Upstream Chrome on iOS source code [6/11].

ios/chrome/browser/ui/qr_scanner/qr_scanner_view.mm

+// Copyright 2016 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/qr_scanner/qr_scanner_view.h"
+
+#include "base/logging.h"
+#include "base/mac/foundation_util.h"
+#include "base/mac/scoped_nsobject.h"
+#include "ios/chrome/browser/ui/icons/chrome_icon.h"
+#include "ios/chrome/browser/ui/ui_util.h"
+#include "ios/chrome/grit/ios_strings.h"
+#include "ios/third_party/material_components_ios/src/components/Buttons/src/MaterialButtons.h"
+#include "ui/base/l10n/l10n_util.h"
+#include "ui/base/l10n/l10n_util_mac.h"
+
+namespace {
+// TODO(crbug.com/629427): Replace the temporary UI constants with correct
+// values for all device types.
+
+// Padding for buttons in the QR scanner UI.
+const CGFloat kButtonPadding = 16.0;
+
+// Width and height of the QR scanner viewport.
+const CGFloat kViewportSize_iPhone = 250.0;
+const CGFloat kViewportSize_iPad = 300.0;
+
+// Length of the viewport borders, starting from the corner.
+const CGFloat kViewportBorderCornerWidth_iPhone = 25.0;
+const CGFloat kViewportBorderCornerWidth_iPad = 30.0;
+
+// Opacity of the preview overlay.
+const CGFloat kPreviewOverlayOpacity = 0.5;
+
+// Corner radius of the border around the viewport.
+const CGFloat kViewportBorderCornerRadius = 2.0;
+// Line width of the viewport border.
+const CGFloat kViewportBorderLineWidth = 4.0;
+// Shadow opacity of the viewport border.
+const CGFloat kViewportBorderShadowOpacity = 1.0;
+// Shadow radius of the viewport border.
+const CGFloat kViewportBorderShadowRadius = 10.0;
+// Padding of the viewport caption, below the viewport.
+const CGFloat kViewportCaptionPadding = 24.0;
+// Shadow opacity of the viewport caption.
+const CGFloat kViewportCaptionShadowOpacity = 1.0;
+// Shadow radius of the viewport caption.
+const CGFloat kViewportCaptionShadowRadius = 5.0;
+
+// Duration of the flash animation played when a code is scanned.
+const CGFloat kFlashDuration = 0.5;
+
+// Returns a square of size |rectSize| centered inside |frameSize|.
+CGRect CenteredRectForViewport(CGSize frameSize, CGFloat rectSize) {
+  CGFloat rectX = AlignValueToPixel((frameSize.width - rectSize) / 2);
+  CGFloat rectY = AlignValueToPixel((frameSize.height - rectSize) / 2);
+  return CGRectMake(rectX, rectY, rectSize, rectSize);
+}
+
+// Returns the size of the viewport based on the device type.
+CGFloat GetViewportSize() {
+  return IsIPadIdiom() ? kViewportSize_iPad : kViewportSize_iPhone;
+}
+
+}  // namespace
+
+// A subclass of UIView with the layerClass property set to
+// AVCaptureVideoPreviewLayer. Contains the video preview for the QR scanner.
+@interface VideoPreviewView : UIView
+
+// Returns the VideoPreviewView's layer cast to AVCaptureVideoPreviewLayer.
+- (AVCaptureVideoPreviewLayer*)previewLayer;
+
+// Returns the rectangle in camera coordinates in which codes should be
+// recognized.
+- (CGRect)viewportRectOfInterest;
+
+@end
+
+@implementation VideoPreviewView
+
++ (Class)layerClass {
+  return [AVCaptureVideoPreviewLayer class];
+}
+
+- (AVCaptureVideoPreviewLayer*)previewLayer {
+  return base::mac::ObjCCastStrict<AVCaptureVideoPreviewLayer>([self layer]);
+}
+
+- (CGRect)viewportRectOfInterest {
+  DCHECK(CGPointEqualToPoint(self.frame.origin, CGPointZero));
+  CGRect viewportRect =
+      CenteredRectForViewport(self.frame.size, GetViewportSize());
+  AVCaptureVideoPreviewLayer* layer = [self previewLayer];
+  // If the layer does not have a connection,
+  // |metadataOutputRectOfInterestForRect:| does not return the right value.
