求助！为什么会出错？

[myjeff]

void CTBitmapDlg::OnTest()
{
HDC MemDC;
char text1[20];
char * text;
text=text1;
strcpy(text,"TEST\0");
int cxImage = 300;
int cyImage = 400;
int numPixels = cxImage*cyImage;
BYTE *pText = new BYTE[numPixels];
for(int i = 0 ; i < numPixels; i++)
{
pText[i] = 0;
}
HBITMAP bitmap = CreateBitmap(cxImage, cyImage, 0, 8, pText);

if (bitmap)
{
MemDC = CreateCompatibleDC(NULL);
SelectObject(MemDC,bitmap);

SetBkMode(MemDC,TRANSPARENT);
SetTextColor(MemDC, RGB(0xff,0,0));

HFONT hFont;
hFont = CreateFont(100, 0, 0, 0, FW_BOLD, FALSE, FALSE, FALSE,
0, OUT_DEFAULT_PRECIS, CLIP_DEFAULT_PRECIS,
DEFAULT_QUALITY, DEFAULT_PITCH, text);
HFONT hfont = (HFONT)::SelectObject(MemDC, hFont);

TextOut(MemDC,30,20,text,strlen(text));

//把数据拷回
HBITMAP *bmp = (HBITMAP*)SelectObject(MemDC,bitmap);
//这儿错了
long len = GetBitmapBits(*bmp,numPixels,(PBYTE)pText);
//int len = GetDIBits(MemDC,bitmap,1,lpbi->biHeight,(PBYTE)pText,(LPBITMAPINFO)lpbi,DIB_RGB_COLORS);
if(len == 0)
{
AfxMessageBox("Wrong");
}
else
{
RGBTRIPLE* prgbText = (RGBTRIPLE*) pText;
for (int i=0; i<numPixels; i++, prgbText++)
{
if( (prgbText->rgbtGreen != 0 )|| (prgbText->rgbtBlue != 0) ||( prgbText->rgbtRed != 0))
{
/*
alpha就是透度，公式如下:a1为字幕透度 a2为视频透度，此处假设视频不透，
为1.0，RGB1为字幕颜色，RGB2为视频颜色，RGB为合成后的颜色，则
RGB = a1 * RGB1 + (1-a1)*RGB2
如果字幕不透，则a1为1.0，其结果是字幕完全遮盖视频
*/
//test
prgbText->rgbtGreen = 255;//prgbText->rgbtGreen;
prgbText->rgbtBlue = 0;//prgbText->rgbtBlue;
prgbText->rgbtRed = 0;//prgbText->rgbtRed;
}
}
}

}

delete pText;

}