Mega Code Archive
Magnifyingglass
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Subject: Re: Round child forms
>Date: Wed, 31 Mar 1999 14:05:46 -0500
>From: "Anthony Farrell" <afarrell@hteinc.com>
>Hi all,
>I am looking for a way to implement a type of magnifying
>glass into an application.
>It needs to be round (ugh), and it cannot extend beyond
>the parent form.
>If anyone has any ideas, please drop me a line.
>thanks
>tony
Search the Win32 programmers help file for "region". Here are some APIs:
CreateEllipticRgn -- Creates elliptic window
CreateEllipticRgnIndirect
CreatePolygonRgn -- Creates customshaped window
CreatePolyPolygonRgn
CreateRectRgn -- Creates rectangular window(default)
CreateRectRgnIndirect
CreateRoundRectRgn -- Creates round-edged window
Here is an example (can't remember the authors name):
----------------------------------------------------------------------------
----
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
ExtCtrls, Buttons;
type
TForm1 = class(TForm)
Image1: TImage;
SpeedButton1: TSpeedButton;
procedure FormCreate(Sender: TObject);
procedure SpeedButton1Click(Sender: TObject);
private
{ Private declarations }
procedure CreateParams(var Params: TCreateParams); override;
public
{ Public declarations }
end;
var
Form1: TForm1;
implementation
procedure TForm1.CreateParams(var Params: TCreateParams);
begin
inherited createparams(params);
{This makes a borderless and captionless form}
params.style:=params.style or ws_popup xor ws_dlgframe;
end;
{$R *.DFM}
procedure TForm1.FormCreate(Sender: TObject);
var
formrgn:hrgn;
begin
{makes the form clear}
form1.brush.style:=bsclear;
{makes the form round}
GetWindowRgn(form1.Handle, formRgn);
DeleteObject(formRgn);
formrgn:= CreateRoundRectRgn(0,
0,form1.width,form1.width,form1.width,form1.width);
SetWindowRgn(form1.Handle, formrgn, TRUE);
end;
procedure TForm1.SpeedButton1Click(Sender: TObject);
begin
form1.close;
end;
end.
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