I'm trying to make the snippingtool in c++. I managed to create a borderless, fullscreen window via this code;
WindProc:
LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wparam, LPARAM lparam)
{
switch (message)
{
case WM_CHAR: //this is just for a program exit besides window's borders/taskbar
if (wparam==VK_ESCAPE)
{
DestroyWindow(hwnd);
}
case WM_DESTROY:
PostQuitMessage(0);
break;
default:
return DefWindowProc(hwnd, message, wparam, lparam);
}
}
Creating the window;
WNDCLASS windowClass={0};
windowClass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
windowClass.hCursor=LoadCursor(NULL, IDC_ARROW);
windowClass.hInstance=NULL;
windowClass.lpfnWndProc=WndProc;
windowClass.lpszClassName=TEXT("Window in Console"); //needs to be the same name
//when creating the window as well
windowClass.style=CS_HREDRAW | CS_VREDRAW;
//also register the class
if (!RegisterClass(&windowClass))
MessageBoxA(NULL, "Could not register class", "Error", MB_OK);
HWND windowHandle=CreateWindowA("Window in Console",
NULL,
WS_POPUP, //borderless
0, //x coordinate of window start point
0, //y start point
GetSystemMetrics(SM_CXSCREEN), //width of window
GetSystemMetrics(SM_CYSCREEN), //height of the window
NULL, //handles and such, not needed
NULL,
NULL,
NULL);
ShowWindow(windowHandle, SW_RESTORE);
Whats left to do is now taking the screenshot of the screen and drawing it on form. Which i fail at this part.
When i googled, i first saw SetPixel function but to draw the form it took like half a minute. it was veerry slow. Then people said use Device Context (its the forms' drawing data in the memory as i understood) and draw on that, it will be much quicker then just update the window. And here's what i did;
int nScreenWidth = GetSystemMetrics(SM_CXSCREEN);
int nScreenHeight = GetSystemMetrics(SM_CYSCREEN);
HDC hdc = GetDC(windowHandle);
BitBlt(hdc, 0, 0, nScreenWidth, nScreenHeight, GetDC(NULL), 0, 0, SRCCOPY | CAPTUREBLT);
UpdateWindow(windowHandle);
ShowWindow(windowHandle, SW_RESTORE);
UpdateWindow(windowHandle);
As you can guess, it didn't work. My form is blank white. I don't understand if i should write this on WM_PAINT message on WindProc or not. I tried many variations to this and actually one point it worked i guess but then stopped working when i changed something and i couldn't get it to work again...
thank you.