ios 模糊效果
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注：该内容从极客网学习而来。先看个效果图：
实现方法一：利用ios8中得系统原生类 UIVisualEffectView 、UIVibrancyEffect
ios8才出得类昂，切记。
// 创建一个模糊view,添加到UIImageView上 UIVisualEffectView *viewEbg = [[UIVisualEffectView alloc] initWithEffect:[UIBlurEffect effectWithStyle:UIBlurEffectStyleLight]]; viewEbg.frame = CGRectMake(0, 100, 375, 500); [self.imgView addSubview:viewEbg]; // 创建一个子模糊view,添加在父模糊view上 UIVisualEffectView *subV = [[UIVisualEffectView alloc] initWithEffect:[UIVibrancyEffect effectForBlurEffect:(UIBlurEffect *)viewEbg.effect]]; // 该类的view 是用 contentView 来添加子控件的 [viewEbg.contentView addSubview:subV]; subV.frame = viewEbg.bounds; UILabel *la = [[UILabel alloc ] initWithFrame:subV.bounds]; la.text = @"你好"; la.textColor = [UIColor redColor]; la.font = [UIFont systemFontOfSize:60.0]; la.textAlignment = NSTextAlignmentCenter; [subV.contentView addSubview:la];
体会：效果跟图片有很大的关系，假如代码不变，只换一张图片，那么效果就是下面这样：
官方文档介绍：
方法二：可以借助别人的分类 UIImage+ImageEffects.h //也支持ios7昂
用起来特别方便
UIImage+ImageEffects.h
@import UIKit;@interface UIImage (ImageEffects)#pragma mark - Blur Image/** * Get blured image. * * @return Blured image. */- (UIImage *)blurImage;/** * Get the blured image masked by another image. * * @param maskImage Image used for mask. * * @return the Blured image. */- (UIImage *)blurImageWithMask:(UIImage *)maskImage;/** * Get blured image and you can set the blur radius. * * @param radius Blur radius. * * @return Blured image. */- (UIImage *)blurImageWithRadius:(CGFloat)radius;/** * Get blured image at specified frame. * * @param frame The specified frame that you use to blur. * * @return Blured image. */- (UIImage *)blurImageAtFrame:(CGRect)frame;#pragma mark - Grayscale Image/** * Get grayScale image. * * @return GrayScaled image. */- (UIImage *)grayScale;#pragma mark - Some Useful Method/** * Scale image with fixed width. * * @param width The fixed width you give. * * @return Scaled image. */- (UIImage *)scaleWithFixedWidth:(CGFloat)width;/** * Scale image with fixed height. * * @param height The fixed height you give. * * @return Scaled image. */- (UIImage *)scaleWithFixedHeight:(CGFloat)height;/** * Get the image average color. * * @return Average color from the image. */- (UIColor *)averageColor;/** * Get cropped image at specified frame. * * @param frame The specified frame that you use to crop. * * @return Cropped image */- (UIImage *)croppedImageAtFrame:(CGRect)frame;@end
UIImage+ImageEffects.m
/* File: UIImage+ImageEffects.m Abstract: This is a category of UIImage that adds methods to apply blur and tint effects to an image. This is the code you’ll want to look out to find out how to use vImage to efficiently calculate a blur. Version: 1.0 Disclaimer: IMPORTANT: This Apple software is supplied to you by Apple Inc. ("Apple") in consideration of your agreement to the following terms, and your use, installation, modification or redistribution of this Apple software constitutes acceptance of these terms. If you do not agree with these terms, please do not use, install, modify or redistribute this Apple software. In consideration of your agreement to abide by the following terms, and subject to these terms, Apple grants you a personal, non-exclusive license, under Apple's copyrights in this original Apple software (the "Apple Software"), to use, reproduce, modify and redistribute the Apple Software, with or without modifications, in source and/or binary forms; provided that if you redistribute the Apple Software in its entirety and without modifications, you must retain this notice and the following text and disclaimers in all such redistributions of the Apple Software. Neither the name, trademarks, service marks or logos of Apple Inc. may be used to endorse or promote products derived from the Apple Software without specific prior written permission from Apple. Except as expressly stated in this notice, no other rights or licenses, express or implied, are granted by Apple herein, including but not limited to any patent rights that may be infringed by your derivative works or by other works in which the Apple Software may be incorporated. The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS. IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. Copyright (C) 2013 Apple Inc. All Rights Reserved. Copyright © 2013 Apple Inc. All rights reserved. WWDC 2013 License NOTE: This Apple Software was supplied by Apple as part of a WWDC 2013 Session. Please refer to the applicable WWDC 2013 Session for further information. IMPORTANT: This Apple software is supplied to you by Apple Inc. ("Apple") in consideration of your agreement to the following terms, and your use, installation, modification or redistribution of this Apple software constitutes acceptance of these terms. If you do not agree with these terms, please do not use, install, modify or redistribute this Apple software. In consideration of your agreement to abide by the following terms, and subject to these terms, Apple grants you a non-exclusive license, under Apple's copyrights in this original Apple software (the "Apple Software"), to use, reproduce, modify and redistribute the Apple Software, with or without modifications, in source and/or binary forms; provided that if you redistribute the Apple Software in its entirety and without modifications, you must retain this notice and the following text and disclaimers in all such redistributions of the Apple Software. Neither the name, trademarks, service marks or logos of Apple Inc. may be used to endorse or promote products derived from the Apple Software without specific prior written permission from Apple. Except as expressly stated in this notice, no other rights or licenses, express or implied, are granted by Apple herein, including but not limited to any patent rights that may be infringed by your derivative works or by other works in which the Apple Software may be incorporated. The Apple Software is provided by Apple on an "AS IS" basis. APPLE MAKES NO WARRANTIES, EXPRESS OR IMPLIED, INCLUDING WITHOUT LIMITATION THE IMPLIED WARRANTIES OF NON-INFRINGEMENT, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, REGARDING THE APPLE SOFTWARE OR ITS USE AND OPERATION ALONE OR IN COMBINATION WITH YOUR PRODUCTS. IN NO EVENT SHALL APPLE BE LIABLE FOR ANY SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) ARISING IN ANY WAY OUT OF THE USE, REPRODUCTION, MODIFICATION AND/OR DISTRIBUTION OF THE APPLE SOFTWARE, HOWEVER CAUSED AND WHETHER UNDER THEORY OF CONTRACT, TORT (INCLUDING NEGLIGENCE), STRICT LIABILITY OR OTHERWISE, EVEN IF APPLE HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. EA1002 5/3/2013 */#import "UIImage+ImageEffects.h"#import <float.h>@import Accelerate;@implementation UIImage (ImageEffects)- (UIImage *)applyLightEffect{ UIColor *tintColor = [UIColor colorWithWhite:1.0 alpha:0.3]; return [self applyBlurWithRadius:30 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];}- (UIImage *)applyExtraLightEffect { UIColor *tintColor = [UIColor colorWithWhite:0.97 alpha:0.82]; return [self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];}- (UIImage *)applyDarkEffect { UIColor *tintColor = [UIColor colorWithWhite:0.11 alpha:0.73]; return [self applyBlurWithRadius:20 tintColor:tintColor saturationDeltaFactor:1.8 maskImage:nil];}- (UIImage *)applyTintEffectWithColor:(UIColor *)tintColor { const CGFloat EffectColorAlpha = 0.6; UIColor *effectColor = tintColor; int componentCount = (int)CGColorGetNumberOfComponents(tintColor.CGColor); if (componentCount == 2) { CGFloat b; if ([tintColor getWhite:&b alpha:NULL]) { effectColor = [UIColor colorWithWhite:b alpha:EffectColorAlpha]; } } else { CGFloat r, g, b; if ([tintColor getRed:&r green:&g blue:&b alpha:NULL]) { effectColor = [UIColor colorWithRed:r green:g blue:b alpha:EffectColorAlpha]; } } return [self applyBlurWithRadius:20 tintColor:effectColor saturationDeltaFactor:1.4 maskImage:nil];}- (UIImage *)blurImage { return [self applyBlurWithRadius:20 tintColor:[UIColor colorWithWhite:0 alpha:0.0] saturationDeltaFactor:1.4 maskImage:nil];}- (UIImage *)blurImageWithRadius:(CGFloat)radius { return [self applyBlurWithRadius:radius tintColor:[UIColor colorWithWhite:0 alpha:0.0] saturationDeltaFactor:1.4 maskImage:nil];}- (UIImage *)blurImageWithMask:(UIImage *)maskImage { return [self applyBlurWithRadius:20 tintColor:[UIColor colorWithWhite:0 