再学 GDI+[53]: 路径 SetFillMode

本例效果图:

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代码文件:

---

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    RadioGroup1: TRadioGroup;
    procedure FormCreate(Sender: TObject);
    procedure FormPaint(Sender: TObject);
    procedure RadioGroup1Click(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GDIPOBJ, GDIPAPI, TypInfo;

procedure TForm1.FormCreate(Sender: TObject);
var
  i: Integer;
begin
  RadioGroup1.Columns := 2;
  RadioGroup1.Caption := '路径填充模式';
  for i := 0 to 1 do
    RadioGroup1.Items.Add(GetEnumName(TypeInfo(TFillMode), i));
  RadioGroup1.ItemIndex := 0;
end;

procedure TForm1.FormPaint(Sender: TObject);
var
  g: TGPGraphics;
  b: TGPBrush;
  p: TGPPen;
  path: TGPGraphicsPath;
  rect: TRect;
begin
  g := TGPGraphics.Create(Canvas.Handle);
  b := TGPHatchBrush.Create(HatchStyleCross, aclSilver, aclKhaki);
  p := TGPPen.Create(aclRed, 1.75);

  path := TGPGraphicsPath.Create;
  rect := Bounds(10, 20, 150, 100);
  path.AddEllipse(MakeRect(rect));
  OffsetRect(rect, 60, 0);
  path.AddEllipse(MakeRect(rect));

  if RadioGroup1.ItemIndex = 1 then path.SetFillMode(FillModeWinding);

  g.FillPath(b, path);
  g.DrawPath(p, path);

  p.Free;
  b.Free;
  path.Free;
  g.Free;
end;

procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
  Repaint;
end;

end.

窗体文件:

---

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 184
  ClientWidth = 233
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnCreate = FormCreate
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
  object RadioGroup1: TRadioGroup
    Left = 5
    Top = 137
    Width = 224
    Height = 39
    Caption = 'RadioGroup1'
    TabOrder = 0
    OnClick = RadioGroup1Click
  end
end