关于屏幕截取，发送的问题，高手进来

Question

我在客户端截取屏幕之后，取得是DDB位图，是否需要转换成DIB位图，才能发到服务器？服务器端收到DIB位图之后，是不是可以直接显示DIB位图，要不要转换成DDB格式？

Answer 1

如果能正常收到的话，就可以直接显示DIB

Answer 2

是啊，在转化为DIB的时候压缩的，是压缩的DIB。

Answer 3

一般采用先jpg压缩,再传输,解压,显示

Answer 4

#define MAXXCount 10 //屏幕X方向最多分割块数
#define MAXYCount 5 //... Y................
#define DestNum 1000 //每块的偏移检测点最大个数
COLORREF Colors[MAXXCount][MAXYCount][DestNum];
COLORREF BakColors[MAXXCount]{MAXYCount][DestNum];
TPoint Dests[DestNum];
int Sw;
int Sh;
int xCount;
int yCount;
int ItemWidth;
int ItemHeight;
int Dnum;
int Qlity;
//得到消息后执行：
//另外：接收到的数据包中分析出 Dnum ，Qlity
//Dnum：偏移观测点数量
//Qlity：图象要求质量
__fastcall TForm1::CopyScreen(int DNum,int Qlity){
ItemWidth=Sw/xCount;
ItemHeight=Sh/yCount;
Sw=Screen->Width;
Sh=Screen->Height;
xCount=(Sw>1000)?8:6;
yCount=(Sh>1000)?3:2;
for (int num1=0;num1 Dests[num1].x=random(ItemWidth);
Dests[num1].y=random(ItemHeight);
}
CatchScreen(DNum,Qlity);
}
//收到刷屏消息后只执行:
CatchScreen(DNum,Qlity);
__fastcall TForm1::CatchScreen(int DNum,int Qlity){
//函数功能：扫描改变的屏幕区域，并切经过优化处理，最后发送这些区域数据
//DNum: 偏移量 Qlity:图象质量
HDC dc=GetDC(GetDesktopWindow());
Graphics::TBitmap *bm=new Graphics::TBitmap;
bm->Width=Sw;
bm->Height=Sh;
BitBlt(bm->Canvas->Handle,0,0,Sw-1,Sh-1,dc,0,0);
int num1,num2,num3;
int nowx,nowy;
bool Change;
bool ItemChange[MAXXCount][MAXYCount];
for (num1=0;num1 nowx=ItemWidth*num1;
for (num2=0;num2 nowy=ItemHeight*num2;
Change=false;
for (num3=0;num3 Colors[num1][num2][num3]=bm->Canvas->Pixels[nowx+Dests[num3].x][nowy+Dests[num3].y];
if (Colors[num1][num2][num3]!=BakColors[num1][num2][num3]){
BakColors[num1][num2][num3]=Colors[num1][num2][num3];
ItemChange[num1][num2]=true;
}
}
}
}
int CNum,MaxCNum;
int ChangedNum=0;
TRect *Rect;
int num4;
int MinSize=10000;
int m;
TRect MinRect;
Graphics::TBitmap *bt2=new Graphics::TBitmap;
TJPEGImage *j=new TJPEGImage;
//************************
j->Quality=Qlity;
//************************
CopyScreenUint CopyScreen;
CopyScreenItemUint CopyScreenItem;
TMemoryStream *ms=new TMemoryStream;
ms->Write(&TcpMsg,sizeof(TcpMsgUint));
ms->Write(&CopyScreen,sizeof(CopyScreenUint));
do{
for (num1=0;num1 for (num2=0;num2 for (num3=num1+1;num3<=xCount;num3++){
MaxCNum=0;
for (num4=num2+1;num4<=yCount;num4++){ //遍历所有矩形
CNum=GetChangedNum(TRect(num1,num2,num3,num4));
if (CNum>MaxCNum) MaxCNum=CNum;
m=(num3-num1)*(num4-num2);
if (2*m-CNum MinSize=2*m-CNum;
MinRect=TRect(num1,num2,num3,num4);
}
}
}
TMemoryStream *ms;
BitBlt(bt2->Canvas->Handle,0,0,ItemWidth-1,ItemHeight-1,bt->Canvas->Handle,0,0);
j->Assign(bt2);
j->SaveToStream(ms2);
CopyScreenItem.Rect=TRect(num1,num2,num3,num4);
CopyScreenItem.FileType=JPEGFILE; //JPEGFILE 定义为：#define JPEGFILE 1
ms2->Position=0;
CopyScreenItem.Length=ms2->Size;
ms->Write(&CopyScreenItem,sizeof(ScreenItemUint));
ms->CopyFrom(ms2,ms2->Size);
ChangedNum++;
}while(MaxCNum>0);
TcpMsg.Type=MsgCopyScreen;
ms->Position=0;
TcpMsg.Length=ms->Size-sizeof(TcpMsgUint);
CopyScreen.Count=ChangedNum;
ms->Write(&TcpMsg,sizeof(TcpMsgUint));
ms->Write(&CopyScreen,sizeof(CopyScreenUInt));
ms->Position=0;
sock->SendStream(ms);
}　　这个程序把屏幕画面切分为了多个部分，并存储画面为JPG格式，这样压缩率就变的十分的高了。通过这种方法压缩处理过的数据，变得十分小，甚至在屏幕没有改变的情况下，传送的数据量为0，你可以仔细看看

