本例效果圖:
代碼文件:unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls;
type
TForm1 = class(TForm)
procedure FormPaint(Sender: TObject);
procedure FormCreate(Sender: TObject);
procedure FormDestroy(Sender: TObject);
procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var rgn: TGPRegion;
procedure TForm1.FormCreate(Sender: TObject);
var
rt: TRect;
path: TGPGraphicsPath;
begin
rt := ClientRect;
InflateRect(rt, -20, -20);
{建立區域}
rgn := TGPRegion.Create(MakeRect(rt));
{建立路徑}
InflateRect(rt, -2, -2);
path := TGPGraphicsPath.Create;
path.AddEllipse(MakeRect(rt));
{從區域中減去路徑}
rgn.Exclude(path);
path.Free;
end;
procedure TForm1.FormDestroy(Sender: TObject);
begin
rgn.Free;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
g: TGPGraphics;
b: TGPBrush;
begin
g := TGPGraphics.Create(Canvas.Handle);
b := TGPHatchBrush.Create(HatchStyleMin, aclSilver, aclRed);
g.FillRegion(b, rgn);
b.Free;
g.Free;
end;
procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X,
Y: Integer);
begin
Text := 'Form1';
if rgn.IsVisible(X, Y) then Text := '在區域中';
end;
end.
窗體文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 129
ClientWidth = 177
Color = clBtnFace
Font.Charset = DEFAULT_CHARSET
Font.Color = clWindowText
Font.Height = -11
Font.Name = 'Tahoma'
Font.Style = []
OldCreateOrder = False
Position = poDesktopCenter
OnCreate = FormCreate
OnDestroy = FormDestroy
OnMouseMove = FormMouseMove
OnPaint = FormPaint
PixelsPerInch = 96
TextHeight = 13
end
