//---------------------------------------------------------------------------

#include <vcl.h>
#pragma hdrstop

#include "Unit1.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;

void done(HBITMAP hbmScreen, HDC hdcMemDC, HDC hdcScreen, HWND hWnd, HDC hdcWindow);
int CaptureAnImage(HWND hWnd, HWND MyBitmap);
//--------------------------------------------------------------------------

BOOL CALLBACK EnumChildProc(HWND hwnd, LPARAM lParam)
{

        char clase[256];

        //memset(clase,0, sizeof(clase));
        GetClassName(hwnd, clase, sizeof(clase));
        if(strcmp(clase, "AfxOleControl42") == 0)
        {
                HWND MyVentana = FindWindow(NULL, "Form1");

                int retval = CaptureAnImage(hwnd, MyVentana);
                return FALSE;
        }
        return TRUE;
}

//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------

void __fastcall TForm1::Button1Click(TObject *Sender)
{
        HWND hwnd;

        hwnd = FindWindow("ThunderRT6FormDC", "Visustin Editor");

        if(!hwnd)
                MessageBox(Application->Handle,"No se encuentra abierto el editor de Visustin.", "Error", MB_OK | MB_APPLMODAL | MB_ICONERROR);
        else
                EnumChildWindows(hwnd, (WNDENUMPROC)EnumChildProc, 0);
}
//---------------------------------------------------------------------------

int CaptureAnImage(HWND hWnd, HWND MyBitmap)
{
    HDC hdcScreen;
    HDC hdcWindow;
    HDC hdcMemDC = NULL;
    HBITMAP hbmScreen = NULL;
    BITMAP bmpScreen;

    // Retrieve the handle to a display device context for the client
    // area of the window.
    hdcScreen = GetDC(hWnd);
    hdcWindow = GetDC(MyBitmap);

    // Create a compatible DC which is used in a BitBlt from the window DC
    hdcMemDC = CreateCompatibleDC(hdcWindow);

    if(!hdcMemDC)
    {
        MessageBox(hWnd, "CreateCompatibleDC has failed", "Failed", MB_OK);
        done(hbmScreen, hdcMemDC, hdcScreen, hWnd, hdcWindow);
        return 1;
    }

    // Get the client area for size calculation
    RECT rcClient;
    GetClientRect(hWnd, &rcClient);

    //This is the best stretch mode
    SetStretchBltMode(hdcWindow,HALFTONE);

    //The source DC is the entire screen and the destination DC is the current window (HWND)
    if(!StretchBlt(hdcWindow,
               0,0,
               rcClient.right, rcClient.bottom,
               hdcScreen,
               0,0,
               GetSystemMetrics (SM_CXSCREEN),
               GetSystemMetrics (SM_CYSCREEN),
               SRCCOPY))
    {
        MessageBox(hWnd, "StretchBlt has failed", "Failed", MB_OK);
        done(hbmScreen, hdcMemDC, hdcScreen, hWnd, hdcWindow);
        return 1;
    }
   
    // Create a compatible bitmap from the Window DC
    hbmScreen = CreateCompatibleBitmap(hdcWindow, rcClient.right-rcClient.left, rcClient.bottom-rcClient.top);
   
    if(!hbmScreen)
    {
        MessageBox(hWnd, "CreateCompatibleBitmap Failed", "Failed", MB_OK);
        done(hbmScreen, hdcMemDC, hdcScreen, hWnd, hdcWindow);
        return 1;
    }

    // Select the compatible bitmap into the compatible memory DC.
    SelectObject(hdcMemDC,hbmScreen);
   
    // Bit block transfer into our compatible memory DC.
    if(!BitBlt(hdcMemDC,
               0,0,
               rcClient.right-rcClient.left, rcClient.bottom-rcClient.top,
               hdcWindow,
               0,0,
               SRCCOPY))
    {
        MessageBox(hWnd, "BitBlt has failed", "Failed", MB_OK);
        done(hbmScreen, hdcMemDC, hdcScreen, hWnd, hdcWindow);
        return 1;
    }

    // Get the BITMAP from the HBITMAP
    GetObject(hbmScreen,sizeof(BITMAP),&bmpScreen);
     
    BITMAPFILEHEADER   bmfHeader;   
    BITMAPINFOHEADER   bi;
     
    bi.biSize = sizeof(BITMAPINFOHEADER);   
    bi.biWidth = bmpScreen.bmWidth;   
    bi.biHeight = bmpScreen.bmHeight; 
    bi.biPlanes = 1;   
    bi.biBitCount = 32;   
    bi.biCompression = BI_RGB;   
    bi.biSizeImage = 0; 
    bi.biXPelsPerMeter = 0;   
    bi.biYPelsPerMeter = 0;   
    bi.biClrUsed = 0;   
    bi.biClrImportant = 0;

    DWORD dwBmpSize = ((bmpScreen.bmWidth * bi.biBitCount + 31) / 32) * 4 * bmpScreen.bmHeight;

    // Starting with 32-bit Windows, GlobalAlloc and LocalAlloc are implemented as wrapper functions that
    // call HeapAlloc using a handle to the process's default heap. Therefore, GlobalAlloc and LocalAlloc
    // have greater overhead than HeapAlloc.
    HANDLE hDIB = GlobalAlloc(GHND,dwBmpSize);
    char *lpbitmap = (char *)GlobalLock(hDIB);   

    // Gets the "bits" from the bitmap and copies them into a buffer
    // which is pointed to by lpbitmap.
    GetDIBits(hdcWindow, hbmScreen, 0,
        (UINT)bmpScreen.bmHeight,
        lpbitmap,
        (BITMAPINFO *)&bi, DIB_RGB_COLORS);

    // A file is created, this is where we will save the screen capture.
    HANDLE hFile = CreateFile("captureqwsx.bmp",
        GENERIC_WRITE,
        0,
        NULL,
        CREATE_ALWAYS,
        FILE_ATTRIBUTE_NORMAL, NULL);
   
    // Add the size of the headers to the size of the bitmap to get the total file size
    DWORD dwSizeofDIB = dwBmpSize + sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER);
 
    //Offset to where the actual bitmap bits start.
    bmfHeader.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER);
   
    //Size of the file
    bmfHeader.bfSize = dwSizeofDIB;
   
    //bfType must always be BM for Bitmaps
    bmfHeader.bfType = 0x4D42; //BM   
 
    DWORD dwBytesWritten = 0;
    WriteFile(hFile, (LPSTR)&bmfHeader, sizeof(BITMAPFILEHEADER), &dwBytesWritten, NULL);
    WriteFile(hFile, (LPSTR)&bi, sizeof(BITMAPINFOHEADER), &dwBytesWritten, NULL);
    WriteFile(hFile, (LPSTR)lpbitmap, dwBmpSize, &dwBytesWritten, NULL);
   
    //Unlock and Free the DIB from the heap
    GlobalUnlock(hDIB);   
    GlobalFree(hDIB);

    //Close the handle for the file that was created
    CloseHandle(hFile);

    done(hbmScreen, hdcMemDC, hdcScreen, hWnd, hdcWindow);

    return 0;
}

void done(HBITMAP hbmScreen, HDC hdcMemDC, HDC hdcScreen, HWND hWnd, HDC hdcWindow)
{
        //Clean up
    DeleteObject(hbmScreen);
    DeleteObject(hdcMemDC);
    ReleaseDC(NULL,hdcScreen);
    ReleaseDC(hWnd,hdcWindow);
}