Click through transparent form

Question

I have a semi transparent fullscreen form and I need can control my computer over this form.

Actualy we need red screen filter on computer for observing the sky, but

Answer 1

Create a new VCL project. In the properties of the main form, set Color to clRed, AlphaBlend to true, AlphaBlendValue to 127, WindowState to wsMaximized, FormStyle to fsStayOnTop, and add the following code:

type
  TForm1 = class(TForm)
  private
  protected
    procedure CreateParams(var Params: TCreateParams); override;

...

procedure TForm1.CreateParams(var Params: TCreateParams);
begin
  inherited;
  Params.ExStyle := Params.ExStyle or WS_EX_LAYERED or WS_EX_TRANSPARENT;
end;

(Sample video, Sample compiled EXE, Source)