因为系统创建的二维码默认都是黑色的，所以突然想改变一下二维码颜色，具体操作有点复杂，而且其中用到了好多C语言的语法，Swift不好写，所以默认用了OC。只贴了.m文件的代码，.h文件就是几个类函数的声明。
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#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 - 创建灰度图，只有灰度图才能改变颜色 + (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不支持设备依赖颜色空间或通用颜色空间。iOS应用程序必须使用设备颜色空间 // 设备颜色空间主要用于IOS应用程序，因为其它颜色空间无法在IOS上使用。大多数情况下，Mac OS X应用程序应使用通用颜色空间，而不使用设备颜色空间。 // CGColorSpaceCreateDeviceGray：创建设备依赖灰度颜色空间 // CGColorSpaceCreateDeviceRGB：创建设备依赖RGB颜色空间 // CGColorSpaceCreateDeviceCMYK：创建设备依赖CMYK颜色空间 CGColorSpaceRef cs = CGColorSpaceCreateDeviceGray();//这个是改变二维码颜色的主要属性，必须是灰度空间，作用是将UIImage转变成了灰度图 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 - 创建二维码的主要代码 + (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 - 改变二维码的颜色 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 |
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原文链接：http://blog.csdn.net/youshaoduo/article/details/53286153