+  DCHECK(layer.connection);
+  return [layer metadataOutputRectOfInterestForRect:viewportRect];
+}
+
+@end
+
+// A subclass of UIView containing the preview overlay. It is responsible for
+// redrawing the preview overlay and the viewport border every time the size
+// of the preview changes. This UIView should always be square, with its width
+// and height being the maximum of the width and height of its parent.
+@interface PreviewOverlayView : UIView {
+  // Creates a transparent preview overlay. The overlay is a sublayer of the
+  // PreviewOverlayView's view to keep the opacity of the view's layer 1.0,
+  // otherwise the viewport border would inherit the opacity of the overlay.
+  base::scoped_nsobject<CALayer> _previewOverlay;
+  // A container for the viewport border to draw a shadow under the border.
+  // Sublayer of PreviewOverlayView's layer.
+  base::scoped_nsobject<CALayer> _viewportBorderContainer;
+  // The preview viewport border. Sublayer of |_viewportBorderContainer|.
+  base::scoped_nsobject<CAShapeLayer> _viewportBorder;
+}
+
+// Creates a square mask for the overlay to keep the viewport transparent.
+- (CAShapeLayer*)getViewportMaskWithFrameSize:(CGSize)frameSize
+                                 viewportSize:(CGFloat)viewportSize;
+// Creates a mask to only draw the corners of the viewport border.
+- (CAShapeLayer*)getViewportBorderMaskWithFrameSize:(CGSize)frameSize
+                                       viewportSize:(CGFloat)viewportSize;
+
+@end
+
+@implementation PreviewOverlayView
+
+- (instancetype)initWithFrame:(CGRect)frame {
+  self = [super initWithFrame:frame];
+  if (!self) {
+    return nil;
+  }
+
+  _previewOverlay.reset([[CALayer alloc] init]);
+  [_previewOverlay setBackgroundColor:[[UIColor blackColor] CGColor]];
+  [_previewOverlay setOpacity:kPreviewOverlayOpacity];
+  [[self layer] addSublayer:_previewOverlay];
+
+  _viewportBorderContainer.reset([[CALayer alloc] init]);
+  [_viewportBorderContainer setShadowColor:[[UIColor blackColor] CGColor]];
+  [_viewportBorderContainer setShadowOffset:CGSizeZero];
+  [_viewportBorderContainer setShadowRadius:kViewportBorderShadowRadius];
+  [_viewportBorderContainer setShadowOpacity:kViewportBorderShadowOpacity];
+  [_viewportBorderContainer setShouldRasterize:YES];
+  [_viewportBorderContainer
+      setRasterizationScale:[[UIScreen mainScreen] scale]];
+
+  _viewportBorder.reset([[CAShapeLayer alloc] init]);
+  [_viewportBorder setStrokeColor:[[UIColor whiteColor] CGColor]];
+  [_viewportBorder setFillColor:nil];
+  [_viewportBorder setOpacity:1.0];
+  [_viewportBorder setLineWidth:kViewportBorderLineWidth];
+  [_viewportBorderContainer addSublayer:_viewportBorder];
+
+  [[self layer] addSublayer:_viewportBorderContainer];
+  return self;
+}
+
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  CGSize frameSize = self.frame.size;
+  CGFloat viewportSize = GetViewportSize();
+  [_previewOverlay
+      setFrame:CGRectMake(0, 0, frameSize.width, frameSize.height)];
+  [_previewOverlay setMask:[self getViewportMaskWithFrameSize:frameSize
+                                                 viewportSize:viewportSize]];
+
+  CGRect borderRect = CenteredRectForViewport(
+      frameSize, viewportSize + kViewportBorderLineWidth);
+  UIBezierPath* borderPath =
+      [UIBezierPath bezierPathWithRoundedRect:borderRect
+                                 cornerRadius:kViewportBorderCornerRadius];
+
+  [_viewportBorder setPath:[borderPath CGPath]];
+  [_viewportBorder
+      setMask:[self getViewportBorderMaskWithFrameSize:frameSize
