ios - 拍摄 AGSMapView 的快照

Question

使用以下代码拍摄 AGSMapView 的快照

此代码将设置 kEAGLDrawablePropertyRetainedBacking 属性，这是必需的，否则它将拍摄白色快照。

let layer =  self.AgsMapView.layer as! CAEAGLLayer
        layer.drawableProperties = [
            kEAGLDrawablePropertyRetainedBacking: NSNumber(int: 1),                                      kEAGLDrawablePropertyColorFormat: kEAGLColorFormatRGBA8]

拍摄快照的代码

func snapshotForEAGLView() -> UIImage {

        //glFlush()
        var width: GLint = 0, height: GLint = 0
        let scale: CGFloat = UIScreen.mainScreen().scale
        let prevGLContext = EAGLContext.currentContext()
glGetRenderbufferParameteriv(GLenum(GL_RENDERBUFFER), GLenum(GL_RENDERBUFFER_WIDTH), &width)
        glGetRenderbufferParameteriv(GLenum(GL_RENDERBUFFER), GLenum(GL_RENDERBUFFER_HEIGHT), &height)

        let dataLength = width * height * 4
        let imageBytes = UnsafeMutablePointer<GLubyte>.alloc(Int(dataLength))

        glPixelStorei(GLenum(GL_PACK_ALIGNMENT), 4)

        glReadPixels(0, 0, GLsizei(width), GLsizei(height), GLenum(GL_RGBA), GLenum(GL_UNSIGNED_BYTE), imageBytes)

        let dataProvider = CGDataProviderCreateWithData(nil, imageBytes, Int(dataLength), nil)

        EAGLContext.setCurrentContext(prevGLContext)

        let colorSpace = CGColorSpaceCreateDeviceRGB()
        if let imageRef = CGImageCreate(Int(width), Int(height), 8, 32, Int(width) * 4, colorSpace, [CGBitmapInfo.ByteOrder32Big, CGBitmapInfo(rawValue: CGImageAlphaInfo.PremultipliedLast.rawValue)], dataProvider, nil, true, CGColorRenderingIntent.RenderingIntentDefault) {
            return UIImage(CGImage: imageRef, scale: scale, orientation: .DownMirrored)
        }
        return UIImage()
    }

在应用程序中，我们在两个 Controller 上有 AGSMapView，比如说 Controller1 和 Controller2，点击 Controller1 上的按钮code>，Controller2 被推送。

我们正在 Controller2 上截屏，但有时它会从 Controller1 截取 AGSMapView 的屏幕截图

它是随机发生的，我们是否可以提供要截取屏幕截图的 View 或任何其他方法来避免这种情况。

非常感谢任何帮助。

Answer 1

drawViewHierarchyInRect

成功了，谢谢大家

    let size = CGSizeMake(viewWidth, viewHeight)

    UIGraphicsBeginImageContextWithOptions(size, false, UIScreen.mainScreen().scale)

    let rec = CGRectMake(0, 0, viewWidth, viewHeight)
    self.agsMapView.drawViewHierarchyInRect(rec, afterScreenUpdates: true)

    let image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;