--- ---

There are two ways to determine the screen's height and width.

Use the global Screen variable

uses
  Forms;
...
Screen.Height { Screen height in pixels }
Screen.Width  { Screen width in pixels  }
...

Use the Windows API `GetSystemMetrics()` function

This function can be useful in applications that don't use the VCL like console applications.

uses
  Windows;
...
GetSystemMetric(SM_CXSCREEN) { Screen height in pixels }
GetSystemMetric(SM_CYSCREEN) { Screen width in pixels  }
...