iOS開發之----產生二維碼

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- (void)viewDidLoad {    [super viewDidLoad];       /*     注意:     1.產生二維碼時, 不建議讓二維碼儲存過多資料, 因為資料越多, 那麼二維碼就越密集,那麼掃描起來就越困難     2.二維碼有三個錨點, 著三個錨點不能被遮擋, 否則掃描不出來     3.二維碼即便缺失一部分也能正常掃描出結果, 但是需要注意, 這個缺失的範圍是由限制的, 如果太多那麼也掃面不出來     */    // 1.建立濾鏡    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];    // 2.還原濾鏡預設屬性    [filter setDefaults];    // 3.將需要產生二維碼的資料轉換為二進位    NSData *data = [@"123" dataUsingEncoding:NSUTF8StringEncoding];    // 4.給濾鏡設定資料    [filter setValue:data forKeyPath:@"inputMessage"];    // 5.產生圖片    CIImage *qrcodeImage =  [filter outputImage];        // 6.顯示圖片//    self.qrcodeImageView.image = [UIImage imageWithCIImage:qrcodeImage];//    self.qrcodeImageView.image = [self createNonInterpolatedUIImageFormCIImage:qrcodeImage withSize:600];        UIImage *bg = [self createNonInterpolatedUIImageFormCIImage:qrcodeImage withSize:600];    UIImage *icon = [UIImage imageNamed:@"icon"];    self.qrcodeImageView.image = [self creteImageWithBg:bg icon:icon];}- (UIImage *)creteImageWithBg:(UIImage *)bg icon:(UIImage *)icon{    // 1.建立圖形上下文    UIGraphicsBeginImageContextWithOptions(bg.size, YES, 0.0);    // 2.繪製背景    [bg drawInRect:CGRectMake(0, 0, bg.size.width, bg.size.height)];    // 3.繪製表徵圖    CGFloat iconW = 60;    CGFloat iconH = 60;    CGFloat iconX = (bg.size.width - iconW) * 0.5;    CGFloat iconY = (bg.size.height - iconH) * 0.5;    [icon drawInRect:CGRectMake(iconX, iconY, iconW, iconH)];    // 4.取出圖片    UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();    // 5.關閉上下文    UIGraphicsEndImageContext();        // 5.返回圖片    return newImage;}/** *  根據CIImage產生指定大小的UIImage * *  @param image CIImage *  @param size  圖片寬度 */- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size{    CGRect extent = CGRectIntegral(image.extent);    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));    // 1.建立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.儲存bitmap到圖片    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);    CGContextRelease(bitmapRef);    CGImageRelease(bitmapImage);    return [UIImage imageWithCGImage:scaledImage];}

 

iOS開發之----產生二維碼