一套可适用于IOT,TV等嵌入式系统的UI框架。

[](https://travis-ci.org/LibVNC/libvncserver) [](https://ci.appveyor.com/project/bk138/libvncserver/branch/master) [](https://liberapay.com/LibVNC/donate) LibVNCServer: A library for easy implementation of a VNC server. Copyright (C) 2001-2003 Johannes E. Schindelin If you already used LibVNCServer, you probably want to read [NEWS](NEWS). What is it? =========== [VNC](https://en.wikipedia.org/wiki/Virtual_Network_Computing) is a set of programs using the [RFB (Remote Frame Buffer)](https://github.com/rfbproto/rfbproto/blob/master/rfbproto.rst) protocol. They are designed to "export" a frame buffer via net (if you don't know VNC, I suggest you read "Basics" below). It is already in wide use for administration, but it is not that easy to program a server yourself. This has been changed by LibVNCServer. There are several examples included, both for [servers](./examples) and [clients](./client_examples). These examples are not too well documented, but easy straight forward and a good starting point. Try 'example', a shared scribble sheet: it outputs on which port it listens (default: 5900), so it is display 0. To view, call `vncviewer :0` You should see a sheet with a gradient and "Hello World!" written on it. Try to paint something. Note that every time you click, there is some bigger blot, whereas when you drag the mouse while clicked you draw a line. The size of the blot depends on the mouse button you click. Open a second vncviewer with the same parameters and watch it as you paint in the other window. This also works over internet. You just have to know either the name or the IP of your machine. Then it is `vncviewer machine.where.example.runs.com:0` or similar for the remote client. Now you are ready to type something. Be sure that your mouse sits still, because every time the mouse moves, the cursor is reset to the position of the pointer! If you are done with that demo, press the down or up arrows. If your viewer supports it, then the dimensions of the sheet change. Just press Escape in the viewer. Note that the server still runs, even if you closed both windows. When you reconnect now, everything you painted and wrote is still there. You can press "Page Up" for a blank page. The demo 'pnmshow' is much simpler: you either provide a filename as argument or pipe a file through stdin. Note that the file has to be a raw pnm/ppm file, i.e. a truecolour graphics. Only the Escape key is implemented. This may be the best starting point if you want to learn how to use LibVNCServer. You are confronted with the fact that the bytes per pixel can only be 8, 16 or 32. If you want to build a VNC client instead, please have a look at the [various client examples](./client_examples). Projects using it ================= VNC for KDE http://www.tjansen.de/krfb GemsVNC http://www.elilabs.com/~rj/gemsvnc/ VNC for Netware http://forge.novell.com/modules/xfmod/project/?vncnw RDesktop http://rdesktop.sourceforge.net VNCpp https://github.com/ocrespo/VNCpp VirtualBox https://www.virtualbox.org/ Veyon https://veyon.io Mail us if your application is missing! How to build ============ LibVNCServer uses CMake, so you can build via: mkdir build cd build cmake .. cmake --build . Crypto support in LibVNCClient and LibVNCServer can use different backends: * OpenSSL (`-DWITH_OPENSSL=ON -DWITH_GCRYPT=OFF`) * Supports all authentication methods in LibVNCClient and LibVNCServer. * Supports WebSockets in LibVNCServer. * Libgcrypt (`-DWITH_OPENSSL=OFF -DWITH_GCRYPT=ON`) * Supports all authentication methods in LibVNCClient and LibVNCServer. * Supports WebSockets in LibVNCServer. * Included (`-DWITH_OPENSSL=OFF -DWITH_GCRYPT=OFF`) * Supports _only VNC authentication_ in LibVNCClient and LibVNCServer. * Supports WebSockets in LibVNCServer. Transport Layer Security support in LibVNCClient and LibVNCServer can use: * OpenSSL (`-DWITH_OPENSSL=ON -DWITH_GNUTLS=OFF`) * GnuTLS (`-DWITH_OPENSSL=OFF -DWITH_GNUTLS=ON`) For some more comprehensive examples that include installation of dependencies, see the [Unix CI](.travis.yml) and [Windows CI](.appveyor.yml) build setups. Crosscompiling from Unix to Android ----------------------------------- See https://developer.android.com/ndk/guides/cmake.html as a reference, but basically it boils down to: mkdir build cd build cmake .. -DANDROID_NDK=<path> -DCMAKE_TOOLCHAIN_FILE=<path> -DANDROID_NATIVE_API_LEVEL=<API level you want> -DWITH_PNG=OFF # NDK not shipping png per default cmake --build . Crosscompiling from Linux to Windows ------------------------------------ Tested with MinGW-w64 on Debian. You can make use of the [provided toolchain file](cmake/Toolchain-cross-mingw32-linux.cmake). It sets CMake to expect (optional) win32 dependencies like libjpeg and friends in the `deps` directory. mkdir build cd build cmake -DCMAKE_TOOLCHAIN_FILE=../cmake/Toolchain-cross-mingw32-linux.cmake .. cmake --build . How to use ========== To make a server, you just have to initialise a server structure using the function rfbDefaultScreenInit, like rfbScreenInfoPtr rfbScreen = rfbGetScreen(argc,argv,width,height,8,3,bpp); where byte per pixel should be 1, 2 or 4. If performance doesn't matter, you may try bpp=3 (internally one cannot use native data types in this case; if you want to use this, look at pnmshow24). You then can set hooks and io functions (see below) or other options (see below). And you allocate the frame buffer like this: rfbScreen->frameBuffer = (char*)malloc(width*height*bpp); After that, you initialize the server, like rfbInitServer(rfbScreen); You can use a blocking event loop, a background (pthread based) event loop, or implement your own using the rfbProcessEvents function. Making it interactive --------------------- Input is handled by IO functions (see below). Whenever you change something in the frame buffer, call rfbMarkRectAsModified. Utility functions ----------------- Whenever you draw something, you have to call rfbMarkRectAsModified(screen,x1,y1,x2,y2). This tells LibVNCServer to send updates to all connected clients. Before you draw something, be sure to call rfbUndrawCursor(screen). This tells LibVNCServer to hide the cursor. Remark: There are vncviewers out there, which know a cursor encoding, so that network traffic is low, and also the cursor doesn't need to be drawn the cursor every time an update is sent. LibVNCServer handles all the details. Just set the cursor and don't bother any more. To set the mouse coordinates (or emulate mouse clicks), call rfbDefaultPtrAddEvent(buttonMask,x,y,cl); IMPORTANT: do this at the end of your function, because this actually draws the cursor if no cursor encoding is active. What is the difference between rfbScreenInfoPtr and rfbClientPtr? ----------------------------------------------------------------- The rfbScreenInfoPtr is a pointer to a rfbScreenInfo structure, which holds information about the server, like pixel format, io functions, frame buffer etc. The rfbClientPtr is a pointer to an rfbClientRec structure, which holds information about a client, like pixel format, socket of the connection, etc. A server can have several clients, but needn't have any. So, if you have a server and three clients are connected, you have one instance of a rfbScreenInfo and three instances of rfbClientRec's. The rfbClientRec structure holds a member rfbScreenInfoPtr screen which points to the server and a member rfbClientPtr next to the next client. The rfbScreenInfo structure holds a member rfbClientPtr rfbClientHead which points to the first client. So, to access the server from the client structure, you use cl