VNC: Repartition some function in preparation for supporting other encoding types

graphics/vnc/server/Make.defs

@@ -35,7 +35,8 @@
 
 ifeq ($(CONFIG_VNCSERVER),y)
 
-CSRCS += vnc_server.c vnc_negotiate.c vnc_updater.c vnc_receiver.c vnc_fbdev.c
+CSRCS += vnc_server.c vnc_negotiate.c vnc_updater.c vnc_receiver.c
+CSRCS += vnc_raw.c vnc_color.c vnc_fbdev.c
 
 ifeq ($(CONFIG_NX_KBD),y)
 CSRCS += vnc_keymap.c

graphics/vnc/server/vnc_color.c

@@ -0,0 +1,197 @@
+/****************************************************************************
+ * graphics/vnc/vnc_color.c
+ *
+ *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+
+#include "vnc_server.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: vnc_convert_rgbNN
+ *
+ * Description:
+ *  Convert the native framebuffer color format (either RGB16 5:6:5 or RGB32
+ *  8:8:8) to the remote framebuffer color format (either RGB16 5:6:5,
+ *  RGB16 5:5:5, or RGB32 8:8:)
+ *
+ * Input Parameters:
+ *   pixel - The src color in local framebuffer format.
+ *
+ * Returned Value:
+ *   The pixel in the remote framebuffer color format.
+ *
+ ****************************************************************************/
+
+#if defined(CONFIG_VNCSERVER_COLORFMT_RGB16)
+
+uint8_t vnc_convert_rgb8_222(lfb_color_t rgb)
+{
+  /* 111111
+   * 54321098 76543210
+   * -----------------
+   * RRRRRGGG GGGBBBBB
+   *          ..RRGGBB
+   */
+
+  return (uint8_t)(((rgb >> 10) & 0x0030)  |
+                   ((rgb >> 7)  & 0x000c)  |
+                   ((rgb >> 3)  & 0x0003));
+}
+
+uint8_t vnc_convert_rgb8_332(lfb_color_t rgb)
+{
+  /* 111111
+   * 54321098 76543210
+   * -----------------
+   * RRRRRGGG GGGBBBBB
+   *          RRRGGGBB
+   */
+
+  return (uint8_t)(((rgb >> 8) & 0x0070)  |
+                   ((rgb >> 6) & 0x001c)  |
+                   ((rgb >> 3) & 0x0003));
+}
+
+uint16_t vnc_convert_rgb16_555(lfb_color_t rgb)
+{
+  /* 111111
+   * 54321098 76543210
+   * -----------------
+   * RRRRRGGG GGGBBBBB
+   * .RRRRRGG GGGBBBBB
+   */
+
+  return (((rgb >> 1) & ~0x1f) | (rgb & 0x1f));
+}
+
+uint16_t vnc_convert_rgb16_565(lfb_color_t rgb)
+{
+  /* Identity mapping */
+
+  return rgb;
+}
+
+uint32_t vnc_convert_rgb32_888(lfb_color_t rgb)
+{
+  /* 33222222 22221111 111111
+   * 10987654 32109876 54321098 76543210
+   * ----------------------------------
+   *                   RRRRRGGG GGGBBBBB
+   *          RRRRR... GGGGGG.. BBBBB...
+   */
+
+  return (((uint32_t)rgb << 8) & 0x00f80000) |
+         (((uint32_t)rgb << 6) & 0x0000fc00) |
+         (((uint32_t)rgb << 3) & 0x000000f8);
+}
+
+#elif defined(CONFIG_VNCSERVER_COLORFMT_RGB32)
+
+uint8_t vnc_convert_rgb8_222(lfb_color_t rgb)
+{
+  /* 33222222 22221111 111111
+   * 10987654 32109876 54321098 76543210
+   * -----------------------------------
+   *          RRRRRRRR GGGGGGGG BBBBBBBB
+   *                            ..RRGGBB
+   */
+
+  return (uint8_t)(((rgb >> 18) & 0x0030)  |
+                   ((rgb >> 12) & 0x000c)  |
+                    (rgb >> 6)  & 0x0003));
+}
+
+uint8_t vnc_convert_rgb8_332(lfb_color_t rgb)
+{
+  /* 33222222 22221111 111111
+   * 10987654 32109876 54321098 76543210
+   * -----------------------------------
+   *          RRRRRRRR GGGGGGGG BBBBBBBB
+   *                            RRRGGGBB
+   */
+
+  return (uint8_t)(((rgb >> 16) & 0x0070)  |
+                   ((rgb >> 11) & 0x001c)  |
+                    (rgb >> 6)  & 0x0003));
+}
+
+uint16_t vnc_convert_rgb16_555(lfb_color_t rgb)
+{
+  /* 33222222 22221111 111111
+   * 10987654 32109876 54321098 76543210
+   * -----------------------------------
+   *          RRRRRRRR GGGGGGGG BBBBBBBB
+   *                   .RRRRRGG GGGBBBBB
+   */
+
+  return (uint16_t)
+    (((rgb >> 9) & 0x00007c00) |
+     ((rgb >> 6) & 0x000003e0) |
+     ((rgb >> 3) & 0x0000001f));
+}
+
+uint16_t vnc_convert_rgb16_565(lfb_color_t rgb)
+{
+  /* 33222222 22221111 111111
+   * 10987654 32109876 54321098 76543210
+   * -----------------------------------
+   *          RRRRRRRR GGGGGGGG BBBBBBBB
+   *                   RRRRRGGG GGGBBBBB
+   */
+
+  return (uint16_t)
+    (((rgb >> 8) & 0x0000f800) |
+     ((rgb >> 5) & 0x000007e0) |
+     ((rgb >> 3) & 0x0000001f));
+}
+
+uint32_t vnc_convert_rgb32_888(lfb_color_t rgb)
+{
+  /* Identity mapping */
+
+  return rgb;
+}
+#else
+#  error Unspecified/unsupported color format
+#endif

