#import "UIImage+CreateQRCode.h"  @implementation UIImage (CreateQRCode)  + (UIImage *)createQRCode:(NSString *)string andSize:(CGSize)size andColor:(UIColor *)color {   UIImage *qrcode = [self createNonInterpolatedUIImageFormCIImage:[self createQRForString:string] withSize:size];   const CGFloat *_components = CGColorGetComponents(color.CGColor);   CGFloat red = _components[0] * 255.f;   CGFloat green = _components[1] * 255.f;   CGFloat blue = _components[2] * 255.f;   return [self imageBlackToTransparent:qrcode withRed:red andGreen:green andBlue:blue]; }  + (void)setImageViewShadow:(UIImageView *)view {   view.layer.shadowOffset = CGSizeMake(0, 2);   view.layer.shadowRadius = 2;   view.layer.shadowColor = [UIColor blackColor].CGColor;   view.layer.shadowOpacity = 0.5;   view.backgroundColor = [UIColor clearColor]; }  #pragma mark - 創建灰度圖，只有灰度圖才能改變顏色 + (UIImage *)createNonInterpolatedUIImageFormCIImage:(CIImage *)image withSize:(CGSize)size {   CGRect extent = CGRectIntegral(image.extent);   CGFloat scale = MIN(size.width/CGRectGetWidth(extent), size.height/CGRectGetHeight(extent));      size_t width = CGRectGetWidth(extent) * scale;   size_t height = CGRectGetHeight(extent) * scale;    //  iOS不支持設備依賴顏色空間或通用顏色空間。iOS應用程序必須使用設備顏色空間 //  設備顏色空間主要用于IOS應用程序，因為其它顏色空間無法在IOS上使用。大多數情況下，Mac OS X應用程序應使用通用顏色空間，而不使用設備顏色空間。 //  CGColorSpaceCreateDeviceGray：創建設備依賴灰度顏色空間 //  CGColorSpaceCreateDeviceRGB：創建設備依賴RGB顏色空間 //  CGColorSpaceCreateDeviceCMYK：創建設備依賴CMYK顏色空間   CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();//這個是改變二維碼顏色的主要屬性，必須是灰度空間，作用是將UIImage轉變成了灰度圖      CGContextRef bitmapRef = CGBitmapContextCreate(NULL, width, height, 8, 0, cs, kCGImageAlphaNone);   CIContext * context = [CIContext contextWithOptions:NULL];   CGImageRef bitmapImage = [context createCGImage:image fromRect:extent];   CGContextSetInterpolationQuality(bitmapRef, kCGInterpolationHigh);   CGContextScaleCTM(bitmapRef, scale, scale);   CGContextDrawImage(bitmapRef, extent, bitmapImage);   CGImageRef scaledImage = CGBitmapContextCreateImage(bitmapRef);      CGContextRelease(bitmapRef);   CGImageRelease(bitmapImage);      return [UIImage imageWithCGImage:scaledImage]; }  #pragma mark - 創建二維碼的主要代碼 + (CIImage *)createQRForString:(NSString *)qrString {   NSData *stringData = [qrString dataUsingEncoding:NSUTF8StringEncoding];   CIFilter *qrFilter = [CIFilter filterWithName:@"CIQRCodeGenerator"];   [qrFilter setValue:stringData forKey:@"inputMessage"];   [qrFilter setValue:@"M" forKey:@"inputCorrectionLevel"];   return qrFilter.outputImage; }  #pragma mark - 改變二維碼的顏色 void ProviderReleaseData (voidvoid *info, const voidvoid *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);      CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();   CGContextRef context = CGBitmapContextCreate(rgbImageBuf, imageWidth, imageHeight, 8, bytesPerRow, colorSpace,                          kCGBitmapByteOrder32Little | kCGImageAlphaNoneSkipLast);   CGContextDrawImage(context, CGRectMake(0, 0, imageWidth, imageHeight), image.CGImage);      int pixelNum = imageWidth * imageHeight;   uint32_t* pCurPtr = rgbImageBuf;   for (int i = 0; i < pixelNum; i++, pCurPtr++){     if ((*pCurPtr & 0xFFFFFF00) < 0x99999900){       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;     }   }      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];      CGImageRelease(imageRef);   CGContextRelease(context);   CGColorSpaceRelease(colorSpace);      return resultUIImage; }  @end