GetDeviceCaps

Returns various device specific information.

Declaration

Source position: winapih.inc line 124

Description

Returns information about any DC (Device Context), which might be the screen DC representing the monitor, a control canvas or a off-screen bitmap canvas. The following constants can be utilized in the index argument:

• HORZSIZE
• VERTSIZE
• HORZRES
• BITSPIXEL
• PLANES
• SIZEPALETTE
• LOGPIXELSX - the DPI in the X axis
• LOGPIXELSY - the DPI in the Y axis
• VERTRES
• NUMRESERVED

An example showing how to obtain the screen DPI for the X axis using GetDeviceCaps, which is the method utilized by TScreen.PixelsPerInch:

var
  DC: HDC;
begin
  DC := GetDC(0);
  FDPI := GetDeviceCaps(DC,LOGPIXELSX); // DPI in pixels per inch
  ReleaseDC(0, DC);
end;

See also