为什么用pDC->StretchBlt()无法打印输出?

Question

我写的打印部分代码如下:
CDC dcMemory;
BOOL bRet = dcMemory.CreateCompatibleDC(pDC);
CBitmap *pOldBitmap=dcMemory.SelectObject(pBitmap); BITMAP bm;
pBitmap->GetObject(sizeof(bm),&bm);
m_sizeSource.cx=bm.bmWidth;
m_sizeSource.cy=bm.bmHeight;
m_sizeDest.cx=m_sizeSource.cx;
m_sizeDest.cy=m_sizeSource.cy;
pDC->DPtoLP(&m_sizeDest); //超过打印区域,则进行缩放
if(m_sizeDest.cx>abs(m_rectPrint.Width()))
{
m_sizeDest.cx=abs(m_rectPrint.Width());
//按比例缩放
m_sizeDest.cy=m_sizeDest.cy*(m_rectPrint.Width()/m_sizeDest.cx);
}
if(m_sizeDest.cy>abs(m_rectPrint.Height()))
{
m_sizeDest.cy=abs(m_rectPrint.Height());
//按比例缩放
m_sizeDest.cx=m_sizeDest.cx*(m_rectPrint.Height()/m_sizeDest.cy);
} int printpicX=m_rectPrint.left+PageRight;
int printpicY=m_rectPrint.top+PageHeaderHeight+nHeight;

pDC->SetStretchBltMode(COLORONCOLOR);
pDC->StretchBlt(printpicX,-printpicY,
m_sizeDest.cx,-m_sizeDest.cy,&dcMemory,
0,0,m_sizeSource.cx,-m_sizeSource.cy,SRCCOPY); dcMemory.SelectObject(pOldBitmap);
我在资源中建了张BMP的图片想把它打印输出
为什么无法输出打印,纸上是白的什么也没有?
纸是用A4的,映射模式是 dc.SetMapMode(MM_LOENGLISH);
请指点谢谢.

Answer 1

打印机DC与屏幕DC的打印方向有点不一样，图片可能被打到上面去了。你可以先输出一些字符或线条试试看。