前言
现在大部分的APP的都会有一个类似于微信扫一扫的功能，但是大部分只是简单的扫码功能，很少像微信那样当二维码较小时去拉近镜头进行扫码识别。这就导致了这篇文章的诞生。
正文
首先，在网上开始找资料，终于找到了一篇类似的。
iOS原生实现二维码拉近放大
整体的结构是采用的这篇文章的。不过对本demo中的整体的业务代码和动画进行了优化。
对原demo进行修改的文件.jpeg
#import "RHScanNative.h"
@interface RHScanNative()<AVCaptureMetadataOutputObjectsDelegate>
{
BOOL bNeedScanResult;
BOOL bHadAutoVideoZoom;
}
@property (assign,nonatomic)AVCaptureDevice * device;
@property (strong,nonatomic)AVCaptureDeviceInput * input;
@property (strong,nonatomic)AVCaptureMetadataOutput * output;
@property (strong,nonatomic)AVCaptureSession * session;
@property (strong,nonatomic)AVCaptureVideoPreviewLayer * preview;
@property(nonatomic,strong) AVCaptureStillImageOutput *stillImageOutput;//拍照
@property(nonatomic,assign)BOOL isNeedCaputureImage;
@property(nonatomic,assign)BOOL isAutoVideoZoom;
@property (assign,nonatomic)CGFloat initialPinchZoom;
///扫码结果
@property (nonatomic, strong) NSMutableArray<NSString*> *arrayResult;
///扫码类型
@property (nonatomic, strong) NSArray* arrayBarCodeType;
///视频预览显示视图
@property (nonatomic,weak)UIView *videoPreView;
/*** 专门用于保存描边的图层 ***/
@property (nonatomic,strong) CALayer *containerLayer;
/*!
* 扫码结果返回
*/
@property(nonatomic,copy)void (^blockScanResult)(NSArray<NSString*> *array);
@property (nonatomic, assign) CGPoint centerPoint;
@end
@implementation RHScanNative
- (void)setNeedCaptureImage:(BOOL)isNeedCaputureImg
{
_isNeedCaputureImage = isNeedCaputureImg;
}
-(void)setNeedAutoVideoZoom:(BOOL)isAutoVideoZoom
{
_isAutoVideoZoom = isAutoVideoZoom;
}
- (CALayer *)containerLayer
{
if (_containerLayer == nil) {
_containerLayer = [[CALayer alloc] init];
}
return _containerLayer;
}
- (instancetype)initWithPreView:(UIView*)preView ObjectType:(NSArray*)objType cropRect:(CGRect)cropRect success:(void(^)(NSArray<NSString*> *array))block
{
if (self = [super init]) {
[self initParaWithPreView:preView ObjectType:objType cropRect:cropRect success:block];
}
return self;
}
- (instancetype)initWithPreView:(UIView*)preView ObjectType:(NSArray*)objType success:(void(^)(NSArray<NSString*> *array))block
{
if (self = [super init]) {
[self initParaWithPreView:preView ObjectType:objType cropRect:CGRectZero success:block];
}
return self;
}
- (void)initParaWithPreView:(UIView*)videoPreView ObjectType:(NSArray*)objType cropRect:(CGRect)cropRect success:(void(^)(NSArray<NSString*> *array))block
{
self.arrayBarCodeType = objType;
self.blockScanResult = block;
self.videoPreView = videoPreView;
_device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
if (!_device) {
return;
}
// Input
_input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];
if ( !_input )
return ;
bNeedScanResult = YES;
// Output
_output = [[AVCaptureMetadataOutput alloc]init];
[_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
if ( !CGRectEqualToRect(cropRect,CGRectZero) )
{
_output.rectOfInterest = cropRect;
}
_stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys:
AVVideoCodecJPEG, AVVideoCodecKey,
nil];
[_stillImageOutput setOutputSettings:outputSettings];
// Session
_session = [[AVCaptureSession alloc]init];
[_session setSessionPreset:AVCaptureSessionPresetHigh];
if ([_session canAddInput:_input])
{
[_session addInput:_input];
}
