再学 GDI+[67]: 路径画刷(7) - 画个五角星

本例效果图:

---

代码1:

---

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);
const
  pt: TPoint = (X:130; Y:130);
  r = 120;
  colors: array[0..0] of TGPColor = (aclRed);
var
  g: TGPGraphics;
  p: TGPPen;
  path: TGPGraphicsPath;
  pb: TGPPathGradientBrush;
  pts: array[0..4] of TGPPoint;
  radian: Single;
  i,num: Integer;
begin
  for i := 0 to 4 do
  begin
    radian := i * (360*2/5) * (Pi/180);
    pts[i].X := pt.X + Round(Sin(radian) * r);
    pts[i].Y := pt.Y - Round(Cos(radian) * r);
  end;

  g := TGPGraphics.Create(Canvas.Handle);
  path := TGPGraphicsPath.Create;
  path.AddPolygon(PGPPoint(@pts), Length(pts));
  pb:= TGPPathGradientBrush.Create(path);

  num := Length(colors);
  pb.SetSurroundColors(@colors, num);

  pb.SetCenterColor(aclYellow);

  {描个边}
  p := TGPPen.Create(aclYellow);
  g.SetSmoothingMode(SmoothingModeAntiAlias);
  g.DrawPath(p, path);

  g.FillPath(pb, path);

  pb.Free;
  path.Free;
  p.Free;
  g.Free;
end;

end.

代码2:

---

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);
const
  pt: TPoint = (X:130; Y:130);
  r = 120;
  colors: array[0..0] of TGPColor = (aclRed);
var
  g: TGPGraphics;
  p: TGPPen;
  path: TGPGraphicsPath;
  pb: TGPPathGradientBrush;
  pts: array[0..9] of TGPPoint;
  radian: Single;
  i,num: Integer;
  rx: Single;
begin
  for i := 0 to 9 do
  begin
    rx := r;
    if Odd(i) then rx := r * (1- (Sqrt(5)-1)/2); {(Sqrt(5)-1)/2 是黄金分割点, 约为 0.618}
    radian := i * (360/10) * (Pi/180);
    pts[i].X := pt.X + Round(Sin(radian) * rx);
    pts[i].Y := pt.Y - Round(Cos(radian) * rx);
  end;

  g := TGPGraphics.Create(Canvas.Handle);
  path := TGPGraphicsPath.Create;
  path.AddPolygon(PGPPoint(@pts), Length(pts));
  pb:= TGPPathGradientBrush.Create(path);

  num := Length(colors);
  pb.SetSurroundColors(@colors, num);

  pb.SetCenterColor(aclYellow);

  {描个边}
  p := TGPPen.Create(aclYellow);
  g.SetSmoothingMode(SmoothingModeAntiAlias);
  g.DrawPath(p, path);

  g.FillPath(pb, path);

  pb.Free;
  path.Free;
  p.Free;
  g.Free;
end;

end.

窗体文件:

---

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 238
  ClientWidth = 259
  Color = clBtnFace
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  Position = poDesktopCenter
  OnPaint = FormPaint
  PixelsPerInch = 96
  TextHeight = 13
end