make iOS scanner UI look the same as Android

Includes a scanner window and pulsing scan line

example/ios/Podfile.lock

@@ -7,7 +7,7 @@ PODS:
 
 DEPENDENCIES:
   - barcode_scan (from `/Users/dustin/Documents/workspace_flutter/flutter_barcode_reader/ios`)
-  - Flutter (from `/Users/dustin/flutter/bin/cache/artifacts/engine/ios-release`)
+  - Flutter (from `/Users/dustin/flutter/bin/cache/artifacts/engine/ios`)
 
 SPEC REPOS:
   https://github.com/cocoapods/specs.git:
@@ -17,7 +17,7 @@ EXTERNAL SOURCES:
   barcode_scan:
     :path: "/Users/dustin/Documents/workspace_flutter/flutter_barcode_reader/ios"
   Flutter:
-    :path: "/Users/dustin/flutter/bin/cache/artifacts/engine/ios-release"
+    :path: "/Users/dustin/flutter/bin/cache/artifacts/engine/ios"
 
 SPEC CHECKSUMS:
   barcode_scan: 8288e70cb430072003bce2c794a1431e7adbcb4d

example/ios/Runner.xcodeproj/project.pbxproj

@@ -273,7 +273,7 @@
 			);
 			inputPaths = (
 				"${SRCROOT}/Pods/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
-				"${PODS_ROOT}/../../../../../../flutter/bin/cache/artifacts/engine/ios-release/Flutter.framework",
+				"${PODS_ROOT}/../../../../../../flutter/bin/cache/artifacts/engine/ios/Flutter.framework",
 			);
 			name = "[CP] Embed Pods Frameworks";
 			outputPaths = (

ios/Classes/BarcodeScanPlugin.h

@@ -1,6 +1,11 @@
 #import <Flutter/Flutter.h>
 #import "BarcodeScannerViewControllerDelegate.h"
 
+#define UIColorFromRGB(rgbValue) \
+[UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 \
+  green:((float)((rgbValue & 0x00FF00) >>  8))/255.0 \
+  blue:((float)((rgbValue & 0x0000FF) >>  0))/255.0 \
+  alpha:1.0]
 
 @interface BarcodeScanPlugin : NSObject<FlutterPlugin, BarcodeScannerViewControllerDelegate>
 

ios/Classes/BarcodeScannerViewController.h

@@ -6,11 +6,15 @@
 #import <MTBBarcodeScanner/MTBBarcodeScanner.h>
 
 #import "BarcodeScannerViewControllerDelegate.h"
+#import "ScannerOverlay.h"
 
 
 @interface BarcodeScannerViewController : UIViewController
 @property(nonatomic, retain) UIView *previewView;
+  @property(nonatomic, retain) ScannerOverlay *scanRect;
 @property(nonatomic, retain) MTBBarcodeScanner *scanner;
 @property(nonatomic, weak) id<BarcodeScannerViewControllerDelegate> delegate;
 
+  
+  -(id) initWithOptions:(NSDictionary *) options;
 @end

ios/Classes/BarcodeScannerViewController.m

@@ -4,6 +4,7 @@
 
 #import "BarcodeScannerViewController.h"
 #import <MTBBarcodeScanner/MTBBarcodeScanner.h>
+#import "ScannerOverlay.h"
 
 
 @implementation BarcodeScannerViewController {
@@ -25,7 +26,26 @@
                                 options:NSLayoutFormatAlignAllBottom
                                 metrics:nil
                                   views:@{@"previewView": _previewView}]];
+  self.scanRect = [[ScannerOverlay alloc] initWithFrame:self.view.bounds];
+  self.scanRect.translatesAutoresizingMaskIntoConstraints = NO;
+  self.scanRect.backgroundColor = UIColor.clearColor;
+  [self.view addSubview:_scanRect];
+  [self.view addConstraints:[NSLayoutConstraint
+                             constraintsWithVisualFormat:@"V:[scanRect]"
+                             options:NSLayoutFormatAlignAllBottom
+                             metrics:nil
+                             views:@{@"scanRect": _scanRect}]];
+  [self.view addConstraints:[NSLayoutConstraint
+                             constraintsWithVisualFormat:@"H:[scanRect]"
+                             options:NSLayoutFormatAlignAllBottom
+                             metrics:nil
+                             views:@{@"scanRect": _scanRect}]];
+  [_scanRect startAnimating];
     self.scanner = [[MTBBarcodeScanner alloc] initWithPreviewView:_previewView];
+  __weak BarcodeScannerViewController *weakSelf = self;
+  self.scanner.didStartScanningBlock = ^{
+    weakSelf.scanner.scanRect = weakSelf.scanRect.scanLineRect;
+  };
     self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancel)];
   [self updateFlashButton];
 }

ios/Classes/ScannerOverlay.h

@@ -0,0 +1,8 @@
+#import <UIKit/UIKit.h>
+
+@interface ScannerOverlay : UIView
+  @property(nonatomic) CGRect scanLineRect;
+  
+  - (void) startAnimating;
+  - (void) stopAnimating;
+@end

