getdcu.pas

Delphi Win32核心API参考光盘源码 本书包含了常用的Windows API函数

unit GetDCU;

interface

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

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

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.FormPaint(Sender: TObject);
var
  FormDC: HDC;      // holds the device context
  OldFont: HFONT;   // holds the original font
begin
  {retrieve a common device context for the form}
  FormDC := GetDC(Form1.Handle);

  {select the form's font into the device context}
  OldFont := SelectObject(FormDC, Form1.Font.Handle);

  {output some text onto the device context}
  SetBkMode(FormDC, TRANSPARENT);
  TextOut(FormDC, 10, 10, 'Delphi Rocks!', Length('Delphi Rocks!'));

  {reselect the original font and release the device context}
  SelectObject(FormDC, OldFont);
  ReleaseDC(Form1.Handle, FormDC);
end;

end.