Question

我想拍摄iPhone屏幕的特定部分。我使用了UIGraphicsBeginImageContextWithOptions，但无法使用此功能捕获部分屏幕。请帮帮我。

Answer 1

您可以使用此代码

UIGraphicsBeginImageContext(self.view.bounds.size);

[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

CGRect rect = CGRectMake(250,61 ,410, 255);
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);

UIImage *img = [UIImage imageWithCGImage:imageRef]; 

UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil); 

CGImageRelease(imageRef);

Answer 2

您可以使用UIGraphicsGetImageFromCurrentContext进行截屏。从内存中写下面的代码，因此可能出错。请自行纠正。

- (UIImage*)captureView:(UIView *)yourView {
    CGRect rect = [[UIScreen mainScreen] bounds];
    UIGraphicsBeginImageContext(rect.size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    [yourView.layer renderInContext:context];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

Answer 3

这是UIView上的快速扩展，可以捕获整个视图或视图中的帧。它考虑了屏幕比例。

extension UIView {

    func imageSnapshot() -> UIImage {
        return self.imageSnapshotCroppedToFrame(nil)
    }

    func imageSnapshotCroppedToFrame(frame: CGRect?) -> UIImage {
        let scaleFactor = UIScreen.mainScreen().scale
        UIGraphicsBeginImageContextWithOptions(bounds.size, false, scaleFactor)
        self.drawViewHierarchyInRect(bounds, afterScreenUpdates: true)
        var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()
        UIGraphicsEndImageContext()

        if let frame = frame {
            // UIImages are measured in points, but CGImages are measured in pixels
            let scaledRect = CGRectApplyAffineTransform(frame, CGAffineTransformMakeScale(scaleFactor, scaleFactor))

            if let imageRef = CGImageCreateWithImageInRect(image.CGImage, scaledRect) {
                image = UIImage(CGImage: imageRef)
            }
        }
        return image
    }
}

Answer 4

@Superdev的回答是正确的，如果你想要捕获父视图并避免子视图（特别是覆盖视图），我想要添加的是一个小技巧你可以做的是使这个子视图成为属性使用以下

CGFloat width = CGRectGetWidth(self.view.bounds);
CGFloat height = CGRectGetHeight(self.view.bounds);
_overlayView.hidden = YES;
UIGraphicsBeginImageContext(self.view.bounds.size);

[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

CGRect rect = CGRectMake(0,0 ,width, height);
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);

UIImage *img = [UIImage imageWithCGImage:imageRef];

UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil);

CGImageRelease(imageRef);

_overlayView.hidden = NO;

这是一个小技巧，希望有人会发现它很有用

Answer 5

捕获清晰屏幕截图的另一种方法;

if ([[UIScreen mainScreen] respondsToSelector:@selector(scale)])
            UIGraphicsBeginImageContextWithOptions(self.captureView.frame.size, NO, [UIScreen mainScreen].scale);
        else
            UIGraphicsBeginImageContext(self.captureView.frame.size);

        [self.captureView.layer renderInContext:UIGraphicsGetCurrentContext()];
        UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
        [viewImage drawInRect:CGRectMake(0.0, 0.0, 640,960)];
        //NSData*m_Imgdata=UIImagePNGRepresentation(viewImage);
        NSData*m_Imgdata=UIImageJPEGRepresentation(viewImage, 1.0);

       // UIImageWriteToSavedPhotosAlbum(viewImage, nil, nil, nil);

        UIGraphicsEndImageContext();

Answer 6

SWIFT 3.0 Xcode8版本 来自@jDutton回答并为我工作。

extension UIView {
    func imageSnapshot() -> UIImage {
        return self.imageSnapshotCroppedToFrame(frame: nil)
    }

    func imageSnapshotCroppedToFrame(frame: CGRect?) -> UIImage {
        let scaleFactor = UIScreen.main.scale
        UIGraphicsBeginImageContextWithOptions(bounds.size, false, scaleFactor)
        self.drawHierarchy(in: bounds, afterScreenUpdates: true)
        var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
        UIGraphicsEndImageContext()

        if let frame = frame {
            // UIImages are measured in points, but CGImages are measured in pixels
            let scaledRect = frame.applying(CGAffineTransform(scaleX: scaleFactor, y: scaleFactor))

            if let imageRef = image.cgImage!.cropping(to: scaledRect) {
                image = UIImage(cgImage: imageRef)
            }
        }
        return image
    }
}

如果您崩溃并收到以下消息：

GContextSaveGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.
CGContextRestoreGState: invalid context 0x0. If you want to see the backtrace, please set CG_CONTEXT_SHOW_BACKTRACE environmental variable.

试试这个solution

希望节省您的时间！

ios如何捕获屏幕的特定部分

6 个答案: