[ericshliao]

I have a question about screen refresh control on iLiad:
in liberdm/erdm.h, there are functions to do refrshing job

// Do a full display update
int     dmDisplay(eDmCmdPriority prior, eDmQuality qual);

// Blank display
int     dmDisplayEraseToWhite(eDmCmdPriority prior);

Is that all we need to make screen refresh on iLiad? If yes, why is the need to write image to /dev/fb0? For example, in source code of ipdf:

void GtkMgr::drawImage(SplashBitmap * bitmap, 
                          int xSrc, int ySrc, 
                          int xDest, int yDest, 
                          int width , int height, 
                          GBool bDrawBorder,
		          int current_screen_height)
{
    if (bitmap) 
    {
        if (width < 0) width = bitmap->getWidth();
        if (height < 0) height = bitmap->getHeight();

        dfb_copyImage(fb_mem, bitmap, xSrc, ySrc, xDest, yDest, width, height, current_screen_height);

        if (bDrawBorder)
        {
            // line 
            XSetForeground(display, GDK_GC_XGC(gc), 0);
            XSetLineAttributes(display, GDK_GC_XGC(gc), 1, LineSolid, CapProjecting, JoinMiter);
            XDrawRectangle(display, GDK_WINDOW_XWINDOW(window->window), GDK_GC_XGC(gc), 
                xDest, yDest, width, height);
        }
    } 
}