仿面包旅行个人中心下拉顶部背景放大高斯模糊效果

HeaderView.h

//

//  HeaderView.h

//  仿面包旅行个人中心

//

//  Created by [email protected] on 15/5/14.

//  Copyright (c) 2015年 wb145230. All rights reserved.

//



#import <UIKit/UIKit.h>



@interface HeaderView : UIView



@property(nonatomic, strong) UIScrollView *imageScrollView;

@property(nonatomic, strong) UIImageView *imageView;                //背景图片

@property(nonatomic, strong) UIImageView *imageBackgroundView;      //要改变的背景图片



/**

 *  改变顶部view的大小和高斯效果

 *

 *  @param offset scrollview滑动的记录

 */

-(void)updateHeaderView:(CGPoint) offset;



@end

 

HeaderView.m

//

//  HeaderView.m

//  仿面包旅行个人中心

//

//  Created by [email protected] on 15/5/14.

//  Copyright (c) 2015年 wb145230. All rights reserved.

//



#import "HeaderView.h"

#import <Accelerate/Accelerate.h>



@implementation HeaderView



- (instancetype)initWithFrame:(CGRect)frame {

    if (self = [super initWithFrame:frame]) {

        self.imageScrollView = [[UIScrollView alloc] initWithFrame:self.bounds];

        [self addSubview:self.imageScrollView];

        

        UIImage *image = [UIImage imageNamed:@"header_bg"];

        //高斯的背景图片

        self.imageBackgroundView = [[UIImageView alloc] initWithFrame:self.imageScrollView.bounds];

        [self setBlurryImage:image];

        self.imageBackgroundView.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;

        self.imageBackgroundView.contentMode = UIViewContentModeScaleAspectFill;

        [self.imageScrollView addSubview:self.imageBackgroundView];

        

        //原图

        self.imageView = [[UIImageView alloc] initWithFrame:self.imageScrollView.bounds];

        self.imageView.image = image;

        self.imageView.autoresizingMask = UIViewAutoresizingFlexibleLeftMargin | UIViewAutoresizingFlexibleRightMargin | UIViewAutoresizingFlexibleTopMargin | UIViewAutoresizingFlexibleBottomMargin | UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;

        self.imageView.contentMode = UIViewContentModeScaleAspectFill;

        [self.imageScrollView addSubview:self.imageView];

    }

    

    return self;

}



/**

 *  通过scrollview的滑动改变顶部view的大小和高斯效果

 *

 *  @param offset scrollview下滑的距离

 */

-(void)updateHeaderView:(CGPoint) offset {

    if (offset.y < 0) {

        CGRect rect = CGRectMake(0, 0, self.frame.size.width, self.frame.size.height);

        CGFloat delta = fabs(MIN(0.0f, offset.y));

        rect.origin.y -= delta;

        rect.size.height += delta;

        self.imageScrollView.frame = rect;

        self.clipsToBounds = NO;

        

        self.imageView.alpha = fabs(offset.y / (2 * CGRectGetHeight(self.bounds) / 3));

    }

}





/**

 *  高斯图片

 *

 *  @param originalImage 需要高斯的图片

 */

- (void)setBlurryImage:(UIImage *)originalImage {

    

    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{

        UIImage *blurredImage = [self blurryImage:originalImage withBlurLevel:0.9];

        

        dispatch_async(dispatch_get_main_queue(), ^{

            self.imageView.alpha = 0.0;

            self.imageBackgroundView.image = blurredImage;

        });

    });

    

}



/**

 *  高斯背景

 *

 *  @param image    需要高斯模糊的图片

 *  @param blur     高斯模糊的值

 *

 *  @return

 */

- (UIImage *)blurryImage:(UIImage *)image withBlurLevel:(CGFloat)blur {

    if ((blur < 0.0f) || (blur > 1.0f)) {

        blur = 0.5f;

    }

    

    int boxSize = (int)(blur * 100);

    boxSize -= (boxSize % 2) + 1;

    

