再学 GDI+[51]: 路径 - IsVisible、IsOutlineVisible

本例效果图:

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代码文件:

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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 FormDestroy(Sender: TObject);

    procedure FormPaint(Sender: TObject);

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

  end;



var

  Form1: TForm1;



implementation



{$R *.dfm}



uses GDIPOBJ, GDIPAPI;



var

  path1,path2,path3: TGPGraphicsPath;

  p: TGPPen;



procedure TForm1.FormCreate(Sender: TObject);

var

  r: TRect;

begin

  path1 := TGPGraphicsPath.Create;

  path2 := TGPGraphicsPath.Create;

  path3 := TGPGraphicsPath.Create;

  p := TGPPen.Create(aclRed, 3);



  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(MakeRect(r));



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

  path3.AddEllipse(MakeRect(r));

end;



procedure TForm1.FormDestroy(Sender: TObject);

begin

  path1.Free;

  path2.Free;

  path3.Free;

  p.Free;

end;



procedure TForm1.FormPaint(Sender: TObject);

var

  g: TGPGraphics;

begin

  g := TGPGraphics.Create(Canvas.Handle);

  g.DrawPath(p, path1);

  g.DrawPath(p, path2);

  g.DrawPath(p, path3);

  g.Free;

end;



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

  Y: Integer);

begin

  Text := '';

//  if path1.IsVisible(MakePoint(X,Y)) then Text := '在 path1 内';

  if path2.IsVisible(MakePoint(X,Y)) then Text := '在矩形内';

  if path3.IsVisible(MakePoint(X,Y)) then Text := '在椭圆内';



  if path1.IsOutlineVisible(X, Y, p) then Text := '在直线上';

  if path2.IsOutlineVisible(X, Y, p) then Text := '在矩形的边线上';

  if path3.IsOutlineVisible(X, Y, p) then Text := '在椭圆的圆周线上';

end;



end.


 
   

窗体文件:

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object Form1: TForm1

  Left = 0

  Top = 0

  Caption = 'Form1'

  ClientHeight = 206

  ClientWidth = 339

  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