GetDIBits doesn't work with HBITMAP captured from the window - winapi

Question

I need to get an array of pixel color data values of a picture captured from the window, and from a file (.bmp).
I checked through a debugger with breakpoints. The HBITMAP_ToPixelData() method with the HBITMAP created from the file, returns an array with the correct values, but if the HBITMAP created by capturing, the returned array is empty, all values are zero, while the "success" variable is also zero. GetDIBits() for some reason does not work, although the same HBITMAP is correctly transferred to the clipboard and inserted into the photo editor. What could be the problem?
Main.cpp code:
#include <windows.h>
#include <iostream>
#include <vector>
#include "ImageProcessing.h"
using namespace std;
int main()
{
ImageProcessing a1;
HBITMAP hbmp1 = a1.CaptureWindow(L"Notepad");
vector<unsigned char> p_data1 = a1.HBITMAP_ToPixelData(hbmp1);
HBITMAP hbmp2 = a1.HBITMAP_FromFile();
vector<unsigned char> p_data2 = a1.HBITMAP_ToPixelData(hbmp2);
}
ImageProcessing.h code:
#pragma once
#include <vector>
#include <windows.h>
using namespace std;
class ImageProcessing
{
#pragma once
public:
HBITMAP HBITMAP_FromFile()
{
wstring a = L"C:/pic.bmp";
HBITMAP hBitmap = (HBITMAP)LoadImage(NULL, a.c_str(), IMAGE_BITMAP, 0, 0, LR_LOADFROMFILE);
return hBitmap;
}
vector<unsigned char> HBITMAP_ToPixelData(HBITMAP hbmp)
{
BITMAP bmp = {};
BITMAPINFO bmp_info = {};
vector <unsigned char> Pixels = vector <unsigned char>();
OpenClipboard(NULL);
EmptyClipboard();
SetClipboardData(CF_BITMAP, hbmp);
CloseClipboard();
HDC DC = CreateCompatibleDC(NULL);
HGDIOBJ old_bmp = SelectObject(DC, hbmp);
GetObject(hbmp, sizeof(bmp), &bmp);
int width = bmp.bmWidth;
int height = bmp.bmHeight;
bmp_info.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
bmp_info.bmiHeader.biWidth = width;
bmp_info.bmiHeader.biHeight = height;
bmp_info.bmiHeader.biPlanes = 1;
bmp_info.bmiHeader.biBitCount = 24;
bmp_info.bmiHeader.biCompression = BI_RGB;
bmp_info.bmiHeader.biSizeImage = width * 3 * height;
Pixels.resize(bmp_info.bmiHeader.biSizeImage);
int success = GetDIBits(DC, hbmp, 0, width, &Pixels[0], &bmp_info, DIB_RGB_COLORS);
SelectObject(DC, old_bmp);
DeleteDC(DC);
return Pixels;
}
HBITMAP CaptureWindow(wstring window_title)
{
SetThreadDpiAwarenessContext(DPI_AWARENESS_CONTEXT_SYSTEM_AWARE);
HWND hwnd = FindWindow(NULL, (window_title.c_str()));
if (hwnd == NULL)
{
return NULL;
}
// get window dimentions
RECT windowsize;
GetClientRect(hwnd, &windowsize);
int w = windowsize.right;
int h = windowsize.bottom;
// copy window to bitmap
HDC hdc = GetDC(hwnd);
HDC hCaptureDC = CreateCompatibleDC(hdc);
HBITMAP hBitmap = CreateCompatibleBitmap(hdc, w, h);
HGDIOBJ hOld = SelectObject(hCaptureDC, hBitmap);
BOOL bOK = BitBlt(hCaptureDC, 0, 0, w, h, hdc, 0, 0, SRCCOPY);
SelectObject(hCaptureDC, hOld);
DeleteDC(hCaptureDC);
ReleaseDC(hwnd, hdc);
return hBitmap;
}
};