系统原生自带的生成二维码

#import <UIKit/UIKit.h>

 

@interface ViewController : UIViewController

 

 

@end

 

 

 

 

 

 

 

 

#import "ViewController.h"

 

@interface ViewController ()

@property (nonatomic)UIImageView *qrcodeImageView;

@end

 

@implementation ViewController

 

- (void)viewDidLoad {

    [super viewDidLoad];

 

    self.qrcodeImageView = [[UIImageView alloc]initWithFrame:CGRectMake(40, 60, 220, 220)];

    UIImage *qrcode = [self createNonInterpolatedUIImageFormCIImage:[self createQRForString:@"www.baidu.com"] withSize:250.0f];

    UIImage *customQrcode = [self imageBlackToTransparent:qrcode withRed:60.0f andGreen:74.0f andBlue:89.0f];

    self.qrcodeImageView.image = customQrcode;

    // set shadow

    //self.qrcodeImageView.layer.shadowOffset = CGSizeMake(0, 0);

    self.qrcodeImageView.layer.shadowRadius = 0;

    self.qrcodeImageView.layer.shadowColor = [UIColor cyanColor].CGColor;

    self.qrcodeImageView.layer.shadowOpacity = 1;

    

    [self.view addSubview:self.qrcodeImageView];

}

 

#pragma mark - InterpolatedUIImage

 

//因为生成的二维码是一个CIImage，我们直接转换成UIImage的话大小不好控制，所以使用下面方法返回需要大小的UIImage

- (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size {

    CGRect extent = CGRectIntegral(image.extent);

    CGFloat scale = MIN(size/CGRectGetWidth(extent), size/CGRectGetHeight(extent));

    // create a bitmap image that we'll draw into a bitmap context at the desired size; // 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);

    // Create an image with the contents of our bitmap // 保存bitmap到图片

    CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);

    // Cleanup

    CGContextRelease(bitmapRef);

    CGImageRelease(bitmapImage);

    return [UIImage imageWithCGImage:scaledImage];

}

 

#pragma mark - QRCodeGenerator

 

//首先是二维码的生成，使用CIFilter很简单，直接传入生成二维码的字符串即可：

- (CIImage *)createQRForString:(NSString *)qrString {

    // Need to convert the string to a UTF-8 encoded NSData object

    NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];

    // Create the filter  创建filter

    CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

    // Set the message content and error-correction level // 设置内容和纠错级别

    [qrFilter setValue:stringData forKey:@"inputMessage"];

    [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];

    // Send the image back 返回CIImage

    return qrFilter.outputImage;

}

 

#pragma mark - imageToTransparent

 

//因为生成的二维码是黑白的，所以还要对二维码进行颜色填充，并转换为透明背景，使用遍历图片像素来更改图片颜色，因为使用的是CGContext，速度非常快：

void ProviderReleaseData (void *info, const void *data, size_t size){

    free((void*)data);

}

- (UIImage*)imageBlackToTransparent:(UIImage*)image withRed:(CGFloat)red andGreen:(CGFloat)green andBlue:(CGFloat)blue{

    const int imageWidth = image.size.width;

    const int imageHeight = image.size.height;

    size_t      bytesPerRow = imageWidth * 4;

    uint32_t* rgbImageBuf = (uint32_t*)malloc(bytesPerRow * imageHeight);

    // create context

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,

                                                 kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);

    CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);

    // traverse pixe  // 遍历像素

    int pixelNum = imageWidth * imageHeight;

    uint32_t* pCurPtr = rgbImageBuf;

    for (int i = 0; i < pixelNum; i++, pCurPtr++){

        if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){  // 将白色变成透明

            // 改成下面的代码，会将图片转成想要的颜色

            uint8_t* ptr = (uint8_t*)pCurPtr;

            ptr[3] = red; //0~255

            ptr[2] = green;

            ptr[1] = blue;

        }else{

            uint8_t* ptr = (uint8_t*)pCurPtr;

            ptr[0] = 0;

        }

    }

    // context to image   输出图片

    CGDataProviderRef dataProvider = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);

    CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpace,

                                        kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProvider,

                                        NULL, true, kCGRenderingIntentDefault);

    CGDataProviderRelease(dataProvider);

    UIImage* resultUIImage = [UIImage imageWithCGImage:imageRef];

    // release   清理空间

    CGImageRelease(imageRef);

    CGContextRelease(context);

    CGColorSpaceRelease(colorSpace);

    return resultUIImage;

}