c# - Show only small part of picture -
i have write program consists server , client. server makes screenshot desktop, , client receives screenshot , shows on form. there problem in data transfer, see small strip. checked before sending image on server ok. however, client receives wrong image. wrong? xaml:
<window x:class="testtcp.mainwindow" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" title="testtcp" height="350" width="525"> <grid> <image x:name="img1" margin="0"/> </grid> </window> code c#:
public partial class mainwindow : window { public mainwindow() { initializecomponent(); task rec = new task(waitclientquery); rec.start(); task tk = new task(send); tk.start(); } private void send()//server part. take screen , send image { bitmap temp = capturescreen(true); memorystream ms3 = new memorystream(); bitmapimage image = new bitmapimage(); byte[] img_byte; try { ((system.drawing.bitmap)temp).save(ms3, system.drawing.imaging.imageformat.bmp); image.begininit(); ms3.seek(0, seekorigin.begin); image.streamsource = ms3; image.endinit(); jpegbitmapencoder encoder = new jpegbitmapencoder(); encoder.frames.add(bitmapframe.create(image)); using (memorystream ms = new memorystream()) { encoder.save(ms); img_byte = ms.toarray(); } try { tcpclient client = new tcpclient("192.168.1.64", 4444); networkstream netstream = client.getstream(); netstream.write(img_byte, 0, img_byte.length); netstream.close(); client.close(); } catch (exception) { } } catch (exception ee) { } } [structlayout(layoutkind.sequential)] struct cursorinfo { public int32 cbsize; public int32 flags; public intptr hcursor; public pointapi ptscreenpos; } [structlayout(layoutkind.sequential)] struct pointapi { public int x; public int y; } [dllimport("user32.dll")] static extern bool getcursorinfo(out cursorinfo pci); [dllimport("user32.dll")] static extern bool drawicon(intptr hdc, int x, int y, intptr hicon); const int32 cursor_showing = 0x00000001; public static bitmap capturescreen(bool capturemouse) { bitmap result = new bitmap(screen.primaryscreen.bounds.width, screen.primaryscreen.bounds.height); try { using (graphics g = graphics.fromimage(result)) { g.copyfromscreen(0, 0, 0, 0, screen.primaryscreen.bounds.size, copypixeloperation.sourcecopy); if (capturemouse) { cursorinfo pci; pci.cbsize = system.runtime.interopservices.marshal.sizeof(typeof(cursorinfo)); if (getcursorinfo(out pci)) { if (pci.flags == cursor_showing) { drawicon(g.gethdc(), pci.ptscreenpos.x, pci.ptscreenpos.y, pci.hcursor); g.releasehdc(); } } } } } catch { result = null; } return result; } void waitclientquery()//receive data(client) { try { ipaddress ip ; ipaddress.tryparse("192.168.1.64", out ip); tcplistener listener = new tcplistener(ip, 4444); listener.start(); while (true) { tcpclient client = listener.accepttcpclient(); thread thread = new thread(new parameterizedthreadstart(readmessage)); thread.isbackground = true; thread.start(client); } } catch (exception ex) { } } void readmessage(object obj) { try { tcpclient client = (tcpclient)obj; networkstream netstream = client.getstream(); byte[] arr = new byte[client.receivebuffersize ]; int len = netstream.read(arr, 0, client.receivebuffersize); if (len > 0) { try { action act = delegate { memorystream strmimg = new memorystream(arr); bitmapimage mybitmapimage = new bitmapimage(); mybitmapimage.begininit(); mybitmapimage.streamsource = strmimg; mybitmapimage.endinit(); img1.source = mybitmapimage; }; this.dispatcher.begininvoke(act); } catch (exception ex) { string message = ex.message; } } netstream.close(); client.close(); } catch (exception ex) { } } } p.s. result, screen program after compile: click view
the main root cause client.receivebuffersize using default value 8192 byte client not receive enough image has been transferred server. in code, see @ client receive correctly size of image use binarywriter transfer length of image. client side have used binaryreader read number of bytes , size of image save bandwidth. hope help
at send method:
tcpclient client = new tcpclient("192.168.1.64", 4444); using (networkstream netstream = client.getstream()) { using (binarywriter bw = new binarywriter(netstream)) { bw.write(img_byte.length); bw.write(img_byte, 0, img_byte.length); } client.close(); } at readmessage(object obj)
private void readmessage(object obj) { try { byte[] arr = null; tcpclient client = (tcpclient) obj; using (networkstream netstream = client.getstream()) { using (binaryreader br = new binaryreader(netstream)) { var arrlen = new byte[4]; br.read(arrlen, 0, 4); int len = bitconverter.toint32(arrlen, 0); if (len > 0) { arr = new byte[len]; int read = 0; while (read != len) { read += br.read(arr, read, arr.length - read); } } } } if (arr != null && arr.length > 0) { try { action act = delegate { memorystream strmimg = new memorystream(arr); bitmapimage mybitmapimage = new bitmapimage(); mybitmapimage.begininit(); mybitmapimage.streamsource = strmimg; mybitmapimage.endinit(); img1.source = mybitmapimage; }; this.dispatcher.begininvoke(act); } catch (exception ex) { string message = ex.message; } } client.close(); } catch (exception ex) { } } 
