本文是查閱網(wǎng)上資料和demo后整理出來的, 為了日后查閱以及其他人需要只用
之前使用的是第三方庫, 最近聽說iOS7后, 蘋果原生的二維碼掃描功能效率更高, 于是學習了一下, 順便也把生成加上.
二維碼生成
- (CIImage *)createTWMForString:(NSString *)string {
CIFilter *ewmFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// 內(nèi)容
[ewmFilter setValue:[string dataUsingEncoding:NSUTF8StringEncoding] forKey:@"inputMessage"];
// 糾錯級別
[ewmFilter setValue:@"M" forKey:@"inputCorrectionLevel"];
return ewmFilter.outputImage;
}
生成CIImage, 參數(shù)string就是需要生成二維碼的內(nèi)容
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
// 位圖
CGRect extent = CGRectIntegral(image.extent);
CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
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);
// 保存bitmap到圖片
CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
CGContextRelease(bitmapRef);
CGImageRelease(bitmapImage);
return [UIImage imageWithCGImage:scaledImage];
}
用生成的CIImage來生成UIImage, 稍微強調(diào)下, 傳入的size參數(shù)決定了圖片的大小, 因為借助UIImageView來顯示, 所以UIImageView.frame相同, size越大, 二維碼圖片越清晰.
void ProviderReleaseData (void *info, const void *data, size_t size) {
free((void*)data);
}
- (UIImage*)imageBlackToTransparent:(UIImage*)image withRed:(CGFloat)red andGreen:(CGFloat)green andBlue:(CGFloat)blue {
const int imageWidth = image.size.width;
const int imageHeight = image.size.height;
size_t bytesPerRow = imageWidth * 4;
uint32_t *rgbImageBuf = (uint32_t *)malloc(bytesPerRow * imageHeight);
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);
CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);
int pixelNum = imageWidth * imageHeight;
uint32_t *pCurPtr = rgbImageBuf;
for (int i = 0; i < pixelNum; i++, pCurPtr++) {
if ((*pCurPtr & 0xFFFFFF00) < 0x99999900) {
// 改成下面的代碼，會將圖片轉(zhuǎn)成想要的顏色
uint8_t *ptr = (uint8_t *)pCurPtr;
ptr[3] = red; //0~255
ptr[2] = green;
ptr[1] = blue;
}
else {
uint8_t *ptr = (uint8_t *)pCurPtr;
ptr[0] = 0;
}
}
CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);
CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpace, kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider, NULL, true, kCGRenderingIntentDefault);
CGDataProviderRelease(dataProvider);
UIImage *resultUIImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
CGContextRelease(context);
CGColorSpaceRelease(colorSpace);
return resultUIImage;
}
如果想更改二維碼顏色, 就把UIImage及顏色傳入這個方法, 用新生成的UIImage賦給ImageView.image.
最后用一個UIImageView接收生成的UIImage, 并且
imageView.contentMode = UIViewContentModeScaleAspectFit;就可以了.
掃描二維碼
- (BOOL)validateCamera {
return [UIImagePickerController isSourceTypeAvailable:UIImagePickerControllerSourceTypeCamera] &&
[UIImagePickerController isCameraDeviceAvailable:UIImagePickerControllerCameraDeviceRear];
}
在進行掃描前要先進行判斷是否有相機及后置鏡頭,
// session
self.session = [[AVCaptureSession alloc] init];
self.session.sessionPreset = AVCaptureSessionPresetHigh; // 采集質(zhì)量
// device
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
// input
AVCaptureDeviceInput *input = [[AVCaptureDeviceInput alloc] initWithDevice:device error:nil];
if (!input) {
// 沒有權(quán)限會崩潰
// alert...
return;
}
if ([self.session canAddInput:input]) {
[self.session addInput:input];
}
// output
AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
if ([self.session canAddOutput:output]) {
[self.session addOutput:output];
}
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode/*二維碼*/, AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code/*一維碼*/]];
// layer
AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
layer.videoGravity = AVLayerVideoGravityResizeAspectFill; // 這句好像沒卵用
layer.frame = self.view.layer.bounds;
[self.view.layer insertSublayer:layer atIndex:0];
[self.session startRunning];
需要導入<AVFoundation/AVFoundation.h>,
并遵守AVCaptureMetadataOutputObjectsDelegate協(xié)議
這里有一個坑, 設(shè)置output的MetadataObjectTypes的時候一定要先寫[self.session addOutput:output];, 否則崩潰.
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
if (metadataObjects > 0) {
[self.session stopRunning];
AVMetadataMachineReadableCodeObject *metadataObject = metadataObjects.firstObject;
NSLog(@"二維碼的內(nèi)容: %@", metadataObject.stringValue);
}
}
然后在代理方法中取到解析出來的二維碼內(nèi)容
另外, 如果想要設(shè)置掃描區(qū)域的話, 需要改變output.rectOfInterest屬性, 這個屬性有點特殊, 并不是正常的CGRect, 據(jù)本人試驗, 它的四個參數(shù)范圍都是[0,1], 分別對應(距離上端,距離左端,高度,寬度), 舉個例子:
如果我想讓掃描區(qū)域為屏幕坐標的(50,100,200,200), 那么需要如下寫:
output.rectOfInterest = CGRectMake(100.f/screenHeight, 50.f/screenWidth, 200.f/screenHeight, 200.f/screenWidth);
至于蘋果為什么要這樣做, 我表示也不太理解...
iOS7二維碼的部分就差不多這樣, 具體掃描界面還是要自己畫的, 希望對各位有幫助, 有什么錯誤之處請指出, 畢竟本人只是菜雞一個. <手動滑稽>