Answer 5

//图形转换
HANDLE DDBtoDIB( HBITMAP bitmap) 
{
BITMAP bm;
BITMAPINFOHEADER bi;
    LPBITMAPINFOHEADER  lpbi;
DWORD dwLen;
HANDLE hDib;
HANDLE handle;
HDC  hdc;
HPALETTE hPal; hPal = (HPALETTE) GetStockObject(DEFAULT_PALETTE ); //获得位图信息
GetObject(bitmap,sizeof(bm),(LPSTR)&bm); // 初始化位图头信息
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = bm.bmWidth;
bi.biHeight  = bm.bmHeight;
bi.biPlanes  = 1; bi.biBitCount = 4;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0; int ncolors = (1 << bi.biBitCount); 
if( ncolors> 256 ) 
ncolors = 0;
dwLen  = bi.biSize + ncolors * sizeof(RGBQUAD); hdc = GetDC(NULL);
hPal = SelectPalette(hdc,hPal,FALSE);
RealizePalette(hdc); hDib = GlobalAlloc(GMEM_FIXED,dwLen); if (!hDib){
SelectPalette(hdc,hPal,FALSE);
ReleaseDC(NULL,hdc);
return NULL;
} lpbi = (LPBITMAPINFOHEADER)hDib; *lpbi = bi; GetDIBits(hdc, bitmap, 0L, (DWORD)bi.biHeight,
(LPBYTE)NULL, (LPBITMAPINFO)lpbi, (DWORD)DIB_RGB_COLORS ); bi = *lpbi; if (bi.biSizeImage == 0)
{
bi.biSizeImage = ((((bi.biWidth * bi.biBitCount) + 31) & ~31) / 8) 
* bi.biHeight;
} dwLen += bi.biSizeImage;
if (handle = GlobalReAlloc(hDib, dwLen, GMEM_MOVEABLE))
hDib = handle;
else
{
GlobalFree(hDib); SelectPalette(hdc,hPal,FALSE);
ReleaseDC(NULL,hdc);
return NULL;
} lpbi = (LPBITMAPINFOHEADER)hDib; BOOL bgotbits = GetDIBits( hdc, bitmap,
0L,
(DWORD)bi.biHeight,
(LPBYTE)lpbi 
+ (bi.biSize + ncolors * sizeof(RGBQUAD)),
(LPBITMAPINFO)lpbi,
(DWORD)DIB_RGB_COLORS); if( !bgotbits )
{
GlobalFree(hDib);

SelectPalette(hdc,hPal,FALSE);
ReleaseDC(NULL,hdc);
return NULL;
} SelectPalette(hdc,hPal,FALSE);
ReleaseDC(NULL,hdc); return hDib;
}

Answer 6

//获得桌面图形
HBITMAP GetSrcBit(DWORD BitWidth,DWORD BitHeight)
{
HDC hdcmy,hbufferdc;
HBITMAP  hBit,hOldBitmap; hdcmy = CreateDC("DISPLAY",NULL,NULL,NULL);
hbufferdc = CreateCompatibleDC(hdcmy); hBit = CreateCompatibleBitmap(hdcmy, BitWidth, BitHeight); hOldBitmap = (HBITMAP)SelectObject(hbufferdc, hBit);
StretchBlt(hbufferdc, 0, 0, BitWidth, BitHeight,
hdcmy, 0, 0,SysWidth,SysHeight, SRCCOPY); hBit = (HBITMAP)SelectObject(hbufferdc, hOldBitmap);

DeleteObject(hOldBitmap);
ReleaseDC(NULL,hdcmy);
ReleaseDC(NULL,hbufferdc); return hBit;
}//---------------------------------------------------------------
//发送桌面屏幕
void SendDesktop() 
{
int BitMsg;
LPBYTE plmagePoint;
HANDLE hDib;
HBITMAP hBit;
int BitHeight,BitWidth; //获得桌面宽度和高度
recv(NewSock,(char*)&BitWidth,sizeof(BitWidth)+1,0);
recv(NewSock,(char*)&BitHeight,sizeof(BitHeight)+1,0);
if (BitWidth > SysWidth)
BitWidth = SysWidth;
if (BitHeight > SysHeight)
BitHeight = SysHeight; //转换为位图形式
hBit = GetSrcBit(BitWidth,BitHeight); hDib = DDBtoDIB(hBit);
DWORD bitSize = GlobalSize(hDib);

send(NewSock,(char*)&bitSize,sizeof(bitSize)+1,MSG_OOB);
recv(NewSock,(char*)&BitMsg,sizeof(BitMsg)+1,0); plmagePoint = (LPBYTE)hDib;
for(WORD i=0;i<bitSize/US_MAXSIZE;i++)
{
send(NewSock,(char*)plmagePoint,sizeof(BYTE)*US_MAXSIZE,MSG_OOB);
plmagePoint = plmagePoint + US_MAXSIZE;
    recv(NewSock,(char*)&BitMsg,sizeof(BitMsg)+1,0);
}
if (bitSize%US_MAXSIZE)
{
send(NewSock,(char*)plmagePoint,sizeof(BYTE)*GlobalSize(hDib)%US_MAXSIZE,MSG_OOB);
    recv(NewSock,(char*)&BitMsg,sizeof(BitMsg)+1,0);
} DeleteObject(hBit);
GlobalFree(hDib);
}