关于arcmap自定义符号渲染的问题

[ts_chen1982]

我想用agg替换arcgis的gdi渲染，仿照logomarkersymbol写了一个测试程序，当加载shp文件时，渲染正确，但加载同样的geodatabase数据时渲染不出来（空白），然而此时如果再将geodatabase的当前要素类加载一遍时，又可以渲染出来，这个问题困惑我很久，请大家帮看看，主要代码如下：

我测试程序用的aggplus，即agg的gdi+封装版本
STDMETHODIMP CCartoSymbolMarker::SetupDC(OLE_HANDLE hDC, ITransformation *Transformation)
{
m_ipTrans = Transformation;
m_pGraphics = Graphics::FromHDC((HDC)hDC);
return S_OK;
}

STDMETHODIMP CCartoSymbolMarker:raw(IGeometry *Geometry)
{
if (!Geometry)
return E_POINTER;

IPointPtr spPoint(Geometry);
if (spPoint == NULL)
return E_FAIL;

double x=0, y=0;
FromMapPoint((IDisplayTransformation*)m_ipTrans, spPoint, &x, &y);

Pen myPen(Color(255,0,0,255), 1);
m_pGraphics->DrawRectangle(&myPen, x, y, 10, 20);
return S_OK;
}

STDMETHODIMP CCartoSymbolMarker::ResetDC()
{
delete m_pGraphics;
m_pGraphics = NULL;
return S_OK;
}

aggplus的graphics类如下：

Graphics *Graphics::FromHDC(HDC hdc) { return(new Graphics(hdc)); }

Graphics::Graphics(HDC hdc) : m_dwConfigFlags(0)
{
RECT clipBox;
::GetClipBox(hdc, &clipBox);
int nW=clipBox.right-clipBox.left;
int nH=clipBox.bottom-clipBox.top;
ASSERT(nW>0 && nH>0);
z_Create(nW, nH, -4*nW, NULL);
m_dwConfigFlags|=def_flag_G_FromHDC;
m_fromhdc_HDC=hdc;
m_fromhdc_X=clipBox.left;
m_fromhdc_Y=clipBox.top;
}


Graphics::~Graphics()
{
#ifdef def_AP_Update_Dc_at_End
if(m_dwConfigFlags & def_flag_G_FromHDC)
{
BITMAPINFO hDib;
memset(&hDib, 0, sizeof(BITMAPINFO));
hDib.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
hDib.bmiHeader.biWidth = m_dwWidth;
hDib.bmiHeader.biHeight = m_dwHeight;
hDib.bmiHeader.biPlanes = 1;
hDib.bmiHeader.biBitCount = 32;
hDib.bmiHeader.biCompression = BI_RGB;
hDib.bmiHeader.biSizeImage = m_dwWidth * m_dwHeight * 4;
#ifndef _X_NODCAlpha_
LPVOID pBits;
HBITMAP hBitmap = CreateDIBSection(m_fromhdc_HDC, &hDib, DIB_RGB_COLORS, &pBits, NULL, 0);

if(!hBitmap) ASSERT(FALSE);
else
{
memcpy(pBits, buffer, m_dwWidth * m_dwHeight * 4);
HDC mdc=CreateCompatibleDC( m_fromhdc_HDC );
if(!mdc) ASSERT(FALSE);
else
{
HBITMAP hbmOld=(HBITMAP)::SelectObject(mdc, hBitmap);
BLENDFUNCTION bln;
bln.BlendOp=AC_SRC_OVER;
bln.BlendFlags=0;
bln.SourceConstantAlpha=255;
bln.AlphaFormat=AC_SRC_ALPHA;
AlphaBlend(m_fromhdc_HDC, m_fromhdc_X, m_fromhdc_Y, m_dwWidth, m_dwHeight, mdc, 0, 0, m_dwWidth, m_dwHeight, bln);

::SelectObject(mdc, hbmOld);

DeleteDC(mdc);
}
::deleteObject(hBitmap);
}
#else
SetDIBitsToDevice(m_fromhdc_HDC, m_fromhdc_X, m_fromhdc_Y, m_dwWidth, m_dwHeight, 0, 0, 0, m_dwHeight, buffer, &hDib, DIB_RGB_COLORS);
#endif //_X_NODCAlpha_
}
#endif //def_AP_Update_Dc_at_End


delete(m_agg_pREN);
delete(m_agg_ppixf);
if(!(m_dwConfigFlags&def_flag_G_ExtBuffer))
{
delete(buffer);
}
}

[沈小夕]