iOS随笔小记--二维码管理类

建立一个公用类YDQRCode管理二维码相关的方法

#import <Foundation/Foundation.h>
#import <UIKit/UIKit.h>

@interface YDQRCode : NSObject

在.h文件中

/**
根据链接，获取输出的二维码

+ (CIImage *)createQRForString:(NSString *)qrString ;

/**
根据CIImage生成指定大小的UIImage
@param image CIImage
@param size 图片宽度

+(UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGFloat) size;

/**
默认产生的黑白色的二维码图片；我们可以让它产生其它颜色的二维码图片，例如：蓝白色的二维码图片

+(UIImage *)specialColorImage:(UIImage*)image withRed:(CGFloat)red green:(CGFloat)green blue:(CGFloat)blue;

/**
使用核心绘图框架CG（Core Graphics）对象操作，合并二维码图片和用于中间显示的图标图片

+(UIImage *)addIconToQRCodeImage:(UIImage *)image withIcon:(UIImage *)icon withIconSize:(CGSize)iconSize;

/**
使用核心绘图框架CG（Core Graphics）对象操作，合并二维码图片和用于中间显示的图标图片

+(UIImage *)addIconToQRCodeImage:(UIImage *)image withIcon:(UIImage *)icon withScale:(CGFloat)scale;

在.m文件中实现具体的方法：

#pragma mark - Private Methods

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

free((void*)data);

}


#pragma mark - Public Methods

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

//创建过滤器,使用CIFilter滤镜类生成二维码
CIFilter * filter = [CIFilter filterWithName:@"CIQRCodeGenerator"];

//恢复默认
[filter setDefaults];

//给过滤器添加数据（正则表达式/账号和密码）
NSData * data = [qrString dataUsingEncoding:NSUTF8StringEncoding];

// 设置内容和纠错级别
[filter setValue:data forKey:@"inputMessage"];
[filter setValue:@"M" forKey:@"inputCorrectionLevel"];

// 返回CIImage
return filter.outputImage;
}


+(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;

//创建一个DeviceGray颜色空间
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];

}


+ (UIImage *)specialColorImage:(UIImage*)image withRed:(CGFloat)red green:(CGFloat)green blue:(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 colorSpaceRef = CGColorSpaceCreateDeviceRGB();

CGContextRef contextRef = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpaceRef, kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);

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

//Traverse pixe
int pixelNum = imageWidth * imageHeight;
uint32_t* pCurPtr = rgbImageBuf;
for (int i = 0; i < pixelNum; i++, pCurPtr++){
    
    if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){
        //Change color
        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;
    }
    }

    //Convert to image
    CGDataProviderRef dataProviderRef = CGDataProviderCreateWithData(NULL, rgbImageBuf, bytesPerRow * imageHeight, ProviderReleaseData);
    CGImageRef imageRef = CGImageCreate(imageWidth, imageHeight, 8, 32, bytesPerRow, colorSpaceRef,
                                    
                                    kCGImageAlphaLast | kCGBitmapByteOrder32Little, dataProviderRef,
                                    NULL, true, kCGRenderingIntentDefault);

    CGDataProviderRelease(dataProviderRef);

    UIImage* img = [UIImage imageWithCGImage:imageRef];
    //Release
    CGImageRelease(imageRef);

    CGContextRelease(contextRef);

    CGColorSpaceRelease(colorSpaceRef);

    return img;

    }


+(UIImage *)addIconToQRCodeImage:(UIImage *)image withIcon:(UIImage *)icon withIconSize:(CGSize)iconSize {

UIGraphicsBeginImageContext(image.size);
//通过两张图片进行位置和大小的绘制，实现两张图片的合并；其实此原理做法也可以用于多张图片的合并
CGFloat widthOfImage = image.size.width;
CGFloat heightOfImage = image.size.height;
CGFloat widthOfIcon = iconSize.width;
CGFloat heightOfIcon = iconSize.height;

[image drawInRect:CGRectMake(0, 0, widthOfImage, heightOfImage)];
[icon drawInRect:CGRectMake((widthOfImage-widthOfIcon)/2, (heightOfImage-heightOfIcon)/2,
                            widthOfIcon, heightOfIcon)];

UIImage *img = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return img;
}


+(UIImage *)addIconToQRCodeImage:(UIImage *)image withIcon:(UIImage *)icon withScale:(CGFloat)scale {

UIGraphicsBeginImageContext(image.size);

//通过两张图片进行位置和大小的绘制，实现两张图片的合并；其实此原理做法也可以用于多张图片的合并
CGFloat widthOfImage = image.size.width;
CGFloat heightOfImage = image.size.height;
CGFloat widthOfIcon = widthOfImage/scale;
CGFloat heightOfIcon = heightOfImage/scale;

[image drawInRect:CGRectMake(0, 0, widthOfImage, heightOfImage)];

[icon drawInRect:CGRectMake((widthOfImage-widthOfIcon)/2, (heightOfImage-heightOfIcon)/2,
                            widthOfIcon, heightOfIcon)];

UIImage *img = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return img;

}