生成二维码，其实也是用到 CoreImage，但是步骤繁琐一些，代码如下
// 创建 ImageView，存放生成的二维码
- (void)createQRCode {
CGFloat margin = 50;
CGRect frame = CGRectMake(margin,
margin + 20,
self.view.bounds.size.width - margin * 2,
self.view.bounds.size.width - margin * 2);
UIImageView *imageView = [[UIImageView alloc] initWithFrame:frame];
[self.view addSubview:imageView];
// 生成二维码
[self createQRCodeToImageView:imageView
fromString:@"qianchia"
withIcon:[UIImage imageNamed:@"demo1"]
withColor:[UIColor redColor]];
}
// 生成二维码
- (void)createQRCodeToImageView:(UIImageView *)imageView
fromString:(NSString *)inputString
withIcon:(UIImage *)icon
withColor:(UIColor *)color {
// 创建过滤器
CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
// 恢复默认
[filter setDefaults];
// 给过滤器添加数据
NSData *data = [inputString dataUsingEncoding:NSUTF8StringEncoding];
// 通过 KVO 设置滤镜 inputMessage 数据
[filter setValue:data forKey:@"inputMessage"];
// 设置二维码颜色
UIColor *onColor = color ? : [UIColor blackColor];
UIColor *offColor = [UIColor whiteColor];
CIFilter *colorFilter = [CIFilter filterWithName:@"CIFalseColor"
keysAndValues:@"inputImage", filter.outputImage,
@"inputColor0", [CIColor colorWithCGColor:onColor.CGColor],
@"inputColor1", [CIColor colorWithCGColor:offColor.CGColor],
nil];
// 获取输出的二维码
CIImage *outputImage = colorFilter.outputImage;
// CIImage *outputImage = [filter outputImage];
CIContext *context = [CIContext contextWithOptions:nil];
CGImageRef cgImage = [context createCGImage:outputImage
fromRect:[outputImage extent]];
// 将 CIImage 转换成 UIImage，并放大显示
UIImage *qrImage = [UIImage imageWithCGImage:cgImage
scale:1.0
orientation:UIImageOrientationUp];
// 重绘 UIImage，默认情况下生成的图片比较模糊
CGFloat scale = 100;
CGFloat width = qrImage.size.width * scale;
CGFloat height = qrImage.size.height * scale;
UIGraphicsBeginImageContext(CGSizeMake(width, height));
CGContextRef context1 = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(context1, kCGInterpolationNone);
[qrImage drawInRect:CGRectMake(0, 0, width, height)];
qrImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRelease(cgImage);
// 添加头像
if (icon) {
UIGraphicsBeginImageContext(qrImage.size);
[qrImage drawInRect:CGRectMake(0, 0, qrImage.size.width, qrImage.size.height)];
// 设置头像大小
CGFloat scale = 5;
CGFloat width = qrImage.size.width / scale;
CGFloat height = qrImage.size.height / scale;
CGFloat x = (qrImage.size.width - width) / 2;
CGFloat y = (qrImage.size.height - height) / 2;
[icon drawInRect:CGRectMake( x, y, width, height)];
UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
imageView.image = newImage;
} else {
imageView.image = qrImage;
}
}
