C 语言

关注公众号 jb51net

关闭
首页 > 软件编程 > C 语言 > C++ 屏幕截图

C++实现屏幕截图(全屏截图)

作者:link-初扬

屏幕截图已经成为了所有IM即时通讯软件的必备模块,也是日常办公中使用最频繁的功能之一。今天我们从C++开发的角度,来看看屏幕截图的主要功能点是如何实现的,感兴趣的可以了解一下

上回分享了一个全屏截图的代码,保存为BMP,

C++实现屏幕截图(全屏截图):https://www.jb51.net/article/140184.htm

实际使用的过程中我发现截图文件实在大,无赖又整成了PNG截图,现在分享出来。

MakePNG.h

//MakePNG.h
 
#pragma once
#include <GdiPlus.h>
using namespace Gdiplus;
#pragma comment(lib,"GdiPlus.lib") 
 
class CMakePNG
{
public:
 CMakePNG(void);
 ~CMakePNG(void);
 
 BOOL MakePNG(HDC hDC,CRect rect,CString strFilePath);
 BOOL BMptoPNG(LPCWSTR StrBMp,LPCWSTR StrPNG);
 BOOL PNGtoBMp(LPCWSTR StrPNG,LPCWSTR StrBMp);
 BOOL GetEncoderClsid(WCHAR* pFormat,CLSID* pClsid);
private:
 GdiplusStartupInput m_gdiplusStartupInput;
 ULONG_PTR m_pGdiToken;
};

MakePNG.cpp

//MakePNG.cpp
 
#include "StdAfx.h"
#include "MakePNG.h"
 
CMakePNG::CMakePNG(void)
{
 GdiplusStartup(&m_pGdiToken,&m_gdiplusStartupInput,NULL);
}
 
CMakePNG::~CMakePNG(void)
{
}
 
/***************************************************************************/
/* 功能:  根据rect屏幕抓图,保存为文件名为strFilePath的PNG图像文件   */
/* 输入参数: HDC hDC     屏幕HDC;                          */
/*    CRect rect    需要的矩形;                        */
/*    CString strFilePath  保存文件全路径(含后缀名);        */
/***************************************************************************/
BOOL CMakePNG::MakePNG(HDC hDC, CRect rect, CString strFilePath)
{
 BITMAP bmp;
 PBITMAPINFO pbmi; 
 PBITMAPINFOHEADER pbih;     // bitmap info-header 
 BITMAPFILEHEADER  hdr;      // bitmap file-header
 WORD    cClrBits; 
 LPBYTE lpBits;              // memory pointer
 DWORD dwTmp; 
 DWORD cb;                   // incremental count of bytes 
 BYTE *hp;                   // byte pointer 
 HANDLE hfile;               // file handle 
 CString szBMPFilename = strFilePath.Left(strFilePath.GetLength() - 3) + _T("bmp");//先保存成位图
 HDC hdcCompatible = CreateCompatibleDC(hDC);
 HBITMAP hbmScreen = CreateCompatibleBitmap(hDC, rect.Width(), rect.Height());
 
 if (hbmScreen == NULL)
 {
     AfxMessageBox(_T("CreateCompatibleBitmap() error")); 
  return FALSE;
 }
 
 // Select the bitmaps into the compatible DC. 
 
 if (!SelectObject(hdcCompatible, hbmScreen)) 
 {
  AfxMessageBox(_T("Compatible Bitmap Selection error")); 
  return FALSE;
 }
 
 //Copy color data for the entire display into a 
 //bitmap that is selected into a compatible DC. 
 
 if (!BitBlt(hdcCompatible, 
  0,0, 
  rect.Width(), rect.Height(), 
  hDC, 
  rect.left,rect.top, 
  SRCCOPY)) 
 {
        AfxMessageBox(_T("Screen to Compat Blt Failed"));
  return FALSE;
 }
 
 
 
 // Retrieve the bitmap's color format, width, and height. 
 if (!GetObject(hbmScreen, sizeof(BITMAP), (LPSTR)&bmp))
 {
        AfxMessageBox(_T("GetObject()出错!"));
  return FALSE;
 }
 // Convert the color format to a count of bits. 
 cClrBits = (WORD)(bmp.bmPlanes * bmp.bmBitsPixel); 
 if (cClrBits == 1) 
  cClrBits = 1; 
 else if (cClrBits <= 4) 
  cClrBits = 4; 
 else if (cClrBits <= 8) 
  cClrBits = 8; 
 else if (cClrBits <= 16) 
  cClrBits = 16; 
 else if (cClrBits <= 24) 
  cClrBits = 24; 
 else cClrBits = 32; 
 
