二维码的生成：
生成二维码的步骤
1>导入CoreImage框架(作用是将数据生成图片)
2>通过滤镜CIFilter生成二维码
二维码的内容(传统的条形码只能放数字)
1>纯文本
2>URL
Objective-C
// 1. 实例化二维码滤镜
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// 2. 恢复滤镜的默认属性
[filter setDefaults];
NSString *str = @"www.qq.com";
// 3. 将字符串转换成NSData
NSData *data = [str dataUsingEncoding:NSUTF8StringEncoding];
// 4. 通过KVO设置滤镜inputMessage数据
[filter setValue:data forKey:@"inputMessage"];
// 5. 获得滤镜输出的图像
CIImage *outputImage = [filter outputImage];
// 6. 将CIImage转换成UIImage，并放大显示
self.imageView.image = [UIImage imageWithCIImage:outputImage scale:20.0 orientation:UIImageOrientationUp];
Swift
@IBOutlet weak var imageView: UIImageView!
var outputImage : CIImage?
//MARK: - 懒加载代码
private var filter: CIFilter =
{
let filter = CIFilter(name: "CIQRCodeGenerator")
// 恢复滤镜的默认设置(主要是防止被担心设置被修改了,导致滤镜不正常)
filter?.setDefaults()
return filter!
}()
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.y
let data = "www.qq.com".dataUsingEncoding(NSUTF8StringEncoding)
// KVC 设置滤镜相关属性
filter .setValue(data, forKey: "inputMessage")
// 利用滤镜输出的图像
outputImage = filter.outputImage
imageView.image = UIImage(CIImage: outputImage!, scale: 20.0, orientation:
UIImageOrientation.Up)
}
生成的图片有点模糊.
可以利用下面的方法,生成一张清晰的
// 此方法利用了位图的原理,不好解释, 不过使用的时候,可以自建一个工具类使用
+ (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat)size
{
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
// 1.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);
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
CGContextScaleCTM(bitmapRef, scale, scale);
CGContextDrawImage(bitmapRef, extent, bitmapImage);
// 2.保存bitmap到图片
CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
return [UIImage imageWithCGImage:scaledImage];
}
总结一下生成二维码有以下几步:
1>实例化二维码滤镜
2>设置滤镜的默认属性
3>将字符串转换成NSData
4>通过KVC设置滤镜inputMessage数据
5>获得滤镜输出的图像
6>将得到的CIImage转换成UIImage,并放大显示
扫描二维码
不能使用模拟器调试,必须使用真机
1.读取二维码需要导入AVFoundation框架
2.利用摄像头识别二维码的内容(模拟器不行)
要求:
1>输入(摄像头)
2>由会话将摄像头采集到的二维码图像转换成字符串数据
3>输出(数据)
4>由预览图层显示扫描场景
Objective-C
/** 捕捉会话 */
@property (nonatomic, weak) AVCaptureSession *session;
/** 预览图层 */
@property (nonatomic, weak) AVCaptureVideoPreviewLayer *layer;
// 1.创建捕捉会话
AVCaptureSession *session = [[AVCaptureSession alloc] init];
self.session = session;
// 2.设置输入设备(摄像头)
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
[session addInput:input];
// 3.设置输出数据(元数据)
AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[session addOutput:output];
[output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];
// 4.添加阅览图层
AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:session];
layer.frame = self.view.bounds;
[self.view.layer addSublayer:layer];
self.layer = layer;
// 5.开始扫描
[session startRunning];
#pragma mark - 实现AVCaptureMetadataOutput的代理方法
// 代理方法中拿到所扫描二维码的数据
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
if (metadataObjects.count > 0) {
// 1.获取元数据
AVMetadataMachineReadableCodeObject *metadata = [metadataObjects lastObject];
// 2.获取具体的值
NSLog(@"%@", metadata.stringValue);
// 3.停止扫描(一旦扫描到信息,就停止扫描)
[self.session stopRunning];
// 4.将预览图层移除
[self.layer removeFromSuperlayer];
}
}
Swift
//MARK: - 设置扫描二维码
private func setupScanQRCode()
{
// 1.判断是否可以添加输入设备
if !session.canAddInput(inputDevice)
{
return
}
// 2.判断是否可以添加输出对象
if !session.canAddOutput(output)
{
return
}
// 3.添加输入和输出到会话中
session.addInput(inputDevice)
session.addOutput(output)
// 4.设置输出解析数据类型
// 必须在输出对象添加到会话之后才可以设置, 否则会报错
output.metadataObjectTypes = output.availableMetadataObjectTypes
// 5.设置输出代理, 监听解析到得结果
output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
// 6.添加预览图层
view.layer.insertSublayer(previewLayer, atIndex: 0)
// 6.利用会话开始扫描
session.startRunning()
}
// MARK: - 懒加载 扫描二维码相关的元素
/// 1.实例化输入设备
private lazy var inputDevice : AVCaptureDeviceInput? =
{
let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
// 因为swift不建议使用指针,所以需要throw来抛出异常 try do--catch
do{
let input = try AVCaptureDeviceInput(device: device)
return input
}catch{
return nil
}
}()
/// 2.设置输出
private lazy var output: AVCaptureMetadataOutput =
{
let out = AVCaptureMetadataOutput()
return out
}()
/// 3.设置回话
private lazy var session: AVCaptureSession =
{
let s = AVCaptureSession()
return s
}()
/// 4.创建预览图层
private lazy var previewLayer: AVCaptureVideoPreviewLayer =
{
let p = AVCaptureVideoPreviewLayer(session: self.session)
p.frame = UIScreen.mainScreen().bounds
return p
}()
// 在代理方法中实现数据的读取
func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!)
{
if metadataObjects.count > 0
{
let metadata = metadataObjects.last?.stringValue
print(metadata)
session.stopRunning()
previewLayer.removeFromSuperlayer()
}
}
