iOS-带图片的二维码的生成(QRCode)

背景

物联网技术这门课程的老师让我们做一个二维码出来，二维码的内容包括：学号、姓名，并且加上一张图片。这不是和微信的二维码很像吗？开发语言当然是首选我喜欢的Objective-C啦~~~

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实现目标

1. 生成二维码
2. 二维码的信息包括学号、姓名
3. 二维码需要加入图片

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实现

1. 导入库
2. 实现代码

代码部分

//
//  ViewController.m
//  QRCode
//
//  Created by HZhenF on 2018/9/23.
//  Copyright © 2018年 HZhenF. All rights reserved.
//

#import "ViewController.h"
#import 
#define screenW [UIScreen mainScreen].bounds.size.width
#define screenH [UIScreen mainScreen].bounds.size.height


@interface ViewController ()

@property(nonatomic,strong) UIImageView *imageView;


@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];

    CGFloat imgW = screenW * 0.5;
    CGFloat imgH = imgW;
    CGFloat imgX = (screenW - imgW)/2;
    CGFloat imgY = (screenH - imgW)/2;
    CGRect imgRect = {imgX,imgY,imgW,imgH};
    self.imageView = [[UIImageView alloc] initWithFrame:imgRect];
    self.imageView.backgroundColor = [UIColor redColor];
    [self.view addSubview:self.imageView];
    
}


- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    // 1. 创建一个二维码滤镜实例(CIFilter)
    CIFilter *filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];
    // 滤镜恢复默认设置
    [filter setDefaults];
    
    // 2. 给滤镜添加数据
    NSString *string = @"学号:3180807001 \n  姓名:黄振锋";
    NSData *data = [string dataUsingEncoding:NSUTF8StringEncoding];
    // 使用KVC的方式给filter赋值
    [filter setValue:data forKeyPath:@"inputMessage"];
    
    // 3. 生成二维码
    CIImage *image = [filter outputImage];

    //4.在中心增加一张图片
    UIImage *img = [self createNonInterpolatedUIImageFormCIImage:image withSize:screenW];
    
    //5.把中央图片划入二维码里面
    //5.1开启图形上下文
    UIGraphicsBeginImageContext(img.size);
    //5.2将二维码的图片画入
    [img drawInRect:CGRectMake(0, 0, img.size.width, img.size.height)];
    UIImage *centerImg = [UIImage imageNamed:@"HZhenF"];
    CGFloat centerW=img.size.width*0.3;
    CGFloat centerH=centerW;
    CGFloat centerX=(img.size.width-centerW)*0.5;
    CGFloat centerY=(img.size.height -centerH)*0.5;
    [centerImg drawInRect:CGRectMake(centerX, centerY, centerW, centerH)];
    //5.3获取绘制好的图片
    UIImage *finalImg=UIGraphicsGetImageFromCurrentImageContext();
    //5.4关闭图像上下文
    UIGraphicsEndImageContext();

    //6.显示最终二维码
    self.imageView.image = finalImg;
}

/**
 *  调用该方法处理图像变清晰
 *  根据CIImage生成指定大小的UIImage
 *
 *  @param image CIImage
 *  @param size  图片宽度以及高度
 */
- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size
{
    CGRect extent = CGRectIntegral(image.extent);
    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));
    
    //1.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);
    
    //2.保存bitmap到图片
    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);
    CGContextRelease(bitmapRef);
    CGImageRelease(bitmapImage);
    return [UIImage imageWithCGImage:scaledImage];
}


@end