ccrun、songhtao和大是们进来看看吧，流操作的问题

nieshigui 2008-03-30 04:14:47

HDC dc = GetDC(0) ;
TCanvas * myCanvas = new TCanvas() ;
Graphics::TBitmap * myBitmap = new Graphics::TBitmap();
TJPEGImage *pimg = new TJPEGImage;
myCanvas->Handle = dc ;
myBitmap->Width = 1024;
myBitmap->Height = 768;
TMemoryStream *Sys_Buffer = new TMemoryStream();
myBitmap->Canvas->CopyRect(Rect(0,0,1024,768),myCanvas,Rect(0,0,1024,768));
pimg->Assign(myBitmap);
pimg->CompressionQuality=100;
pimg->SaveToStream(Sys_Buffer);
Sys_Buffer->Position=0;
//上面的不用管
int Y=108;
int len = (int)Sys_Buffer->Size+2;
char *socket_buffer=new char[(int)Sys_Buffer->Size+1];
socket_buffer[0]=(char)Y;
socket_buffer[1]=(char)len;
Sys_Buffer->Position=0;
ShowMessage (Sys_Buffer->Size);
memcpy(&socket_buffer[2],Sys_Buffer,Sys_Buffer->Size);
Sys_Buffer->Clear();

TMemoryStream *Buffer= new TMemoryStream();
Buffer->SetSize(len-2);
Buffer->Position=0;
memcpy(Buffer->Memory,&socket_buffer[2],len-2);
Buffer->Position=0;
pimg->LoadFromStream(Buffer);
myBitmap->Assign(pimg);
Image1->Canvas->CopyRect(Rect(0,0,1024,768),myBitmap->Canvas,Rect(0,0,1024,768));

Sys_Buffer->Clear();

ReleaseDC(0,dc) ;
delete myCanvas ;
delete myBitmap ;
delete pimg;

为什么我把流存入socket_buffer后在取出来没办法显示啊提示JPEG 52错误

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过客猫2022 2008-04-07

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路过

CACACACACA 2008-04-02

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结贴吧。又一白进来了。

zhao2008gang 2008-04-02

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我把我写的读图片给你参考一下
DataModule1->ClientDataSet1->Close();
DataModule1->ClientDataSet1->CommandText = "select * from Machine where [index]='" + MacBox_1->Text +"'";
DataModule1->ClientDataSet1->Open();//上面的就是从数据库中相应的表中读取
TStream *stream;
MacBitmap=new Graphics::TBitmap();
stream=DataModule1->ClientDataSet1->CreateBlobStream(DataModule1->ClientDataSet1->FieldByName("PIC"),bmRead);//PIC是存储二进制文件的字段
MacBitmap->LoadFromStream(stream);
TRect TheRect;
TheRect=Rect(ML,MT,PaintBox1->Width,PaintBox1->Height);//放在此矩形里面
PaintBox1->Canvas->StretchDraw(TheRect,MacBitmap);//利用paintbox把图片描出来！
if(stream)
delete stream;
delete MacBitmap;

我不懂电脑 2008-03-31

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楼上各位都很好。

海嵌 2008-03-31

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void __fastcall TForm1::btn_1Click(TObject *Sender)

{

    HDC dc = GetDC(0) ;

    TCanvas * myCanvas = new TCanvas() ;

    Graphics::TBitmap * myBitmap  = new Graphics::TBitmap();

    TJPEGImage *pimg = new TJPEGImage;

    myCanvas->Handle = dc ;

    myBitmap->Width = 1024;

    myBitmap->Height = 768;

    TMemoryStream *Sys_Buffer    = new TMemoryStream();

    myBitmap->Canvas->CopyRect(Rect(0,0,1024,768),myCanvas,Rect(0,0,1024,768));

    pimg->Assign(myBitmap);

    pimg->CompressionQuality=100;

    pimg->SaveToStream(Sys_Buffer);

    Sys_Buffer->Position=0;



    //上面的不用管

    int Y=108; 

    int len = (int)Sys_Buffer->Size+2;

    char *socket_buffer=new char[(int)Sys_Buffer->Size+1];

    socket_buffer[0]=(char)Y; 

    socket_buffer[1]=(char)len;

    Sys_Buffer->Position=0;



    ShowMessage (Sys_Buffer->Size);



    Sys_Buffer->Read(&socket_buffer[2],Sys_Buffer->Size);

    // memcpy(&socket_buffer[2],Sys_Buffer,Sys_Buffer->Size);



    Sys_Buffer->Clear();





    TMemoryStream *Buffer= new TMemoryStream();

    Buffer->SetSize(len-2);

    Buffer->Position=0;



    Buffer->Write(&socket_buffer[2],len-2);

    //memcpy(Buffer->Memory,&socket_buffer[2],len-2);



    Buffer->Position=0;

    pimg->LoadFromStream(Buffer);

    myBitmap->Assign(pimg);



    img_1->Canvas->CopyRect(Rect(0,0,1024,768),myBitmap->Canvas,Rect(0,0,1024,768));





    Sys_Buffer->Clear();





    ReleaseDC(0,dc) ;

    delete myCanvas ;

    delete myBitmap ;

    delete pimg;

}