GDIPlus DrawImage white color is getting black - c++

Question

I'm using GDIPlus to scale image from a buffer.
I'm taking a screenshot of my desktop.
Here is my code:
BYTE *Duplication::scaleBuffer(unsigned char *data, int width, int height)
{
Gdiplus::Bitmap bitmap(width, height, 4 * width, PixelFormat32bppARGB, data);
INT n_width = mWidthResolution;
INT n_height = mHeightResolution;
double ratio = ((double)width) / ((double)height);
if (width > height) {
n_height = (double)n_width / ratio;
}
else {
n_width = n_height * ratio;
}
Gdiplus::Bitmap newBitmap(n_width, n_height, bitmap.GetPixelFormat());
Gdiplus::Graphics graphics(&newBitmap);
graphics.SetInterpolationMode(Gdiplus::InterpolationModeBilinear);
graphics.DrawImage(&bitmap, 0, 0, n_width, n_height);
Gdiplus::Rect rect(0, 0, newBitmap.GetWidth(), newBitmap.GetHeight());
Gdiplus::BitmapData bitmapData;
BYTE *buffer = nullptr;
if (Gdiplus::Ok == newBitmap.LockBits(&rect, Gdiplus::ImageLockModeRead, PixelFormat32bppARGB, &bitmapData)) {
int len = bitmapData.Height * std::abs(bitmapData.Stride);
buffer = new BYTE[len];
RtlZeroMemory(buffer, len);
memcpy(buffer, bitmapData.Scan0, len);
newBitmap.UnlockBits(&bitmapData);
}
return buffer;
}
On windows with white background, I got a black background and color is corrupted.. It happens only on some program like "File Browser".. I don't understand why ...