if ([_session canAddOutput:_output])
{
[_session addOutput:_output];
}
if ([_session canAddOutput:_stillImageOutput])
{
[_session addOutput:_stillImageOutput];
}
if (!objType) {
objType = [self defaultMetaDataObjectTypes];
}
_output.metadataObjectTypes = objType;
// Preview
_preview =[AVCaptureVideoPreviewLayer layerWithSession:_session];
_preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
CGRect frame = videoPreView.frame;
frame.origin = CGPointZero;
_preview.frame = frame;
[videoPreView.layer insertSublayer:self.preview atIndex:0];
// // 7.添加容器图层
// [videoPreView.layer addSublayer:self.containerLayer];
// self.containerLayer.frame = frame;
//
//
// [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]];
//// AVCaptureConnection *videoConnection = [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]];
//// CGFloat scale = videoConnection.videoScaleAndCropFactor;
//
// [_input.device lockForConfiguration:nil];
//
// //自动白平衡
// if ([_device isWhiteBalanceModeSupported:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance])
// {
// [_input.device setWhiteBalanceMode:AVCaptureWhiteBalanceModeContinuousAutoWhiteBalance];
// }
// //先进行判断是否支持控制对焦,不开启自动对焦功能，很难识别二维码。
// if (_device.isFocusPointOfInterestSupported &&[_device isFocusModeSupported:AVCaptureFocusModeAutoFocus])
// {
// [_input.device setFocusMode:AVCaptureFocusModeContinuousAutoFocus];
// }
// //自动曝光
// if ([_device isExposureModeSupported:AVCaptureExposureModeContinuousAutoExposure])
// {
// [_input.device setExposureMode:AVCaptureExposureModeContinuousAutoExposure];
// }
// [_input.device unlockForConfiguration];
}
- (BOOL)getFlashMode
{
AVCaptureTorchMode torch = self.input.device.torchMode;
if(torch == AVCaptureTorchModeOn)
{
return YES;
}
return NO;
}
- (CGFloat)getVideoMaxScale
{
[_input.device lockForConfiguration:nil];
AVCaptureConnection *videoConnection = [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]];
CGFloat maxScale = videoConnection.videoMaxScaleAndCropFactor;
[_input.device unlockForConfiguration];
return maxScale;
}
-(CGFloat)getVideoZoomFactor
{
return _input.device.videoZoomFactor;
}
-(AVCaptureVideoPreviewLayer *)getVideoPreview
{
return _preview;
}
- (void)setVideoScale:(CGFloat)scale
{
[_input.device lockForConfiguration:nil];
AVCaptureConnection *videoConnection = [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]];
CGFloat maxScaleAndCropFactor = ([[self.stillImageOutput connectionWithMediaType:AVMediaTypeVideo] videoMaxScaleAndCropFactor])/16;
if (scale > maxScaleAndCropFactor)
scale = maxScaleAndCropFactor;
CGFloat zoom = scale / videoConnection.videoScaleAndCropFactor;
videoConnection.videoScaleAndCropFactor = scale;
[_input.device unlockForConfiguration];
CGAffineTransform transform = _videoPreView.transform;
if (scale == 1) {
_videoPreView.transform = CGAffineTransformScale(transform, zoom, zoom);
CGRect rect = _videoPreView.frame;
rect.origin = CGPointZero;
_videoPreView.frame = rect;
} else {
CGFloat x = _videoPreView.center.x - self.centerPoint.x;
CGFloat y = _videoPreView.center.y - self.centerPoint.y;
CGRect rect = _videoPreView.frame;
rect.origin.x = rect.size.width / 2.0 * (1 - scale);
rect.origin.y = rect.size.height / 2.0 * (1 - scale);
