将平移限制为Silverlight MultiScaleImage中的可见图像区域

Question

Silverlight专家在外面，我需要帮助。我使用Deep Zoom Composer为一个客户端生成了一个大地图图像(20MB+)的Silverlight应用程序。但是客户端不希望用户平移到MultiScaleImage中图像边界之外的黑色区域。我该怎么做呢？谢谢!

Answer 1

我找到了解决这个问题的小方法。当ViewPortChanged事件触发时，我将新更改的MultiScaleImage的ViewportOrigin传递给下面的方法。问题是视图端口是异步更改的，用户实际上可以看到图像被移回它的边界。

public void SetViewportOrigin(Point point)
    {
        Point bottomRight = ZoomImage.ElementToLogicalPoint(new Point(ZoomImage.ActualWidth / ZoomImage.ViewportWidth - ZoomImage.ActualWidth, ZoomImage.ActualWidth / (ZoomImage.ViewportWidth * 1.33184438 /*ZoomImage.AspectRatio*/) - ZoomImage.ActualHeight));
        bottomRight.X -= ZoomImage.ViewportOrigin.X;
        bottomRight.Y -= ZoomImage.ViewportOrigin.Y;

        if (point.X < 0)
        { //left edge
            point.X = 0;
            Debug.WriteLine("left edge");
        }
        else if (point.X > bottomRight.X)
        {//right edge
            point.X = bottomRight.X;
            Debug.WriteLine("right edge");
        }

        if (point.Y > 1.0)
        {//bottom edge

            point.Y = 1.0;
            Debug.WriteLine("bottom edge1");
        }

        if (point.Y < 0)
        {//top edge
            point.Y = 0;
            Debug.WriteLine("top edge");
        }
        else if (point.Y > bottomRight.Y) //bottom edge
        {
            point.Y = bottomRight.Y;
        }

        ZoomImage.ViewportOrigin = point;
    }