// CaptureScreen.cpp: implementation of the CaptureScreen.
//
//////////////////////////////////////////////////////////////////////

#include "stdafx.h"
#include "CaptureScreen.h"

//////////////////////////////////////////////////////////////////////
LPSTR lpBmpData=NULL;
DWORD dwBmpSize=0;
DWORD dwBmpInfoSize=0;
int   CaptureThreadCount=0;
CRITICAL_SECTION csCaptureScreen;
int	  iBmpCX;
int   iBmpCY;
////////////////////////////////////////
//進(jìn)行掃尾工作,釋放內(nèi)存
void CleanScreenInfo(void)
{
	if(lpBmpData)
	{
		GlobalUnlock(lpBmpData);
		lpBmpData=(char*)GlobalFree(lpBmpData);
	}
	dwBmpSize=0;
	dwBmpInfoSize=0;
}

//捕捉屏幕數(shù)據(jù)
bool GetScreenData(int nBits)
{
	//位圖位數(shù)不能為大于2^24的值,主要考慮到傳輸特性
	if (nBits>24)
		return false;
	HDC		hScrDC, hMemDC;			// 屏幕和內(nèi)存設(shè)備描述表
	HBITMAP		hBitmap, hOldBitmap;		// 位圖句柄
	int		xScrn, yScrn;			// 屏幕分辨率 

	HDC		hDC;				//設(shè)備描述表
	WORD		wBitCount;			//位圖中每個像素所占字節(jié)數(shù)

	//定義調(diào)色板大小， 位圖中像素字節(jié)大小 ，位圖文件大小 ， 寫入文件字節(jié)數(shù)
	DWORD		dwPaletteSize=0, dwBmBitsSize=0;//,dwBmpInfoSize=0;
	BITMAP		Bitmap;			//位圖屬性結(jié)構(gòu)
	BITMAPINFOHEADER	bi;		//位圖信息頭結(jié)構(gòu) 
	LPBITMAPINFOHEADER	lpbi;		//指向位圖信息頭結(jié)構(gòu)

	//定義文件，分配內(nèi)存句柄，調(diào)色板句柄  
	HANDLE			hDib;
	HPALETTE		hPal,hOldPal=NULL;

	//為屏幕創(chuàng)建設(shè)備描述表
	hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
	// 獲得屏幕分辨率
	xScrn = GetDeviceCaps(hScrDC, HORZRES);
	yScrn = GetDeviceCaps(hScrDC, VERTRES);
	//為屏幕設(shè)備描述表創(chuàng)建兼容的內(nèi)存設(shè)備描述表
	hMemDC = CreateCompatibleDC(hScrDC);
	// 創(chuàng)建一個與屏幕設(shè)備描述表兼容的位圖
	hBitmap = CreateCompatibleBitmap (hScrDC,xScrn,yScrn);
	// 把新位圖選到內(nèi)存設(shè)備描述表中
	hOldBitmap = (HBITMAP) SelectObject(hMemDC, hBitmap);
	// 把屏幕設(shè)備描述表拷貝到內(nèi)存設(shè)備描述表中
	BitBlt(hMemDC, 0, 0, xScrn, yScrn, 
			hScrDC, 0, 0, SRCCOPY);
	//得到屏幕位圖的句柄
	hBitmap = (HBITMAP) SelectObject(hMemDC, hOldBitmap);


	//計(jì)算位圖每個像素所占字節(jié)數(shù)
	if (nBits <= 1)
		wBitCount = 1;
	else if (nBits <= 4)
		wBitCount = 4;
	else if (nBits <= 8)
		wBitCount = 8;
	else if (nBits <= 16)
		wBitCount = 16;
	else if (nBits <= 24)
		wBitCount = 24;
	//計(jì)算調(diào)色板大小
	if (wBitCount <24)
		dwPaletteSize = (1 << wBitCount) * sizeof(RGBQUAD);
	//設(shè)置位圖信息頭結(jié)構(gòu)
	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)& ~31)/8 *Bitmap.bmHeight;
	dwBmpInfoSize = dwPaletteSize + sizeof(BITMAPINFOHEADER);
	//臨時位圖數(shù)據(jù)大小變量
	DWORD dwNewBmpSize;
	dwNewBmpSize = dwBmBitsSize + dwBmpInfoSize;
	iBmpCX=Bitmap.bmWidth;
	iBmpCY=Bitmap.bmHeight;
	//為位圖內(nèi)容分配內(nèi)存
	if(dwNewBmpSize!=dwBmpSize)//位圖相關(guān)信息沒有變化
	{
		if(!lpBmpData)
		{
			hDib  = GlobalAlloc(GHND,dwNewBmpSize);
			if(!hDib)
			{
				DeleteObject(hBitmap);
				DeleteDC(hScrDC);
				DeleteDC(hMemDC);
				dwBmpSize=0;
				dwBmpInfoSize=0;
				return false;
			}
		}
		else
		{
			GlobalUnlock(lpBmpData);
			lpBmpData=(char*)GlobalFree(lpBmpData);
			hDib  = GlobalAlloc(GHND,dwNewBmpSize);
			if(!hDib)
			{
				DeleteObject(hBitmap);
				DeleteDC(hScrDC);
				DeleteDC(hMemDC);
				dwBmpSize=0;
				dwBmpInfoSize=0;
				return false;
			}
		}
		lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
		*lpbi = bi;
	}
	else//位圖相關(guān)信息沒有變化
	{
		lpbi = (LPBITMAPINFOHEADER)lpBmpData;
		*lpbi = bi;
	}

	// 處理調(diào)色板   
	hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE);
	if (hPal)
	{
		hDC = GetDC (NULL);
		hOldPal = SelectPalette(hDC, hPal, FALSE);
		RealizePalette(hDC);
	}
	// 獲取該調(diào)色板下新的像素值
	GetDIBits(
			hDC,
			hBitmap,
			0, 
			(UINT) Bitmap.bmHeight,
			(LPSTR)lpbi + sizeof(BITMAPINFOHEADER) + dwPaletteSize,
			(BITMAPINFO *)lpbi,
			DIB_RGB_COLORS
		  );
	//恢復(fù)調(diào)色板
	if (hOldPal)
	{
		SelectPalette(hScrDC, hOldPal, TRUE);
		RealizePalette(hScrDC);
		ReleaseDC(NULL, hDC);
	}

	lpBmpData = (char *)lpbi;
	dwBmpSize = dwNewBmpSize;
	//清除
	DeleteObject (hBitmap);
	DeleteDC(hScrDC);
	DeleteDC(hMemDC);

	return TRUE;
}