DirectFB同时显示到X11和VNC上

                DirectFB同时显示到X11和VNC上

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作者联系方式：李先静 <xianjimli at hotmail dot com>

DirectFB可以使用多种后端作为输入输出设备，典型的有VNC、X11、SDL和fbdev等等，这种设计可以说非常巧妙了。但美中不足的是它在任意时刻只能使用一种后端，更换成其它后端需要重新起动DirectFB应用程序。大多数情况下，这也没有问题，但我想broncho手机在正常使用的情况下，还能通过VNC访问，这样就可以在PC上操作broncho手机的所有功能，甚至到把手机屏幕显示到投影仪上。

对于让DirectFB同时支持多个后端的情况，从设计的角度来看，当然是首选Composite模式，用一种新的后端把其它几个后端组合起来，即不用修改DirectFB框架，又不用修改现有的后端，改一下配置文件就行了。麻烦的是DirectFB-1.1.1中带的VNC根本就不能用，单进程的情况，那些问题我都修改掉了，支持多进程的情况遇到些困难了。最后懒得管它了，先给X11加上VNC功能试一下再说。

先编译LibVNCServer-0.9.1。从sf下载软件包，按正常方式编译即可。

接下来修改X11后端。

1.修改Makefile.am，连接VNC的库。

libdirectfb_x11_la_LDFLAGS = /
    $(X11_LIBS)    $(VNC_LIBS) /
    -avoid-version    /
    -module

2.初始化VNC

     int argc = 0;
     char** argv = NULL;

     D_DEBUG( "DirectFB/VNC: layer config properties/n");

     if(rfb_screen) /*!!! FIXME*/
         return DFB_OK;

     /* Set video mode */
     rfb_screen = rfbGetScreen(&argc, argv, config->width, config->height, 8,3,4);

     if(DFB_COLOR_BITS_PER_PIXEL(config->format) == DSPF_RGB16)
     {
        rfb_screen->serverFormat.redShift = 11;
        rfb_screen->serverFormat.greenShift = 5;
        rfb_screen->serverFormat.blueShift = 0;
        rfb_screen->serverFormat.redMax = 31;
        rfb_screen->serverFormat.greenMax = 63;
        rfb_screen->serverFormat.blueMax = 31;
     }

     rfb_screen->frameBuffer = malloc(rfb_screen->width * rfb_screen->height * rfb_screen->depth / 8) ;

     rfb_screen->kbdAddEvent = process_key_event;
     rfb_screen->ptrAddEvent = process_pointer_event;
     rfb_screen->newClientHook = newclient;

     rfbInitServer(rfb_screen);

     direct_thread_create( DTT_OUTPUT, vnc_server_thread, rfb_screen, "VNC Output" );

     if ( !(config->surface_caps & (DSCAPS_DOUBLE | DSCAPS_TRIPLE)) )
          direct_thread_create( DTT_OUTPUT, vnc_refresh_thread, rfb_screen, "VNC Refresh" );

     return DFB_OK;

3.更新VNC显示

static DFBResult
vnc_update_screen(void* src, int x, int y, int w, int h )
{
     int          i, j, k;
     void        *dst;
     int          pitch;
     DFBResult    ret;
     unsigned short* p = NULL;
     unsigned int* q = NULL;
     D_ASSERT( surface != NULL );
     D_ASSERT( rfb_screen != NULL );
     D_ASSERT( rfb_screen->frameBuffer != NULL );

     dst = rfb_screen->frameBuffer;

     if(g_vnc_client_nr > 0)
     {
        direct_memcpy( dst, src, w * h * rfb_screen->depth/8 );
        rfbMarkRectAsModified ( rfb_screen, x, y, x+w, y+h );
        printf("%s %d %d %d %d/n", __func__, x, y, w, h);
     }

     return DFB_OK;
}

4.处理VNC输入

static void
process_pointer_event(int buttonMask, int x, int y, rfbClientPtr cl)
{

    DFBInputEvent evt = {0};
    int button = 0;

    if( vncPointerDevice == NULL ){
        /* Attach to first input device */
        dfb_input_enumerate_devices( attach_pointer_device,NULL,
            DICAPS_BUTTONS|DICAPS_AXES);
        D_ASSERT(vncPointerDevice);
    }

    ClientData* cd=cl->clientData;
    if(buttonMask != cd->oldButtonMask ) {
        int mask = buttonMask^cd->oldButtonMask;
        if( mask & (1 << 0)) {
            button=DIBI_LEFT;
        } else if( mask & (1 << 1)) {
            button=DIBI_MIDDLE;
        } else if( mask & (1 << 2)) {
            button=DIBI_RIGHT;
        } else {
            return;
        }
        evt.flags = DIEF_NONE;

        if(cd->pressed)
        {
            evt.type = DIET_BUTTONRELEASE;
            cd->pressed=0;
            cd->oldButtonMask = 0;
        }else {
            evt.type = DIET_BUTTONPRESS;
            cd->pressed=1;
            cd->oldButtonMask=buttonMask;
        }
        evt.button=button;
        printf("%s %d %d %d %d/n", __func__, button, cd->pressed, x, y);
        dfb_input_dispatch( vncPointerDevice, &evt );
        cd->oldx=x;
        cd->oldy=y;
        return;
    }

    evt.type    = DIET_AXISMOTION;
    evt.flags   = DIEF_AXISABS;

    if( cd->oldx != x ) {
          evt.axis    = DIAI_X;
          evt.axisabs = x;
          dfb_input_dispatch( vncPointerDevice, &evt );
    }

    if( cd->oldy != y ) {
          evt.axis    = DIAI_Y;
          evt.axisabs = y;
          dfb_input_dispatch( vncPointerDevice, &evt );
    }
    cd->oldx=x;
    cd->oldy=y;

    dfb_input_dispatch( vncPointerDevice, &evt );
    rfbDefaultPtrAddEvent(buttonMask,x,y,cl);

}

static void
process_key_event(rfbBool down, rfbKeySym key, rfbClientPtr cl)
{
    DFBInputEvent evt;
    if( vncKeyboardDevice == NULL ){
        /* Attach to first input device */
        dfb_input_enumerate_devices( attach_keyboard_device,NULL, DICAPS_KEYS);
        D_ASSERT(vncKeyboardDevice);
    }
     if (down)
          evt.type = DIET_KEYPRESS;
     else
          evt.type = DIET_KEYRELEASE;

     if (translate_key( key, &evt )) {
          dfb_input_dispatch( vncKeyboardDevice, &evt );
     }

}

5.处理VNC客户端连接

static void clientgone(rfbClientPtr cl)
{
g_vnc_client_nr--;
free(cl->clientData);

return;
}

static enum rfbNewClientAction newclient(rfbClientPtr cl)
{
g_vnc_client_nr++;
cl->clientData = (void*)calloc(sizeof(ClientData),1);
cl->clientGoneHook = clientgone;
return RFB_CLIENT_ACCEPT;
}

编译完成后运行broncho，然后用VNC viewer连接到本机，效果如下：

色彩有点不对，有时间再看看。

~~end~~

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DirectFB同时显示到X11和VNC上

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