如何将显示器上某个指定区域的内容抓成BMP图像文件?

Question

如何将显示器上某个指定区域的内容抓成BMP图像文件?

Answer 1

可以下个抓屏软件，如HyperCam，可以是图片也可是动态的。

Answer 2

procedure TForm1.FormClick(Sender: TObject);
var winHWND, hCur:integer; 
     winDC:integer;
     rect:TRect;
     //AFormat : Word;
     //AData,APalette : THandle;
     pt:TPoint;
     fBitmap:TBitmap;
begin
     hCur := GetCursor(); // 获 得 光 标 句 柄 
     GetCursorPos(pt); // 记 录 光 标 位 置 
     winHWND := GetDesktopWindow(); 
     winDC := GetDC(winHWND); 
     GetWindowRect(winHWND, rect); 
     fBitmap := TBitmap.create; 
     fBitmap.width := rect.right-rect.left; 
     fBitmap.height := rect.bottom-rect.top; 
     BitBlt(fBitmap.canvas.handle, 0, 0, fBitmap.width, fBitmap.height, winDC, 0, 0, SRCCOPY); 
     DrawIcon(fBitmap.canvas.handle, pt.x, pt.y, hCur); // 画 光 标 
     ReleaseDC(winHWND, winDC); 
     Image1.Picture.Bitmap.Assign(fBitmap);
     fBitmap.Free;
end;

Answer 3

var
  hScr :long;
  bmp  :TBitmap;
  sw,sh,sl,st,w,h:integer;
begin
  sl := 0;
  st := 0;
  sw := 100;
  sh := 100;
  w  := 200;
  h  := 200;
  hScr := CreateDC("DISPLAY",0,0,0);
  if(hScr<>0)
    begin
      bmp := TBitmap.Create();
      bmp.Width:=w;
      bmp.Height:=h;
      StretchBlt(bmp.Canvas.Handle,0,0,w,h,hScr,sl,st,sw,sh,SRCCOPY);
      DeleteDC(hScr);
      bmp.SaveToFile('my.bmp');
      bmp.Destroy();
    end
end

Answer 4

BCB写的代码，可以抓整屏、自己由鼠标选区域抓取。
#ifndef untCaptureH
#define untCaptureH#include <Classes.hpp>
#include <Controls.hpp>
#include <StdCtrls.hpp>
#include <Forms.hpp>
#include <Dialogs.hpp>
#include <ExtCtrls.hpp>
#include <Menus.hpp>class TForm1 : public TForm
{
__published: // IDE-managed Components
    TScrollBox *ScrollBox1;
    TMainMenu *MainMenu1;
    TSaveDialog *SaveDialog1;
    TImage *Image1;
    TMenuItem *File1;
    TMenuItem *Save1;
    TMenuItem *Exit1;
    TMenuItem *Action1;
    TMenuItem *N1;
    TMenuItem *N2;
    TMenuItem *N3;
    void __fastcall FormCreate(TObject *Sender);
    void __fastcall FormDestroy(TObject *Sender);
    void __fastcall Save1Click(TObject *Sender);
    void __fastcall N1Click(TObject *Sender);
    void __fastcall N2Click(TObject *Sender);
    void __fastcall N3Click(TObject *Sender);
    void __fastcall Exit1Click(TObject *Sender);
    void __fastcall CaptureDesktop(HDC DesImage);
    HWND __fastcall GetTopWndHandle(void);
    void __fastcall CaptureWndImage(TRect rect);
private: // User declarations
public: // User declarations
    __fastcall TForm1(TComponent* Owner);
};extern PACKAGE TForm1 *Form1;
#endif
////实现代码///////////
#include <vcl.h>
#include <math.h>
#pragma hdrstop#include "untCapture.h"
#include "untShow.h"#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
Graphics::TBitmap *KABitmap;//捕获整个窗口
void __fastcall TForm1::CaptureDesktop(HDC DesImage)
{
    HDC hdc = GetDC(0);
    BitBlt(DesImage,0,0,Screen->Width,Screen->Height,hdc,0,0,SRCCOPY);
    ReleaseDC(0,hdc);
}//捕获活动窗口
HWND __fastcall TForm1::GetTopWndHandle(void)
{
    HWND hwnd = GetTopWindow(0);
    while(hwnd != 0)
    {
        if(IsWindowVisible(hwnd) && (GetWindowLong(hwnd,GWL_EXSTYLE) & WS_EX_TOPMOST) == 0)
        {
            if(IsIconic(hwnd))
                hwnd = GetDesktopWindow();
            return hwnd;
        }
        hwnd = GetNextWindow(hwnd,GW_HWNDNEXT);
    }
    return 0;
}void __fastcall TForm1::CaptureWndImage(TRect rect)
{
    // First set the size of the Bitmap.
    KABitmap->Width = rect.Right - rect.Left;
    KABitmap->Height = rect.Bottom - rect.Top;
    // Get the seleted part of the Desktop Image
    //    ScreenDC = GetDC( 0 );
    HDC  ScreenDC= GetDC(0);
    try
    {
        StretchBlt(KABitmap->Canvas->Handle, 0, 0,
                 KABitmap->Width, KABitmap->Height, ScreenDC,
                 rect.Left, rect.Top,
                 KABitmap->Width,
                 KABitmap->Height,
                 SRCCOPY);
    }
    __finally
    {
        ReleaseDC(0, ScreenDC);
    }
}__fastcall TForm1::TForm1(TComponent* Owner)
    : TForm(Owner)
{
}void __fastcall TForm1::FormCreate(TObject *Sender)
{
    KABitmap = new Graphics::TBitmap();
}void __fastcall TForm1::FormDestroy(TObject *Sender)
{
    KABitmap->Free();
}void __fastcall TForm1::Save1Click(TObject *Sender)
{
    int i=1;
    SaveDialog1->FileName = "Captured1.bmp";
    while (FileExists(SaveDialog1->FileName))
    {
      i++;
      SaveDialog1->FileName = "Captured"+IntToStr(i)+".bmp";
    }
    if(SaveDialog1->Execute())
    {
      Image1->Picture->SaveToFile(SaveDialog1->FileName);
    }
}void __fastcall TForm1::N1Click(TObject *Sender)
{
    Form1->Visible=false;
    // Initializations
    Image1->Width=Screen->Width;
    Image1->Height=Screen->Height;    // Give the Display time to refresh
    Sleep(2000);    // Copy the Desktop to Image1
    CaptureDesktop(Image1->Canvas->Handle);    // Show Form1
    Form1->Visible=true;
}void __fastcall TForm1::N2Click(TObject *Sender)
{
    TRect rect;
    Application->Minimize();
    // Give some time to refresh and to use to select a window
    Sleep(3000);
    // Get the handle of the top active window
    HWND WinHandle =GetTopWndHandle();
    // Get the size of this window
    GetWindowRect(WinHandle, &rect);
    // Put the Image of the top active window in the KABitmap
    CaptureWndImage(rect);
    // Now Copy the KABitmao to Image1
    Image1->Width = KABitmap->Width;
    Image1->Height = KABitmap->Height;
    Image1->Picture->Bitmap = KABitmap;
    Application->Restore();
}void __fastcall TForm1::N3Click(TObject *Sender)
{
    Form1->Visible=false;
    // Initializations
    Image1->Width=Screen->Width;
    Image1->Height=Screen->Height;
    Form2->Origin.x = Form2->MovePt.x =0;
    Form2->Origin.y = Form2->MovePt.y =0;
    Form2->IsRegionSelected=false;    // Give the Display time to refresh
    Sleep(500);    // Copy the Desktop Image to Form2 Image
    CaptureDesktop(Form2->Image1->Canvas->Handle);
    // Show Form2
    Form2->Visible=true;
}void __fastcall TForm1::Exit1Click(TObject *Sender)
{
    Application->Terminate();
}

