二维码生成 使用系统自带类库
一、导入 CoreImage库
#import <CoreImage/CoreImage.h>
二、生成二维码
- (CIImage *) creatQRCodeWithURL:(NSString *)urlStr {
// 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];
// 3. 将字符串转换成
NSData *data = [urlStr 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];
return outputImage;
// // 6. 将CIImage转换成UIImage，并放大显示
// return [UIImage imageWithCIImage:outputImage scale:20.0 orientation:UIImageOrientationUp];
}
三、 改变二维码大小
- (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);
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);
return [UIImage imageWithCGImage:scaledImage];
}