ios/Classes/ScannerOverlay.m

@@ -0,0 +1,101 @@
+#import "ScannerOverlay.h"
+
+@interface ScannerOverlay()
+  @property(nonatomic, retain) UIView *line;
+@end
+
+@implementation ScannerOverlay
+  
+  - (instancetype)initWithFrame:(CGRect)frame
+  {
+    self = [super initWithFrame:frame];
+    if (self) {
+      _line = [[UIView alloc] init];
+      _line.backgroundColor = UIColor.redColor;
+      _line.translatesAutoresizingMaskIntoConstraints = NO;
+      [self addSubview:_line];
+    }
+    return self;
+  }
+
+- (void)drawRect:(CGRect)rect {
+  CGContextRef context = UIGraphicsGetCurrentContext();
+  
+  UIColor * overlayColor = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:0.55];
+  UIColor *scanLineColor = UIColor.redColor;
+  
+  CGContextSetFillColorWithColor(context, overlayColor.CGColor);
+  CGContextFillRect(context, self.bounds);
+  
+  // make a hole for the scanner
+  CGRect holeRect = [self scanRect];
+  CGRect holeRectIntersection = CGRectIntersection( holeRect, rect );
+  [[UIColor clearColor] setFill];
+  UIRectFill(holeRectIntersection);
+  
+  // draw a horizontal line over the middle
+  CGRect lineRect = [self scanLineRect];
+  _line.frame = lineRect;
+  
+  // drw the green corners
+  CGFloat cornerSize = 30;
+  UIBezierPath *path = [UIBezierPath bezierPath];
+  //top left corner
+  [path moveToPoint:CGPointMake(holeRect.origin.x, holeRect.origin.y + cornerSize)];
+  [path addLineToPoint:CGPointMake(holeRect.origin.x, holeRect.origin.y)];
+  [path addLineToPoint:CGPointMake(holeRect.origin.x + cornerSize, holeRect.origin.y)];
+  
+  //top right corner
+  CGFloat rightHoleX = holeRect.origin.x + holeRect.size.width;
+  [path moveToPoint:CGPointMake(rightHoleX - cornerSize, holeRect.origin.y)];
+  [path addLineToPoint:CGPointMake(rightHoleX, holeRect.origin.y)];
+  [path addLineToPoint:CGPointMake(rightHoleX, holeRect.origin.y + cornerSize)];
+  
+  // bottom right corner
+  CGFloat bottomHoleY = holeRect.origin.y + holeRect.size.height;
+  [path moveToPoint:CGPointMake(rightHoleX, bottomHoleY - cornerSize)];
+  [path addLineToPoint:CGPointMake(rightHoleX, bottomHoleY)];
+  [path addLineToPoint:CGPointMake(rightHoleX - cornerSize, bottomHoleY)];
+  
+  // bottom left corner
+  [path moveToPoint:CGPointMake(holeRect.origin.x + cornerSize, bottomHoleY)];
+  [path addLineToPoint:CGPointMake(holeRect.origin.x, bottomHoleY)];
+  [path addLineToPoint:CGPointMake(holeRect.origin.x, bottomHoleY - cornerSize)];
+  
+  path.lineWidth = 2;
+  [[UIColor greenColor] setStroke];
+  [path stroke];
+  
+}
+  
+  - (void)startAnimating {
+    CABasicAnimation *flash = [CABasicAnimation animationWithKeyPath:@"opacity"];
+    flash.fromValue = [NSNumber numberWithFloat:0.0];
+    flash.toValue = [NSNumber numberWithFloat:1.0];
+    flash.duration = 0.25;
+    flash.autoreverses = YES;
+    flash.repeatCount = HUGE_VALF;
+    [_line.layer addAnimation:flash forKey:@"flashAnimation"];
+  }
+  
+  - (void)stopAnimating {
+    [self.layer removeAnimationForKey:@"flashAnimation"];
+  }
+  
+  - (CGRect)scanRect {
+    CGRect rect = self.frame;
+    CGFloat heightMultiplier = 3.0/4.0; // 4:3 aspect ratio
+    CGFloat scanRectWidth = rect.size.width * 0.8f;
+    CGFloat scanRectHeight = scanRectWidth * heightMultiplier;
+    CGFloat scanRectOriginX = (rect.size.width / 2) - (scanRectWidth / 2);
+    CGFloat scanRectOriginY = (rect.size.height / 2) - (scanRectHeight / 2);
+    return CGRectMake(scanRectOriginX, scanRectOriginY, scanRectWidth, scanRectHeight);
+  }
+  
+  - (CGRect)scanLineRect {
+    CGRect scanRect = [self scanRect];
+    CGRect rect = self.frame;
+    return CGRectMake(scanRect.origin.x, rect.size.height / 2, scanRect.size.width, 1);
+  }
+
+@end