+                                          viewportSize:viewportSize]];
+}
+
+- (CAShapeLayer*)getViewportMaskWithFrameSize:(CGSize)frameSize
+                                 viewportSize:(CGFloat)viewportSize {
+  CGRect frameRect = CGRectMake(0, 0, frameSize.width, frameSize.height);
+  CGRect viewportRect = CenteredRectForViewport(frameSize, viewportSize);
+  UIBezierPath* maskPath = [UIBezierPath bezierPathWithRect:frameRect];
+  [maskPath appendPath:[UIBezierPath bezierPathWithRect:viewportRect]];
+
+  CAShapeLayer* mask = [[[CAShapeLayer alloc] init] autorelease];
+  [mask setFillColor:[[UIColor blackColor] CGColor]];
+  [mask setFillRule:kCAFillRuleEvenOdd];
+  [mask setFrame:frameRect];
+  [mask setPath:maskPath.CGPath];
+  return mask;
+}
+
+- (CAShapeLayer*)getViewportBorderMaskWithFrameSize:(CGSize)frameSize
+                                       viewportSize:(CGFloat)viewportSize {
+  CGFloat viewportBorderCornerWidth = IsIPadIdiom()
+                                          ? kViewportBorderCornerWidth_iPad
+                                          : kViewportBorderCornerWidth_iPhone;
+  CGRect maskRect = CenteredRectForViewport(
+      frameSize, viewportSize - 2 * viewportBorderCornerWidth);
+  CGFloat sizeX = maskRect.origin.x;
+  CGFloat sizeY = maskRect.origin.y;
+  CGFloat offsetX = sizeX + maskRect.size.width;
+  CGFloat offsetY = sizeY + maskRect.size.height;
+
+  UIBezierPath* path =
+      [UIBezierPath bezierPathWithRect:CGRectMake(0, 0, sizeX, sizeY)];
+  [path appendPath:[UIBezierPath bezierPathWithRect:CGRectMake(0, offsetY,
+                                                               sizeX, sizeY)]];
+  [path appendPath:[UIBezierPath bezierPathWithRect:CGRectMake(offsetY, 0,
+                                                               sizeX, sizeY)]];
+  [path appendPath:[UIBezierPath bezierPathWithRect:CGRectMake(offsetX, offsetY,
+                                                               sizeX, sizeY)]];
+
+  CAShapeLayer* mask = [[[CAShapeLayer alloc] init] autorelease];
+  [mask setFillColor:[[UIColor blackColor] CGColor]];
+  [mask setFrame:CGRectMake(0, 0, frameSize.width, frameSize.height)];
+  [mask setPath:path.CGPath];
+  return mask;
+}
+
+@end
+
+@interface QRScannerView () {
+  // A button to toggle the torch.
+  base::scoped_nsobject<MDCFlatButton> _torchButton;
+  // A view containing the preview layer for camera input.
+  base::scoped_nsobject<VideoPreviewView> _previewView;
+  // A transparent overlay on top of the preview layer.
+  base::scoped_nsobject<PreviewOverlayView> _previewOverlay;
+  // The constraint specifying that the preview overlay should be square.
+  base::scoped_nsobject<NSLayoutConstraint> _overlaySquareConstraint;
+  // The constraint relating the size of the |_previewOverlay| to the width of
+  // the QRScannerView.
+  base::scoped_nsobject<NSLayoutConstraint> _overlayWidthConstraint;
+  // The constraint relating the size of the |_previewOverlay| to the height of
+  // te QRScannerView.
+  base::scoped_nsobject<NSLayoutConstraint> _overlayHeightConstraint;
+}
+
+// Creates an image with template rendering mode for use in icons.
+- (UIImage*)templateImageWithName:(NSString*)name;
+// Creates an icon for torch turned on.
+- (UIImage*)torchOnIcon;
+// Creates an icon for torch turned off.
+- (UIImage*)torchOffIcon;
+
+// Sets common configuration properties of a button in the QR scanner UI and
+// adds it to self.view.
+- (void)configureButton:(MDCFlatButton*)button
+               withIcon:(UIImage*)icon
+                 action:(SEL)action;
+// Adds a close button.
