unit Unit1;interfaceuses  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,  Dialogs, StdCtrls;type  TForm1 = class(TForm)    Button1: TButton;    Button2: TButton;    procedure Button1Click(Sender: TObject);    procedure Button2Click(Sender: TObject);  end;var  Form1: TForm1;implementation{$R *.dfm}//把文字输出到屏幕procedure TForm1.Button1Click(Sender: TObject);var  cvs: TCanvas;  Rect: TRect;  Str: string;begin  cvs := TCanvas.Create; // 现场创建  cvs.Handle := GetDC(0);  SetBkMode(cvs.Handle, TRANSPARENT); // 设置指定DC的背景混合模式，应用于文字、画刷和画笔风格（当它们不是sold风格的时候），有OPAQUE和TRANSPARENT两种模式  //cvs.Font.Name := ‘宋体‘;  cvs.Font.Style := [fsBold, fsItalic];  cvs.Font.Size := 48;  Randomize;  cvs.Font.Color := Random($FFFFFF);  Rect := Screen.DesktopRect; // 取得屏幕的区域  Str := ‘万一的 Delphi 博客‘;  cvs.TextRect(Rect, Str, [tfSingleLine, tfCenter, tfVerticalCenter]); // 在指定区域内输出文字，单行，居中，竖向居中  cvs.Free;end;//刷新显示procedure TForm1.Button2Click(Sender: TObject);begin  InvalidateRect(0, nil, False);end;end.