Answer 5

还有一个使用Delphi写的，只支持抓取某窗体（或窗体控件）的区域。
{***************************************************************
 * 方 法 名  : g_fun_SnatchScreen
 * 编写目的   : 拷屏
 * 作    者  : 黄仁光
 * 参    数  : HWnd:THandle
 * 结    果  : None
 * 编写日期   :2002年12月31日
 ****************************************************************}
procedure g_fun_SnatchScreen(HWnd:THandle);
var
  TheRECT: TRect;
  TheWidth: integer;
  TheHeight: integer;
  SourceDC: integer;
  DestDC: integer;
  BHandle: integer;
  Wnd: integer;
begin
  GetWindowRect(HWnd, therect);
  thewidth := therect.Right - therect.left;
  TheHeight := therect.Bottom - therect.Top;
  sourcedc := CreateDC('Display', 0, 0, 0);
  DestDC := CreateCompatibleDC(sourcedc);
  BHandle := CreateCompatibleBitmap(sourcedc, thewidth, TheHeight);
  SelectObject(DestDC, BHandle);
  BitBlt(DestDC, 0, 0, TheWidth, TheHeight, SourceDC, TheRECT.Left, TheRECT.Top, MERGECOPY);
  wnd := HWnd;
  OpenClipboard(Wnd);
  EmptyClipboard;
  SetClipboardData(2, BHandle);
  CloseClipboard;
  DeleteDC(DestDC);
  ReleaseDC(BHandle, SourceDC);
end;

Answer 6

会有损失吗?抓屏不过是通过GDI 复制窗体(桌面,可视控件都是窗体)内容的过程,这种方法会忠实的纪录每一个像素,要说到像素丢失,只可能在用GDI StretchBlt进行图像放缩时发生,而上面的代码只有 halibut 的用了,用BitBlt是无法放缩图像的,也就不可能丢失像素!其实在Delphi中,TCanvas类已经封装了这些,将HDC传递给一个Canvas实例,即可直接操作,如
Canvas.Handle:=GetDC(0);对应BitBlt,StretchBlt分别有Canvas.Draw,Canvas.StretchD

Answer 7

var
  hScr :long;
  bmp  :TBitmap;
  sw,sh,sl,st,w,h:integer;
begin
  sl := 0;
  st := 0;
  sw := 100;
  sh := 100;
  w  := 200;
  h  := 200;
  hScr := CreateDC("DISPLAY",0,0,0);
  if(hScr<>0)
    begin
      bmp := TBitmap.Create();
      bmp.Width:=w;
      bmp.Height:=h;
      StretchBlt(bmp.Canvas.Handle,0,0,w,h,hScr,sl,st,sw,sh,SRCCOPY);
      DeleteDC(hScr);
      bmp.SaveToFile('my.bmp');
      bmp.Destroy();
    end
end