+- (void)addCloseButton;
+// Adds a torch button and stores it in |_torchButton|.
+- (void)addTorchButton;
+// Adds a caption to the viewport.
+- (void)addViewportCaptionLabel;
+// Adds a preview view to |self| and configures its layout constraints.
+- (void)setupPreviewView;
+// Adds a transparent overlay with a viewport border to |self| and configures
+// its layout constraints.
+- (void)setupPreviewOverlayView;
+
+@end
+
+@implementation QRScannerView
+
+@synthesize delegate = _delegate;
+
+#pragma mark lifecycle
+
+- (instancetype)initWithFrame:(CGRect)frame
+                     delegate:(id<QRScannerViewDelegate>)delegate {
+  self = [super initWithFrame:frame];
+  if (!self) {
+    return nil;
+  }
+  DCHECK(delegate);
+  _delegate = delegate;
+  [self setupPreviewView];
+  [self setupPreviewOverlayView];
+  [self addCloseButton];
+  [self addTorchButton];
+  [self addViewportCaptionLabel];
+  return self;
+}
+
+- (instancetype)initWithFrame:(CGRect)frame {
+  NOTREACHED();
+  return nil;
+}
+
+- (instancetype)initWithCoder:(NSCoder*)coder {
+  NOTREACHED();
+  return nil;
+}
+
+#pragma mark UIView
+
+// TODO(crbug.com/633577): Replace the preview overlay with a UIView which is
+// not resized.
+- (void)layoutSubviews {
+  [super layoutSubviews];
+  [self setBackgroundColor:[UIColor blackColor]];
+  if (CGRectEqualToRect([_previewView bounds], CGRectZero)) {
+    [_previewView setBounds:self.bounds];
+  }
+  [_previewView setCenter:CGPointMake(CGRectGetMidX(self.bounds),
+                                      CGRectGetMidY(self.bounds))];
+}
+
+#pragma mark public methods
+
+- (AVCaptureVideoPreviewLayer*)getPreviewLayer {
+  return [_previewView previewLayer];
+}
+
+- (void)enableTorchButton:(BOOL)torchIsAvailable {
+  [_torchButton setEnabled:torchIsAvailable];
+  if (!torchIsAvailable) {
+    [self setTorchButtonTo:NO];
+  }
+}
+
+- (void)setTorchButtonTo:(BOOL)torchIsOn {
+  DCHECK(_torchButton);
+  UIImage* icon = nil;
+  NSString* accessibilityValue = nil;
+  if (torchIsOn) {
+    icon = [self torchOnIcon];
+    accessibilityValue =
+        l10n_util::GetNSString(IDS_IOS_QR_SCANNER_TORCH_ON_ACCESSIBILITY_VALUE);
+  } else {
+    icon = [self torchOffIcon];
+    accessibilityValue = l10n_util::GetNSString(
+        IDS_IOS_QR_SCANNER_TORCH_OFF_ACCESSIBILITY_VALUE);
+  }
+  [_torchButton setImage:icon forState:UIControlStateNormal];
+  [_torchButton setAccessibilityValue:accessibilityValue];
+}
+
+- (void)resetPreviewFrame:(CGSize)size {
+  [_previewView setTransform:CGAffineTransformIdentity];
+  [_previewView setFrame:CGRectMake(0, 0, size.width, size.height)];
+}
+
+- (void)rotatePreviewByAngle:(CGFloat)angle {
+  [_previewView
+      setTransform:CGAffineTransformRotate([_previewView transform], angle)];
+}
+
+- (void)finishPreviewRotation {
+  CGAffineTransform rotation = [_previewView transform];
+  // Check that the current transform is either an identity or a 90, -90, or 180
+  // degree rotation.
