Ios 如何添加图像下载等模糊效果
我正在制作一个聊天应用程序,希望添加一个类似whatsapp的图像下载的模糊效果,因为我也尝试了UIVisualEffectView,但没有达到类似的效果,还尝试减少UIVisualEffectView的alpha,但没有达到接近此效果。有人能告诉我怎么做吗。提前谢谢 我尝试使用UIVisualEffectView,但无法达到相同的效果Ios 如何添加图像下载等模糊效果,ios,objective-c,swift,uiimageview,uivisualeffectview,Ios,Objective C,Swift,Uiimageview,Uivisualeffectview,我正在制作一个聊天应用程序,希望添加一个类似whatsapp的图像下载的模糊效果,因为我也尝试了UIVisualEffectView,但没有达到类似的效果,还尝试减少UIVisualEffectView的alpha,但没有达到接近此效果。有人能告诉我怎么做吗。提前谢谢 我尝试使用UIVisualEffectView,但无法达到相同的效果 您可以通过在imageview上添加blureffect视图来创建此视图。但当图像显示在imageview中时,这将起作用 let effect = UI
您可以通过在imageview上添加blureffect视图来创建此视图。但当图像显示在imageview中时,这将起作用
let effect = UIVisualEffectView(effect: UIBlurEffect(style: UIBlurEffectStyle.light))
effect.frame = imageView.frame
imageView.addSubview(effect)
可以通过在imageview上添加blureffect视图来创建此视图。但当图像显示在imageview中时,这将起作用
let effect = UIVisualEffectView(effect: UIBlurEffect(style: UIBlurEffectStyle.light))
effect.frame = imageView.frame
imageView.addSubview(effect)
您可以使用任何第三方库,如 使用此选项创建模糊图像,并将其添加到特定事件的单元格中 或者,您可以使用Apple提供的以下方法:
// This method is taken from Apple's UIImageEffects category provided in WWDC 2013 sample code
- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage
{
// Check pre-conditions.
if (self.size.width < 1 || self.size.height < 1) {
NSLog (@"*** error: invalid size: (%.2f x %.2f). Both dimensions must be >= 1: %@", self.size.width, self.size.height, self);
return nil;
}
if (!self.CGImage) {
NSLog (@"*** error: image must be backed by a CGImage: %@", self);
return nil;
}
if (maskImage && !maskImage.CGImage) {
NSLog (@"*** error: maskImage must be backed by a CGImage: %@", maskImage);
return 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) {
// A description of how to compute the box kernel width from the Gaussian
// radius (aka standard deviation) appears in the SVG spec:
// http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
//
// For larger values of 's' (s >= 2.0), an approximation can be used: Three
// successive box-blurs build a piece-wise quadratic convolution kernel, which
// approximates the Gaussian kernel to within roughly 3%.
//
// let d = floor(s * 3*sqrt(2*pi)/4 + 0.5)
//
// ... if d is odd, use three box-blurs of size 'd', centered on the output pixel.
//
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, (uint32_t) radius, (uint32_t) radius, 0, kvImageEdgeExtend);
vImageBoxConvolve_ARGB8888(&effectOutBuffer, &effectInBuffer, NULL, 0, 0, (uint32_t) radius, (uint32_t) radius, 0, kvImageEdgeExtend);
vImageBoxConvolve_ARGB8888(&effectInBuffer, &effectOutBuffer, NULL, 0, 0, (uint32_t) radius, (uint32_t) 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();
}
// Set up output context.
UIGraphicsBeginImageContextWithOptions(self.size, NO, [[UIScreen mainScreen] scale]);
CGContextRef outputContext = UIGraphicsGetCurrentContext();
CGContextScaleCTM(outputContext, 1.0, -1.0);
CGContextTranslateCTM(outputContext, 0, -self.size.height);
// Draw base image.
CGContextDrawImage(outputContext, imageRect, self.CGImage);
// Draw effect image.
if (hasBlur) {
CGContextSaveGState(outputContext);
if (maskImage) {
CGContextClipToMask(outputContext, imageRect, maskImage.CGImage);
}
CGContextDrawImage(outputContext, imageRect, effectImage.CGImage);
CGContextRestoreGState(outputContext);
}
// Add in color tint.
if (tintColor) {
CGContextSaveGState(outputContext);
CGContextSetFillColorWithColor(outputContext, tintColor.CGColor);
CGContextFillRect(outputContext, imageRect);
CGContextRestoreGState(outputContext);
}
// Output image is ready.
UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return outputImage;
}
//Usage:
[imageToBlur applyBlurWithRadius:2.0f tintColor:[UIColor clearColor] saturationDeltaFactor:1.0 maskImage:nil];
//此方法取自WWDC 2013示例代码中提供的苹果UIImageEffects类别
-(UIImage*)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor*)tintColor饱和DeltaFactor:(CGFloat)饱和DeltaFactor maskImage:(UIImage*)maskImage
{
//检查前提条件。
if(self.size.width<1 | | self.size.height<1){
NSLog(@“***错误:无效大小:(.2f x%.2f)。两个维度必须>=1:%@”、self.size.width、self.size.height、self);
返回零;
}
如果(!self.CGImage){
NSLog(@“***错误:映像必须由CGImage:%@”,self支持);
返回零;
}
if(maskImage&&!maskImage.CGImage){
NSLog(@“***错误:maskImage必须由CGImage:%@”maskImage支持);
返回零;
}
CGRect imageRect={CGPointZero,self.size};
UIImage*effectImage=self;
BOOL hasBlur=blurRadius>\uuuu FLT\u EPSILON\uuuuuu;
BOOL hasSaturationChange=fabs(饱和DeltaFactor-1.)>\uu FLT\u EPSILON;
如果(hasBlur | | hasSaturationChange){
UIGraphicsBeginImageContextWithOptions(self.size,NO,[[UIScreen Main Screen]scale]);
CGContextRef effectInContext=UIGraphicsGetCurrentContext();
CGContextScaleCTM(effectInText,1.0,-1.0);
CGContextTranslateCm(effectInText,0,-self.size.height);
CGContextDrawImage(effectInContext、imageRect、self.CGImage);
vImage_缓冲效应缓冲;
effectInBuffer.data=CGBitmapContextGetData(effectInContext);
effectInBuffer.width=CGBitmapContextGetWidth(effectInContext);
effectInBuffer.height=CGBitmapContextGetHeight(effectInContext);
effectInBuffer.rowBytes=CGBitmapContextGetBytesPerRow(effectInContext);
UIGraphicsBeginImageContextWithOptions(self.size,NO,[[UIScreen Main Screen]scale]);
CGContextRef effectOutContext=UIGraphicsGetCurrentContext();
vImage_缓冲效应器;
effectBuffer.data=CGBitmapContextGetData(effectOutContext);
effectBuffer.width=CGBitmapContextGetWidth(effectOutContext);
effectBuffer.height=CGBitmapContextGetHeight(effectOutContext);
effectBuffer.rowBytes=CGBitmapContextGetBytesPerRow(effectOutContext);
如果(hasBlur){
//描述如何从高斯分布计算盒核宽度
//半径(又称标准偏差)出现在SVG规范中:
// http://www.w3.org/TR/SVG/filters.html#feGaussianBlurElement
//
//对于较大的“s”(s>=2.0)值,可以使用近似值:三个
//连续框模糊构建分段二次卷积核
//将高斯核近似到大约3%以内。
//
//设d=楼层(s*3*sqrt(2*pi)/4+0.5)
//
//…如果d为奇数,则使用三个大小为“d”的框模糊,以输出像素为中心。
//
CGFloat inputRadius=模糊半径*[[UIScreen Main Screen]比例];
NSUInteger半径=地板(inputRadius*3.*sqrt(2*M_PI)/4+0.5);
如果(半径%2!=1){
radius+=1;//强制半径为奇数,以便三框模糊方法有效。
}
VimageBoxConvalve_argb888(&effectInBuffer,&effectOutBuffer,NULL,0,0,(uint32_t)半径,(uint32_t)半径,0,kvImageEdgeExtend);
VimageBoxConvalve_argb888(&effecterBuffer,&effectInBuffer,NULL,0,0,(uint32_t)半径,(uint32_t)半径,0,kvImageEdgeExtend);
VimageBoxConvalve_argb888(&effectInBuffer,&effectOutBuffer,NULL,0,0,(uint32_t)半径,(uint32_t)半径,0,kvImageEdgeExtend);
}
BOOL effectImageBuffersAreSwapped=否;
如果(hasSaturationChange){
CGFloat s=饱和DeltaFactor;
CGFloat浮点饱和矩阵[]={
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,
};
常数int32_t除数=256;
NSUInteger Matrix size=sizeof(floatingPointSaturationMatrix)/sizeof(floatingPointSaturationMatrix[0]);
int16_t饱和矩阵[matrixSize];
对于(整数i=0;i