几何变换也就是 Matrix 变换, 画笔的 Matrix 会忽略 dx、dy 平移参数; 选择 LineCapRound 线帽效果比较好.

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本例效果图:

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代码文件:

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unit Unit1;interfaceusesWindows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,Dialogs, ComCtrls, StdCtrls, ExtCtrls;typeTForm1 = class(TForm)Panel1: TPanel;Button1: TButton;TrackBar1: TTrackBar;TrackBar2: TTrackBar;TrackBar3: TTrackBar;TrackBar4: 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);end;varForm1: TForm1;implementation{$R *.dfm}uses GDIPOBJ, GDIPAPI;procedure TForm1.FormCreate(Sender: TObject);
constn = 40;
beginTrackBar1.Min := -n;TrackBar1.Max := n;TrackBar2.Min := -n;TrackBar2.Max := n;TrackBar3.Min := -n;TrackBar3.Max := n;TrackBar4.Min := -n;TrackBar4.Max := n;TrackBar1.Position := 10;TrackBar2.Position := 0;TrackBar3.Position := 0;TrackBar4.Position := 10;Button1.OnClick := FormCreate;
end;procedure TForm1.FormPaint(Sender: TObject);
varg: TGPGraphics;b: TGPBrush;p: TGPPen;matrix: TGPMatrix;m11, m12, m21, m22: Single;
beging := TGPGraphics.Create(Canvas.Handle);b := TGPHatchBrush.Create(HatchStyleLargeGrid, aclForestGreen);p := TGPPen.Create(b, 16);m11 := TrackBar1.Position / 10;m12 := TrackBar2.Position / 10;m21 := TrackBar3.Position / 10;m22 := TrackBar4.Position / 10;matrix := TGPMatrix.Create(m11, m12, m21, m22, 0, 0);p.SetTransform(matrix);p.SetStartCap(LineCapRound);p.SetEndCap(LineCapRound);g.DrawLine(p, 30, 30, ClientWidth - Panel1.Width - 30, ClientHeight - 30);matrix.Free;b.Free;p.Free;g.Free;
end;procedure TForm1.TrackBar1Change(Sender: TObject);
beginRepaint;
end;procedure TForm1.TrackBar2Change(Sender: TObject);
beginRepaint;
end;procedure TForm1.TrackBar3Change(Sender: TObject);
beginRepaint;
end;procedure TForm1.TrackBar4Change(Sender: TObject);
beginRepaint;
end;end.

窗体文件:

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object Form1: TForm1Left = 0Top = 0Caption = 'Form1'ClientHeight = 184ClientWidth = 327Color = clBtnFaceFont.Charset = DEFAULT_CHARSETFont.Color = clWindowTextFont.Height = -11Font.Name = 'Tahoma'Font.Style = []OldCreateOrder = FalsePosition = poDesktopCenterOnCreate = FormCreateOnPaint = FormPaintPixelsPerInch = 96TextHeight = 13object Panel1: TPanelLeft = 228Top = 0Width = 99Height = 184Align = alRightTabOrder = 0ExplicitLeft = 225ExplicitHeight = 170object Button1: TButtonLeft = 14Top = 8Width = 75Height = 25Caption = #21021#22987#21270TabOrder = 0endobject TrackBar1: TTrackBarLeft = 0Top = 39Width = 100Height = 20ShowSelRange = FalseTabOrder = 1OnChange = TrackBar1Changeendobject TrackBar2: TTrackBarLeft = 0Top = 72Width = 100Height = 20ShowSelRange = FalseTabOrder = 2OnChange = TrackBar2Changeendobject TrackBar3: TTrackBarLeft = 0Top = 106Width = 100Height = 20ShowSelRange = FalseTabOrder = 3OnChange = TrackBar3Changeendobject TrackBar4: TTrackBarLeft = 0Top = 140Width = 100Height = 20ShowSelRange = FalseTabOrder = 4OnChange = TrackBar4Changeendend
end