 // Allocate memory for the BITMAPINFO structure. (This structure 
 // contains a BITMAPINFOHEADER structure and an array of RGBQUAD 
 // data structures.) 
 
 if (cClrBits != 24) 
  pbmi = (PBITMAPINFO) LocalAlloc(LPTR, 
  sizeof(BITMAPINFOHEADER) + 
  sizeof(RGBQUAD) * (1<< cClrBits)); 
 
 // There is no RGBQUAD array for the 24-bit-per-pixel format. 
 
 else 
  pbmi = (PBITMAPINFO) LocalAlloc(LPTR, 
  sizeof(BITMAPINFOHEADER)); 
 
 // Initialize the fields in the BITMAPINFO structure. 
 
 pbmi->bmiHeader.biSize = sizeof(BITMAPINFOHEADER); 
 pbmi->bmiHeader.biWidth = bmp.bmWidth; 
 pbmi->bmiHeader.biHeight = bmp.bmHeight; 
 pbmi->bmiHeader.biPlanes = bmp.bmPlanes; 
 pbmi->bmiHeader.biBitCount = bmp.bmBitsPixel; 
 if (cClrBits < 24) 
  pbmi->bmiHeader.biClrUsed = (1<<cClrBits); 
 
 // If the bitmap is not compressed, set the BI_RGB flag. 
 pbmi->bmiHeader.biCompression = BI_RGB; 
 
 // Compute the number of bytes in the array of color 
 // indices and store the result in biSizeImage. 
 pbmi->bmiHeader.biSizeImage = ((pbmi->bmiHeader.biWidth * cClrBits +31) & ~31) /8
  * pbmi->bmiHeader.biHeight; 
 // Set biClrImportant to 0, indicating that all of the device colors are important. 
 pbmi->bmiHeader.biClrImportant = 0; 
 
 pbih = (PBITMAPINFOHEADER) pbmi; 
 lpBits = (LPBYTE) GlobalAlloc(GMEM_FIXED, pbih->biSizeImage);
 
 if (!lpBits) 
 {
     AfxMessageBox(_T("内存分配错误!"));
  return FALSE;
 }
 // Retrieve the color table (RGBQUAD array) and the bits 
 // (array of palette indices) from the DIB. 
 if (!GetDIBits(hDC, hbmScreen, 0, (WORD) pbih->biHeight, lpBits, pbmi, 
  DIB_RGB_COLORS)) 
 {
  AfxMessageBox(_T("GetDIBits() error"));
  return FALSE;
 }
 
 // Create the .BMP file. 
 hfile = CreateFile(szBMPFilename, 
  GENERIC_READ | GENERIC_WRITE, 
  (DWORD) 0, 
  NULL, 
  CREATE_ALWAYS, 
  FILE_ATTRIBUTE_NORMAL, 
  (HANDLE) NULL); 
 if (hfile == INVALID_HANDLE_VALUE) 
 {
   AfxMessageBox(_T("创建文件失败"));
  return false;
 }
 hdr.bfType = 0x4d42;        // 0x42 = "B" 0x4d = "M" 
 // Compute the size of the entire file. 
 hdr.bfSize = (DWORD) (sizeof(BITMAPFILEHEADER) + 
  pbih->biSize + pbih->biClrUsed 
  * sizeof(RGBQUAD) + pbih->biSizeImage); 
 hdr.bfReserved1 = 0; 
 hdr.bfReserved2 = 0; 
 
 // Compute the offset to the array of color indices. 
 hdr.bfOffBits = (DWORD) sizeof(BITMAPFILEHEADER) + 
  pbih->biSize + pbih->biClrUsed 
  * sizeof (RGBQUAD); 
 
 // Copy the BITMAPFILEHEADER into the .BMP file. 
 if (!WriteFile(hfile, (LPVOID) &hdr, sizeof(BITMAPFILEHEADER), 
  (LPDWORD) &dwTmp,  NULL)) 
 {
   AfxMessageBox(_T("写BMP文件头失败"));
  return FALSE;
 }
 
 // Copy the BITMAPINFOHEADER and RGBQUAD array into the file. 
 if (!WriteFile(hfile, (LPVOID) pbih, sizeof(BITMAPINFOHEADER) 
  + pbih->biClrUsed * sizeof (RGBQUAD), 
  (LPDWORD) &dwTmp, ( NULL))) 
 {
   AfxMessageBox(_T("写BMP文件头失败"));
  return FALSE;
 }
 
