远程控制篇：抓取远程屏幕图像

{抓屏幕图像，保存为内存流--BMP流,压缩BMP流,JPG流，以及使用流}

{在网络中传送BMP流和JPG流的速度没测试过}

{BMP流的压缩是无损压缩}

{

全局变量

memoryStream:TMemoryStream;

memoryStream:=TMemoryStream.create;

}

var

image:Timage;

jpgstream:TJPEGImage;

ss:tcanvas;

begin

ss:=tcanvas.Create;

ss.Handle:=getdc(0);

image:=timage.Create(self);

image.width:=Screen.width;

image.Height:=screen.Height ;

image.picture.bitmap.PixelFormat:= pf16bit;

bitblt(image.canvas.handle,0,0,image.width,image.height,ss.handle,0,0,srccopy);

{大大的原始BMP流

image.picture.bitmap.SaveToStream(memoryStream);

}

{无损压缩BMP流  uses Zlib.pas

{先定义变量count,DestStream,SourceStream}

image.picture.bitmap.SaveToStream(memoryStream);

Count:=memoryStream.Size;

DestStream:=TMemoryStream.Create;

{压缩方式:clnone,clfastest,cldefault,clmax}

SourceStream:=TCompressionStream.Create(cldefault, DestStream);

try

memoryStream.SaveToStream(SourceStream);

SourceStream.Free;

memoryStream.Clear;

memoryStream.WriteBuffer(Count, SizeOf(Count));

memoryStream.CopyFrom(DestStream, 0);

finally

DestStream.Free;

end;

}

{JPG流  uses jpeg

jpgstream:= TJPEGImage.Create;

jpgstream.Assign(image.picture.bitmap);

jpgstream.CompressionQuality:=50; {压缩质量}

jpgstream.Compress;

jpgstream.SaveToStream(memoryStream);{保存为JPG流}

jpgstream.free;

}

ReleaseDC(0,ss.Handle);

image.free;

{发送内存流...}

-----------------------------------------------------

{接收内存流...}

{使用BMP流

image.Picture.Bitmap.LoadFromStream(bmpStream);}

{还原压缩的BMP流  uses:Zlib.pas

先定义变量count,buffer,DestStream,SourceStream

memoryStream是压缩的BMP流

memoryStream.ReadBuffer(Count, SizeOf(Count));

GetMem(Buffer, Count);

DestStream:=TMemoryStream.Create;

SourceStream:=TDecompressionStream.Create(memoryStream);

Try

SourceStream.ReadBuffer(Buffer^, Count);

  DestStream.WriteBuffer(Buffer^, Count);

  DestStream.Position:=0;

  image.Picture.Bitmap.LoadFromStream(DestStream);

finally

FreeMem(Buffer);

DestStream.Free;

end;

}

使用JPG流 image.Picture.Assign(jpgstream);