graphics/vnc/server/vnc_raw.c

@@ -0,0 +1,462 @@
+/****************************************************************************
+ * graphics/vnc/vnc_raw.c
+ *
+ *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <stdint.h>
+#include <assert.h>
+#include <errno.h>
+#include <debug.h>
+
+#include "vnc_server.h"
+
+/****************************************************************************
+ * Private Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: vnc_copy8
+ *
+ * Description:
+ *   Copy a 16/32-bit pixels from the source rectangle to a 8-bit pixel
+ *   destination rectangle.
+ *
+ * Input Parameters:
+ *   session      - A reference to the VNC session structure.
+ *   row,col      - The upper left X/Y (pixel/row) position of the rectangle
+ *   width,height - The width (pixels) and height (rows of the rectangle)
+ *   convert      - The function to use to convert from the local framebuffer
+ *                  color format to the remote framebuffer color format.
+ *
+ * Returned Value:
+ *   The size of the transfer in bytes.
+ *
+ ****************************************************************************/
+
+static size_t vnc_copy8(FAR struct vnc_session_s *session,
+                         nxgl_coord_t row, nxgl_coord_t col,
+                         nxgl_coord_t height, nxgl_coord_t width,
+                         vnc_convert8_t convert)
+{
+  FAR struct rfb_framebufferupdate_s *update;
+  FAR const uint16_t *srcleft;
+  FAR const lfb_color_t *src;
+  FAR uint8_t *dest;
+  nxgl_coord_t x;
+  nxgl_coord_t y;
+
+  /* Destination rectangle start address */
+
+  update = (FAR struct rfb_framebufferupdate_s *)session->outbuf;
+  dest   = (FAR uint8_t *)update->rect[0].data;
+
+  /* Source rectangle start address (left/top)*/
+
+  srcleft = (FAR lfb_color_t *)
+    (session->fb + RFB_STRIDE * row + RFB_BYTESPERPIXEL * col);
+
+  /* Transfer each row from the source buffer into the update buffer */
+
+  for (y = 0; y < height; y++)
+    {
+      src = srcleft;
+      for (x = 0; x < width; x++)
+        {
+          *dest++ = convert(*src);
+          src++;
+        }
+
+      srcleft = (FAR lfb_color_t *)((uintptr_t)srcleft + RFB_STRIDE);
+    }
+
+  return (size_t)((uintptr_t)dest - (uintptr_t)update->rect[0].data);
+}
+
+/****************************************************************************
+ * Name: vnc_copy16
+ *
+ * Description:
+ *   Copy a 16/32-bit pixels from the source rectangle to a 16-bit pixel
+ *   destination rectangle.
+ *
+ * Input Parameters:
+ *   session      - A reference to the VNC session structure.
+ *   row,col      - The upper left X/Y (pixel/row) position of the rectangle
+ *   width,height - The width (pixels) and height (rows of the rectangle)
+ *   convert      - The function to use to convert from the local framebuffer
+ *                  color format to the remote framebuffer color format.
+ *
+ * Returned Value:
+ *   The size of the transfer in bytes.
+ *
+ ****************************************************************************/
+
+static size_t vnc_copy16(FAR struct vnc_session_s *session,
+                         nxgl_coord_t row, nxgl_coord_t col,
+                         nxgl_coord_t height, nxgl_coord_t width,
+                         vnc_convert16_t convert)
+{
+  FAR struct rfb_framebufferupdate_s *update;
