ArcEngine中实现对符号的预览图输出

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;

}

}

}

引用：http://www.gissky.com/Gis/ShowSContent.asp?SbjID=1&ID=1133

下面是自己用VC开发出来的符号浏览器：