一个抓屏的函数 delphi

最新推荐文章于 2024-11-27 08:30:00 发布

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原文链接：http://www.cnblogs.com/fubin/archive/2009/05/27/1491178.html

本文介绍了一个用于屏幕截图的函数，该函数可以捕获指定区域的屏幕内容并保存为位图文件。通过两个按钮触发，一个用于截图并显示图片，另一个用于关闭程序。

一个抓屏的函数,在其它Blog上看到的

Code
unit Main;

interface

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

type
  TMainFrm = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Image1: TImage;
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
  private
    { Private declarations }
    procedure ScreenShot(x : integer; y : integer; Width : integer; Height : integer; bm : TBitMap);
  public
    { Public declarations }
  end;

var
  MainFrm: TMainFrm;

implementation

{$R *.dfm}

//调用方法
procedure TMainFrm.Button1Click(Sender: TObject);
var
  tBM : TBitmap;
begin
  try
    tBM := TBitmap.Create;
    ScreenShot(0,0,Screen.Width,Screen.height,tBM);
    tBM.SaveToFile('c:\ScreenShot.BMP');
    Image1.Picture.Bitmap := tBM;
    //image1.Picture.LoadFromFile('c:\screenshot.bmp');
  finally
    tBm.FreeImage;
    FreeAndNil(tBM);
  end;
end;

procedure TMainFrm.Button2Click(Sender: TObject);
begin
  Self.Close;
end;

procedure TMainFrm.ScreenShot(x : integer; y : integer; Width : integer; Height : integer; bm : TBitMap);
var
dc: HDC; lpPal : PLOGPALETTE;
begin
  // 检测所需抓屏的区域
  if ((Width = 0) or (Height = 0)) then exit;
  bm.Width := Width;
  bm.Height := Height;
  //获取设备上下文
  dc := GetDc(0);
  if (dc = 0) then exit;
  {do we have a palette device?}
  if (GetDeviceCaps(dc, RASTERCAPS) AND
    RC_PALETTE = RC_PALETTE) then
    begin
    {allocate memory for a logical palette}
    GetMem(lpPal, sizeof(TLOGPALETTE) + (255 * sizeof(TPALETTEENTRY)));
    {zero it out to be neat}
    FillChar(lpPal^, sizeof(TLOGPALETTE) + (255 * sizeof(TPALETTEENTRY)), #0);
    {fill in the palette version}
    lpPal^.palVersion := $300;
    {grab the system palette entries}
    lpPal^.palNumEntries :=
      GetSystemPaletteEntries(dc,0,256,lpPal^.palPalEntry);
    if (lpPal^.PalNumEntries <> 0) then
    begin
      {create the palette}
      bm.Palette := CreatePalette(lpPal^);
    end;
    FreeMem(lpPal, sizeof(TLOGPALETTE) + (255 * sizeof(TPALETTEENTRY)));
    end;
  {copy from the screen to the bitmap}
  BitBlt(bm.Canvas.Handle,0,0,Width,Height,Dc,x,y,SRCCOPY);
  {release the screen dc}
  ReleaseDc(0, dc);
end;

end.

转载于:https://www.cnblogs.com/fubin/archive/2009/05/27/1491178.html