = [self adjustPointToEdge:currentPoint];
+
+  CGFloat distance = currentPoint.x;
+  // The snap back animation is 0.1 seconds, so convert the velocity distance
+  // to where the |x| position would in .1 seconds.
+  CGFloat velocityOffset = velocityPoint.x * kSwipeVelocityFraction;
+  CGFloat width = CGRectGetWidth(self.targetView.bounds);
+  if (gesture.direction == UISwipeGestureRecognizerDirectionLeft) {
+    distance = width - distance;
+    velocityOffset = -velocityOffset;
+  }
+
+  if (!canNavigate_) {
+    // shrink distance a bit to make the drag feel springier.
+    distance /= 3;
+  }
+
+  CGRect frame = self.targetView.frame;
+  if (gesture.direction == UISwipeGestureRecognizerDirectionLeft) {
+    frame.origin.x = -distance;
+  } else {
+    frame.origin.x = distance;
+  }
+  self.targetView.frame = frame;
+
+  [self updateFrameAndAnimateContents:distance forGesture:gesture];
+
+  if (gesture.state == UIGestureRecognizerStateEnded ||
+      gesture.state == UIGestureRecognizerStateCancelled ||
+      gesture.state == UIGestureRecognizerStateFailed) {
+    CGFloat threshold = width * kSwipeThreshold;
+    CGFloat finalDistance = distance + velocityOffset;
+    // Ensure the actual distance traveled has met the minimum arrow threshold
+    // and that the distance including expected velocity is over |threshold|.
+    if (distance > kArrowThreshold && finalDistance > threshold &&
+        canNavigate_ && gesture.state == UIGestureRecognizerStateEnded) {
+      // Speed up the animation for higher velocity swipes.
+      CGFloat animationTime = MapValueToRange(
+          {threshold, width},
+          {kSelectionAnimationDuration, kSelectionAnimationDuration / 2},
+          finalDistance);
+      [self animateTargetViewCompleted:YES
+                         withDirection:gesture.direction
+                          withDuration:animationTime];
+      [self explodeSelection:onOverThresholdCompletion];
+      if (IsSwipingForward(gesture.direction)) {
+        base::RecordAction(base::UserMetricsAction(
+            "MobileEdgeSwipeNavigationForwardCompleted"));
+      } else {
+        base::RecordAction(
+            base::UserMetricsAction("MobileEdgeSwipeNavigationBackCompleted"));
+      }
+    } else {
+      [self animateTargetViewCompleted:NO
+                         withDirection:gesture.direction
+                          withDuration:0.1];
+      onUnderThresholdCompletion();
+      if (IsSwipingForward(gesture.direction)) {
+        base::RecordAction(base::UserMetricsAction(
+            "MobileEdgeSwipeNavigationForwardCancelled"));
+      } else {
+        base::RecordAction(
+            base::UserMetricsAction("MobileEdgeSwipeNavigationBackCancelled"));
+      }
+    }
+  }
+}
+
+- (void)animateTargetViewCompleted:(BOOL)completed
+                     withDirection:(UISwipeGestureRecognizerDirection)direction
+                      withDuration:(CGFloat)duration {
+  void (^animationBlock)(void) = ^{
+    CGRect targetFrame = self.targetView.frame;
+    CGRect frame = self.frame;
+    CGFloat width = CGRectGetWidth(self.targetView.bounds);
+    // Animate self.targetFrame to the side if completed and to the center if
+    // not. Animate self.view to the center if completed or to the size if not.
+    if (completed) {
+      frame.origin.x = 0;
+      frame.size.width = width;
+      self.frame = frame;
+      targetFrame.origin.x =
+          direction == UISwipeGestureRecognizerDirectionRight ? width : -width;
+      self.targetView.frame = targetFrame;
+    } else {
+      targetFrame.origin.x = 0;
+      self.targetView.frame = targetFrame;
+      frame.origin.x =
+          direction == UISwipeGestureRecognizerDirectionLeft ? width : 0;
+      frame.size.width = 0;
+      self.frame = frame;
+    }
+    CGRect bounds = self.bounds;
+    CGPoint center = CGPointMake(CGRectGetMidX(bounds), CGRectGetMidY(bounds));
+    [arrowView_ setCenter:AlignPointToPixel(center)];
+  };
+  CGFloat cleanUpDelay = completed ? kSelectionAnimationDuration - duration : 0;
+  [UIView animateWithDuration:duration
+                   animations:animationBlock
+                   completion:^(BOOL finished) {
+                     // Give the other animations time to complete.
+                     dispatch_after(dispatch_time(DISPATCH_TIME_NOW,
+                                                  cleanUpDelay * NSEC_PER_SEC),
+                                    dispatch_get_main_queue(), ^{
+                                      // Reset target frame.
+                                      CGRect frame = self.targetView.frame;
+                                      frame.origin.x = 0;
+                                      self.targetView.frame = frame;
+                                      [self removeFromSuperview];
+                                    });
+                   }];
+}
+
+- (CAShapeLayer*)newSelectionCircleLayer {
+  const CGRect bounds = CGRectMake(0, 0, kSelectionSize, kSelectionSize);
+  CAShapeLayer* selectionCircleLayer = [[CAShapeLayer alloc] init];
+  selectionCircleLayer.bounds = bounds;
+  selectionCircleLayer.backgroundColor = [[UIColor clearColor] CGColor];
+  selectionCircleLayer.fillColor = [[UIColor whiteColor] CGColor];
+  selectionCircleLayer.opacity = 0;
+  selectionCircleLayer.transform =
+      CATransform3DMakeScale(kSelectionDownScale, kSelectionDownScale, 1);
+  selectionCircleLayer.path =
+      [[UIBezierPath bezierPathWithOvalInRect:bounds] CGPath];
+
+  return selectionCircleLayer;
+}
+
+@end