+  DCHECK(fabs(atan2f(rotation.b, rotation.a)) < 0.001 ||
+         fabs(fabs(atan2f(rotation.b, rotation.a)) - M_PI) < 0.001 ||
+         fabs(fabs(atan2f(rotation.b, rotation.a)) - M_PI / 2) < 0.001);
+  rotation.a = round(rotation.a);
+  rotation.b = round(rotation.b);
+  rotation.c = round(rotation.c);
+  rotation.d = round(rotation.d);
+  [_previewView setTransform:rotation];
+}
+
+- (CGRect)viewportRectOfInterest {
+  return [_previewView viewportRectOfInterest];
+}
+
+- (void)animateScanningResultWithCompletion:(void (^)(void))completion {
+  UIView* whiteView = [[[UIView alloc] init] autorelease];
+  whiteView.frame = self.bounds;
+  [self addSubview:whiteView];
+  whiteView.backgroundColor = [UIColor whiteColor];
+  [UIView animateWithDuration:kFlashDuration
+      animations:^{
+        whiteView.alpha = 0.0;
+      }
+      completion:^void(BOOL finished) {
+        [whiteView removeFromSuperview];
+        if (completion) {
+          completion();
+        }
+      }];
+}
+
+#pragma mark private methods
+
+- (UIImage*)templateImageWithName:(NSString*)name {
+  UIImage* image = [[UIImage imageNamed:name]
+      imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
+  DCHECK(image);
+  return image;
+}
+
+- (UIImage*)torchOnIcon {
+  UIImage* icon = [self templateImageWithName:@"qr_scanner_torch_on"];
+  return icon;
+}
+
+- (UIImage*)torchOffIcon {
+  UIImage* icon = [self templateImageWithName:@"qr_scanner_torch_off"];
+  return icon;
+}
+
+- (void)configureButton:(MDCFlatButton*)button
+               withIcon:(UIImage*)icon
+                 action:(SEL)action {
+  [button setTintColor:[UIColor whiteColor]];
+  [button setImage:icon forState:UIControlStateNormal];
+  [button setInkStyle:MDCInkStyleUnbounded];
+  [button addTarget:_delegate
+                action:action
+      forControlEvents:UIControlEventTouchUpInside];
+  [self addSubview:button];
+}
+
+- (void)addCloseButton {
+  MDCFlatButton* closeButton =
+      [[[MDCFlatButton alloc] initWithFrame:CGRectZero] autorelease];
+  UIImage* closeIcon = [ChromeIcon closeIcon];
+  UIImage* closeButtonIcon =
+      [closeIcon imageWithRenderingMode:UIImageRenderingModeAlwaysTemplate];
+  [closeButton setAccessibilityLabel:[closeIcon accessibilityLabel]];
+  [closeButton setAccessibilityIdentifier:[closeIcon accessibilityIdentifier]];
+  [self configureButton:closeButton
+               withIcon:closeButtonIcon
+                 action:@selector(dismissQRScannerView:)];
+
+  // Constraints for closeButton.
+  [closeButton setTranslatesAutoresizingMaskIntoConstraints:NO];
+  [NSLayoutConstraint activateConstraints:@[
+    [[closeButton leadingAnchor] constraintEqualToAnchor:[self leadingAnchor]
+                                                constant:kButtonPadding],
+    [[closeButton bottomAnchor] constraintEqualToAnchor:[self bottomAnchor]
+                                               constant:-kButtonPadding]
+  ]];
+}
+
+- (void)addTorchButton {
+  DCHECK(!_torchButton);
+  _torchButton.reset([[MDCFlatButton alloc] initWithFrame:CGRectZero]);
+  [_torchButton setEnabled:NO];
+  [self configureButton:_torchButton
+               withIcon:[self torchOffIcon]
+                 action:@selector(toggleTorch:)];
+  [_torchButton setAccessibilityIdentifier:@"qr_scanner_torch_button"];
+  [_torchButton setAccessibilityLabel:
+                    l10n_util::GetNSString(
+                        IDS_IOS_QR_SCANNER_TORCH_BUTTON_ACCESSIBILITY_LABEL)];
+  [_torchButton setAccessibilityValue:
+                    l10n_util::GetNSString(
+                        IDS_IOS_QR_SCANNER_TORCH_OFF_ACCESSIBILITY_VALUE)];
+
+  // Constraints for _torchButton.
