Solved

Click-through forms

Posted on 2001-08-03
4
635 Views
Last Modified: 2010-05-18
Delphi 6 now provides the ability to create an alpha-blended (i.e. translucent) form. What I would like to do is create a form like this, with FormStyle = fsStayOnTop, as a sort of 'watermark' that always shows as a light overlay in front of whatever's on the screen. The problem, of course, is that with my form in front of whatever else is on the system, mouse clicks go to my form, not to things behind my form. So my question is, how can a Delphi form be made 'transparent' to mouse clicks - i.e. make sure all mouse clicks are routed to the window in the second-topmost position at the pixel that was clicked. Bonus points if you write the code for me. :-)
0
Comment
Question by:ghjm
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
  • 2
4 Comments
 
LVL 21

Expert Comment

by:gemarti
ID: 6351070
This works, but may not be what your looking for. I'm just guessing since D6 is new to me:

Create a new application.
Place a Button and a edit control on the first form (Form1)
procedure TForm1.Button1Click(Sender: TObject);
begin
  Form2.Show;
end;

Create a second form (form2)

Set AlphaBlend := true;
AlphaBlendValue := 100 (or any value from 0..255 where 255 is the least transparent)
Set TransParentColor := true;
Set TransParentColorValue := clBtnFace (or whatever color works for you)

Add these lines of code:
procedure TForm2.FormActivate(Sender: TObject);
begin
  Form1.Button1.Parent := Form2;
  Form1.Edit1.Parent := Form2;
  Form2.AlphaBlendValue := 200; //if you leave at 100 you can't see the components very well.
  Form1.Button1.GetParentComponent;
end;

procedure TForm2.FormClose(Sender: TObject; var Action: TCloseAction);
begin
  Form1.Button1.Parent := Form1;
  Form1.Edit1.Parent := Form1;
  Form2.AlphaBlendValue := 100;
end;
0
 
LVL 9

Accepted Solution

by:
ITugay earned 100 total points
ID: 6351234
Hi ghjm,

may be this code would be usefull for you.

procedure TForm1.MouseRedirect(Sender: TObject; Action: Integer; X,Y: Integer);
var
  C: TPoint;
  H: HRgn;
  L: HRgn;
begin
  C.X := X;
  C.Y := Y;
  C := TControl(Sender).ClientToScreen(C);

  // create empty region and assign it to the form to make form
  // transparent for mouse clicks
  H := CreateRectRgn(0, 0, 0, 0);
  GetWindowRgn(Handle, L);
  SetWindowRgn(Handle, H, False);
  DeleteObject(L);

  mouse_event(Action, X, Y, 0 ,0);

  // restore form region
  GetWindowRgn(Handle, L);
  SetWindowRgn(Handle, 0, False);
  DeleteObject(L);

end;

procedure TForm1.FormMouseDown(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if Button = mbLeft then
    MouseRedirect(Self, MOUSEEVENTF_LEFTDOWN, X, Y)
  else
    MouseRedirect(Self, MOUSEEVENTF_RIGHTDOWN, X, Y);
end;

procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
  Shift: TShiftState; X, Y: Integer);
begin
  if Button = mbLeft then
    MouseRedirect(Self, MOUSEEVENTF_LEFTUP, X, Y)
  else
    MouseRedirect(Self, MOUSEEVENTF_RIGHTUP, X, Y);
end;


Set OnMouseDown and OnMouseUp for rest of control that should be transparent for mouse clicks to the same handles (TForm1.OnMouseDown, OnMouseUp).

-----
Igor
0
 
LVL 1

Author Comment

by:ghjm
ID: 6351874
Well, I understand what you're trying to do, but I haven't been able to make it work. I'm still trying, but...I sure wish a Win32 API call existed to set the _mouse_ region without also setting the _display_ region.
0
 
LVL 1

Author Comment

by:ghjm
ID: 6351890
Okay, well I have it working, sort of. The remaining problem is that whenever a click event goes through, the transparent form disappears and reappears - even though bRedraw is set to FALSE. Any suggestions how to avoid this?
0

Featured Post

Industry Leaders: We Want Your Opinion!

We value your feedback.

Take our survey and automatically be enter to win anyone of the following:
Yeti Cooler, Amazon eGift Card, and Movie eGift Card!

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Objective: - This article will help user in how to convert their numeric value become words. How to use 1. You can copy this code in your Unit as function 2. than you can perform your function by type this code The Code   (CODE) The Im…
Have you ever had your Delphi form/application just hanging while waiting for data to load? This is the article to read if you want to learn some things about adding threads for data loading in the background. First, I'll setup a general applica…
There are cases when e.g. an IT administrator wants to have full access and view into selected mailboxes on Exchange server, directly from his own email account in Outlook or Outlook Web Access. This proves useful when for example administrator want…
In this video, viewers will be given step by step instructions on adjusting mouse, pointer and cursor visibility in Microsoft Windows 10. The video seeks to educate those who are struggling with the new Windows 10 Graphical User Interface. Change Cu…

729 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question