組合語言 Assembly Language

Capture Screen and store it in a buffer C++ on Windows

----------------------------------Source.cpp----------------------
#include <Windows.h>
#include <iostream>
#include <math.h>
#include <stdio.h>
using namespace std;

HBITMAP GetScreenBmp(HDC hdc) {
    // Get screen dimensions
    int nScreenWidth = GetSystemMetrics(SM_CXSCREEN);
    int nScreenHeight = GetSystemMetrics(SM_CYSCREEN);

    // Create compatible DC, create a compatible bitmap and copy the screen using BitBlt()
    HDC hCaptureDC = CreateCompatibleDC(hdc);
    HBITMAP hBitmap = CreateCompatibleBitmap(hdc, nScreenWidth, nScreenHeight);
    HGDIOBJ hOld = SelectObject(hCaptureDC, hBitmap);
    BOOL bOK = BitBlt(hCaptureDC, 0, 0, nScreenWidth, nScreenHeight, hdc, 0, 0, SRCCOPY | CAPTUREBLT);

    SelectObject(hCaptureDC, hOld); // always select the previously selected object once done
    DeleteDC(hCaptureDC);
    return hBitmap;
}

BYTE* get_screen_image(HDC hdc,HBITMAP hBitmap) {

    BITMAPINFO MyBMInfo = { 0 };
    MyBMInfo.bmiHeader.biSize = sizeof(MyBMInfo.bmiHeader);

    // Get the BITMAPINFO structure from the bitmap
    if (0 == GetDIBits(hdc, hBitmap, 0, 0, NULL, &MyBMInfo, DIB_RGB_COLORS)) {
        cout << "error" << endl;
        return NULL;
    }

    // create the bitmap buffer
    BYTE* lpPixels = new BYTE[MyBMInfo.bmiHeader.biSizeImage];
    cout << "Image Size : " << MyBMInfo.bmiHeader.biSizeImage << endl;
    // Better do this here - the original bitmap might have BI_BITFILEDS, which makes it
    // necessary to read the color table - you might not want this.
    MyBMInfo.bmiHeader.biCompression = BI_RGB;

    // get the actual bitmap buffer
    if (0 == GetDIBits(hdc, hBitmap, 0, MyBMInfo.bmiHeader.biHeight, (LPVOID)lpPixels, &MyBMInfo, DIB_RGB_COLORS)) {
        cout << "error2" << endl;
        return NULL;
    }
    return lpPixels;
}

int main() {
    HDC hdc = GetDC(0);
    HBITMAP hBitmap = GetScreenBmp(hdc);

    BYTE* lpPixels = get_screen_image(hdc, hBitmap);

    for (int i = 0; i < 256; i++) {
        cout << (int)lpPixels[i] << " ";
    }

    DeleteObject(hBitmap);
    ReleaseDC(NULL, hdc);
    delete[] lpPixels;
    return 0;
}