Draw cursor multiple display (only draw text icon) GDI

Question

I select displays in multiple display environments and produce captured programs.

And try to draw a cursor by selecting dc among multiple displays.

I draw cursors with bitblt bitmap images and it works well.

HDC HDCC = CreateDC((L"Display"), NULL, NULL, NULL);

But When I select from createDC multuple display value,

DISPLAY_DEVICEW info = { 0 };
info.cb = sizeof(DISPLAY_DEVICEW);
EnumDisplayDevicesW(NULL, 0, &info, EDD_GET_DEVICE_INTERFACE_NAME); 
HDCC = CreateDC(info.DeviceName, NULL, NULL, NULL);

I am working hard to get other display images. But there is no drawing cursor. (Other forms of cursor are not drawn, only text cursor is drawn)

This is my code.

const int d_count = GetSystemMetrics(SM_CMONITORS);  //I have 3 display and count is 3.
HDC hCaptureDC;
HDC HDCC;
HBITMAP hBitmap;
HGDIOBJ hOld;
BYTE *src;


bool GetMouse() {
     CURSORINFO cursor = { sizeof(cursor) };
     ::GetCursorInfo(&cursor);

     ICONINFOEXW info = { sizeof(info) };
     ::GetIconInfoExW(cursor.hCursor, &info);

     BITMAP bmpCursor = { 0 };
     GetObject(info.hbmColor, sizeof(bmpCursor), &bmpCursor);

     POINT point;
     GetCursorPos(&point);

     bool res = DrawIconEx(hCaptureDC, point.x, point.y, cursor.hCursor, bmpCursor.bmWidth, bmpCursor.bmHeight, 0, NULL, DI_NORMAL);
     return res;
}

void screencap(){
    BITMAPINFO MyBMInfo;
    BITMAPINFOHEADER bmpInfoHeader;
    HWND m_hWndCopy= GetDesktopWindow();
    GetClientRect(m_hWndCopy, &ImageRect);  
    const int nWidth = ImageRect.right - ImageRect.left; 
    const int nHeight = ImageRect.bottom - ImageRect.top;

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

    bmpInfoHeader = { sizeof(BITMAPINFOHEADER) };
    bmpInfoHeader.biWidth = nWidth;
    bmpInfoHeader.biHeight = nHeight;
    bmpInfoHeader.biPlanes = 1;
    bmpInfoHeader.biBitCount = 32;

    b_size = ((nWidth * bmpInfoHeader.biBitCount + 31) / 32) * 4 * nHeight;

     //HDCC = CreateDC((L"Display"), NULL, NULL, NULL);   //It's good.
    DISPLAY_DEVICEW info = { 0 };
    info.cb = sizeof(DISPLAY_DEVICEW);
    EnumDisplayDevicesW(NULL, 0, &info, EDD_GET_DEVICE_INTERFACE_NAME); 
    HDCC = CreateDC(info.DeviceName, NULL, NULL, NULL);   // It draws only text cursor.

    hCaptureDC = CreateCompatibleDC(HDCC);
    hBitmap = CreateCompatibleBitmap(HDCC, nWidth, nHeight);
    hOld = SelectObject(hCaptureDC, hBitmap);

    BitBlt(hCaptureDC, 0, 0, nWidth, nHeight, HDCC, 0, 0, SRCCOPY);

    GetMouse();

    SelectObject(hCaptureDC, hOld);

    src = (BYTE*)malloc(b_size);
    if (GetDIBits(hCaptureDC, hBitmap, 0, nHeight, src, (BITMAPINFO*)&bmpInfoHeader, DIB_RGB_COLORS)) {
        if (RGBSaveBMP(src) == true) 
        free(src);
    }  
}

I'm using windows 10.

How can I solved?

Any links, idea, Thanks.

ADD

It does not draw cursor....(except text cursor.)

HDCC = CreateDC(TEXT("\\\\.\\Display1"), NULL, NULL, NULL);

It draws cursor..

HDCC = CreateDC(TEXT("Display"), NULL, NULL, NULL);

SOLVED:

Now, I changed my algorithm.

CreateDC(L"Display", NULL, NULL, NULL) create DC for all monitors, so what is your problem? – user2120666 Apr 22 at 15:37

This comment is very helpful but It was not kind. (Or I was stupid.) :(

HDC HDCC = CreateDC((L"Display"), NULL, NULL, NULL);

HDCC has "All Virtual Screens" DC.

When I selected the monitor I needed, and accordingly selected and used the area to capture on the virtual screen.

HDC hCaptureDC = CreateCompatibleDC(HDCC);  
HBITMAP hBitmap = CreateCompatibleBitmap(HDCC, nWidth, nHeight);
HDC HDCC = CreateDC((L"Display"), NULL, NULL, NULL);
DEVMODE dev;

std::string str = "\\\\.\\Display" + std::to_string(select);
std::wstring temp;
temp.assign(str.begin(), str.end());

EnumDisplaySettingsW(temp.c_str(), ENUM_CURRENT_SETTINGS, &dev);
printf("Display%d : (%d * %d) (%d, %d)\n", select, dev.dmPelsWidth, dev.dmPelsHeight, dev.dmPosition.x, dev.dmPosition.y);

nWidth = dev.dmPelsWidth;
nHeight = dev.dmPelsHeight;
nposx = dev.dmPosition.x;
nposy = dev.dmPosition.y;

hOld = SelectObject(hCaptureDC, hBitmap);
BitBlt(hCaptureDC, 0, 0, nWidth, nHeight, HDCC, nposx, nposy, SRCCOPY);
int colorcheck = GetSystemMetrics(SM_SAMEDISPLAYFORMAT);

CURSORINFO cursor = { sizeof(cursor) };
bool check = ::GetCursorInfo(&cursor);
bool check2 = ::GetCursorInfo(&cursor);
int count = ShowCursor(TRUE);

info = { sizeof(info) };
::GetIconInfoExW(cursor.hCursor, &info);

GetCursorPos(&point);

if (point.x > nWidth) {
    point.x = point.x - nWidth;
}
else if (point.x < 0) {
    point.x = nWidth + point.x;
}
if (point.y > nHeight) {
    point.y = point.y - nHeight;
}
else if (point.y < 0) {
    point.y = nHeight + point.y;
}
cursor.ptScreenPos.x = point.x;
cursor.ptScreenPos.y = point.y;

bool res = ::DrawIconEx(hCaptureDC, point.x, point.y, cursor.hCursor, 0, 0, 0, NULL, DI_NORMAL);


BYTE* src = (BYTE*)malloc(b_size);
GetDIBits(hCaptureDC, hBitmap, 0, nHeight, src, (BITMAPINFO*)&bmpInfoHeader, DIB_RGB_COLORS)

Thanks for the comment!

Answer 1

Your call GetClientRect(m_hWndCopy, &ImageRect); is wrong.

From documentation:

The rectangle of the desktop window returned by GetWindowRect or GetClientRect is always equal to the rectangle of the primary monitor, for compatibility with existing applications.

So you are capturing only primary display.