再學GDI+[2]: DrawLine - 繪制直線

本例效果圖:

unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs;
type
　TForm1 = class(TForm)
　　procedure FormPaint(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　p: TGPPen;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(MakeColor(255,0,0), 2);
　g.Clear(MakeColor(255,255,255));
　g.DrawLine(p, 20, 40, 200, 40);　　　　　　　　　　　　　　　　 {參數是整數}
　g.DrawLine(p, MakePoint(20,60), MakePoint(200,60));　　　　　　 {參數是點(整數)}
　g.DrawLine(p, 20.9, 80.0, 200.9, 80.0);　　　　　　　　　　　　 {參數是小數}
　g.DrawLine(p, MakePoint(20.9, 100.0), MakePoint(200.9, 100.0)); {參數是點(小數)}
　g.Free;
　p.Free;
end;
end.