iOS 模糊效果相关

最新推荐文章于 2022-01-13 15:33:22 发布

原创最新推荐文章于 2022-01-13 15:33:22 发布 · 置顶 · 256 阅读

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#iOS #高斯模糊

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博客介绍了项目中图片高斯模糊处理的代码，该方法写在UIImage的Category中，用于处理图片效果尚可但耗内存。因项目需对视频进行模糊处理，原方法不再适用，于是找到苹果的UIVisualEffectView进行视频模糊处理。

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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];