+  [_torchButton setTranslatesAutoresizingMaskIntoConstraints:NO];
+  [NSLayoutConstraint activateConstraints:@[
+    [[_torchButton trailingAnchor] constraintEqualToAnchor:[self trailingAnchor]
+                                                  constant:-kButtonPadding],
+    [[_torchButton bottomAnchor] constraintEqualToAnchor:[self bottomAnchor]
+                                                constant:-kButtonPadding]
+  ]];
+}
+
+- (void)addViewportCaptionLabel {
+  UILabel* viewportCaption = [[[UILabel alloc] init] autorelease];
+  NSString* label = l10n_util::GetNSString(IDS_IOS_QR_SCANNER_VIEWPORT_CAPTION);
+  [viewportCaption setText:label];
+  [viewportCaption setAccessibilityLabel:label];
+  [viewportCaption setAccessibilityIdentifier:@"qr_scanner_viewport_caption"];
+  [viewportCaption setTextColor:[UIColor whiteColor]];
+  [viewportCaption.layer setShadowColor:[UIColor blackColor].CGColor];
+  [viewportCaption.layer setShadowOffset:CGSizeZero];
+  [viewportCaption.layer setShadowRadius:kViewportCaptionShadowRadius];
+  [viewportCaption.layer setShadowOpacity:kViewportCaptionShadowOpacity];
+  [viewportCaption.layer setMasksToBounds:NO];
+  [viewportCaption.layer setShouldRasterize:YES];
+  [self addSubview:viewportCaption];
+
+  // Constraints for viewportCaption.
+  [viewportCaption setTranslatesAutoresizingMaskIntoConstraints:NO];
+  [NSLayoutConstraint activateConstraints:@[
+    [[viewportCaption centerXAnchor]
+        constraintEqualToAnchor:[self centerXAnchor]],
+    [[viewportCaption centerYAnchor]
+        constraintEqualToAnchor:[self centerYAnchor]
+                       constant:GetViewportSize() / 2 + kViewportCaptionPadding]
+  ]];
+}
+
+- (void)setupPreviewView {
+  DCHECK(!_previewView);
+  _previewView.reset([[VideoPreviewView alloc] initWithFrame:self.frame]);
+  [self insertSubview:_previewView atIndex:0];
+}
+
+- (void)setupPreviewOverlayView {
+  DCHECK(!_previewOverlay);
+  _previewOverlay.reset([[PreviewOverlayView alloc] initWithFrame:CGRectZero]);
+  [self addSubview:_previewOverlay];
+
+  // Add a multiplier of sqrt(2) to the width and height constraints to make
+  // sure that the overlay covers the whole screen during rotation.
+  _overlayWidthConstraint.reset(
+      [[NSLayoutConstraint constraintWithItem:_previewOverlay
+                                    attribute:NSLayoutAttributeWidth
+                                    relatedBy:NSLayoutRelationGreaterThanOrEqual
+                                       toItem:self
+                                    attribute:NSLayoutAttributeWidth
+                                   multiplier:sqrt(2)
+                                     constant:0.0] retain]);
+
+  _overlayHeightConstraint.reset(
+      [[NSLayoutConstraint constraintWithItem:_previewOverlay
+                                    attribute:NSLayoutAttributeHeight
+                                    relatedBy:NSLayoutRelationGreaterThanOrEqual
+                                       toItem:self
+                                    attribute:NSLayoutAttributeHeight
+                                   multiplier:sqrt(2)
+                                     constant:0.0] retain]);
+
+  _overlaySquareConstraint.reset([[[_previewOverlay heightAnchor]
+      constraintEqualToAnchor:[_previewOverlay widthAnchor]] retain]);
+
+  // Constrains the preview overlay to be square, centered, with both width and
+  // height greater than or equal to the width and height of the QRScannerView.
+  [_previewOverlay setTranslatesAutoresizingMaskIntoConstraints:NO];
+  [NSLayoutConstraint activateConstraints:@[
+    [[_previewOverlay centerXAnchor]
+        constraintEqualToAnchor:[self centerXAnchor]],
+    [[_previewOverlay centerYAnchor]
+        constraintEqualToAnchor:[self centerYAnchor]],
+    _overlaySquareConstraint, _overlayWidthConstraint, _overlayHeightConstraint
+  ]];
+}
+
+@end