抓取屏幕中选中区域并存取为bmp位图的类

/******************************************************************************

* FILE NAME: CopyScreenToBitmap.h                                             *

*                                                                             *

* DESCRIPTION:                                                                *

*   截屏位图文件                                                              *

*                                                                             *

* COPYRIGHT:                                                                  *

*   (C) Copyright LiuYong                                                     *

*   All Rights Reserved                                                       *

*                                                                             *

* AUTHOR:                                                                     *

* liu yong                                                                  *

* DATE : 2006-11-29                                                         *

*                                                                             *

*******************************************************************************/

class CCopyScreenToBitmap

{

public:

CCopyScreenToBitmap();

~CCopyScreenToBitmap();

//截取指定区域的屏幕到位图文件，文件目录默认让用户自己选择

BOOL SaveRectToBitmap( LPRECT lpRect, LPSTR lpFileName = NULL );

//截取全屏幕到位图文件，文件目录默认让用户自己选择

BOOL SaveScreenToBitmap( LPSTR lpFileName = NULL );

private:

HBITMAP SaveBitmapCopyScreenToBitmap( LPRECT lpRect );

BOOL SaveBitmapToFile( HBITMAP hBitmap , LPSTR lpFileName ) ;

void SaveBitmapToClipboard( HBITMAP hBitmap, HWND hWnd );

};

///

// CopyScreenToBitmap.cpp: implementation of the CCopyScreenToBitmap class.

//

//

#include “stdafx.h”

#include “CopyScreenToBitmap.h”

#include <afxdlgs.h>

#ifdef _DEBUG

#undef THIS_FILE

static char THIS_FILE[]=__FILE__;

#define new DEBUG_NEW

#endif

//

// Construction/Destruction

//

CCopyScreenToBitmap::CCopyScreenToBitmap()

{

}

CCopyScreenToBitmap::~CCopyScreenToBitmap()

{

}

BOOL CCopyScreenToBitmap::SaveRectToBitmap(LPRECT lpRect, LPSTR lpFileName)

{

if(!lpRect)

{

::MessageBox( NULL,”请指定要截图的区域！”,”提示”,MB_ICONINFORMATION );

return FALSE;

}

HBITMAP hBitmap = SaveBitmapCopyScreenToBitmap(lpRect);

if( !lpFileName )

{

CString Path;

CFileDialog dlg(FALSE,”*.*”,”新图形”,NULL,

“位图文件(*.bmp)|*.bmp|所有文件(*.*)|*.*||”,NULL);

//not change the default dir

dlg.m_ofn.Flags |= OFN_EXPLORER|OFN_OVERWRITEPROMPT|OFN_HIDEREADONLY|OFN_NOCHANGEDIR;

dlg.m_ofn.lpstrTitle = “保存图形”;

if (dlg.DoModal() == IDCANCEL)

{

::DeleteObject(hBitmap);

return FALSE;

}

Path = dlg.GetPathName();

//save the bitmap

return SaveBitmapToFile(hBitmap,Path.GetBuffer( Path.GetLength() ) );

}

else

{

return SaveBitmapToFile( hBitmap, lpFileName );

}

}

BOOL CCopyScreenToBitmap::SaveScreenToBitmap( LPSTR lpFileName )

{

int cxSrc = GetSystemMetrics (SM_CXSCREEN) ; //源设备宽–屏幕宽

int cySrc = GetSystemMetrics (SM_CYSCREEN) ; //源设备高–屏幕高

CRect rect(0,0,cxSrc,cySrc);

HBITMAP hBitmap = SaveBitmapCopyScreenToBitmap( &rect );

if( !lpFileName )

{

CString Path;

CFileDialog dlg(FALSE,”*.*”,”新图形”,NULL,

“位图文件(*.bmp)|*.bmp|所有文件(*.*)|*.*||”,NULL);

//not change the default dir

dlg.m_ofn.Flags |= OFN_EXPLORER|OFN_OVERWRITEPROMPT|OFN_HIDEREADONLY|OFN_NOCHANGEDIR;

dlg.m_ofn.lpstrTitle = “保存图形”;

if (dlg.DoModal() == IDCANCEL)

{

::DeleteObject(hBitmap);

return FALSE;

}

Path = dlg.GetPathName();

//save the bitmap

return SaveBitmapToFile(hBitmap,Path.GetBuffer( Path.GetLength() ) );

}

else

{

return SaveBitmapToFile( hBitmap, lpFileName );

}

}

//lpRect 代表选定区域

HBITMAP CCopyScreenToBitmap::SaveBitmapCopyScreenToBitmap(LPRECT lpRect)

{

// 屏幕和内存设备描述表

HDC hScrDC, hMemDC;

// 位图句柄

HBITMAP hBitmap, hOldBitmap;

// 选定区域坐标

int nX, nY, nX2, nY2;

// 位图宽度和高度

int nWidth, nHeight;

// 屏幕分辨率

int xScrn, yScrn;

// 确保选定区域不为空矩形

if (IsRectEmpty(lpRect))

return NULL;

//为屏幕创建设备描述表

hScrDC = CreateDC(“DISPLAY”, NULL, NULL, NULL);

//为屏幕设备描述表创建兼容的内存设备描述表

hMemDC = CreateCompatibleDC(hScrDC);

// 获得选定区域坐标

nX = lpRect->left;

nY = lpRect->top;

nX2 = lpRect->right;

nY2 = lpRect->bottom;

