Get a process window size without borders

Question

Using the WinApi GetWindowRect() it returns the complete window size, but I would like to get the size without the borders and the title bar, something like the red square:

There is any functions to do that?

Thanks

Answer 1

The Windows API function you are looking for is GetClientRect. If you subsequently need to convert these coordinates into screen relative coordinates, call ClientToScreen.

Answer 2

This works:

RECT getInnerWindowScreenRectangle(HWND window) {
    RECT client;
    RECT output;
    // client coordinates are (0, 0) in the top left corner
    // of the window inside the border.
    GetClientRect(window, &client);
    POINT point;
    point.x = 0;
    point.y = 0;
    // screen coordinates are virtual screen coordinates with (0, 0)
    // in the top left corner of the primary display.
    ClientToScreen(window, &point);
    output.left = point.x;
    output.top = point.y;
    output.right = point.x + client.right;
    output.bottom = point.y + client.bottom;
    return output;
}