How to detect Windows Aero theme on Delphi 7?

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;