代码文件:
unit Unit1;interfaceuses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms, Dialogs, StdCtrls, ExtCtrls;type TForm1 = class(TForm) CheckBox1: TCheckBox; ColorListBox1: TColorListBox; procedure FormPaint(Sender: TObject); procedure ColorListBox1Click(Sender: TObject); procedure CheckBox1Click(Sender: TObject); end;var Form1: TForm1;implementation{$R *.dfm}procedure TForm1.CheckBox1Click(Sender: TObject);begin Repaint;end;procedure TForm1.ColorListBox1Click(Sender: TObject);begin Self.Color := ColorListBox1.Selected;end;procedure TForm1.FormPaint(Sender: TObject);const str = 'A';var Rgn: HRGN; x,y: Integer;begin Canvas.Font.Size := 120; Canvas.Font.Style := [fsBold]; SetBkMode(Canvas.Handle, TRANSPARENT); x := (ClientWidth - ColorListBox1.Width - Canvas.TextWidth(str)) div 2; y := -20; {建立路径} BeginPath(Canvas.Handle); Canvas.TextOut(x, y, str); EndPath(Canvas.Handle); {将路径转换为区域} Rgn := PathToRegion(Canvas.Handle); {区域颜色取反} if CheckBox1.Checked then InvertRgn(Canvas.Handle, Rgn); {绘制} Canvas.Brush.Color := clSilver; Canvas.Brush.Style := bsDiagCross; FillRgn(Canvas.Handle, Rgn, Canvas.Brush.Handle); Canvas.Brush.Color := clRed; Canvas.Brush.Style := bsSolid; FrameRgn(Canvas.Handle, Rgn, Canvas.Brush.Handle, 1, 1); DeleteObject(Rgn);end;end. 窗体文件: object Form1: TForm1 Left = 366 Top = 269 Caption = 'Form1' ClientHeight = 179 ClientWidth = 239 Color = clBtnFace Font.Charset = DEFAULT_CHARSET Font.Color = clWindowText Font.Height = -11 Font.Name = 'Tahoma' Font.Style = [] OldCreateOrder = False Position = poDesigned OnPaint = FormPaint PixelsPerInch = 96 TextHeight = 13 object CheckBox1: TCheckBox Left = 32 Top = 152 Width = 97 Height = 25 Caption = #21306#22495#39068#33394#21462#21453 TabOrder = 0 OnClick = CheckBox1Click end object ColorListBox1: TColorListBox Left = 147 Top = 0 Width = 92 Height = 179 Align = alRight ItemHeight = 16 TabOrder = 1 OnClick = ColorListBox1Click endend