ArcGis Engine中实现对符号的预览图输出

ArcGis Engine中实现对符号的预览图输出

07-11-12 11:24:09 作者:Aji 出处：中国GIS资讯网

在ArcGis Engine中实现对符号的预览，生成预览图片。使用的时候只要调用SymbolToBitmp(符号，宽，高)就可以返回生成的图片了。关键代码如下： public System.Drawing.Bitmap SymbolToBitmp(ESRI.ArcGIS.Display.ISymbol pSymbol,int iwidth,int iheight) { //根据高宽创建图象 Bitmap bmp = new Bitmap(iwidth,iheight); Graphics gImage = Graphics.FromImage(bmp); gImage.Clear(Color.White); double dpi = gImage.DpiX; IEnvelope pEnvelope = new EnvelopeClass(); pEnvelope.PutCoords(0,0,(double)bmp.Width,(double)bmp.Height); tagRECT deviceRect; deviceRect.left = 0; deviceRect.right = bmp.Width; deviceRect.top = 0; deviceRect.bottom = bmp.Height; IDisplayTransformation pDisplayTransformation = new DisplayTransformationClass(); pDisplayTransformation.VisibleBounds = pEnvelope; pDisplayTransformation.Bounds = pEnvelope; pDisplayTransformation.set_DeviceFrame(ref deviceRect); pDisplayTransformation.Resolution = dpi; IGeometry pGeo = CreateSymShape(pSymbol,pEnvelope); System.IntPtr hdc = new IntPtr(); hdc = gImage.GetHdc(); //将符号的形状绘制到图象中 pSymbol.SetupDC((int)hdc,pDisplayTransformation); pSymbol.Draw(pGeo); pSymbol.ResetDC(); gImage.ReleaseHdc(hdc); gImage.Dispose(); return bmp; } public ESRI.ArcGIS.Geometry.IGeometry CreateSymShape(ISymbol pSymbol,IEnvelope pEnvelope) {// 根据传入的符号以及外包矩形区域返回对应的几何空间实体（点，线、面） //判断是否为“点”符号 ESRI.ArcGIS.Display.IMarkerSymbol IMarkerSym; IMarkerSym = pSymbol as IMarkerSymbol; if (IMarkerSym != null) { // 为“点”符号则返回IEnvelope的中心点 IArea pArea ; pArea = pEnvelope as IArea; return pArea.Centroid as IGeometry; } else { //判断是否为“线”符号 ESRI.ArcGIS.Display.ILineSymbol IlineSym; ESRI.ArcGIS.Display.ITextSymbol ITextSym; IlineSym = pSymbol as ILineSymbol; ITextSym = pSymbol as ITextSymbol; if(IlineSym != null || ITextSym != null) { //返回45度的对角线 ESRI.ArcGIS.Geometry.IPolyline IpLine; IpLine = new PolylineClass(); IpLine.FromPoint = pEnvelope.LowerLeft; IpLine.ToPoint = pEnvelope.UpperRight; return IpLine as IGeometry; } else { //直接返回一个IEnvelope矩形区域 return pEnvelope as IGeometry; } } }