通过udp如何把一个BMP文件传输到另一台主机上？ -------急，在线等待

Question

我把一个bmp文件读入流中，通过流来传输出去，如何发送这些包？如果这个文件有600K，每次只发2048字节，要处理流吗？还是直接把一个流数据都发出去？接收方又如何处理？

Answer 1

以下是CB代码，Delphi也差不多
1.接收端
//---------------------------------------------------------------------------#include <vcl.h>
#pragma hdrstop#include "Unit1.h"
#include <jpeg.hpp>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
TForm1 *Form1;
//---------------------------------------------------------------------------
__fastcall TForm1::TForm1(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------void __fastcall TForm1::FormCreate(TObject *Sender)
{
   ResultStream =new TMemoryStream();
   TempStream =new TMemoryStream();
   ResultStream->Size = 1024*768*3;
   TempStream->Size = 1024*768*3;
   ResultStream->Clear();
}
//---------------------------------------------------------------------------void __fastcall TForm1::FormDestroy(TObject *Sender)
{
     delete ResultStream;
    delete TempStream;   
}
//---------------------------------------------------------------------------
void __fastcall TForm1::NMUDP1DataReceived(TComponent *Sender,
      int NumberBytes, AnsiString FromIP, int Port)
{
    if(NumberBytes!=1)
     {
      TempStream->Clear();
      NMUDP1->ReadStream(TempStream);
      ResultStream->CopyFrom(TempStream,NumberBytes);
      Edit1->Text = IntToStr(ResultStream->Size)+ "字节";
      }
     else if (NumberBytes ==1)
      {
       try
          {
            ResultStream->Position = 0;
            TJPEGImage *jpeg=new TJPEGImage();
            jpeg->LoadFromStream(ResultStream);
            Graphics::TBitmap* bit = new Graphics::TBitmap();
            bit->Width = jpeg->Width;
            bit->Height = jpeg->Height;
            bit->Canvas->StretchDraw(Rect(0,0,bit->Width,bit->Height),jpeg);
            Image1->Picture->Graphic =bit;
            //ScrollBar1->Max=jpeg->Width;
            
            //Image1->Refresh();
            //Refresh();
             //jpeg->SaveToFile("h:\rec_temp.jpg");
            delete jpeg;
            delete bit;
            }
          catch(...)
           {
             ShowMessage("Error");
           }
           }}
//---------------------------------------------------------------------------
void __fastcall TForm1::BitBtn1Click(TObject *Sender)
{
    char Reqcode[29];
    AnsiString ReqCodeStr;
    ReqCodeStr = "Show"+ Edit2->Text;
    StrCopy(Reqcode,ReqCodeStr.c_str());
    ResultStream->Clear();
    TempStream->Clear();
    NMUDP1->RemoteHost =Edit2->Text;
    NMUDP1->SendBuffer(Reqcode,30,30);
}
//---------------------------------------------------------------------------
2.截屏端
//---------------------------------------------------------------------------#include <vcl.h>
#pragma hdrstop#include "Unit1.h"
#include <jpeg.hpp>
//---------------------------------------------------------------------------
#pragma package(smart_init)
#pragma resource "*.dfm"
Thehe *hehe;
//---------------------------------------------------------------------------
__fastcall Thehe::Thehe(TComponent* Owner)
        : TForm(Owner)
{
}
//---------------------------------------------------------------------------void __fastcall Thehe::FormCreate(TObject *Sender)
{
   BmpStream =new TMemoryStream();
   ResultStream =new TMemoryStream();
   TempStream = new TMemoryStream();
   ResultStream->Size =1024*768*3;
   
