我最近用了好几个抓屏软件，其中他们都有一个capture control的功能，也就是能够抓取屏幕中某窗口中的按键，菜单，我只知道通过下面：
GetCursorPos()
WindowFromPoint()
GetWindowRect()
这三个函数可以知道控件的位置，然后将全屏幕抓下来，最后用BitBlt函数将控件所在全屏幕图形中位置的控件图形提取出来完成了。但是在这些抓屏软件中这个功能你可以选择要抓取的控件，在被选中的控件周围就会有一个表示被选中的框，你就知道这个框被选中了，我不明白这个被选中的功能是如何做的，希望知道的高手能讲一讲。谢谢。
GetCursorPos()
WindowFromPoint()
GetWindowRect()
这三个函数可以知道控件的位置，然后将全屏幕抓下来，最后用BitBlt函数将控件所在全屏幕图形中位置的控件图形提取出来完成了。但是在这些抓屏软件中这个功能你可以选择要抓取的控件，在被选中的控件周围就会有一个表示被选中的框，你就知道这个框被选中了，我不明白这个被选中的功能是如何做的，希望知道的高手能讲一讲。谢谢。
希望能讲详细点。
#pragma hdrstop#include "untShow.h"
#include "untCapture.h"
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm2 *Form2;
//---------------------------------------------------------------------------
__fastcall TForm2::TForm2(TComponent* Owner)
: TForm(Owner)
{
}
//---------------------------------------------------------------------------
void __fastcall TForm2::CaptureRegion(void)
{
if((MovePt.y-Origin.y)!=0)
{
int KAWidth=abs(MovePt.x-Origin.x);
int KAHeight=abs(MovePt.y-Origin.y);
int Orgx=Origin.x,Orgy=Origin.y;
if (MovePt.y < Origin.y) Orgy = MovePt.y;
if (MovePt.x < Origin.x) Orgx = MovePt.x;
// Copy the selected part of the Desktop to Form1 Image
StretchBlt(Form1->Image1->Canvas->Handle,
0,0,
KAWidth,
KAHeight,
Image1->Canvas->Handle,
Orgx, Orgy,
KAWidth,
KAHeight,
SRCCOPY);
// Adjust Form1 Image size
Form1->Image1->Width=abs(MovePt.x-Origin.x);
Form1->Image1->Height=abs(MovePt.y-Origin.y);
}
else
{
Form1->Image1->Picture->Bitmap->Canvas->Brush->Color=clWhite;
Form1->Image1->Picture->Bitmap->Canvas->FillRect(Canvas->ClipRect) ;
}
}
//---------------------------------------------------------------------------
void __fastcall TForm2::DrawRect(TPoint TopLeft, TPoint BottomRight, TPenMode KAMode)
{
Canvas->Pen->Mode = KAMode;
Canvas->Pen->Width = 2;
Canvas->Rectangle(TopLeft.x, TopLeft.y, BottomRight.x, BottomRight.y);
}
void __fastcall TForm2::Image1MouseDown(TObject *Sender,
TMouseButton Button, TShiftState Shift, int X, int Y)
{
IsRegionSelected = true;
Origin = Point(X,Y);
MovePt = Origin;
}
//---------------------------------------------------------------------------
void __fastcall TForm2::FormCreate(TObject *Sender)
{
SetBounds( 0, 0, Screen->Width, Screen->Height );
}
//---------------------------------------------------------------------------
void __fastcall TForm2::Image1MouseMove(TObject *Sender, TShiftState Shift,
int X, int Y)
{
if(IsRegionSelected)
{
DrawRect(Origin, MovePt, pmNotXor);
MovePt = Point(X, Y);
MovePt.x=MovePt.x+Image1->Left;
MovePt.y=MovePt.y+Image1->Top;
DrawRect(Origin, MovePt, pmNotXor);
}
}
//---------------------------------------------------------------------------
void __fastcall TForm2::Image1MouseUp(TObject *Sender, TMouseButton Button,
TShiftState Shift, int X, int Y)
{
if(IsRegionSelected)
{
MovePt = Point(X, Y);
IsRegionSelected=false;
CaptureRegion();
}
Form1->Visible=true;
Form2->Visible=false;
}
//---------------------------------------------------------------------------
* 方 法 名 : g_fun_SnatchScreen
* 编写目的 :
* 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;
#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();
}
//---------------------------------------------------------------------------