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第三期博客（SafeKit，混淆，m34）

CATransform3D 的 m34 属性

m34的默认值是0，我们可以通过设置m34为-1.0 / d来应用透视效果，d代表了想象中视角相机和屏幕之间的距离，以像素为单位

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#import "ViewController.h"
#import <QuartzCore/QuartzCore.h>
#define WIDTH 10
#define HEIGHT 10
#define DEPTH 10
#define SIZE 100
#define SPACING 150
#define CAMERA_DISTANCE 500
@interface ViewController ()

@property (nonatomic, strong) IBOutlet UIScrollView *scrollView;
@end
@implementation ViewController
- (void)viewDidLoad
{
    [super viewDidLoad];
    self.scrollView.contentSize = CGSizeMake((WIDTH - 1)*SPACING, (HEIGHT - 1)*SPACING);
    CATransform3D transform = CATransform3DIdentity;
    transform.m34 = -1.0 / CAMERA_DISTANCE;
    self.scrollView.layer.sublayerTransform = transform;
    for (int z = DEPTH - 1; z >= 0; z--) {
        for (int y = 0; y < HEIGHT; y++) {
            for (int x = 0; x < WIDTH; x++) {
                //create layer
                CALayer *layer = [CALayer layer];
                layer.frame = CGRectMake(0, 0, SIZE, SIZE);
                layer.position = CGPointMake(x*SPACING, y*SPACING);
                layer.zPosition = -z*SPACING;
                //set background color
                layer.backgroundColor = [UIColor colorWithWhite:1-z*(1.0/DEPTH) alpha:1].CGColor;
                //attach to scroll view
                [self.scrollView.layer addSublayer:layer];
            }
        }
    }
}
@end

m34的运用例子: XYDebugView

详情查看

SafeKit 及其他 by Joliy

CLSafeKit 具体见:README.md