再学 GDI+[36]: TGPPen - SetLineCap

本例效果图:

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代码文件:

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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 := '虚线样式';

  ComboBox2.Text := '起点线帽';

  ComboBox3.Text := '中间线帽';

  ComboBox4.Text := '终点线帽';



  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.


 
   

窗体文件:

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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