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Delphi代码

unit Unit1;

interface

uses
SysUtils, WinTypes, WinProcs, Messages, Classes, Graphics, Controls,
Forms, Dialogs, Buttons, DdeMan, StdCtrls;

type
TTitleBtnForm = class(TForm)
Button1: TButton;
procedure FormResize(Sender: TObject);
private
TitleButton : TRect;
procedure DrawTitleButton;
{Paint-related messages}
procedure WMSetText(var Msg : TWMSetText); message WM_SETTEXT;
procedure WMNCPaint(var Msg : TWMNCPaint); message WM_NCPAINT;
procedure WMNCActivate(var Msg : TWMNCActivate); message WM_NCACTIVATE;
{Mouse down-related messages}
procedure WMNCHitTest(var Msg : TWMNCHitTest); message WM_NCHITTEST;
procedure WMNCLButtonDown(var Msg : TWMNCLButtonDown); message WM_NCLBUTTONDOWN;
function GetVerInfo : DWORD;
end;

var
TitleBtnForm: TTitleBtnForm;

const
htTitleBtn = htSizeLast + 1;

implementation
{$R *.DFM}

procedure TTitleBtnForm.DrawTitleButton;
var
bmap : TBitmap; {Bitmap to be drawn - 16 X 16 : 16 Colors}
XFrame, {X and Y size of Sizeable area of Frame}
YFrame,
XTtlBit, {X and Y size of Bitmaps in caption}
YTtlBit : Integer;
begin
{Get size of form frame and bitmaps in title bar}
XFrame := GetSystemMetrics(SM_CXFRAME);
YFrame := GetSystemMetrics(SM_CYFRAME);
XTtlBit := GetSystemMetrics(SM_CXSIZE);
YTtlBit := GetSystemMetrics(SM_CYSIZE);

{$IFNDEF WIN32}
TitleButton := Bounds(Width - (3 * XTtlBit) - ((XTtlBit div 2) - 2),
YFrame - 1,
XTtlBit + 2,
YTtlBit + 2);

{$ELSE} {Delphi 2.0 positioning}
if (GetVerInfo = VER_PLATFORM_WIN32_NT) then
TitleButton := Bounds(Width - (3 * XTtlBit) - ((XTtlBit div 2) - 2),
YFrame - 1,
XTtlBit + 2,
YTtlBit + 2)
else
TitleButton := Bounds(Width - XFrame - 4*XTtlBit + 2,
XFrame + 2,
XTtlBit + 2,
YTtlBit + 2);
{$ENDIF}


Canvas.Handle := GetWindowDC(Self.Handle); {Get Device context for drawing}
try
{Draw a button face on the TRect}
DrawButtonFace(Canvas, TitleButton, 1, bsAutoDetect, False, False, False);
bmap := TBitmap.Create;
bmap.LoadFromFile('c:windowsdesktopaaa.bmp');
with TitleButton do
{$IFNDEF WIN32}
Canvas.Draw(Left + 2, Top + 2, bmap);
{$ELSE}
if (GetVerInfo = VER_PLATFORM_WIN32_NT) then
Canvas.Draw(Left + 2, Top + 2, bmap)
else
Canvas.StretchDraw(TitleButton, bmap);
{$ENDIF}

finally
ReleaseDC(Self.Handle, Canvas.Handle);
bmap.Free;
Canvas.Handle := 0;
end;
end;

{Paint triggering events}
procedure TTitleBtnForm.WMNCActivate(var Msg : TWMNCActivate);
begin
Inherited;
DrawTitleButton;
end;

procedure TTitleBtnForm.FormResize(Sender: TObject);
begin
Perform(WM_NCACTIVATE, Word(Active), 0);
end;

{Painting events}
procedure TTitleBtnForm.WMNCPaint(var Msg : TWMNCPaint);
begin
Inherited;
DrawTitleButton;
end;

procedure TTitleBtnForm.WMSetText(var Msg : TWMSetText);
begin
Inherited;
DrawTitleButton;
end;

{Mouse-related procedures}
procedure TTitleBtnForm.WMNCHitTest(var Msg : TWMNCHitTest);
begin
Inherited;
{Check to see if the mouse was clicked in the area of the button}
with Msg do
if PtInRect(TitleButton, Point(XPos - Left, YPos - Top)) then
Result := htTitleBtn;
end;

procedure TTitleBtnForm.WMNCLButtonDown(var Msg : TWMNCLButtonDown);
begin
inherited;
if (Msg.HitTest = htTitleBtn) then
ShowMessage('You pressed the new button');
end;

function TTitleBtnForm.GetVerInfo : DWORD;
var
verInfo : TOSVERSIONINFO;
begin
result:=0;
verInfo.dwOSVersionInfoSize := SizeOf(TOSVersionInfo);
if GetVersionEx(verInfo) then
Result := verInfo.dwPlatformID;
{Returns:
VER_PLATFORM_WIN32s Win32s on Windows 3.1
VER_PLATFORM_WIN32_WINDOWS Win32 on Windows 95
VER_PLATFORM_WIN32_NT Windows NT }
end;

end.