rect.origin.x += x * zoom;
rect.origin.y += y * zoom;
rect.size.width = rect.size.width * scale;
rect.size.height = rect.size.height * scale;
[UIView animateWithDuration:.5f animations:^{
_videoPreView.transform = CGAffineTransformScale(transform, zoom, zoom);
_videoPreView.frame = rect;
} completion:^(BOOL finished) {
}];
}
}
- (void)changeScanType:(NSArray*)objType
{
_output.metadataObjectTypes = objType;
}
- (void)startScan
{
if ( _input && !_session.isRunning )
{
[_session startRunning];
bNeedScanResult = YES;
[_videoPreView.layer insertSublayer:self.preview atIndex:0];
// [_input.device addObserver:self forKeyPath:@"torchMode" options:0 context:nil];
}
[self.containerLayer.sublayers makeObjectsPerformSelector:@selector(removeFromSuperlayer)];
bNeedScanResult = YES;
bHadAutoVideoZoom = NO;
[self setVideoScale:1];
}
- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
if ( object == _input.device ) {
}
}
- (void)stopScan
{
bNeedScanResult = NO;
if ( _input && _session.isRunning )
{
bNeedScanResult = NO;
[_session stopRunning];
}
}
- (void)setTorch:(BOOL)torch {
[self.input.device lockForConfiguration:nil];
self.input.device.torchMode = torch ? AVCaptureTorchModeOn : AVCaptureTorchModeOff;
[self.input.device unlockForConfiguration];
}
- (void)changeTorch
{
AVCaptureTorchMode torch = self.input.device.torchMode;
switch (_input.device.torchMode) {
case AVCaptureTorchModeAuto:
break;
case AVCaptureTorchModeOff:
torch = AVCaptureTorchModeOn;
break;
case AVCaptureTorchModeOn:
torch = AVCaptureTorchModeOff;
break;
default:
break;
}
[_input.device lockForConfiguration:nil];
_input.device.torchMode = torch;
[_input.device unlockForConfiguration];
}
-(UIImage *)getImageFromLayer:(CALayer *)layer size:(CGSize)size
{
UIGraphicsBeginImageContextWithOptions(size, YES, [[UIScreen mainScreen]scale]);
[layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
- (AVCaptureConnection *)connectionWithMediaType:(NSString *)mediaType fromConnections:(NSArray *)connections
{
for ( AVCaptureConnection *connection in connections ) {
for ( AVCaptureInputPort *port in [connection inputPorts] ) {
if ( [[port mediaType] isEqual:mediaType] ) {
return connection;
}
}
}
return nil;
}
- (void)captureImage
{
AVCaptureConnection *stillImageConnection = [self connectionWithMediaType:AVMediaTypeVideo fromConnections:[[self stillImageOutput] connections]];
[[self stillImageOutput] captureStillImageAsynchronouslyFromConnection:stillImageConnection
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error)
{
[self stopScan];
if (_blockScanResult)
{
_blockScanResult(_arrayResult);
}
}];
}
- (void)changeVideoScale:(AVMetadataMachineReadableCodeObject *)objc
{
NSArray *array = objc.corners;
NSLog(@"cornersArray = %@",array);
CGPoint point = CGPointZero;
// 把字典转换为点，存在point里，成功返回true 其他false
CGPointMakeWithDictionaryRepresentation((__bridge CFDictionaryRef)array[0], &point);
NSLog(@"X:%f -- Y:%f",point.x,point.y);
CGPoint point2 = CGPointZero;
CGPointMakeWithDictionaryRepresentation((__bridge CFDictionaryRef)array[2], &point2);
NSLog(@"X:%f -- Y:%f",point2.x,point2.y);
self.centerPoint = CGPointMake((point.x + point2.x) / 2, (point.y + point2.y) / 2);
