iOS 模糊效果相关

桃扇骨 2022-05-15 08:19 226阅读 0赞

项目中一直有使用到模糊处理, 例如图片的高斯模糊, 一直使用的代码如下:

// 内部方法,核心代码,封装了毛玻璃效果 参数:半径,颜色,色彩饱和度

\- (UIImage \*)imgBluredWithRadius:(CGFloat)blurRadius tintColor:(UIColor \*)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage \*)maskImage

UIImage \*outputImage =nil;

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, radius, radius, 0, kvImageEdgeExtend);

vImageBoxConvolve\_ARGB8888(&effectOutBuffer, &effectInBuffer, NULL, 0, 0, radius, radius, 0, kvImageEdgeExtend);

vImageBoxConvolve\_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, radius, 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

outputImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

return outputImage;

该方法是写在UIImage的一个Category中, 一直以来只用于处理图片, 效果还好, 但是比较耗内存

最近项目中要实现对视频模糊处理, 再使用该方法很明显是不可能的

于是找到了下面这种方法, 苹果直接原来有一套模糊处理的view:  UIVisualEffectView

UIBlurEffect \*effect = \[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight\];

\_effectView = \[\[UIVisualEffectView alloc\] initWithEffect:effect\];

\_effectView.frame = CGRectMake(0, 0, SCREEN\_WIDTH, SCREEN\_HEIGHT);

\[self.chattingView.remoteImageView addSubview:\_effectView\];

iOS 模糊效果相关

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