ios - IOS 7 截图调整

Question

我正在尝试为 iOS 7 创建屏幕截图调整，但我能保存的只是一张空白图像。这是我的代码：

UIView *screenshotView = [[UIScreen mainScreen] snapshotViewAfterScreenUpdates:NO];
        UIGraphicsBeginImageContext(screenshotView.bounds.size);
        [[screenshotView layer] renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
        UIGraphicsEndImageContext();

[UIImageJPEGRepresentation(image, 1.0) writeToFile:fname atomically:YES];

有没有人有办法解决吗？

谢谢你

Answer 1

出于兼容性原因，我仍未使用snapshotViewAfterScreenUpdates，但以下代码有效。试试看。

UIGraphicsBeginImageContextWithOptions(size, myView.opaque, 2.0);
[myView.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *theImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
// do something with theImage

Answer 2

在 UIImageView 上设置输出

- (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;
}

Answer 3

看来您不应该使用snapshotViewAfterScreenUpdates来渲染图像（请参阅raywenderlich 论坛），drawViewHierarchyInRect而是：

UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, 0.0f);
[self.view drawViewHierarchyInRect:self.view.frame afterScreenUpdates:NO];
UIImage *snapshotImage = UIGraphicsGetImageFromCurrentImageContext();