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 程式師世界 >> 編程語言 >> 更多編程語言 >> Delphi >> 再學GDI+[9]: DrawPolygon - 繪制多邊形

再學GDI+[9]: DrawPolygon - 繪制多邊形

編輯:Delphi

本例效果圖:

代碼文件:unit Unit1;
interface
uses
 Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
 Dialogs, StdCtrls;
type
 TForm1 = class(TForm)
  Button1: TButton;
  Button2: TButton;
  procedure FormMouseUp(Sender: TObject; Button: TMouseButton;
   Shift: TShiftState; X, Y: Integer);
  procedure FormPaint(Sender: TObject);
  procedure Button1Click(Sender: TObject);
  procedure Button2Click(Sender: TObject);
 end;
var
 Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
 PtArr: array of TGPPoint;
 i: Integer = 0;
procedure TForm1.FormMouseUp(Sender: TObject; Button: TMouseButton;
 Shift: TShiftState; X, Y: Integer);
begin
 Canvas.Ellipse(X-2, Y-2, X+2, Y+2);
 Inc(i);
 SetLength(PtArr, i);
 PtArr[i-1].X := X;
 PtArr[i-1].Y := Y;
 Text := IntToStr(i);
end;
procedure TForm1.FormPaint(Sender: TObject);
var
 g: TGPGraphics;
 p: TGPPen;
begin
 g := TGPGraphics.Create(Canvas.Handle);
 p := TGPPen.Create(aclRed, 2);
 g.Clear(aclWhite);
 {如果是動態數組的話, 需要 @PtArr, 但動態數組本身就是個指針}
 g.DrawPolygon(p, PGPPoint(PtArr), Length(PtArr));
 g.Free;
 p.Free;
end;
procedure TForm1.Button1Click(Sender: TObject);
begin
 i := 0;
 SetLength(PtArr, i);
 Repaint;
 Text := IntToStr(i);
end;
procedure TForm1.Button2Click(Sender: TObject);
begin
 Repaint;
end;
end.

窗體文件:object Form1: TForm1
 Left = 0
 Top = 0
 Caption = 'Form1'
 ClientHeight = 188
 ClientWidth = 264
 Color = clBtnFace
 Font.Charset = DEFAULT_CHARSET
 Font.Color = clWindowText
 Font.Height = -11
 Font.Name = 'Tahoma'
 Font.Style = []
 OldCreateOrder = False
 Position = poDesktopCenter
 OnMouseUp = FormMouseUp
 OnPaint = FormPaint
 PixelsPerInch = 96
 TextHeight = 13
 object Button1: TButton
  Left = 98
  Top = 155
  Width = 75
  Height = 25
  Caption = #25830#38500
  TabOrder = 0
  OnClick = Button1Click
 end
 object Button2: TButton
  Left = 179
  Top = 155
  Width = 75
  Height = 25
  Caption = #32472#21046
  TabOrder = 1
  OnClick = Button2Click
 end
end

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