当用户点击按钮后，让整个屏幕产生毛玻璃效果，模糊背景，在此基础上显示一些View，提示用户操作成功！
在iOS开发中，可以给整个屏幕截个图，通过一定的算法对这张图片进行模糊，显示在一个蒙板上，并在这个蒙板上添加想要的UI效果
核心代码如下：
1 /*** 添加蒙版 ***/ 2 - (void)addLayer{ 3 // 截屏，并添加毛玻璃效果 4 UIGraphicsBeginImageContext(CGSizeMake(kScreenW, kScreenH)); 5 [self.view.window.layer renderInContext:UIGraphicsGetCurrentContext()]; 6 UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext(); 7 UIGraphicsEndImageContext(); 8 UIImage *image = [UIImage blurryImage:viewImage withBlurLevel:0.15]; 9 //添加的蒙层 10 UIWindow *keyWindow = [[UIWindow alloc]initWithFrame:[UIScreen mainScreen].bounds]; 11 [keyWindow setWindowLevel:UIWindowLevelAlert]; 12 [keyWindow setBackgroundColor:[[UIColor whiteColor] colorWithAlphaComponent:0.8]]; 13 [keyWindow makeKeyAndVisible]; 14 self.pwdWindow = keyWindow; 15 16 //将模糊后的image设置到UIImageView上展示，并可以在UIWindow上添加其他的控件 17 UIImageView *imageView = [[UIImageView alloc] initWithFrame:CGRectMake(0, 0, kScreenW , kScreenH)]; 18 imageView.image = image; 19 imageView.userInteractionEnabled = YES; 20 [self.pwdWindow addSubview:imageView]; 21 } 22 /** 23 * 把截屏照片传进去，进行模糊 24 * 该方法可以作为UIImageView的分类 25 **/ 26 + (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur { 27 //模糊度, 28 if ((blur < 0.1f) || (blur > 2.0f)) { 29 blur = 0.5f; 30 } 31 32 //boxSize必须大于0 33 int boxSize = (int)(blur * 100); 34 boxSize -= (boxSize % 2) + 1; 35 NSLog(@"boxSize:%i",boxSize); 36 //图像处理 37 CGImageRef img = image.CGImage; 38 //需要引入 39 /* 40 This document describes the Accelerate Framework, which contains C APIs for vector and matrix math, digital signal processing, large number handling, and image processing. 41 本文档介绍了Accelerate Framework，其中包含C语言应用程序接口（API）的向量和矩阵数学，数字信号处理，大量处理和图像处理。 42 */ 43 44 //图像缓存,输入缓存，输出缓存 45 vImage_Buffer inBuffer, outBuffer; 46 vImage_Error error; 47 //像素缓存 48 void *pixelBuffer; 49 //数据源提供者，Defines an opaque type that supplies Quartz with data. 50 CGDataProviderRef inProvider = CGImageGetDataProvider(img); 51 // provider’s data. 52 CFDataRef inBitmapData = CGDataProviderCopyData(inProvider); 53 //宽，高，字节/行，data 54 inBuffer.width = CGImageGetWidth(img); 55 inBuffer.height = CGImageGetHeight(img); 56 inBuffer.rowBytes = CGImageGetBytesPerRow(img); 57 inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData); 58 //像数缓存，字节行*图片高 59 pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img)); 60 outBuffer.data = pixelBuffer; 61 outBuffer.width = CGImageGetWidth(img); 62 outBuffer.height = CGImageGetHeight(img); 63 outBuffer.rowBytes = CGImageGetBytesPerRow(img); 64 // 第三个中间的缓存区,抗锯齿的效果 65 void *pixelBuffer2 = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img)); 66 vImage_Buffer outBuffer2; 67 outBuffer2.data = pixelBuffer2; 68 outBuffer2.width = CGImageGetWidth(img); 69 outBuffer2.height = CGImageGetHeight(img); 70 outBuffer2.rowBytes = CGImageGetBytesPerRow(img); 71 72 //Convolves a region of interest within an ARGB8888 source image by an implicit M x N kernel that has the effect of a box filter. 73 error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend); 74 // error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend); 75 error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend); 76 if (error) { 77 NSLog(@"error from convolution %ld", error); 78 } 79 // NSLog(@"字节组成部分：%zu",CGImageGetBitsPerComponent(img)); 80 //颜色空间DeviceRGB 81 CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); 82 //用图片创建上下文,CGImageGetBitsPerComponent(img),7,8 83 CGContextRef ctx = CGBitmapContextCreate( 84 outBuffer.data, 85 outBuffer.width, 86 outBuffer.height, 87 8, 88 outBuffer.rowBytes, 89 colorSpace, 90 CGImageGetBitmapInfo(image.CGImage)); 91 //根据上下文，处理过的图片，重新组件 92 CGImageRef imageRef = CGBitmapContextCreateImage (ctx); 93 UIImage *returnImage = [UIImage imageWithCGImage:imageRef]; 94 //clean up 95 CGContextRelease(ctx); 96 CGColorSpaceRelease(colorSpace); 97 free(pixelBuffer); 98 free(pixelBuffer2); 99 CFRelease(inBitmapData); 100 CGColorSpaceRelease(colorSpace); 101 CGImageRelease(imageRef); 102 return returnImage; 103 }
效果图：
