生成一张模糊图片

从网上找了很多代码但是效果都不是很好 这个是最好的效果

需要导入头文件

#import <Accelerate/Accelerate.h>   

/**

* blurRadius 模糊程度  

* tintColor   颜色 可以为空

*saturationDeltaFactor 色彩饱和度

* maskImage  图片 可以为空  按照这张图片的形状去切图片

*/

- (UIImage *)imageBluredWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage;

- (UIImage *)imageBluredWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage { CGRect imageRect = { CGPointZero, self.size }; UIImage *effectImage = self; BOOL hasBlur = blurRadius > __FLT_EPSILON__; BOOL hasSaturationChange = fabs(saturationDeltaFactor - 1.) > __FLT_EPSILON__; if (hasBlur || hasSaturationChange) { UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]); CGContextRef effectInContext = UIGraphicsGetCurrentContext(); CGContextScaleCTM(effectInContext, 1.0, -1.0); CGContextTranslateCTM(effectInContext, 0, -self.size.height); CGContextDrawImage(effectInContext, imageRect, self.CGImage); vImage_Buffer effectInBuffer; effectInBuffer.data = CGBitmapContextGetData(effectInContext); effectInBuffer.width = CGBitmapContextGetWidth(effectInContext); effectInBuffer.height = CGBitmapContextGetHeight(effectInContext); effectInBuffer.rowBytes = CGBitmapContextGetBytesPerRow(effectInContext); UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]); CGContextRef effectOutContext = UIGraphicsGetCurrentContext(); vImage_Buffer effectOutBuffer; effectOutBuffer.data = CGBitmapContextGetData(effectOutContext); effectOutBuffer.width = CGBitmapContextGetWidth(effectOutContext); effectOutBuffer.height = CGBitmapContextGetHeight(effectOutContext); effectOutBuffer.rowBytes = CGBitmapContextGetBytesPerRow(effectOutContext); if (hasBlur) { CGFloat inputRadius = blurRadius * [[UIScreen mainScreen] scale]; NSUInteger radius = floor(inputRadius * 3. * sqrt(2 * M_PI) / 4 + 0.5); if (radius % 2 != 1) { radius += 1; // force radius to be odd so that the three box-blur methodology works. } vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, (short)radius, (short)radius, 0, kvImageEdgeExtend); vImageBoxConvolve_ARGB8888(&effectOutBuffer, &effectInBuffer, NULL, 0, 0, (short)radius, (short)radius, 0, kvImageEdgeExtend); vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, (short)radius, (short)radius, 0, kvImageEdgeExtend); } BOOL effectImageBuffersAreSwapped = NO; if (hasSaturationChange) { CGFloat s = saturationDeltaFactor; CGFloat floatingPointSaturationMatrix[] = { 0.0722 + 0.9278 * s, 0.0722 - 0.0722 * s, 0.0722 - 0.0722 * s, 0, 0.7152 - 0.7152 * s, 0.7152 + 0.2848 * s, 0.7152 - 0.7152 * s, 0, 0.2126 - 0.2126 * s, 0.2126 - 0.2126 * s, 0.2126 + 0.7873 * s, 0, 0, 0, 0, 1, }; const int32_t divisor = 256; NSUInteger matrixSize = sizeof(floatingPointSaturationMatrix)/sizeof(floatingPointSaturationMatrix[0]); int16_t saturationMatrix[matrixSize]; for (NSUInteger i = 0; i < matrixSize; ++i) { saturationMatrix[i] = (int16_t)roundf(floatingPointSaturationMatrix[i] * divisor); } if (hasBlur) { vImageMatrixMultiply_ARGB8888(&effectOutBuffer, &effectInBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags); effectImageBuffersAreSwapped = YES; } else { vImageMatrixMultiply_ARGB8888(&effectInBuffer, &effectOutBuffer, saturationMatrix, divisor, NULL, NULL, kvImageNoFlags); } } if (!effectImageBuffersAreSwapped) effectImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); if (effectImageBuffersAreSwapped) effectImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); } // 开启上下文 用于输出图像 UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]); CGContextRef outputContext = UIGraphicsGetCurrentContext(); CGContextScaleCTM(outputContext, 1.0, -1.0); CGContextTranslateCTM(outputContext, 0, -self.size.height); // 开始画底图 CGContextDrawImage(outputContext, imageRect, self.CGImage); // 开始画模糊效果 if (hasBlur) { CGContextSaveGState(outputContext); if (maskImage) { CGContextClipToMask(outputContext, imageRect, maskImage.CGImage); } CGContextDrawImage(outputContext, imageRect, effectImage.CGImage); CGContextRestoreGState(outputContext); } // 添加颜色渲染 if (tintColor) { CGContextSaveGState(outputContext); CGContextSetFillColorWithColor(outputContext, tintColor.CGColor); CGContextFillRect(outputContext, imageRect); CGContextRestoreGState(outputContext); } // 输出成品,并关闭上下文 UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return outputImage; }