ugetbkcolor.pas

DelphiWin32核心API参考光盘内容.是学习书籍中的源码,便于学习.

unit UGetBkColor;

interface

uses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
  {if the background color is not red, make it so}
  if GetBkColor(Canvas.Handle)<>clRed then
    SetBkColor(Canvas.Handle, clRed);

  {output some text. the background color will be used}
  Canvas.TextOut(20, 20, 'Text with a background color');

  {if the background mode is not transparent, make it so}
  if GetBkMode(Canvas.Handle)<>TRANSPARENT then
    SetBkMode(Canvas.Handle, TRANSPARENT);

  {draw some text. the background color will not be used}
  Canvas.TextOut(20, 40, 'Text drawn with a transparent background');
end;

end.