+  FAR const uint16_t *srcleft;
+  FAR const lfb_color_t *src;
+  FAR uint16_t *dest;
+  nxgl_coord_t x;
+  nxgl_coord_t y;
+
+  /* Destination rectangle start address */
+
+  update = (FAR struct rfb_framebufferupdate_s *)session->outbuf;
+  dest   = (FAR lfb_color_t *)update->rect[0].data;
+
+  /* Source rectangle start address (left/top)*/
+
+  srcleft = (FAR uint16_t *)(session->fb + RFB_STRIDE * row + RFB_BYTESPERPIXEL * col);
+
+  /* Transfer each row from the source buffer into the update buffer */
+
+  for (y = 0; y < height; y++)
+    {
+      src = srcleft;
+      for (x = 0; x < width; x++)
+        {
+          *dest++ = convert(*src);
+          src++;
+        }
+
+      srcleft = (FAR lfb_color_t *)((uintptr_t)srcleft + RFB_STRIDE);
+    }
+
+  return (size_t)((uintptr_t)dest - (uintptr_t)update->rect[0].data);
+}
+
+/****************************************************************************
+ * Name: vnc_copy32
+ *
+ * Description:
+ *   Copy a 16/32-bit pixels from the source rectangle to a 32-bit pixel
+ *   destination rectangle.
+ *
+ * Input Parameters:
+ *   session      - A reference to the VNC session structure.
+ *   row,col      - The upper left X/Y (pixel/row) position of the rectangle
+ *   width,height - The width (pixels) and height (rows of the rectangle)
+ *   convert      - The function to use to convert from the local framebuffer
+ *                  color format to the remote framebuffer color format.
+ *
+ * Returned Value:
+ *   The size of the transfer in bytes.
+ *
+ ****************************************************************************/
+
+static size_t vnc_copy32(FAR struct vnc_session_s *session,
+                         nxgl_coord_t row, nxgl_coord_t col,
+                         nxgl_coord_t height, nxgl_coord_t width,
+                         vnc_convert32_t convert)
+{
+  FAR struct rfb_framebufferupdate_s *update;
+  FAR const uint16_t *srcleft;
+  FAR const lfb_color_t *src;
+  FAR uint32_t *dest;
+  nxgl_coord_t x;
+  nxgl_coord_t y;
+
+  /* Destination rectangle start address */
+
+  update = (FAR struct rfb_framebufferupdate_s *)session->outbuf;
+  dest   = (FAR uint32_t *)update->rect[0].data;
+
+  /* Source rectangle start address (left/top)*/
+
+  srcleft = (FAR lfb_color_t *)(session->fb + RFB_STRIDE * row + RFB_BYTESPERPIXEL * col);
+
+  /* Transfer each row from the source buffer into the update buffer */
+
+  for (y = 0; y < height; y++)
+    {
+      src = srcleft;
+      for (x = 0; x < width; x++)
+        {
+          *dest++ = convert(*src);
+          src++;
+        }
+
+      srcleft = (FAR lfb_color_t *)((uintptr_t)srcleft + RFB_STRIDE);
+    }
+
+  return (size_t)((uintptr_t)srcleft - (uintptr_t)update->rect[0].data);
+}
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: vnc_raw
+ *
+ * Description:
+ *  As a fallback, send the framebuffer update using the RAW encoding which
+ *  must be supported by all VNC clients.
+ *
+ * Input Parameters:
+ *   pixel - The src color in local framebuffer format.
+ *   rect  - Describes the rectangle in the local framebuffer.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; A negated errno value is returned on failure that
+ *   indicates the the natture of the failure.  A failure is only returned