alpha:0.0] saturationDeltaFactor:1.4 maskImage:maskImage];}- (UIImage *)blurImageAtFrame:(CGRect)frame { return [self applyBlurWithRadius:20 tintColor:[UIColor colorWithWhite:0 alpha:0.0] saturationDeltaFactor:1.4 maskImage:nil atFrame:frame];}- (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;}- (UIImage *)grayScale { int width = self.size.width; int height = self.size.height; CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray(); CGContextRef context = CGBitmapContextCreate(nil, width, height, 8, // bits per component 0, colorSpace, kCGBitmapByteOrderDefault); CGColorSpaceRelease(colorSpace); if (context == NULL) { return nil; } CGContextDrawImage(context, CGRectMake(0, 0, width, height), self.CGImage); CGImageRef image = CGBitmapContextCreateImage(context); UIImage *grayImage = [UIImage imageWithCGImage:image]; CFRelease(image); CGContextRelease(context); return grayImage;}- (UIImage *)scaleWithFixedWidth:(CGFloat)width { float newHeight = self.size.height * (width / self.size.width); CGSize size = CGSizeMake(width, newHeight); UIGraphicsBeginImageContextWithOptions(size, NO, 0); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(context, 0.0, size.height); CGContextScaleCTM(context, 1.0, -1.0); CGContextSetBlendMode(context, kCGBlendModeCopy); CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, size.width, size.height), self.CGImage); UIImage *imageOut = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return imageOut;}- (UIImage *)scaleWithFixedHeight:(CGFloat)height { float newWidth = self.size.width * (height / self.size.height); CGSize size = CGSizeMake(newWidth, height); UIGraphicsBeginImageContextWithOptions(size, NO, 0); CGContextRef context = UIGraphicsGetCurrentContext(); CGContextTranslateCTM(context, 0.0, size.height); CGContextScaleCTM(context, 1.0, -1.0); CGContextSetBlendMode(context, kCGBlendModeCopy); CGContextDrawImage(context, CGRectMake(0.0f, 0.0f, size.width, size.height), self.CGImage); UIImage *imageOut = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return imageOut;}- (UIColor *)averageColor { CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); unsigned char rgba[4]; CGContextRef context = CGBitmapContextCreate(rgba, 1, 1, 8, 4, colorSpace, kCGImageAlphaPremultipliedLast | kCGBitmapByteOrder32Big); CGContextDrawImage(context, CGRectMake(0, 0, 1, 1), self.CGImage); CGColorSpaceRelease(colorSpace); CGContextRelease(context); if(rgba[3] > 0) { CGFloat alpha = ((CGFloat)rgba[3])/255.0; CGFloat multiplier = alpha/255.0; return [UIColor colorWithRed:((CGFloat)rgba[0])*multiplier green:((CGFloat)rgba[1])*multiplier blue:((CGFloat)rgba[2])*multiplier alpha:alpha]; } else { return [UIColor colorWithRed:((CGFloat)rgba[0])/255.0 green:((CGFloat)rgba[1])/255.0 blue:((CGFloat)rgba[2])/255.0 alpha:((CGFloat)rgba[3])/255.0]; }}- (UIImage *)croppedImageAtFrame:(CGRect)frame { frame = CGRectMake(frame.origin.x * self.scale, frame.origin.y * self.scale, frame.size.width * self.scale, frame.size.height * self.scale); CGImageRef sourceImageRef = [self CGImage]; CGImageRef newImageRef = CGImageCreateWithImageInRect(sourceImageRef, frame); UIImage *newImage = [UIImage imageWithCGImage:newImageRef scale:[self scale] orientation:[self imageOrientation]]; CGImageRelease(newImageRef); return newImage;}- (UIImage *)addImageToImage:(UIImage *)img atRect:(CGRect)cropRect { CGSize size = CGSizeMake(self.size.width, self.size.height); UIGraphicsBeginImageContextWithOptions(size, NO, self.scale); CGPoint pointImg1 = CGPointMake(0,0); [self drawAtPoint:pointImg1]; CGPoint pointImg2 = cropRect.origin; [img drawAtPoint: pointImg2]; UIImage* result = UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext(); return result;}- (UIImage *)applyBlurWithRadius:(CGFloat)blurRadius tintColor:(UIColor *)tintColor saturationDeltaFactor:(CGFloat)saturationDeltaFactor maskImage:(UIImage *)maskImage atFrame:(CGRect)frame{ UIImage *blurredFrame = \ [[self croppedImageAtFrame:frame] applyBlurWithRadius:blurRadius tintColor:tintColor saturationDeltaFactor:saturationDeltaFactor maskImage:maskImage]; return [self addImageToImage:blurredFrame atRect:frame];}@end 0 0
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