再學 GDI+[36]: TGPPen - SetLineCap

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)
　　ComboBox1: TComboBox;
　　ComboBox2: TComboBox;
　　ComboBox3: TComboBox;
　　ComboBox4: TComboBox;
　　procedure FormCreate(Sender: TObject);
　　procedure FormPaint(Sender: TObject);
　　procedure ComboBox1Change(Sender: TObject);
　　procedure ComboBox2Change(Sender: TObject);
　　procedure ComboBox3Change(Sender: TObject);
　　procedure ComboBox4Change(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI, TypInfo;
var StartCap,EndCap,DashCap: Integer;
procedure TForm1.FormCreate(Sender: TObject);
var
　i: Integer;
begin
　ComboBox1.Text := '虛線樣式';
　ComboBox2.Text := '起點線帽';
　ComboBox3.Text := '中間線帽';
　ComboBox4.Text := '終點線帽';
　for i := 0 to 5 do
　　ComboBox1.Items.Add(GetEnumName(TypeInfo(TDashStyle), i));
　ComboBox2.Items.Add('LineCapFlat');
　ComboBox2.Items.Add('LineCapSquare');
　ComboBox2.Items.Add('LineCapRound');
　ComboBox2.Items.Add('LineCapTriangle');
　ComboBox2.Items.Add('LineCapNoAnchor');
　ComboBox2.Items.Add('LineCapSquareAnchor');
　ComboBox2.Items.Add('LineCapRoundAnchor');
　ComboBox2.Items.Add('LineCapDiamondAnchor');
　ComboBox2.Items.Add('LineCapArrowAnchor');
　ComboBox3.Items := ComboBox2.Items;
　ComboBox4.Items := ComboBox2.Items;
end;
procedure TForm1.FormPaint(Sender: TObject);
const
　ColorArr: array[0..2] of TGPColor = (aclRed, aclGreen, aclBlue);
var
　g: TGPGraphics;
　p: TGPPen;
　x1,x2,y: Integer;
　i: Integer;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create($FF000000, 16);
　p.SetDashStyle(TDashStyle(ComboBox1.ItemIndex));
　p.SetLineCap(StartCap, EndCap, DashCap);
　x1 := 50;
　x2 := ClIEntWidth - 50;
　y := 60;
　for i := 0 to 2 do
　begin
　　p.SetColor(ColorArr[i]);
　　g.DrawLine(p, x1, y, x2, y);
　　Inc(y, 40);
　end;
　p.Free;
　g.Free;
end;
procedure TForm1.ComboBox1Change(Sender: TObject);
begin
　Repaint;
end;
procedure TForm1.ComboBox2Change(Sender: TObject);
var
　i: Integer;
begin
　i := 0;
　case TComboBox(Sender).ItemIndex of
　　0 : i := LineCapFlat;
　　1 : i := LineCapSquare;
　　2 : i := LineCapRound;
　　3 : i := LineCapTriangle;
　　4 : i := LineCapNoAnchor;
　　5 : i := LineCapSquareAnchor;
　　6 : i := LineCapRoundAnchor;
　　7 : i := LineCapDiamondAnchor;
　　8 : i := LineCapArrowAnchor;
　　9 : i := LineCapCustom;
　　10: i := LineCapAnchorMask;
　end;
　if TComboBox(Sender) = ComboBox2 then StartCap := i;
　if TComboBox(Sender) = ComboBox3 then DashCap := i;
　if TComboBox(Sender) = ComboBox4 then EndCap := i;
　Repaint;
end;
procedure TForm1.ComboBox3Change(Sender: TObject);
begin
　ComboBox2Change(Sender);
end;
procedure TForm1.ComboBox4Change(Sender: TObject);
begin
　ComboBox2Change(Sender);
end;
end.窗體文件:object Form1: TForm1
　Left = 0
　Top = 0
　Caption = 'Form1'
　ClIEntHeight = 165
　ClIEntWidth = 515
　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 ComboBox1: TComboBox
　　Left = 8
　　Top = 8
　　Width = 121
　　Height = 21
　　ItemHeight = 13
　　TabOrder = 0
　　Text = 'ComboBox1'
　　OnChange = ComboBox1Change
　end
　object ComboBox2: TComboBox
　　Left = 135
　　Top = 8
　　Width = 121
　　Height = 21
　　ItemHeight = 13
　　TabOrder = 1
　　Text = 'ComboBox2'
　　OnChange = ComboBox2Change
　end
　object ComboBox3: TComboBox
　　Left = 262
　　Top = 8
　　Width = 121
　　Height = 21
　　ItemHeight = 13
　　TabOrder = 2
　　Text = 'ComboBox3'
　　OnChange = ComboBox3Change
　end
　object ComboBox4: TComboBox
　　Left = 389
　　Top = 8
　　Width = 121
　　Height = 21
　　ItemHeight = 13
　　TabOrder = 3
　　Text = 'ComboBox4'
　　OnChange = ComboBox4Change
　end
end