ArcGis 9.2客戶端開發簡介(2)

縮小

       public void ZoomOut(PictureBox m_PictureBox)

        {

            fuzhou.MapDescription pMapDescription = m_sMapDesc;

            fuzhou.EnvelopeN pEnvelope = pMapDescription.MapArea.Extent as fuzhou.EnvelopeN;

            double eWidth = Math.Abs(pEnvelope.XMax - pEnvelope.XMin);

            double eHeight = Math.Abs(pEnvelope.YMax - pEnvelope.YMin);

            double xFactor = (eWidth - (eWidth * 1.5)) / 2;

            double yFactor = (eHeight - (eHeight * 1.5)) / 2;

            pEnvelope.XMax = pEnvelope.XMax - xFactor;

            pEnvelope.XMin = pEnvelope.XMin + xFactor;

            pEnvelope.YMax = pEnvelope.YMax - yFactor;

            pEnvelope.YMin = pEnvelope.YMin + yFactor;

            fuzhou.MapExtent pMapExtext = new fuzhou.MapExtent();

            pMapExtext.Extent = pEnvelope;

            pMapDescription.MapArea = pMapExtext;

            m_sMapDesc = pMapDescription;

            drawMap(ref pMapDescription, m_PictureBox);

         }

放大操作的基本原理是取得當前的地圖描述MapDescription，然後按照比例計算出放大或縮小的比例。在得出按照比例計算出來的周邊坐標，然後將其提交服務器，取得圖形進行顯示。

漫游

       漫游的過程中需要監控鼠標在整個過程中的變化，如鼠標點擊，移動等等，因此漫游的實現也需要在地圖顯示空間的MouseDown、MouseMove、MouseUp事件中實現，在例程中使用的PictureBox空間名為piCGIs，代碼如下所示：

     private void piCGIs_MouseDown(object sender, MouseEventArgs e)

        {

            if (e.Button != MouseButtons.Left)

                return;

 if (ispanning == true)

            {

                PointClass m_point=new PointClass();

                m_point.X = e.X;

                m_point.Y = e.Y;

                IPoint m_ipoint = m_MapOperate.ScreenPointToMapPoint(m_point);//將鼠標的位置坐標轉換成圖形坐標

                startX = m_ipoint.X;

                startY = m_ipoint.Y;

                startDragX = e.X;

                startDragY = e.Y;

            }

        }

        private void piCGIs_MouseMove(object sender, MouseEventArgs e)

        {

            if (e.Button != MouseButtons.Left)

                return;

            if (ispanning==true)

            {

                // drag the image

                piCGIs.Image = null;

                deltaDragX = startDragX - e.X;

                deltaDragY = startDragY - e.Y;

                piCGIs.Invalidate();

            }

        }

        private void piCGIs_MouseUp(object sender, MouseEventArgs e)

        {if (e.Button != MouseButtons.Left)

                return;

            if (ispanning==true )

            {

                this.Cursor = Cursors.WaitCursor;

                PointClass m_point = new PointClass();

                m_point.X = e.X;

                m_point.Y = e.Y;

                IPoint  m_ipoint = m_MapOperate.ScreenPointToMapPoint(m_point);//記錄漫游終結點的屏幕坐標並將其轉換成圖形坐標

                double deltaX = m_ipoint.X - startX;

                double deltaY = m_ipoint.Y - startY;

                //change the extent and draw

                fuzhou.MapDescription pMapDescription =m_MapOperate.getMapDescription() ;

                fuzhou.EnvelopeN pEnvelope = pMapDescription.MapArea.Extent as fuzhou.EnvelopeN;

                pEnvelope.XMax = pEnvelope.XMax - deltaX;

                pEnvelope.XMin = pEnvelope.XMin - deltaX;

                pEnvelope.YMax = pEnvelope.YMax - deltaY;

                pEnvelope.YMin = pEnvelope.YMin - deltaY;

                fuzhou.MapExtent pMapExtext = new fuzhou.MapExtent();

                pMapExtext.Extent = pEnvelope;

                pMapDescription.MapArea = pMapExtext;

                // save the map description and draw the map

                m_MapOperate.SetMapDescription( pMapDescription);

