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Draw the caption of a TForm programmatically (Views: 100)


Problem/Question/Abstract:

I need to be able to draw the text in a TForm's caption area manually, without using WM_SETTEXT (setting the TForm's Caption property, or using the API call SetWindowText, both use this method so they are unsuitable). I need functionality similar to DrawText where the text is drawn directly rather than sent to a message handler. Can anyone help?

Answer:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs;

type
  TForm1 = class(TForm)
    procedure WMPaint(var Message: TWMPaint); message WM_PAINT;
    procedure FormShow(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure WriteTexttoDC(WinHandle: HWND; Text: string; X, Y: Integer);
var
  DC: HDC;
begin
  DC := GetWindowDC(WinHandle);
  ExtTextOut(DC, 1, 1, ETO_CLIPPED, nil, PChar(Text), Length(Text), nil);
  ReleaseDC(WinHandle, DC);
end;

procedure TForm1.WMPaint(var Message: TWMPaint);
begin
  WriteTexttoDC(Handle, 'Is it OK?', 5, 5);
end;

procedure TForm1.FormShow(Sender: TObject);
begin
  WriteTexttoDC(Handle, 'Is it OK?', 5, 5);
end;

end.

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