CGFloat scace = 150 / (point2.x - point.x); //当二维码图片宽小于150，进行放大
[self setVideoScale:scace];
return;
}
- (void)drawLine:(AVMetadataMachineReadableCodeObject *)objc
{
NSArray *array = objc.corners;
// 1.创建形状图层, 用于保存绘制的矩形
CAShapeLayer *layer = [[CAShapeLayer alloc] init];
// 设置线宽
layer.lineWidth = 2;
// 设置描边颜色
layer.strokeColor = [UIColor greenColor].CGColor;
layer.fillColor = [UIColor clearColor].CGColor;
// 2.创建UIBezierPath, 绘制矩形
UIBezierPath *path = [[UIBezierPath alloc] init];
CGPoint point = CGPointZero;
int index = 0;
CFDictionaryRef dict = (__bridge CFDictionaryRef)(array[index++]);
// 把点转换为不可变字典
// 把字典转换为点，存在point里，成功返回true 其他false
CGPointMakeWithDictionaryRepresentation(dict, &point);
// 设置起点
[path moveToPoint:point];
NSLog(@"X:%f -- Y:%f",point.x,point.y);
// 2.2连接其它线段
for (int i = 1; i<array.count; i++) {
CGPointMakeWithDictionaryRepresentation((__bridge CFDictionaryRef)array[i], &point);
[path addLineToPoint:point];
NSLog(@"X:%f -- Y:%f",point.x,point.y);
}
// 2.3关闭路径
[path closePath];
layer.path = path.CGPath;
// 3.将用于保存矩形的图层添加到界面上
[self.containerLayer addSublayer:layer];
}
- (void)clearLayers
{
if (self.containerLayer.sublayers)
{
for (CALayer *subLayer in self.containerLayer.sublayers)
{
[subLayer removeFromSuperlayer];
}
}
}
#pragma mark AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
if (!bNeedScanResult) {
return;
}
bNeedScanResult = NO;
if (!_arrayResult) {
self.arrayResult = [NSMutableArray arrayWithCapacity:1];
}
else
{
[_arrayResult removeAllObjects];
}
//识别扫码类型
for(AVMetadataObject *current in metadataObjects)
{
if ([current isKindOfClass:[AVMetadataMachineReadableCodeObject class]] )
{
bNeedScanResult = NO;
NSString *scannedResult = [(AVMetadataMachineReadableCodeObject *) current stringValue];
if (scannedResult && ![scannedResult isEqualToString:@""])
{
[_arrayResult addObject:scannedResult];
}
//测试可以同时识别多个二维码
}
}
if (_arrayResult.count < 1)
{
bNeedScanResult = YES;
return;
}
if (_isAutoVideoZoom && !bHadAutoVideoZoom) {
AVMetadataMachineReadableCodeObject *obj = (AVMetadataMachineReadableCodeObject *)[self.preview transformedMetadataObjectForMetadataObject:metadataObjects.lastObject];
[self changeVideoScale:obj];
// [self drawLine:obj];
bNeedScanResult = YES;
bHadAutoVideoZoom =YES;
return;
}
if (_isNeedCaputureImage)
{
[self captureImage];
}
else
{
[self stopScan];
if (_blockScanResult) {
_blockScanResult(_arrayResult);
}
}
}
/**
@brief 默认支持码的类别
@return 支持类别 数组
*/
- (NSArray *)defaultMetaDataObjectTypes
{
NSMutableArray *types = [@[AVMetadataObjectTypeQRCode,
AVMetadataObjectTypeUPCECode,
AVMetadataObjectTypeCode39Code,
AVMetadataObjectTypeCode39Mod43Code,
AVMetadataObjectTypeEAN13Code,
AVMetadataObjectTypeEAN8Code,
AVMetadataObjectTypeCode93Code,
AVMetadataObjectTypeCode128Code,
AVMetadataObjectTypePDF417Code,
AVMetadataObjectTypeAztecCode] mutableCopy];
if (floor(NSFoundationVersionNumber) > NSFoundationVersionNumber_iOS_8_0)
{
[types addObjectsFromArray:@[
AVMetadataObjectTypeInterleaved2of5Code,
AVMetadataObjectTypeITF14Code,
AVMetadataObjectTypeDataMatrixCode
]];
}
return types;
}
#pragma mark --识别条码图片
+ (void)recognizeImage:(UIImage*)image success:(void(^)(NSArray<NSString*> *array))block;
{