&n
bsp;               m_MapOperate.drawMap(ref pMapDescription, piCGIs);

                deltaDragX = 0;

                deltaDragY = 0;

                piCGIs.Invalidate();

                this.Cursor = Cursors.Default;

            }

        }

實例圖：

全圖

public void Extend(PictureBox m_PictureBox)

        {

            try

            {

                String  m_sDataFrame = map.GetDefaultMapName();

                fuzhou.MapServerInfo mapi = map.GetServerInfo(m_sDataFrame);

                fuzhou.Envelope pEnvelope = mapi.FullExtent;

                fuzhou.MapDescription pMapDescription = m_sMapDesc;

                fuzhou.MapExtent pMapExtext = new fuzhou.MapExtent();

                pMapExtext.Extent = pEnvelope;

                pMapDescription.MapArea = pMapExtext;

                // save the map description and draw the map

                m_sMapDesc = pMapDescription;

                drawMap(ref pMapDescription, m_PictureBox);

            }

catch (Exception exception)

            {

                MessageBox.Show(exception.Message, "An error has occurred");

            }

        }

放大操作的基本原理是取得mapserver服務器該地圖的FullExtent，然後將其轉換提交服務器，取得圖形進行顯示。

鷹眼操作

       由於在實際使用過程中。有很多針對地圖的操作需要在鷹眼上來實現，所以在本實例中添加了鷹眼點擊漫游的功能：具體實現代碼如下：

       private void Eager_eye_MouseDown(object sender, MouseEventArgs e)

        {

            if (e.Button.ToString() =="Left")

            {

                PointClass m_Point=new PointClass() ;

                m_Point.X = e.X;

                m_Point.Y = e.Y;

                m_MapOperate.CenterAtByEye(e.X, e.Y,Eager_eye  ,piCGIs);

             }

        }

     public void CenterAtByEye(int X, int Y,PictureBox m_eyePictureBox, PictureBox m_PictureBox)

        {

            String m_sDataFrame = map.GetDefaultMapName();

            fuzhou.MapServerInfo mapi = map.GetServerInfo(m_sDataFrame);

            m_sEyeMapDesc = mapi.DefaultMapDescription;

            //fuzhou.Envelope pEnvelope = mapi.FullExtent;

            fuzhou.fujian_MapServer  map1 = new fuzhou.fujian_MapServer ();

            PointClass m_tmpPoint = new PointClass();

            fuzhou.ImageDisplay idisp1;

            idisp1 = new fuzhou.ImageDisplay();

   idisp1.ImageHeight = m_eyePictureBox.Height;

            idisp1.ImageWidth = m_eyePictureBox.Width;

            idisp1.ImageDPI = 150;

            int[] Xs = { X };

            int[] Ys = { Y };

            fuzhou.MultipointN mpnt = map1.ToMapPoints(m_sEyeMapDesc, idisp1, Xs, Ys) as fuzhou.MultipointN;

            fuzhou.Point[] pnta = mpnt.PointArray;

            fuzhou.PointN pnt = pnta[0] as fuzhou.PointN;

            m_tmpPoint.X = pnt.X;

            m_tmpPoint.Y = pnt.Y;

            fuzhou.MapDescription pMapDescription = m_sMapDesc;

            fuzhou.EnvelopeN pEnvelope = pMapDescription.MapArea.Extent as fuzhou.EnvelopeN;

            double m_Width = Math.Abs(pEnvelope.XMax - pEnvelope.XMin) / 2;

            double m_Height = Math.Abs(pEnvelope.YMax - pEnvelope.YMin) / 2;

            pEnvelope.XMax = m_tmpPoint.X + m_Width;

            pEnvelope.XMin = m_tmpPoint.X - m_Width;

            pEnvelope.YMax = m_tmpPoint.Y + m_Height;

            pEnvelope.YMin = m_tmpPoint.Y - m_Height;

            fuzhou.MapExtent pMapExtext = new fuzhou.MapExtent();

            pMapExtext.Extent = pEnvelope;

            pMapDescription.MapArea = pMapExtext;

            // save the map description and draw the map

            m_sMapDesc = pMapDescription;

            drawMap(ref pMapDescription, m_PictureBox);

            return ;

        }

圖層操作