Question

How do you detect that the user is running the Windows Aero theme on his operating system by code on Delphi 7?

Answer 1

The function we need to use is Dwmapi.DwmIsCompositionEnabled, but that is not included in the Windows header translations that ship with Delphi 7 and was added in Vista, released after Delphi 7. Also it crashes the application on Windows XP – so call it after check if Win32MajorVersion >= 6.

function IsAeroEnabled: Boolean;
type
  TDwmIsCompositionEnabledFunc = function(out pfEnabled: BOOL): HRESULT; stdcall;
var
  IsEnabled: BOOL;
  ModuleHandle: HMODULE;
  DwmIsCompositionEnabledFunc: TDwmIsCompositionEnabledFunc;
begin
  Result := False;
  if Win32MajorVersion >= 6 then // Vista or Windows 7+
  begin
    ModuleHandle := LoadLibrary('dwmapi.dll');
    if ModuleHandle <> 0 then
    try
      @DwmIsCompositionEnabledFunc := GetProcAddress(ModuleHandle, 'DwmIsCompositionEnabled');
      if Assigned(DwmIsCompositionEnabledFunc) then
        if DwmIsCompositionEnabledFunc(IsEnabled) = S_OK then
          Result := IsEnabled;
    finally
      FreeLibrary(ModuleHandle);
    end;
  end;
end;