问题描述

iphone中模糊图片的指定区域

在iPhone中怎么样模糊图片的指定区域？我在网上找到的都是模糊整个图片的方法，有没有只模糊指定区域（圆形，方形）的方法？谢谢。

解决方案

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

解决方案二：

把下面的Pangesture添加到view或者imageview中：

UIPanGestureRecognizer *panGesture=[[UIPanGestureRecognizer alloc]initWithTarget:self action:@selector(imageTaped:)];
[panGesture setMaximumNumberOfTouches:1];
[self.view addGestureRecognizer:panGesture];

模糊图片的方法

- (void)imageTaped:(UIPanGestureRecognizer *)gestureRecognizer
{

    CIContext *context = [CIContext contextWithOptions:nil];
    CGPoint touchLocation = [gestureRecognizer locationInView:self.imgviewMain];

    CGRect temp=CGRectMake(touchLocation.x-25, ((self.imgviewMain.frame.size.height-50) - touchLocation.y)+25, 50, 50);

    CIImage *inputImage0 = [[CIImage alloc] initWithImage:self.imgviewMain.image];

    CIImage *inputImage = [[CIImage alloc] initWithImage:[UIImage imageWithCGImage:[context createCGImage:inputImage0 fromRect:temp]]];
    CIFilter *blurFilter = [CIFilter filterWithName:@"CIGaussianBlur"];
    [blurFilter setDefaults];
    [blurFilter setValue: inputImage forKey: @"inputImage"];
    [blurFilter setValue: [NSNumber numberWithFloat:0.1]
                  forKey:@"inputRadius"];

    CIImage *outputImage = [blurFilter valueForKey: @"outputImage"];
    UIImageView *imgtest=[[UIImageView alloc]init];

    imgtest.image=[UIImage imageWithCGImage:[context createCGImage:outputImage fromRect:outputImage.extent]];

    UIImage *image;

    UIImage *bottomImage = self.imgviewMain.image;
          image = imgtest.image;    

    CGSize newSize = CGSizeMake(self.imgviewMain.frame.size.width, self.imgviewMain.frame.size.height);
    UIGraphicsBeginImageContext( newSize );

    [bottomImage drawInRect:CGRectMake(0,0,768,1024)];

    CGRect newRect2=CGRectMake(temp.origin.x,((self.imgviewMain.frame.size.height-50) - temp.origin.y), image.size.width, image.size.height);
    image=[self makeRoundedImage:image radius:10];

    [image drawInRect:newRect2 blendMode:kCGBlendModeNormal alpha:0.5];
     UIImage *newImage = UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    self.imgviewMain.image=newImage;
   }
RoundedImage Method

-(UIImage *)makeRoundedImage:(UIImage *) image
                      radius: (float) radius;
{
    CALayer *imageLayer = [CALayer layer];
    imageLayer.frame = CGRectMake(0, 0, image.size.width, image.size.height);
    imageLayer.contents = (id) image.CGImage;

    imageLayer.masksToBounds = YES;
    imageLayer.cornerRadius = radius;

    UIGraphicsBeginImageContext(image.size);
    [imageLayer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *roundedImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    return roundedImage;
}