if ([[[UIDevice currentDevice]systemVersion]floatValue] < 8.0 )
{
if (block) {
block(@[@"只支持ios8.0之后系统"]);
}
return;
}
CIDetector*detector = [CIDetector detectorOfType:CIDetectorTypeQRCode context:nil options:@{ CIDetectorAccuracy : CIDetectorAccuracyHigh }];
NSArray *features = [detector featuresInImage:[CIImage imageWithCGImage:image.CGImage]];
NSMutableArray<NSString*> *mutableArray = [[NSMutableArray alloc]initWithCapacity:1];
for (int index = 0; index < [features count]; index ++)
{
CIQRCodeFeature *feature = [features objectAtIndex:index];
NSString *scannedResult = feature.messageString;
[mutableArray addObject:scannedResult];
}
if (block) {
block(mutableArray);
}
}
#pragma mark --生成条码
//下面引用自 https://github.com/yourtion/Demo_CustomQRCode
#pragma mark - InterpolatedUIImage
+ (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
// 创建bitmap;
size_t width = CGRectGetWidth(extent) * scale;
size_t height = CGRectGetHeight(extent) * scale;
CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
CGColorSpaceRelease(cs);
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
CGContextScaleCTM(bitmapRef, scale, scale);
CGContextDrawImage(bitmapRef, extent, bitmapImage);
// 保存bitmap到图片
CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
UIImage *aImage = [UIImage imageWithCGImage:scaledImage];
CGImageRelease(scaledImage);
return aImage;
}
#pragma mark - QRCodeGenerator
+ (CIImage *)createQRForString:(NSString *)qrString {
NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];
// 创建filter
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// 设置内容和纠错级别
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"];
// 返回CIImage
return qrFilter.outputImage;
}
#pragma mark - 生成二维码，背景色及二维码颜色设置
+ (UIImage*)createQRWithString:(NSString*)text QRSize:(CGSize)size
{
NSData *stringData = [text dataUsingEncoding: NSUTF8StringEncoding];
//生成
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"];
CIImage *qrImage = qrFilter.outputImage;
//绘制
CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:qrImage fromRect:qrImage.extent];
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, kCGInterpolationNone);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage);
UIImage *codeImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRelease(cgImage);
return codeImage;
}
//引用自:http://www.jianshu.com/p/e8f7a257b612
+ (UIImage*)createQRWithString:(NSString*)text QRSize:(CGSize)size QRColor:(UIColor*)qrColor bkColor:(UIColor*)bkColor
{
NSData *stringData = [text dataUsingEncoding: NSUTF8StringEncoding];
//生成
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"];
//上色
CIFilter *colorFilter = [CIFilter filterWithName:@"CIFalseColor"
keysAndValues:
@"inputImage",qrFilter.outputImage,
@"inputColor0",[CIColor colorWithCGColor:qrColor.CGColor],
@"inputColor1",[CIColor colorWithCGColor:bkColor.CGColor],
nil];
CIImage *qrImage = colorFilter.outputImage;
//绘制
CGImageRef cgImage = [[CIContext contextWithOptions:nil] createCGImage:qrImage fromRect:qrImage.extent];
UIGraphicsBeginImageContext(size);
CGContextRef context = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context, kCGInterpolationNone);
CGContextScaleCTM(context, 1.0, -1.0);
