iOS常用功能 - 根据链接生成二维码图片

根据链接生成二维码

 1 -(void)generatingTwoDimensionalCode {
 2     
 3     //创建过滤器
 4     CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
 5     
 6     //过滤器恢复默认
 7     [filter setDefaults];
 8     
 9     //给过滤器添加数据
10     NSString *string = @"https://www.baidu.com"; // 路径，以百度为例
11     NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding allowLossyConversion:YES];
12     
13     [filter setValue:data forKeyPath:@"inputMessage"];
14     
15     //获取二维码过滤器生成的二维码
16     CIImage *image = [filter outputImage];// 此时的 image 是 模糊的
17     
18     //高清处理：将获取到的二维码添加到 imageview
19     self.imageView.image =[self createNonInterpolatedUIImageFormCIImage:image withSize:300];// withSize 大于等于要显示的尺寸
20 }
21 
22 //生成高清二维码
23 - (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {
24     
25     CGRect extent = CGRectIntegral(image.extent);
26     CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
27     
28     //1 创建 bitmap
29     size_t width = CGRectGetWidth(extent) * scale;
30     size_t height = CGRectGetHeight(extent) * scale;
31     CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();
32     CGContextRef bitmapRef = CGBitmapContextCreate(nil, width, height, 8, 0, cs, (CGBitmapInfo)kCGImageAlphaNone);
33     CIContext *context = [CIContext contextWithOptions:nil];
34     CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];
35     CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationNone);
36     CGContextScaleCTM(bitmapRef, scale, scale);
37     CGContextDrawImage(bitmapRef, extent, bitmapImage);
38     
39     //保存 bitmap 到图片
40     CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
41     CGContextRelease(bitmapRef);
42     CGImageRelease(bitmapImage);
43     return [UIImage imageWithCGImage:scaledImage];
44 }