GdiPlus[32]: IGPPen: LineJoin、MiterLimit

LineJoin 测试效果图:

---

LineJoin 测试代码:

---

uses GdiPlus;

procedure TForm1.FormPaint(Sender: TObject);
const
  Pts: array[0..2] of TGPPoint = ((X:90;Y:80), (X:240;Y:30), (X:240;Y:80));
var
  Graphics: IGPGraphics;
  Pen: IGPPen;
begin
  Graphics := TGPGraphics.Create(Handle);
  Pen := TGPPen.Create(TGPColor.Red, 28);

  Pen.LineJoin := LineJoinMiter; //默认值
  Graphics.DrawPolygon(Pen, Pts);
  Graphics.TranslateTransform(0, 80);

  Pen.LineJoin := LineJoinBevel;
  Graphics.DrawPolygon(Pen, Pts);
  Graphics.TranslateTransform(0, 80);

  Pen.LineJoin := LineJoinRound;
  Graphics.DrawPolygon(Pen, Pts);
end;

MiterLimit 测试效果图:

---

MiterLimit 测试代码:

---

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    TrackBar1: TTrackBar;
    procedure FormPaint(Sender: TObject);
    procedure TrackBar1Change(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

uses GdiPlus;

procedure TForm1.FormCreate(Sender: TObject);
begin
  TrackBar1.ShowSelRange := False;
  TrackBar1.Height := 23;
  TrackBar1.Min := 0;
  TrackBar1.Max := 100;
  TrackBar1.Position := TrackBar1.Max;
end;

procedure TForm1.FormPaint(Sender: TObject);
const
  PtArr: array[0..2] of TGPPoint = ((X:90;Y:80), (X:240;Y:30), (X:240;Y:80));
var
  Graphics: IGPGraphics;
  Pen: IGPPen;
begin
  Graphics := TGPGraphics.Create(Canvas.Handle);
  Pen := TGPPen.Create($FF2E8B57, 28);

  Pen.MiterLimit := TrackBar1.Position / 10;
  Graphics.DrawPolygon(Pen, PtArr);
end;

procedure TForm1.TrackBar1Change(Sender: TObject);
begin
  Repaint;
end;

end.

MiterLimit 测试窗体:

---

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 138
  ClientWidth = 266
  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 TrackBar1: TTrackBar
    Left = 2
    Top = 112
    Width = 261
    Height = 45
    TabOrder = 0
    OnChange = TrackBar1Change
  end
end