 // Copy the array of color indices into the .BMP file. 
 cb = pbih->biSizeImage; 
 hp = lpBits; 
 if (!WriteFile(hfile, (LPSTR) hp, (int) cb, (LPDWORD) &dwTmp,NULL)) 
 {
  AfxMessageBox(_T("写入BMP文件失败"));
  return FALSE;
 }
 
 // Close the .BMP file. 
 if (!CloseHandle(hfile)) 
 {
   AfxMessageBox(_T("Can't close BMP file.")); 
 }
 
  // Free memory. 
  GlobalFree((HGLOBAL)lpBits);
 
 //转换成PNG
 if(!BMptoPNG(szBMPFilename,strFilePath))
 {
  DeleteFile(szBMPFilename);
  return FALSE;
 }
 DeleteObject(hbmScreen);
 DeleteFile(szBMPFilename);
 return TRUE;
}
// //转换BMP文件为PNG文件            
BOOL CMakePNG::BMptoPNG(LPCWSTR StrBMp,LPCWSTR StrPNG)
{
 CLSID encoderClsid;
 Status stat;
 Image* image = NULL;
 image = Bitmap::FromFile(StrBMp,TRUE);
 if (!GetEncoderClsid(L"image/png",&encoderClsid))
 {
  return FALSE;
 }
 stat = image->Save(StrPNG,&encoderClsid,NULL);
 if (stat != Ok)
 {
  return FALSE;
 }
 delete image;
 return TRUE;
}
 
// 功能描述:  转换PNG文件为BMP文件      
BOOL CMakePNG::PNGtoBMp(LPCWSTR StrPNG,LPCWSTR StrBMp)
{
 CLSID encoderClsid;
 Status stat;
 Image* pImage;
 pImage = Bitmap::FromFile(StrPNG,TRUE);
 if (!GetEncoderClsid(L"image/bmp",&encoderClsid))
 {
  return FALSE;
 }
 stat = pImage->Save(StrBMp,&encoderClsid,NULL);
 if (stat != Ok)
 {
  return FALSE;
 }
 delete pImage;
 return TRUE;
}
 
BOOL CMakePNG::GetEncoderClsid(WCHAR* pFormat,CLSID* pClsid)
{
 UINT num = 0,size = 0;
 ImageCodecInfo* pImageCodecInfo = NULL;
 GetImageEncodersSize(&num,&size);
 if (size == 0)
 {
  return FALSE;
 }
 pImageCodecInfo = (ImageCodecInfo*)(malloc(size));
 if (pImageCodecInfo == NULL)
 {
  return FALSE;
 }
 GetImageEncoders(num,size,pImageCodecInfo);
 BOOL bfound = FALSE;
 for (UINT i = 0;!bfound && i < num;  i++)
 {
  if (_wcsicmp(pImageCodecInfo[i].MimeType,pFormat) == 0)
  {
   *pClsid = pImageCodecInfo[i].Clsid;
   bfound = TRUE;
  }
 }
 free(pImageCodecInfo);
 return bfound;
}

以上两个文件实际上是CMakePNG类,使用时需要把他们添加到项目中,调用方法如下:

wstring GetAppPathW()
{
 wchar_t szExePath[MAX_PATH] = {0};
 GetModuleFileNameW(NULL, szExePath, MAX_PATH);
 wchar_t *pstr = wcsrchr(szExePath, '\\');
 memset(pstr + 1, 0, 2);
 wstring strAppPath(szExePath);
 return strAppPath;
}
 
// 屏幕截图
CString CDemoDlg::ScreenShot(void)
{
 CWnd *pDesktop = GetDesktopWindow();  
 CDC *pDC = pDesktop->GetDC();  
 CRect rect;  
 //获取窗口的大小  
 pDesktop->GetClientRect(&rect);
 
 //保存到的文件名
 CString strFileName(GetAppPathW().c_str());
 strFileName += _T("ScreenShot\\");
 CreateDirectory((LPCTSTR)strFileName,NULL);
 CTime t = CTime::GetCurrentTime();
 CString tt = t.Format("%Y%m%d_%H%M%S");
 strFileName += tt;
 strFileName += _T(".PNG");
 //保存为PNG
 CMakePNG MakePNG;
 MakePNG.MakePNG(pDC->m_hDC,rect,strFileName);
 ReleaseDC(pDC);
 return strFileName;
}

到此这篇关于C++实现屏幕截图(全屏截图)的文章就介绍到这了,更多相关C++ 屏幕截图内容请搜索脚本之家以前的文章或继续浏览下面的相关文章希望大家以后多多支持脚本之家!

您可能感兴趣的文章:
阅读全文