+ *   in cases of a network failure and unexpected internal failures.
+ *
+ ****************************************************************************/
+
+int vnc_raw(FAR struct vnc_session_s *session, FAR struct nxgl_rect_s *rect)
+{
+  FAR struct rfb_framebufferupdate_s *update;
+  FAR const uint8_t *src;
+  nxgl_coord_t srcwidth;
+  nxgl_coord_t srcheight;
+  nxgl_coord_t destwidth;
+  nxgl_coord_t destheight;
+  nxgl_coord_t deststride;
+  nxgl_coord_t updwidth;
+  nxgl_coord_t updheight;
+  nxgl_coord_t width;
+  nxgl_coord_t x;
+  nxgl_coord_t y;
+  unsigned int bytesperpixel;
+  unsigned int maxwidth;
+  size_t size;
+  ssize_t nsent;
+  uint8_t colorfmt;
+
+  union
+  {
+    vnc_convert8_t bpp8;
+    vnc_convert16_t bpp16;
+    vnc_convert32_t bpp32;
+  } convert;
+
+  /* Set up characteristics of the client pixel format to use on this
+   * update.  These can change at any time if a SetPixelFormat is
+   * received asynchronously.
+   */
+
+  bytesperpixel = (session->bpp + 7) >> 3;
+  maxwidth      = CONFIG_VNCSERVER_UPDATE_BUFSIZE / bytesperpixel;
+
+  /* Set up the color conversion */
+
+  colorfmt = session->colorfmt;
+  switch (colorfmt)
+    {
+      case FB_FMT_RGB8_222:
+        convert.bpp8 = vnc_convert_rgb8_222;
+        break;
+
+      case FB_FMT_RGB8_332:
+        convert.bpp8 = vnc_convert_rgb8_332;
+        break;
+
+      case FB_FMT_RGB16_555:
+        convert.bpp16 = vnc_convert_rgb16_555;
+        break;
+
+      case FB_FMT_RGB16_565:
+        convert.bpp16 = vnc_convert_rgb16_565;
+        break;
+
+      case FB_FMT_RGB32:
+        convert.bpp32 = vnc_convert_rgb32_888;
+        break;
+
+      default:
+        gdbg("ERROR: Unrecognized color format: %d\n", session->colorfmt);
+        return -EINVAL;
+    }
+
+  /* Get with width and height of the source and destination rectangles.
+   * The source rectangle many be larger than the destination rectangle.
+   * In that case, we will have to emit multiple rectangles.
+   */
+
+  DEBUGASSERT(rect->pt1.x <= rect->pt2.x);
+  srcwidth = rect->pt2.x - rect->pt1.x + 1;
+
+  DEBUGASSERT(rect->pt1.y <= rect->pt2.y);
+  srcheight = rect->pt2.y - rect->pt1.y + 1;
+
+  deststride = srcwidth * bytesperpixel;
+  if (deststride > maxwidth)
+    {
+      deststride = maxwidth;
+    }
+
+  destwidth  = deststride / bytesperpixel;
+  destheight = CONFIG_VNCSERVER_UPDATE_BUFSIZE / deststride;
+
+  if (destheight > srcheight)
+    {
+      destheight = srcheight;
+    }
+
+  /* Format the rectangle header.  We may have to send several update
+   * messages if the pre-allocated outbuf is smaller than the rectangle.
+   * Each update contains a small "sub-rectangle" of the origin update.
+   *
+   * Loop until all sub-rectangles have been output.  Start with the
+   * top row and transfer rectangles horizontally across each swath.
+   * The height of the swath is destwidth (the last may be shorter).
+   *
+   * NOTE that the loop also terminates of the color format changes
+   * asynchronously.
+   */
+
+  for (y = rect->pt1.y;
+       srcheight > 0 && colorfmt == session->colorfmt;
+       srcheight -= updheight, y += updheight)
+    {
+      /* updheight = Height to update on this pass through the loop.
+       * This will be destheight unless fewer than that number of rows
+       * remain.
+       */
+
+      updheight = destheight;
