Fade all other windows of an application when a dialog is shown?

Question

How to dim / fade all other windows of an application in Delphi 2009.

Form has an AlphaBlend property, but it controls only transparency level. But it would be nice if

Answer 1

Here is a unit I just knocked together for you.

To use this unit drop a TApplication component on your main form and in the OnModalBegin call _GrayForms and then in the OnModalEnd call the _NormalForms method.

This is a very simple example and could be made to be more complex very easily. Checking for multiple call levels etc....

For things like system (open, save, etc) dialogs you can wrap the dialog execute method in a try...finally block calling the appropriate functions to get a similar reaction.

This unit should work on Win2k, WinXP, Vista and should even work on Win7.

Ryan.

unit GrayOut;

interface

procedure _GrayForms;
procedure _GrayDesktop;
procedure _NormalForms;

implementation

uses windows, classes, forms, Contnrs, Types, Graphics, sysutils;

var
   gGrayForms : TComponentList;

procedure _GrayDesktop;
var
   loop : integer;
   wScrnFrm : TForm;
   wForm : TForm;
   wPoint : TPoint;

begin
   if not assigned(gGrayForms) then
   begin
      gGrayForms := TComponentList.Create;
      gGrayForms.OwnsObjects := true;

      for loop := 0 to Screen.MonitorCount - 1 do
      begin
         wForm := TForm.Create(nil);
         gGrayForms.Add(wForm);

         wForm.Position := poDesigned;
         wForm.AlphaBlend := true;
         wForm.AlphaBlendValue := 64;
         wForm.Color := clBlack;
         wForm.BorderStyle := bsNone;
         wForm.Enabled := false;
         wForm.BoundsRect := Screen.Monitors[loop].BoundsRect;
         SetWindowPos(wForm.handle, HWND_TOP, 0,0,0,0, SWP_NOSIZE or SWP_NOMOVE);
         wForm.Visible := true;
      end;
   end;
end;

procedure _GrayForms;
var
   loop : integer;
   wScrnFrm : TForm;
   wForm : TForm;
   wPoint : TPoint;
   wScreens : TList;

begin
   if not assigned(gGrayForms) then
   begin
      gGrayForms := TComponentList.Create;
      gGrayForms.OwnsObjects := true;

      wScreens := TList.create;
      try
         for loop := 0 to Screen.FormCount - 1 do
            wScreens.Add(Screen.Forms[loop]);

         for loop := 0 to wScreens.Count - 1 do
         begin
            wScrnFrm := wScreens[loop];

            if wScrnFrm.Visible then
            begin
               wForm := TForm.Create(wScrnFrm);
               gGrayForms.Add(wForm);

               wForm.Position := poOwnerFormCenter;
               wForm.AlphaBlend := true;
               wForm.AlphaBlendValue := 64;
               wForm.Color := clBlack;
               wForm.BorderStyle := bsNone;
               wForm.Enabled := false;
               wForm.BoundsRect := wScrnFrm.BoundsRect;
               SetWindowLong(wForm.Handle, GWL_HWNDPARENT, wScrnFrm.Handle);
               SetWindowPos(wForm.handle, wScrnFrm.handle, 0,0,0,0, SWP_NOSIZE or SWP_NOMOVE);
               wForm.Visible := true;
            end;
         end;
      finally
         wScreens.free;
      end;
   end;
end;

procedure _NormalForms;
begin
   FreeAndNil(gGrayForms);
end;

initialization
   gGrayForms := nil;

end.