控件开发六

目标：

-DeepZoom基本知识

-DeepZoomComposer工具

-MultiScaleImage控件

一．DeepZoom基本知识

-源于遥感影像的金字塔显示方式

-提供了与高分辨率图像进行交互的能力

-可以快速缩放图像而不影响应用的性能

-加载或平移图像时可以光滑过渡

-spring animations

应用

-高分辨率、极大图像的浏览；3D合成图像；广告。

分类

-Single Collection

二．DeepZoom Composer

-制件DeepZoom图片工具，http://www.microsoft.com/downloads/en/details.aspx?familyid=457b17b7-52bf-4bda-87a3-fa8a4673f8bf

三．MultiScaleImage控件

-打开、放大和平移多分辨率图片

-快速任意缩放展示大图形、高分辨率图像的应用程序

属性：

-Source – Web Uri

-UserSprings – springs animations

-ViewportOrigin - CenterPoint

-ViewportWidth – ZoomLevel

事件：

-ImageFailed

-ImageOpenFailed

-ImageOpenSucceeded

使用

Demo:

public partial class MainPage : PhoneApplicationPage
    {
        private double zoom = 1;
        private bool isMoving = false;
        private bool isDown = false;
        private Point lastMouseDownPos = new Point();
        private Point lastMousePos = new Point();
        private Point lastMouseViewPort = new Point();
        // Constructor
        public MainPage()
        {
            InitializeComponent();
        }

        private void MultiScaleImage_ImageOpenSucceeded(object sender, RoutedEventArgs e)
        {
            msi.ViewportOrigin = new Point(0,0);
            msi.ViewportWidth = 1;
        }

        private void PhoneApplicationPage_MouseLeftButtonDown(object sender, MouseButtonEventArgs e)
        {
            lastMouseDownPos = e.GetPosition(msi);
            lastMouseViewPort = msi.ViewportOrigin;
            isDown = true;
            msi.CaptureMouse();
        }

        private void PhoneApplicationPage_MouseMove(object sender, MouseEventArgs e)
        {
            lastMousePos = e.GetPosition(msi);
            if(isDown && !isMoving)
            {
                isMoving = true;
                double w =msi.ViewportWidth;
                Point p = new Point(msi.ViewportOrigin.X,msi.ViewportOrigin.Y);
                msi.UseSprings =false;
                msi.ViewportOrigin = new Point(p.X,p.Y);
                msi.ViewportWidth = w;
                zoom = 1/w;
                msi.UseSprings = true;
            }
            if(isMoving)
            {
                Point point = lastMouseViewPort;
                point.X = (lastMouseDownPos.X - lastMousePos.X)/msi.ActualWidth*msi.ViewportWidth;
                point.Y = (lastMouseDownPos.Y -lastMousePos.Y)/msi.ActualWidth*msi.ViewportWidth;
                msi.ViewportOrigin = point;
            }
        }

        private void PhoneApplicationPage_MouseLeave(object sender, MouseEventArgs e)
        {
            if (isMoving)
            {
                bool isShift = (Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift;
                double newzoom = zoom;
                if (isShift)
                    newzoom /= 2;
                else
                    newzoom *= 2;
                Zoom(newzoom, msi.ElementToLogicalPoint(this.lastMousePos));
            }

            isMoving = false;
            isDown = false;
            msi.ReleaseMouseCapture();
        }

        private void Zoom(double zoomnew, Point p)
        {
            if (zoomnew < 0.5)
            {
                zoomnew = 0.5;
            }
            msi.ZoomAboutLogicalPoint(zoomnew / zoom, p.X, p.Y);
            zoom = zoomnew;
        }

        private void PhoneApplicationPage_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
        {

        }

        /// <summary>
        /// 放大
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ApplicationBarIconButton_Click(object sender, EventArgs e)
        {
            msi.ZoomAboutLogicalPoint(1.5, 0, 0);
        }

        /// <summary>
        /// 还原
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void ApplicationBarIconButton_Click_1(object sender, EventArgs e)
        {
            this.msi.ViewportWidth = 1;
            this.msi.ViewportOrigin = new Point(0,0);
        }

        private void ApplicationBarMenuItem_Click(object sender, EventArgs e)
        {
            Zoom(zoom*1.3,msi.ElementToLogicalPoint(new Point(.5*msi.ActualWidth,.5*msi.ActualHeight)));
        }
    }