CGContextDrawImage(context, CGContextGetClipBoundingBox(context), cgImage);
UIImage *codeImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRelease(cgImage);
return codeImage;
}
+ (UIImage*)createQRWithString:(NSString*)text QRSize:(CGSize)size QRColor:(UIColor*)qrColor bkColor:(UIColor*)bkColor logo:(UIImage *)logo
{
NSData *stringData = [text dataUsingEncoding: NSUTF8StringEncoding];
//生成
CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
[qrFilter setValue:stringData forKey:@"inputMessage"];
[qrFilter setValue:@"H" forKey:@"inputCorrectionLevel"];
//上色
CIFilter *colorFilter = [CIFilter filterWithName:@"CIFalseColor"
keysAndValues:
@"inputImage",qrFilter.outputImage,
@"inputColor0",[CIColor colorWithCGColor:qrColor.CGColor],
@"inputColor1",[CIColor colorWithCGColor:bkColor.CGColor],
nil];
// 取出输出图片
CIImage *outputImage = [colorFilter outputImage];
outputImage = [outputImage imageByApplyingTransform:CGAffineTransformMakeScale(20, 20)];
// 转化图片
UIImage *image = [UIImage imageWithCIImage:outputImage];
// 为二维码加自定义图片
// 开启绘图, 获取图片 上下文<图片大小>
CGFloat logoWidth = image.size.width/4.0;
UIGraphicsBeginImageContext(image.size);
// 将二维码图片画上去
[image drawInRect:CGRectMake(0, 0, image.size.width,image.size.height)];
// 将小图片画上去
UIImage *smallImage =logo;
[smallImage drawInRect:CGRectMake((image.size.width - logoWidth) / 2, (image.size.width - logoWidth) / 2, logoWidth, logoWidth)];
// 获取最终的图片
UIImage *finalImage = UIGraphicsGetImageFromCurrentImageContext();
// 关闭上下文
UIGraphicsEndImageContext();
// 显示
return finalImage;
}
+ (UIImage*)createBarCodeWithString:(NSString*)text QRSize:(CGSize)size
{
NSData *data = [text dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:false];
CIFilter *filter = [CIFilter filterWithName:@"CICode128BarcodeGenerator"];
[filter setValue:data forKey:@"inputMessage"];
CIImage *barcodeImage = [filter outputImage];
// 消除模糊
CGFloat scaleX = size.width / barcodeImage.extent.size.width; // extent 返回图片的frame
CGFloat scaleY = size.height / barcodeImage.extent.size.height;
CIImage *transformedImage = [barcodeImage imageByApplyingTransform:CGAffineTransformScale(CGAffineTransformIdentity, scaleX, scaleY)];
return [UIImage imageWithCIImage:transformedImage];
}
+(UIImage*)image:(UIImage *)theImage
{
UIImage* bigImage = theImage;
float actualHeight = bigImage.size.height;
float actualWidth = bigImage.size.width;
float newWidth =0;
float newHeight =0;
if(actualWidth > actualHeight) {
//宽图
newHeight =256.0f;
newWidth = actualWidth / actualHeight * newHeight;
}
else
{
//长图
newWidth =256.0f;
newHeight = actualHeight / actualWidth * newWidth;
}
CGRect rect =CGRectMake(0.0,0.0, newWidth, newHeight);
UIGraphicsBeginImageContext(rect.size);
[bigImage drawInRect:rect];// scales image to rect
theImage =UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
//RETURN
return theImage;
}
@end
代码中涉及拉近镜头的比较重要的三个方法分别是
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
- (void)changeVideoScale:(AVMetadataMachineReadableCodeObject *)objc
- (void)setVideoScale:(CGFloat)scale
也是主要修改的三个方法。
第一个是扫码的代理方法
这其中transformedMetadataObjectForMetadataObject这个方法又涉及到了很多普通数据识别 以及 人脸识别等。
时间有限，只是简单了解。
第二个方法主要获取识别到的二维码位于屏幕中的点，同时计算出中心点
第三个方法就是缩放到二维码的中心位置，适当的缩放屏幕。
后记
简单接触，后续有时间继续会深入研究。
