iphone中模糊图片的指定区域的实现

问答小助手 2013-01-11 01:23:40

加精

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 mark - 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 mark - 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 mark - 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 mark - 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;



@end

UIImage+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;

}



@end