iOS生成图片二维码 - lidaoyuan/Notes GitHub Wiki

#import <UIKit/UIKit.h>

NS_ASSUME_NONNULL_BEGIN

@interface UIImage (QRCode)

/**
 生成二维码图片

 @param message 二维码信息
 @param imagesize 图片尺寸
 @return 二维码图片
 */
+ (UIImage *)QRCodeImageForMessage:(NSString *)message imageSize:(CGFloat)imageSize;
@end

NS_ASSUME_NONNULL_END

#import "UIImage+ORCode.h"

@implementation UIImage (QRCode)

+ (UIImage *)QRCodeImageForMessage:(NSString *)message imageSize:(CGFloat)imageSize {
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    [filter setDefaults];
    
    NSData *data = [message dataUsingEncoding:NSUTF8StringEncoding];
    // 生成二维码,  必须是data格式
    [filter setValue:data forKey:@"inputMessage"];
    // 设置二维码的纠错水平，越高纠错水平越高，可以污损的范围越大
    [filter setValue:@"H" forKey:@"inputCorrectionLevel"];
    // 拿到二维码图片
    CIImage *outputImage = [filter outputImage];
    return [self createNonInterpolatedUIImageFormCIImage:outputImage withSize:imageSize];
}

/**
 *  根据CIImage生成指定大小的UIImage
 *  @param image CIImage
 *  @param size  图片尺寸
 *  @return 生成高清的UIImage
 */
+ (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图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}
@end