}
//---------------------------------------------------------------------------
 void __fastcall Cut_Screen(int LeftPos,int TopPos,int RightPos,int BottomPos)
  {
      int RectWidth, RectHeight;
      HDC SourceDC,DestDC,Bhandle;
      Graphics::TBitmap *Bitmap =new Graphics::TBitmap();
      RectWidth = RightPos-LeftPos;
      RectHeight = BottomPos-TopPos;      SourceDC = CreateDC("DISPLAY",NULL,NULL,NULL);
      DestDC = CreateCompatibleDC(SourceDC);
      Bhandle = CreateCompatibleBitmap(SourceDC,RectWidth,RectHeight);
      SelectObject(DestDC,Bhandle);
      BitBlt(DestDC,0,0,RectWidth,RectHeight,SourceDC,LeftPos,TopPos,SRCCOPY);
      Bitmap->Handle = Bhandle;
      hehe->BmpStream->Clear();
      Bitmap->SaveToStream(hehe->BmpStream);
      delete Bitmap;
      DeleteDC(DestDC);
      ReleaseDC(Bhandle,SourceDC);
       //保存
      hehe->BmpStream->SaveToFile("temp.bmp");
      //bmp->jmp
      Graphics::TBitmap* Bitmap1 = new Graphics::TBitmap();
      Bitmap1->LoadFromFile("temp.bmp");
      //Bitmap1->LoadFromStream(hehe->BmpStream);
      Graphics::TBitmap* tmpBitmap = new Graphics::TBitmap();
      tmpBitmap->Width = Bitmap1->Width;
      tmpBitmap->Height = Bitmap1->Height;
      tmpBitmap->Canvas->StretchDraw(TRect(0,0,tmpBitmap->Width,tmpBitmap->Height),Bitmap1);
      TJPEGImage *jpeg =new TJPEGImage();
      jpeg->PixelFormat = jf8Bit;
      jpeg->CompressionQuality =100;
      jpeg->Assign((TPersistent*) tmpBitmap);
      jpeg->Compress();      hehe->BmpStream->Clear();
      jpeg->SaveToStream(hehe->BmpStream);      //ShowMessage(hehe->BmpStream->Size);
      jpeg->SaveToFile("temp.jpg");
      delete tmpBitmap;
      delete jpeg;
      delete Bitmap1;
            
  }
//---------------------------------------------------------------------------void __fastcall Thehe::NMUDP1DataReceived(TComponent *Sender,
      int NumberBytes, AnsiString FromIP, int Port)
{
            Cut_Screen(0,0,Screen->Width,Screen->Height);
           // ShowMessage("已截图");
            const int ThreshHold =2048;
            
            BmpStream->Position =0;
            char* Buffer =new char[ThreshHold];
            int Buffersize = hehe->BmpStream->Size;            int Buffers = Buffersize/ThreshHold;
            //ShowMessage(Buffers);
            NMUDP1->RemoteHost = FromIP;
            Label1->Caption = "请求来源:"+FromIP;
            Label2->Caption = "已经发送:0字节";
            Refresh();
          //  Socket->SendBuf("s",1); //标志开始发送
            for(int i=0;i<=Buffers;i++)
              {
              // ShowMessage("已开始for");
               if(Buffersize>=ThreshHold)
                 {
                  Sleep(1);
                  hehe->BmpStream->Read(Buffer,ThreshHold);
                  NMUDP1->SendBuffer(Buffer,ThreshHold,ThreshHold);
                 // ShowMessage(i);
                  }
                else
                  {
                   if(Buffersize <=0)
                     break;
                   else
                     {
                     hehe->BmpStream->Read(Buffer,Buffersize);
                    NMUDP1->SendBuffer(Buffer,ThreshHold,ThreshHold);
                     }                   }
                 Buffersize-=ThreshHold;
                 Label2->Caption = "已发送:"+IntToStr(BmpStream->Size-Buffersize);
                }
             NMUDP1->SendBuffer("E",1,1);
             delete Buffer;
}
//---------------------------------------------------------------------------
void __fastcall Thehe::FormDestroy(TObject *Sender)
{
       delete BmpStream;
    delete ResultStream;
    delete TempStream;
}
//---------------------------------------------------------------------------

Answer 2

delphi的源码我有，就是看人家屏幕的，要的话我可以发给你