    CGImageRef img = image.CGImage;

    

    vImage_Buffer inBuffer, outBuffer;

    vImage_Error error;

    void *pixelBuffer;

    

    CGDataProviderRef inProvider = CGImageGetDataProvider(img);

    CFDataRef inBitmapData = CGDataProviderCopyData(inProvider);

    

    inBuffer.width = CGImageGetWidth(img);

    inBuffer.height = CGImageGetHeight(img);

    inBuffer.rowBytes = CGImageGetBytesPerRow(img);

    inBuffer.data = (void*)CFDataGetBytePtr(inBitmapData);

    

    pixelBuffer = malloc(CGImageGetBytesPerRow(img) * CGImageGetHeight(img));

    

    outBuffer.data = pixelBuffer;

    outBuffer.width = CGImageGetWidth(img);

    outBuffer.height = CGImageGetHeight(img);

    outBuffer.rowBytes = CGImageGetBytesPerRow(img);

    

    error = vImageBoxConvolve_ARGB8888(&inBuffer, &outBuffer, NULL, 0, 0, boxSize, boxSize, NULL, kvImageEdgeExtend);

    

    

    if (error) {

        NSLog(@"error from convolution %ld", error);

    }

    

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceRGB();

    CGContextRef ctx = CGBitmapContextCreate(outBuffer.data, outBuffer.width, outBuffer.height, 8, outBuffer.rowBytes, colorSpace, CGImageGetBitmapInfo(image.CGImage));

    

    CGImageRef imageRef = CGBitmapContextCreateImage (ctx);

    UIImage *returnImage = [UIImage imageWithCGImage:imageRef];

    

    //clean up

    CGContextRelease(ctx);

    CGColorSpaceRelease(colorSpace);

    

    free(pixelBuffer);

    CFRelease(inBitmapData);

    

    CGColorSpaceRelease(colorSpace);

    CGImageRelease(imageRef);

    

    return returnImage;

}





@end

 

ViewController.h

//

//  ViewController.h

//  仿面包旅行个人中心

//

//  Created by [email protected] on 15/5/14.

//  Copyright (c) 2015年 wb145230. All rights reserved.

//



#import <UIKit/UIKit.h>

#import "HeaderView.h"



@interface ViewController : UIViewController<UITableViewDataSource, UITableViewDelegate>



@property(nonatomic, strong) UITableView *tableView;

@property(nonatomic, strong) HeaderView *headerView;



@end

 

ViewController.m

//

//  ViewController.m

//  仿面包旅行个人中心

//

//  Created by [email protected] on 15/5/14.

//  Copyright (c) 2015年 wb145230. All rights reserved.

//



#import "ViewController.h"



@interface ViewController ()



@end



@implementation ViewController



- (void)viewDidLoad {

    [super viewDidLoad];

    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent animated:YES];

    

    self.view.backgroundColor = [UIColor whiteColor];

    

    self.tableView = [[UITableView alloc] initWithFrame:self.view.bounds style:UITableViewStylePlain];

    self.tableView.dataSource = self;

    self.tableView.delegate = self;

    self.tableView.autoresizingMask = UIViewAutoresizingFlexibleHeight | UIViewAutoresizingFlexibleWidth;

    self.tableView.separatorColor = [UIColor clearColor];

    self.tableView.showsVerticalScrollIndicator = NO;

    

    self.headerView = [[HeaderView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, 250)];

    self.tableView.tableHeaderView = self.headerView;

    [self.view addSubview:self.tableView];

    

}



-(void)scrollViewDidScroll:(UIScrollView *)scrollView {

    [self.headerView updateHeaderView:scrollView.contentOffset];

}



-(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {

    return 10;

}



- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath{

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@"cell"];

    if (cell == nil) {

        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:@"cell"];

    }

    cell.selectionStyle = UITableViewCellSelectionStyleNone;

    return cell;

}



- (void)didReceiveMemoryWarning {

    [super didReceiveMemoryWarning];

}



@end

 

效果

 

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