ios - 如何在该 View 内为图像设置动画时捕获 UIView 快照

Question

一个 UIView包含动画图像 (UIImage)。

我想使用 renderInContext:UIGraphicsGetCurrentContext 在循环中截取父 View 的屏幕截图

在捕获父 View (previewContainer) 的屏幕截图时，它不会将图像捕获为动画。

每次只捕获 View 中图像的最后一个位置(将显示在 thmbView 中)。

捕获代码

- (void) startCapturing{

UIGraphicsBeginImageContext(previewContainer.frame.size);
[previewContainer.layer renderInContext:UIGraphicsGetCurrentContext()];
thmb.image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();


double delayInSeconds = 0.2;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
    if (sec++ < 15) {
    [self startCapturing];
    }
});}

动画代码

- (void) animate{
    CABasicAnimation * appearance =[CABasicAnimation animationWithKeyPath:@"transform.translation.y"];
    [appearance setValue:@"animation1" forKey:@"id"];
    appearance.delegate = self;
    [UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:)];
    appearance.duration = 10;
    appearance.fromValue = [NSNumber numberWithFloat:0];
    appearance.toValue = [NSNumber numberWithFloat:340];
    appearance.repeatCount = 1;
    appearance.fillMode = kCAFillModeForwards;
    appearance.removedOnCompletion = NO;
    [imgPreview.layer addAnimation:appearance forKey:@"transform.translation.y"];

}

Answer 1

在可以渲染表示层的 View 中截取动画的唯一方法。

而不是这条线

[previewContainer.layer renderInContext:UIGraphicsGetCurrentContext()];

用这个

[previewContainer.layer.presentationLayer renderInContext:UIGraphicsGetCurrentContext()];