弹性变化放大图片

//
//  ProfileViewController.m
//  TwProfile
//
//  Created by hunk on 4/30/13.
//  Copyright (c) 2013 mx.com.hunk. All rights reserved.
//
#import "ProfileViewController.h"
static CGFloat ImageHeight  = 150.0;
static CGFloat ImageWidth  = 320.0;
@interface ProfileViewController ()
@end
@implementation ProfileViewController
- (void)updateImg {
    CGFloat yOffset   = _tableView.contentOffset.y;
      
    if (yOffset < 0) {
          
        CGFloat factor = ((ABS(yOffset)+ImageHeight)*ImageWidth)/ImageHeight;
        CGRect f = CGRectMake(-(factor-ImageWidth)/2, 0, factor, ImageHeight+ABS(yOffset));
        self.imgProfile.frame = f;
    } else {
        CGRect f = self.imgProfile.frame;
        f.origin.y = -yOffset;
        self.imgProfile.frame = f;
    }
}
#pragma mark - Table View Delegate
- (void)scrollViewDidScroll:(UIScrollView *)scrollView {
    [self updateImg];
}
#pragma mark - Table View Datasource
- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return 2;
}
- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if (section == 0)
        return 1;
    else
        return 12;
      
}
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath {
    if (indexPath.section == 0)
        return ImageHeight;
    else
        return 44.0;
      
}
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    NSString *cellReuseIdentifier   = @"SectionTwoCell";
    NSString *windowReuseIdentifier = @"SectionOneCell";
      
    UITableViewCell *cell = nil;
      
    if (indexPath.section == 0) {
        cell = [tableView dequeueReusableCellWithIdentifier:windowReuseIdentifier];
        if (!cell) {
              
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:windowReuseIdentifier];
        }
    } else {
        cell = [tableView dequeueReusableCellWithIdentifier:cellReuseIdentifier];
        if (!cell) {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellReuseIdentifier];
            cell.contentView.backgroundColor = [UIColor lightGrayColor];
              
              
        }
        cell.textLabel.text = [ NSString stringWithFormat:@"cell %i",indexPath.row];
    }
      
    cell.selectionStyle              = UITableViewCellSelectionStyleNone;
      
    return cell;
}
- (id)init
{
    self = [super init];
    if (self) {
        // Custom initialization
          
        UIImage *p_w_picpath = [UIImage p_w_picpathNamed:@"bg.png"];
        self.imgProfile = [[UIImageView alloc] initWithImage:p_w_picpath];       
        self.imgProfile.frame             = CGRectMake(0, 0, ImageWidth, ImageHeight);
          
        self.tableView = [[UITableView alloc] init];
        self.tableView.dataSource = self;
        self.tableView.delegate = self;
        self.tableView.separatorStyle = UITableViewCellSeparatorStyleNone;
        self.tableView.backgroundColor = [UIColor clearColor];
        [self.view addSubview:self.imgProfile];
        [self.view addSubview:self.tableView];
          
        self.title = @"with UITableView";
    }
    return self;
}
#pragma mark - View lifecycle
- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
      
    CGRect bounds = self.view.bounds;
    _tableView.frame = bounds;
}
- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view.
}
- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
@end