再學 GDI+[29]: TGPPen - 自定義復合畫筆 - SetCompoundArray

本例效果圖:

　　代碼文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, StdCtrls, ExtCtrls;
type
　TForm1 = class(TForm)
　　LabeledEdit1: TLabeledEdit;
　　RadioGroup1: TRadioGroup;
　　procedure FormCreate(Sender: TObject);
　　procedure FormPaint(Sender: TObject);
　　procedure RadioGroup1Click(Sender: TObject);
　　procedure LabeledEdit1Change(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
　arr1: array[0..5] of Single; {用於均分線復合畫筆; 數組大小沒有限制, 可用動態數組}
　arr2: array[0..3] of Single; {用於粗細線復合畫筆; 數組大小沒有限制, 可用動態數組}
procedure TForm1.FormCreate(Sender: TObject);
begin
　{均分線復合畫筆; 6 個元素決定 3 條子線; 數組元素為百分比, 應在 0-1 之間}
　arr1[0] := 0.00; {第一線起點}
　arr1[1] := 0.10; {第一線終點}
　arr1[2] := 0.45; {第二線起點}
　arr1[3] := 0.55; {第二線終點}
　arr1[4] := 0.90; {第三線起點}
　arr1[5] := 1.00; {第三線終點}
　{粗細線復合畫筆; 4 個元素決定 2 條子線; }
　arr2[0] := 0.00; {第一線起點}
　arr2[1] := 0.50; {第一線終點}
　arr2[2] := 0.90; {第二線起點}
　arr2[3] := 1.00; {第二線終點}
　LabeledEdit1.EditLabel.Caption := '筆寬';
　LabeledEdit1.Text := '10';
　RadioGroup1.Caption := '線型';
　RadioGroup1.Items.CommaText := '單實線,均分線,粗細線';
　RadioGroup1.ItemIndex := 0;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　p: TGPPen;
　r: TRect;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　g.Clear($FFFFFFFF);
　p := TGPPen.Create(aclCoral);
　p.SetWidth(StrToFloatDef(LabeledEdit1.Text, 10));
　case RadioGroup1.ItemIndex of
　　1: p.SetCompoundArray(@arr1, Length(arr1));
　　2: p.SetCompoundArray(@arr2, Length(arr2));
　end;
　g.DrawLine(p, 0, 0, ClientWidth, ClIEntHeight);
　r := ClIEntRect;
　g.DrawEllipse(p, MakeRect(r));
　InflateRect(r, -ClientWidth div 4, -ClIEntHeight div 4);
　g.DrawLine(p, 0, 0, ClientWidth, ClIEntHeight);
　g.DrawRectangle(p, MakeRect(r));
　p.Free;
　g.Free;
end;
procedure TForm1.LabeledEdit1Change(Sender: TObject);
begin
　Repaint;
end;
procedure TForm1.RadioGroup1Click(Sender: TObject);
begin
　Repaint;
end;
end.窗體文件: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
　OnPaint = FormPaint
　PixelsPerInch = 96
　TextHeight = 13
　object LabeledEdit1: TLabeledEdit
　　Left = 264
　　Top = 19
　　Width = 67
　　Height = 21
　　EditLabel.Width = 61
　　EditLabel.Height = 13
　　EditLabel.Caption = 'LabeledEdit1'
　　TabOrder = 0
　　OnChange = LabeledEdit1Change
　end
　object RadioGroup1: TRadioGroup
　　Left = 264
　　Top = 46
　　Width = 67
　　Height = 66
　　Caption = 'RadioGroup1'
　　TabOrder = 1
　　OnClick = RadioGroup1Click
　end
end