在我的iPad应用程序中，我想制作一张UIView占据屏幕很大一部分的屏幕截图.不幸的是，子视图嵌套得很深，所以需要很长时间才能制作屏幕截图并在之后设置页面curl 的动画.
有没有比"通常"更快的方法？
UIGraphicsBeginImageContext(self.bounds.size);
[self.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *resultingImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
如果可能，我希望避免缓存或重新构建我的视图.
我已经找到了一种更好的方法，只要有可能就使用快照API.
我希望这会有帮助.
class func screenshot() -> UIImage {
var imageSize = CGSize.zero
let orientation = UIApplication.shared.statusBarOrientation
if UIInterfaceOrientationIsPortrait(orientation) {
imageSize = UIScreen.main.bounds.size
} else {
imageSize = CGSize(width: UIScreen.main.bounds.size.height, height: UIScreen.main.bounds.size.width)
}
UIGraphicsBeginImageContextWithOptions(imageSize, false, 0)
for window in UIApplication.shared.windows {
window.drawHierarchy(in: window.bounds, afterScreenUpdates: true)
}
let image = UIGraphicsGetImageFromCurrentImageContext()
UIGraphicsEndImageContext()
return image!
}
Wanna know more about iOS 7 Snapshots?
Objective-C版本:
+ (UIImage *)screenshot
{
CGSize imageSize = CGSizeZero;
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
if (UIInterfaceOrientationIsPortrait(orientation)) {
imageSize = [UIScreen mainScreen].bounds.size;
} else {
imageSize = CGSizeMake([UIScreen mainScreen].bounds.size.height, [UIScreen mainScreen].bounds.size.width);
}
UIGraphicsBeginImageContextWithOptions(imageSize, NO, 0);
CGContextRef context = UIGraphicsGetCurrentContext();
for (UIWindow *window in [[UIApplication sharedApplication] windows]) {
CGContextSaveGState(context);
CGContextTranslateCTM(context, window.center.x, window.center.y);
CGContextConcatCTM(context, window.transform);
CGContextTranslateCTM(context, -window.bounds.size.width * window.layer.anchorPoint.x, -window.bounds.size.height * window.layer.anchorPoint.y);
if (orientation == UIInterfaceOrientationLandscapeLeft) {
CGContextRotateCTM(context, M_PI_2);
CGContextTranslateCTM(context, 0, -imageSize.width);
} else if (orientation == UIInterfaceOrientationLandscapeRight) {
CGContextRotateCTM(context, -M_PI_2);
CGContextTranslateCTM(context, -imageSize.height, 0);
} else if (orientation == UIInterfaceOrientationPortraitUpsideDown) {
CGContextRotateCTM(context, M_PI);
CGContextTranslateCTM(context, -imageSize.width, -imageSize.height);
}
if ([window respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)]) {
[window drawViewHierarchyInRect:window.bounds afterScreenUpdates:YES];
} else {
[window.layer renderInContext:context];
}
CGContextRestoreGState(context);
}
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}