自定義的虛線樣式依賴與一個數組, 數組的元素分別代表虛線中線與間的長度, 數組大小好 像沒有限制;
本例使用了六個元素的數組, 也就是表示虛線有三個線段和和三個間隔構成.
本例效果圖:
代碼文件:unit Unit1;
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, StdCtrls, ExtCtrls, ComCtrls;
type
TForm1 = class(TForm)
Panel1: TPanel;
TrackBar1: TTrackBar;
TrackBar2: TTrackBar;
TrackBar3: TTrackBar;
TrackBar4: TTrackBar;
TrackBar5: TTrackBar;
TrackBar6: TTrackBar;
procedure FormCreate(Sender: TObject);
procedure FormPaint(Sender: TObject);
procedure TrackBar1Change(Sender: TObject);
procedure TrackBar2Change(Sender: TObject);
procedure TrackBar3Change(Sender: TObject);
procedure TrackBar4Change(Sender: TObject);
procedure TrackBar5Change(Sender: TObject);
procedure TrackBar6Change(Sender: TObject);
end;
var
Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
DashArr: array[0..5] of Single;
procedure TForm1.FormCreate(Sender: TObject);
const
n = 100;
begin
TrackBar1.Max := n;
TrackBar2.Max := n;
TrackBar3.Max := n;
TrackBar4.Max := n;
TrackBar5.Max := n;
TrackBar6.Max := n;
TrackBar1.Position := n div 2;
TrackBar2.Position := n div 2;
TrackBar3.Position := n div 2;
TrackBar4.Position := n div 2;
TrackBar5.Position := n div 2;
TrackBar6.Position := n div 2;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
g: TGPGraphics;
p: TGPPen;
rect: TRect;
begin
g := TGPGraphics.Create(Canvas.Handle);
p := TGPPen.Create(aclRed, 4);
DashArr[0] := TrackBar1.Position / 10;
DashArr[1] := TrackBar2.Position / 10;
DashArr[2] := TrackBar3.Position / 10;
DashArr[3] := TrackBar4.Position / 10;
DashArr[4] := TrackBar5.Position / 10;
DashArr[5] := TrackBar6.Position / 10;
p.SetDashPattern(@DashArr, Length(DashArr)); {設置虛線}
g.DrawLine(p, 0, 0, ClientWidth - Panel1.Width, ClientHeight);
rect := Bounds(0, 0, ClientWidth - Panel1.Width, ClientHeight);
InflateRect(rect, -30, -30);
g.DrawEllipse(p, MakeRect(rect));
p.Free;
g.Free;
end;
procedure TForm1.TrackBar1Change(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.TrackBar2Change(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.TrackBar3Change(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.TrackBar4Change(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.TrackBar5Change(Sender: TObject);
begin
Repaint;
end;
procedure TForm1.TrackBar6Change(Sender: TObject);
begin
Repaint;
end;
end.
窗體文件:object Form1: TForm1
Left = 0
Top = 0
Caption = 'Form1'
ClientHeight = 153
ClientWidth = 306
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 Panel1: TPanel
Left = 207
Top = 0
Width = 99
Height = 153
Align = alRight
TabOrder = 0
ExplicitLeft = 200
ExplicitHeight = 205
object TrackBar1: TTrackBar
Left = 0
Top = 8
Width = 97
Height = 20
ShowSelRange = False
TabOrder = 0
OnChange = TrackBar1Change
end
object TrackBar2: TTrackBar
Left = 0
Top = 31
Width = 97
Height = 20
ShowSelRange = False
TabOrder = 1
OnChange = TrackBar2Change
end
object TrackBar3: TTrackBar
Left = 0
Top = 55
Width = 97
Height = 20
ShowSelRange = False
TabOrder = 2
OnChange = TrackBar3Change
end
object TrackBar4: TTrackBar
Left = 0
Top = 79
Width = 97
Height = 20
ShowSelRange = False
TabOrder = 3
OnChange = TrackBar4Change
end
object TrackBar5: TTrackBar
Left = 0
Top = 103
Width = 97
Height = 20
ShowSelRange = False
TabOrder = 4
OnChange = TrackBar5Change
end
object TrackBar6: TTrackBar
Left = 0
Top = 127
Width = 97
Height = 20
ShowSelRange = False
TabOrder = 5
OnChange = TrackBar6Change
end
end
end
