GdiPlus[35]: IGPGraphicsPath (二) 命中测试

IGPGraphicsPath.IsVisible        //指定点是否在路径内

IGPGraphicsPath.IsOutlineVisible //指定点是否在路径轮廓上


 
   

本例测试图:

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本例代码:

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unit Unit1;



interface



uses

  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

  Dialogs;



type

  TForm1 = class(TForm)

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

    procedure FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);

    procedure FormResize(Sender: TObject);

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GdiPlus;



var

  Path1,Path2,Path3: IGPGraphicsPath;

  Pen: IGPPen;



procedure TForm1.FormCreate(Sender: TObject);

var

  R: TRect;

begin

  Pen := TGPPen.Create($FFFF0000, 3);



  Path1 := TGPGraphicsPath.Create;

  Path2 := TGPGraphicsPath.Create;

  Path3 := TGPGraphicsPath.Create;



  Path1.AddLine(0, 0, ClientWidth, ClientHeight);



  R := ClientRect;

  InflateRect(R, -ClientWidth div 3, -ClientHeight div 3);

  OffsetRect(R, -Trunc((R.Right-R.Left) * 0.6), -Trunc((R.Bottom-R.Top) * 0.6));

  Path2.AddRectangle(TGPRect.Create(R));



  OffsetRect(R, R.Right-R.Left, R.Bottom-R.Top);

  Path3.AddEllipse(TGPRect.Create(R));

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  Graphics: IGPGraphics;

begin

  Graphics := TGPGraphics.Create(Handle);

  with Graphics do

  begin

    DrawPath(Pen, Path1);

    DrawPath(Pen, Path2);

    DrawPath(Pen, Path3);

  end;

end;



procedure TForm1.FormMouseMove(Sender: TObject; Shift: TShiftState; X, Y: Integer);

var

  Pt: TGPPoint;

  str: string;

begin

  Pt.Initialize(X, Y);

  str := '';

  if Path2.IsVisible(Pt) then str := '在矩形内';

  if Path3.IsVisible(Pt) then str := '在椭圆内';



  if Path1.IsOutlineVisible(Pt, Pen) then str := '在直线上';

  if Path2.IsOutlineVisible(Pt, Pen) then str := '在矩形的边线上';

  if Path3.IsOutlineVisible(Pt, Pen) then str := '在椭圆的圆周线上';



  if Text <> str then Text := str;

end;



procedure TForm1.FormResize(Sender: TObject);

begin

  OnCreate(Sender);

  Repaint;

end;



end.