App设计时往往会用到一些模糊效果或者毛玻璃效果,iOS目前已提供一些模糊API可以让我们方便是使用。
第一种使用Core Image进行模糊
- (UIImage *)blurryImage:(UIImage *)image
withBlurLevel:(CGFloat)blur {
CIImage *inputImage = [CIImage imageWithCGImage:image.CGImage];
CIFilter *filter = [CIFilter filterWithName:@"CIGaussianBlur"
keysAndValues:kCIInputImageKey, inputImage,
@"inputRadius", @(blur),
nil];
CIImage *outputImage = filter.outputImage;
CGImageRef outImage = [self.context createCGImage:outputImage
fromRect:[outputImage extent]];
return [UIImage imageWithCGImage:outImage];
}
第二种使用vImage API进行模糊
- (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur {
if (blur < 0.f || blur > 1.f) {
blur = 0.5f;
}
int boxSize = (int)(blur * 100);
boxSize = boxSize - (boxSize % 2) + 1;
CGImageRef img = image.CGImage;
vImage_Buffer inBuffer, outBuffer;
vImage_Error error;
void *pixelBuffer;
CGDataProviderRef inProvider = CGImageGetDataProvider(img);
CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);
inBuffer.width = CGImageGetWidth(img);
inBuffer.height = CGImageGetHeight(img);
inBuffer.rowBytes = CGImageGetBytesPerRow(img);
inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);
pixelBuffer = malloc(CGImageGetBytesPerRow(img) *
CGImageGetHeight(img));
if(pixelBuffer == NULL)
NSLog(@"No pixelbuffer");
outBuffer.data = pixelBuffer;
outBuffer.width = CGImageGetWidth(img);
outBuffer.height = CGImageGetHeight(img);
outBuffer.rowBytes = CGImageGetBytesPerRow(img);
error = vImageBoxConvolve_ARGB8888(&inBuffer,
&outBuffer,
NULL,
0,
0,
boxSize,
boxSize,
NULL,
kvImageEdgeExtend);
if (error) {
NSLog(@"error from convolution %ld", error);
}
CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();
CGContextRef ctx = CGBitmapContextCreate(
outBuffer.data,
outBuffer.width,
outBuffer.height,
8,
outBuffer.rowBytes,
colorSpace,
kCGImageAlphaNoneSkipLast);
CGImageRef imageRef = CGBitmapContextCreateImage (ctx);
UIImage *returnImage = [UIImage imageWithCGImage:imageRef];
//clean up
CGContextRelease(ctx);
CGColorSpaceRelease(colorSpace);
free(pixelBuffer);
CFRelease(inBitmapData);
CGColorSpaceRelease(colorSpace);
CGImageRelease(imageRef);
return returnImage;
}
第三种方法是网上找到的(毛玻璃效果)
// 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 *)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;
}
原创文章，作者：奋斗，如若转载，请注明出处：https://blog.ytso.com/5173.html