iphone中模糊图片的指定区域的实现

在iOS开发中会遇到模糊图片的，这里给大家介绍一个可以模糊掉图片指定区域的防范，原文：http://ask.csdn.net/questions/1002 更多解决方案也请看上边链接
设置UIImageView的属性名字为：imageView，然后同一序列添加下面四个方法到实现文件中，然后设置ImageViewMode为Redraw，添加模糊效果的UIImage自定义或默认类，就OK了。method 1 - 剪裁图片
#pragma  - Croping the Image - (UIImage *)croppIngimageByImageName:(UIImage *)imageToCrop toRect:(CGRect)rect{    CGImageRef imageRef = CGImageCreateWithImageInRect([imageToCrop CGImage], rect);    
    UIImage *cropped = [UIImage imageWithCGImage:imageRef];
    CGImageRelease(imageRef);    return cropped;   
}
Method 2 -#pragma  - Marge two Images - (UIImage *) addImageToImage:(UIImage *)img withImage2:(UIImage *)img2 andRect:(CGRect)cropRect{    CGSize size = CGSizeMake(imageView.image.size.width, imageView.image.size.height);
    UIGraphicsBeginImageContext(size);    CGPoint pointImg1 = CGPointMake(0,0);
    [img drawAtPoint:pointImg1];     CGPoint pointImg2 = cropRect.origin;
    [img2 drawAtPoint: pointImg2];    UIImage* result = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();    return result;
}
Method 3 - 圆角矩形#pragma  - RoundRect the Image- (UIImage *)roundedRectImageFromImage:(UIImage *)image withRadious:(CGFloat)radious {    if(radious == 0.0f)
        return image;    if( image != nil) {        CGFloat imageWidth = image.size.width;
        CGFloat imageHeight = image.size.height;        CGRect rect = CGRectMake(0.0f, 0.0f, imageWidth, imageHeight);
        UIWindow *window = [[[UIApplication sharedApplication] windows] objectAtIndex:0];
        const CGFloat scale = window.screen.scale;
        UIGraphicsBeginImageContextWithOptions(rect.size, NO, scale);        CGContextRef context = UIGraphicsGetCurrentContext();        CGContextBeginPath(context);
        CGContextSaveGState(context);
        CGContextTranslateCTM (context, CGRectGetMinX(rect), CGRectGetMinY(rect));
        CGContextScaleCTM (context, radious, radious);        CGFloat rectWidth = CGRectGetWidth (rect)/radious;
        CGFloat rectHeight = CGRectGetHeight (rect)/radious;        CGContextMoveToPoint(context, rectWidth, rectHeight/2.0f);
        CGContextAddArcToPoint(context, rectWidth, rectHeight, rectWidth/2.0f, rectHeight, radious);
        CGContextAddArcToPoint(context, 0.0f, rectHeight, 0.0f, rectHeight/2.0f, radious);
        CGContextAddArcToPoint(context, 0.0f, 0.0f, rectWidth/2.0f, 0.0f, radious);
        CGContextAddArcToPoint(context, rectWidth, 0.0f, rectWidth, rectHeight/2.0f, radious);
        CGContextRestoreGState(context);
        CGContextClosePath(context);
        CGContextClip(context);        [image drawInRect:CGRectMake(0.0f, 0.0f, imageWidth, imageHeight)];        UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();        return newImage;
    } 
    return nil;
}
Method 4 -触摸移动#pragma  - Touch Methods- (void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event {
    UIImage *croppedImg = nil;    UITouch *touch = [touches anyObject];
    CGPoint currentPoint = [touch locationInView:self.imageView];    double ratioW=imageView.image.size.width/imageView.frame.size.width ;    double ratioH=imageView.image.size.height/imageView.frame.size.height;    currentPoint.x *= ratioW;
    currentPoint.y *= ratioH;    double circleSizeW = 30 * ratioW;
    double circleSizeH = 30 * ratioH;
    currentPoint.x = (currentPoint.x - circleSizeW/2<0)? 0 : currentPoint.x - circleSizeW/2;
    currentPoint.y = (currentPoint.y - circleSizeH/2<0)? 0 : currentPoint.y - circleSizeH/2;
    CGRect cropRect = CGRectMake(currentPoint.x , currentPoint.y,   circleSizeW,  circleSizeH);    NSLog(@"x %0.0f, y %0.0f, width %0.0f, height %0.0f", cropRect.origin.x, cropRect.origin.y,   cropRect.size.width,  cropRect.size.height );    croppedImg = [self croppIngimageByImageName:self.imageView.image toRect:cropRect];    // Blur Effect 
    croppedImg = [croppedImg imageWithGaussianBlur9];    // Contrast Effect 
    // croppedImg = [croppedImg imageWithContrast:50];    croppedImg = [self roundedRectImageFromImage:croppedImg withRadious:4];     imageView.image = [self addImageToImage:imageView.image withImage2:croppedImg andRect:cropRect];  
} 
UIImage Category类UIImage+ImageBlur.h
#import <UIKit/UIKit.h>@interface UIImage (ImageBlur)- (UIImage *)imageWithGaussianBlur9;@endUIImage+ImageBlur.m
#import "UIImage+ImageBlur.h"@implementation UIImage (ImageBlur)- (UIImage *)imageWithGaussianBlur9 {
    float weight[5] = {0.1270270270, 0.1945945946, 0.1216216216, 0.0540540541, 0.0162162162};
    // Blur horizontally
    UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
    [self drawInRect:CGRectMake(0, 0, self.size.width, self.size.height) blendMode:kCGBlendModeNormal alpha:weight[0]];
    for (int x = 1; x < 5; ++x) {
        [self drawInRect:CGRectMake(x, 0, self.size.width, self.size.height) blendMode:kCGBlendModeNormal alpha:weight[x]];
        [self drawInRect:CGRectMake(-x, 0, self.size.width, self.size.height) blendMode:kCGBlendModeNormal alpha:weight[x]];
    }
    UIImage *horizBlurredImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    // Blur vertically
    UIGraphicsBeginImageContextWithOptions(self.size, NO, self.scale);
    [horizBlurredImage drawInRect:CGRectMake(0, 0, self.size.width, self.size.height) blendMode:kCGBlendModeNormal alpha:weight[0]];
    for (int y = 1; y < 5; ++y) {
        [horizBlurredImage drawInRect:CGRectMake(0, y, self.size.width, self.size.height) blendMode:kCGBlendModeNormal alpha:weight[y]];
        [horizBlurredImage drawInRect:CGRectMake(0, -y, self.size.width, self.size.height) blendMode:kCGBlendModeNormal alpha:weight[y]];
    }
    UIImage *blurredImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    //
    return blurredImage;
}@endiphoneios