写真をタッチすると、
たくさんの小さな写真に分裂、
フォトモザイク（？）のできあがり。
というiPhoneアプリのサンプルを作ってみました。
ポイント
UIGraphicsImageContextを使って、小さな写真にする部分の
画像をUIImageとして抜き出しています。
サンプルコード
#import “ViewController.h”
#import <QuartzCore/QuartzCore.h>
@interface ViewController () {
UIImageView *photo;
}
@end
@implementation ViewController
– (void)viewDidLoad
{
[super viewDidLoad];
self.view.backgroundColor = [UIColor blackColor];
[self loadImage];
}
– (void)loadImage
{
UIImage *img = [UIImage imageNamed:@”image”];
photo = [[UIImageView alloc] initWithImage:img];
photo.contentMode = UIViewContentModeScaleAspectFit;
photo.frame = self.view.bounds;
photo.backgroundColor = [UIColor blackColor];
[self.view addSubview:photo];
}
– (void)randomCutting
{
for (int i = 0; i<36; i++) {
float x = (i%6) * 40 + (arc4random() % 30) + 20;
float y = (i/6) * 40 + (arc4random() % 30) + 140;
float size = (arc4random() % 20) + 40;
CGRect rect = CGRectMake(x, y, size, size);
float angle = (arc4random() % 10) * M_PI * 0.01;
UIImage *img = [self cutImage:rect angle:angle];
UIImageView *cutimg = [[UIImageView alloc] initWithImage:img];
cutimg.frame = rect;
cutimg.layer.borderWidth = 2;
cutimg.layer.borderColor = [UIColor whiteColor].CGColor;
cutimg.layer.shadowColor = [UIColor whiteColor].CGColor;
cutimg.layer.shadowOffset = CGSizeMake(1, 1);
cutimg.layer.shadowRadius = 3;
cutimg.layer.shadowOpacity = 0.8;
[self.view addSubview:cutimg];
cutimg.userInteractionEnabled = YES;
cutimg.transform = CGAffineTransformMakeScale(0, 0);
[UIView animateWithDuration:0.1 delay:i*0.01 options:UIViewAnimationOptionCurveEaseIn animations:^{
cutimg.transform = CGAffineTransformMakeRotation(angle);
} completion:^(BOOL finished) {}];
}
}
– (UIImage*)cutImage:(CGRect)frame angle:(float)angle
{
UIGraphicsBeginImageContext(frame.size);
CGContextRef ctx = UIGraphicsGetCurrentContext();
CGContextRotateCTM(ctx, -angle);
CGContextTranslateCTM(ctx, -frame.origin.x, -frame.origin.y);
[photo.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *outputImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return outputImage;
}
– (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
static BOOL flag = YES;
if (flag) {
flag = NO;
[self randomCutting];
[UIView animateWithDuration:1.0 animations:^{
photo.alpha = 0.0;
}];
} else {
photo.alpha = 1;
for (UIView *v in self.view.subviews) {
if (v != photo) {
[v removeFromSuperview];
}
}
flag = YES;
}
}
– (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}
@end