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| unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
Buttons;
type
TForm1 = class(TForm)
procedure FormResize(Sender: TObject);
private
{ Private-Deklarationen }
CaptionBtn : TRect;
procedure DrawCaptButton;
procedure WMNCPaint(var Msg : TWMNCPaint); message WM_NCPaint;
procedure WMNCActivate(var Msg : TWMNCActivate); message WM_NCACTIVATE;
procedure WMSetText(var Msg : TWMSetText); message WM_SETTEXT;
procedure WMNCHitTest(var Msg : TWMNCHitTest); message WM_NCHITTEST;
procedure WMNCLButtonDown(var Msg : TWMNCLButtonDown); message WM_NCLBUTTONDOWN;
public
{ Public-Deklarationen }
end;
var
Form1: TForm1;
const
htCaptionBtn = htSizeLast + 1;
implementation
{$R *.DFM}
procedure TForm1.DrawCaptButton;
var
xFrame,
yFrame,
xSize,
ySize : Integer;
R : TRect;
begin
//Dimensions of Sizeable Frame
xFrame := GetSystemMetrics(SM_CXFRAME);
yFrame := GetSystemMetrics(SM_CYFRAME);
//Dimensions of Caption Buttons
xSize := GetSystemMetrics(SM_CXSIZE);
ySize := GetSystemMetrics(SM_CYSIZE);
//Define the placement of the new caption button
//next to the existing caption buttons
CaptionBtn := Bounds(Width - xFrame - 4*xSize + 2,
yFrame + 2, xSize - 2, ySize - 4);
//Get the handle to canvas using Form's device context
Canvas.Handle := GetWindowDC(Self.Handle);
Canvas.Font.Name := 'Symbol';
Canvas.Font.Color := clBlue;
Canvas.Font.Style := [fsBold];
Canvas.Pen.Color := clYellow;
Canvas.Brush.Color := clBtnFace;
try
DrawButtonFace(Canvas, CaptionBtn, 1, bsAutoDetect, False, False, False);
//Define a smaller drawing rectangle within the button
R := Bounds(Width - xFrame - 4 * xSize + 2,
yFrame + 3, xSize - 6, ySize - 7);
with CaptionBtn do
Canvas.TextRect(R, R.Left + 2, R.Top - 1, 'W');
finally
//Get rid of the device context and set the
//canvas handle to default
ReleaseDC(Self.Handle, Canvas.Handle);
Canvas.Handle := 0;
end;
end;
//This traps the default form painting
procedure TForm1.WMNCPaint(var Msg : TWMNCPaint);
begin
inherited;
DrawCaptButton;
end;
//This traps form activation
procedure TForm1.WMNCActivate(var Msg : TWMNCActivate);
begin
inherited;
DrawCaptButton;
end;
//This traps any text being sent to the window
procedure TForm1.WMSetText(var Msg : TWMSetText);
begin
inherited;
DrawCaptButton;
end;
//This traps when the form's caption bar is hit with a mouse
procedure TForm1.WMNCHitTest(var Msg : TWMNCHitTest);
begin
inherited;
with Msg do
if PtInRect(CaptionBtn, Point(XPos - Left, YPos - Top)) then
Result := htCaptionBtn;
end;
//Traps a left-click on the caption bar
procedure TForm1.WMNCLButtonDown(var Msg : TWMNCLButtonDown);
begin
inherited;
if (Msg.HitTest = htCaptionBtn) then
ShowMessage('You hit the button on the caption bar');
end;
//Have to perform an NC_ACTIVATE when the form is resized
//so that the caption bar and button are redrawn. This is
//necessary because Win95/NT4+ draw all buttons relative to the
//right side of a window.
procedure TForm1.FormResize(Sender: TObject);
begin
//Force a redraw of caption bar if form is resized
Perform(WM_NCACTIVATE, Word(Active), 0);
end;
end. |
