标签:des style blog http io ar color sp for
废话不多说,先来看看没有蒙版的效果 ,再来看看有蒙版的效果
,明显可以看出有明显的区别。
先说说实现的的思路:
当程序即将进入后台时,把当前屏幕截个图,此时要将图片毛玻璃化,并作为UIImageView的image,然后将imageView放在window的最上面,等即将进入前台时移除毛玻璃蒙版。
下面就来说代码实现吧(在代理文件中实现):
@interface AppDelegate () @property (nonatomic, weak)UIImageView *cover; @end
主要代码:
- (void)applicationDidEnterBackground:(UIApplication *)application { UIImageView *imgView = [[UIImageView alloc] initWithFrame:[UIApplication sharedApplication].keyWindow.bounds]; self.cover = imgView; [[UIApplication sharedApplication].keyWindow addSubview:imgView]; UIGraphicsBeginImageContext([UIApplication sharedApplication].keyWindow.size); // 将当前layer的截图写进上下中 [[UIApplication sharedApplication].keyWindow.layer renderInContext:UIGraphicsGetCurrentContext()]; // 从上下中读取图片 UIImage *image = UIGraphicsGetImageFromCurrentImageContext(); // 压缩图片,并转成JPEG类型 NSData *imageData = UIImageJPEGRepresentation(image, 0.01); image = [UIImage imageWithData:imageData]; // 注意:不能直接将图片毛玻璃化,要转成data后,再转成image,此时的image才能毛玻璃化,不然调用blurryImage:withBlurLevel会报错。 imgView.image = [UIImage blurryImage:image withBlurLevel:0.15]; } - (void)applicationDidBecomeActive:(UIApplication *)application { [self.cover removeFromSuperview]; }
//下面代码是 blurryImage:withBlurLeve方法l的具体实现,我将它写成了UIImage的分类,所以可以直接用UIImage调用。
//加模糊效果,image是图片,blur是模糊度 + (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur { //模糊度, if ((blur < 0.1f) || (blur > 2.0f)) { blur = 0.5f; } //boxSize必须大于0 int boxSize = (int)(blur * 100); boxSize -= (boxSize % 2) + 1; NSLog(@"boxSize:%i",boxSize); //图像处理 CGImageRef img = image.CGImage; //需要引入#import <Accelerate/Accelerate.h> /* This document describes the Accelerate Framework, which contains C APIs for vector and matrix math, digital signal processing, large number handling, and image processing. 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。 */ //图像缓存,输入缓存,输出缓存 vImage_Buffer inBuffer, outBuffer; vImage_Error error; //像素缓存 void *pixelBuffer; //数据源提供者,Defines an opaque type that supplies Quartz with data. CGDataProviderRef inProvider = CGImageGetDataProvider(img); // provider’s data. CFDataRef inBitmapData = CGDataProviderCopyData(inProvider); //宽,高,字节/行,data inBuffer.width = CGImageGetWidth(img); inBuffer.height = CGImageGetHeight(img); inBuffer.rowBytes = CGImageGetBytesPerRow(img); inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData); //像数缓存,字节行*图片高 pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img)); outBuffer.data = pixelBuffer; outBuffer.width = CGImageGetWidth(img); outBuffer.height = CGImageGetHeight(img); outBuffer.rowBytes = CGImageGetBytesPerRow(img); // 第三个中间的缓存区,抗锯齿的效果 void *pixelBuffer2 = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img)); vImage_Buffer outBuffer2; outBuffer2.data = pixelBuffer2; outBuffer2.width = CGImageGetWidth(img); outBuffer2.height = CGImageGetHeight(img); outBuffer2.rowBytes = CGImageGetBytesPerRow(img); //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. error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer2, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend); error = vImageBoxConvolve_ARGB8888(&outBuffer2, &inBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend); error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend); if (error) { NSLog(@"error from convolution %ld", error); } // NSLog(@"字节组成部分:%zu",CGImageGetBitsPerComponent(img)); //颜色空间DeviceRGB CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB(); //用图片创建上下文,CGImageGetBitsPerComponent(img),7,8 CGContextRef ctx = CGBitmapContextCreate( outBuffer.data, outBuffer.width, outBuffer.height, 8, outBuffer.rowBytes, colorSpace, CGImageGetBitmapInfo(image.CGImage)); //根据上下文,处理过的图片,重新组件 CGImageRef imageRef = CGBitmapContextCreateImage (ctx); UIImage *returnImage = [UIImage imageWithCGImage:imageRef]; //clean up CGContextRelease(ctx); CGColorSpaceRelease(colorSpace); free(pixelBuffer); free(pixelBuffer2); CFRelease(inBitmapData); CGColorSpaceRelease(colorSpace); CGImageRelease(imageRef); return returnImage; }
Code4App里有详细的Demo:http://code4app.com/member/53908169933bf0c8238b4d43
标签:des style blog http io ar color sp for
原文地址:http://www.cnblogs.com/Fc-ios/p/4153401.html