帮我用c++和mfc写图像旋转的函数RotateDIB(lpSrcDib, iRotateAngle)

好的，我会帮您实现这个图像旋转函数。下面是具体的代码实现：

void RotateDIB(BITMAPINFO* lpSrcDib, int iRotateAngle)
{
    if (nullptr == lpSrcDib || iRotateAngle == 0) {
        return;
    }

    // 获取源图像信息
    LPSTR lpSrcStartBits = (LPSTR)lpSrcDib + lpSrcDib->bmiHeader.biSize + GetColorTableSize(lpSrcDib);
    LONG lSrcWidth = lpSrcDib->bmiHeader.biWidth;
    LONG lSrcHeight = abs(lpSrcDib->bmiHeader.biHeight);

    // 计算旋转后的图像宽度和高度
    double dRotate = (double)iRotateAngle * PI / 180;
    double dSin = fabs(sin(dRotate));
    double dCos = fabs(cos(dRotate));
    LONG lNewWidth = (LONG)(lSrcWidth * dCos + lSrcHeight * dSin);
    LONG lNewHeight = (LONG)(lSrcWidth * dSin + lSrcHeight * dCos);

    // 申请新图像内存
    HGLOBAL hNewDib = GlobalAlloc(GMEM_MOVEABLE, sizeof(BITMAPINFOHEADER) + GetColorTableSize(lpSrcDib) + lNewWidth * lNewHeight * 4);
    if (nullptr == hNewDib) {
        return;
    }

    BITMAPINFO* lpNewDib = (BITMAPINFO*)GlobalLock(hNewDib);
    memcpy(lpNewDib, lpSrcDib, sizeof(BITMAPINFOHEADER) + GetColorTableSize(lpSrcDib));

    lpNewDib->bmiHeader.biWidth = lNewWidth;
    lpNewDib->bmiHeader.biHeight = lpSrcDib->bmiHeader.biHeight > 0 ? lNewHeight : -lNewHeight;

    LPSTR lpNewStartBits = (LPSTR)lpNewDib + lpNewDib->bmiHeader.biSize + GetColorTableSize(lpNewDib);
    memset(lpNewStartBits, 0, lNewWidth * lNewHeight * 4);

    // 计算旋转中心点
    LONG lSrcMidX = lSrcWidth / 2;
    LONG lSrcMidY = lSrcHeight / 2;
    LONG lNewMidX = lNewWidth / 2;
    LONG lNewMidY = lNewHeight / 2;

    // 逐像素旋转
    for (LONG y = 0; y < lSrcHeight; y++) {
        for (LONG x = 0; x < lSrcWidth; x++) {
            // 计算旋转后的像素坐标
            LONG lNewX = (LONG)((x - lSrcMidX) * dCos + (y - lSrcMidY) * dSin + lNewMidX);
            LONG lNewY = (LONG)((x - lSrcMidX) * dSin + (y - lSrcMidY) * dCos + lNewMidY);

            // 判断新坐标是否在图像范围内
            if (lNewX >= 0 && lNewX < lNewWidth && lNewY >= 0 && lNewY < lNewHeight) {
                // 获取旧像素值
                LONG lSrcPos = (y * lSrcWidth + x) * 4;
                BYTE bRed = lpSrcStartBits[lSrcPos + 2];
                BYTE bGreen = lpSrcStartBits[lSrcPos + 1];
                BYTE bBlue = lpSrcStartBits[lSrcPos];
                BYTE bAlpha = lpSrcStartBits[lSrcPos + 3];

                // 设置新像素值
                LONG lNewPos = (lNewY * lNewWidth + lNewX) * 4;
                lpNewStartBits[lNewPos + 2] = bRed;
                lpNewStartBits[lNewPos + 1] = bGreen;
                lpNewStartBits[lNewPos] = bBlue;
                lpNewStartBits[lNewPos + 3] = bAlpha;
            }
        }
    }

    // 更新图像信息
    lpSrcDib->bmiHeader.biWidth = lNewWidth;
    lpSrcDib->bmiHeader.biHeight = lpNewDib->bmiHeader.biHeight;
    memcpy(lpSrcStartBits, lpNewStartBits, lNewWidth * lNewHeight * 4);

    // 释放内存
    GlobalUnlock(hNewDib);
    GlobalFree(hNewDib);
}

这个函数中，我们首先获取源图像信息，然后计算旋转后的图像宽度和高度，申请新的内存空间，并对图像进行旋转。最后，我们更新源图像信息，并将新的像素数据拷贝到旧的内存空间中，最后释放内存。