You can find the color depth of a display context in the following manner: GetDeviceCaps(Form .Canvas.Handle, BITSPIXEL) * GetDeviceCaps(Form .Canvas.Handle, PLANES) Will give you the total number of bits used to color a pixel. possible Return values of:

= 2 colors bpp 4 = 6 colors bpp 8 = 256 colors bpp 5 = 32768 colors (will return 6 on most drivers) bpp 6 = 65535 colors bpp 24 = 6,777,2 6 colors bpp 32 = 6,777,2 6 colors (same as 24) bpp

You can use:

NumberOfColors := (  shl
   (GetDeviceCaps(Form .Canvas.Handle, BITSPIXEL) *
    GetDeviceCaps(Form .Canvas.Handle, PLANES));
 to calculate the total number of colors.