// 获得屏幕分辨率

xScrn = GetDeviceCaps(hScrDC, HORZRES);

yScrn = GetDeviceCaps(hScrDC, VERTRES);

//确保选定区域是可见的

if (nX < 0)

nX = 0;

if (nY < 0)

nY = 0;

if (nX2 > xScrn)

nX2 = xScrn;

if (nY2 > yScrn)

nY2 = yScrn;

nWidth = nX2 – nX;

nHeight = nY2 – nY;

// 创建一个与屏幕设备描述表兼容的位图

hBitmap = CreateCompatibleBitmap(hScrDC, nWidth, nHeight);

// 把新位图选到内存设备描述表中

hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);

// 把屏幕设备描述表拷贝到内存设备描述表中

BitBlt(hMemDC, 0, 0, nWidth, nHeight,hScrDC, nX, nY, SRCCOPY);

//得到屏幕位图的句柄

hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);

//清除

DeleteDC(hScrDC);

DeleteDC(hMemDC);

// 返回位图句柄

return hBitmap;

}

/得到屏幕位图句柄以后,我们

/可以把屏幕内容粘贴到剪贴板上.

void CCopyScreenToBitmap::SaveBitmapToClipboard(HBITMAP hBitmap,HWND hWnd)

{

//hWnd为程序窗口句柄

if (OpenClipboard(hWnd))

{

//清空剪贴板

EmptyClipboard();

SetClipboardData(CF_BITMAP, hBitmap);

//关闭剪贴板

CloseClipboard();

}

}

//我们也可以把屏幕内容以位图格式存到磁盘文件上.

//lpFileName 为位图文件名

BOOL CCopyScreenToBitmap::SaveBitmapToFile(HBITMAP hBitmap , LPSTR lpFileName)

{

//设备描述表

HDC hDC;

//当前显示分辨率下每个像素所占字节数

int iBits;

//位图中每个像素所占字节数

WORD wBitCount=32;

//定义调色板大小，位图中像素字节大小，

//位图文件大小，写入文件字节数

DWORD dwPaletteSize=0,

dwBmBitsSize,

dwDIBSize, dwWritten;

//位图属性结构

BITMAP Bitmap;

//位图文件头结构

BITMAPFILEHEADER bmfHdr;

//位图信息头结构

BITMAPINFOHEADER bi;

//指向位图信息头结构

LPBITMAPINFOHEADER lpbi;

//定义文件，分配内存句柄，调色板句柄

HANDLE fh, hDib;

HPALETTE hPal,hOldPal=NULL;

//计算位图文件每个像素所占字节数

hDC = CreateDC(“DISPLAY”,NULL,NULL,NULL);

iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);

DeleteDC(hDC);

if (iBits <= 1)

wBitCount = 1;

else if (iBits <= 4)

wBitCount = 4;

else if (iBits <= 8)

wBitCount = 8;

else if (iBits <= 24)

wBitCount = 24;

//计算调色板大小

if (wBitCount <= 8)

dwPaletteSize = (1 << wBitCount) *sizeof(RGBQUAD);

//设置位图信息头结构

GetObject(hBitmap, sizeof(BITMAP), (LPSTR)&Bitmap);

bi.biSize            = sizeof(BITMAPINFOHEADER);

bi.biWidth           = Bitmap.bmWidth;

bi.biHeight          = Bitmap.bmHeight;

bi.biPlanes          = 1;

bi.biBitCount         = wBitCount;

bi.biCompression      = BI_RGB;

bi.biSizeImage        = 0;

bi.biXPelsPerMeter     = 0;

bi.biYPelsPerMeter     = 0;

bi.biClrUsed         = 0;

bi.biClrImportant      = 0;

dwBmBitsSize = ((Bitmap.bmWidth *wBitCount+31)/32)* 4*Bitmap.bmHeight ;

//为位图内容分配内存

hDib = GlobalAlloc(GHND,dwBmBitsSize+dwPaletteSize+sizeof(BITMAPINFOHEADER));

lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);

*lpbi = bi;

// 处理调色板

hPal = (HPALETTE)GetStockObject(DEFAULT_PALETTE);

if (hPal)

{

hDC = GetDC(NULL);

hOldPal = SelectPalette(hDC, hPal, FALSE);

RealizePalette(hDC);

}

// 获取该调色板下新的像素值

GetDIBits(hDC, hBitmap, 0, (UINT)Bitmap.bmHeight,(LPSTR)lpbi + sizeof(BITMAPINFOHEADER)+dwPaletteSize,(LPBITMAPINFO)lpbi, DIB_RGB_COLORS);

//恢复调色板

if (hOldPal)

{

SelectPalette(hDC, hOldPal, TRUE);

RealizePalette(hDC);

ReleaseDC(NULL, hDC);

}

//创建位图文件

fh = CreateFile(lpFileName, GENERIC_WRITE, 0, NULL, CREATE_ALWAYS,

FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);

if (fh == INVALID_HANDLE_VALUE)

return FALSE;

//设置位图文件头

bmfHdr.bfType = 0x4D42; // “BM”

dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;

bmfHdr.bfSize = dwDIBSize;

bmfHdr.bfReserved1 = 0;

bmfHdr.bfReserved2 = 0;

bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER)+ dwPaletteSize;

// 写入位图文件头

WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);

// 写入位图文件其余内容

WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);

//清除

GlobalUnlock(hDib);

GlobalFree(hDib);

CloseHandle(fh);

return TRUE;

}

原文链接：https://blog.csdn.net/liushaoyi0704/article/details/1426292

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