+      if (updheight > srcheight)
+        {
+          updheight = srcheight;
+        }
+
+      /* Loop until this horizontal swath has sent to the VNC client.
+       * Start with the leftmost pixel and transfer rectangles
+       * horizontally with width of destwidth until all srcwidth
+       * columns have been transferred (the last rectangle may be
+       * narrower).
+       *
+       * NOTE that the loop also terminates of the color format
+       * changes asynchronously.
+       */
+
+      for (width = srcwidth, x = rect->pt1.x;
+           width > 0 && colorfmt == session->colorfmt;
+           width -= updwidth, x += updwidth)
+        {
+          /* updwidth = Width to update on this pass through the loop.
+           * This will be destwidth unless fewer than that number of
+           * columns remain.
+           */
+
+          updwidth = destwidth;
+          if (updwidth > width)
+            {
+              updwidth = width;
+            }
+
+          /* Transfer the frame buffer data into the rectangle,
+           * performing the necessary color conversions.
+           */
+
+          if (bytesperpixel == 1)
+            {
+              size = vnc_copy8(session, y, x, updheight, updwidth,
+                               convert.bpp8);
+            }
+          else if (bytesperpixel == 2)
+            {
+              size = vnc_copy16(session, y, x, updheight, updwidth,
+                                convert.bpp16);
+            }
+          else /* bytesperpixel == 4 */
+            {
+              size = vnc_copy32(session, y, x, updheight, updwidth,
+                                convert.bpp32);
+            }
+
+          /* Format the FramebufferUpdate message */
+
+          update          = (FAR struct rfb_framebufferupdate_s *)session->outbuf;
+          update->msgtype = RFB_FBUPDATE_MSG;
+          update->padding = 0;
+          rfb_putbe16(update->nrect, 1);
+
+          rfb_putbe16(update->rect[0].xpos, x);
+          rfb_putbe16(update->rect[0].ypos, y);
+          rfb_putbe16(update->rect[0].width, updwidth);
+          rfb_putbe16(update->rect[0].height, updheight);
+          rfb_putbe32(update->rect[0].encoding, RFB_ENCODING_RAW);
+
+          DEBUGASSERT(size <= CONFIG_VNCSERVER_UPDATE_BUFSIZE);
+
+          /* We are ready to send the update packet to the VNC client */
+
+          size += SIZEOF_RFB_FRAMEBUFFERUPDATE_S(SIZEOF_RFB_RECTANGE_S(0));
+          src   = session->outbuf;
+
+          /* At the very last most, make certain that the color format
+           * has not changed asynchronously.
+           */
+
+          if (colorfmt == session->colorfmt)
+            {
+              /* Okay send until all of the bytes are out.  This may
+               * loop for the case where TCP write buffering is enabled
+               * and there are a limited number of IOBs available.
+               */
+
+              do
+                {
+                  nsent = psock_send(&session->connect, src, size, 0);
+                  if (nsent < 0)
+                    {
+                      int errcode = get_errno();
+                      gdbg("ERROR: Send FrameBufferUpdate failed: %d\n",
+                           errcode);
+                      DEBUGASSERT(errcode > 0);
+                      return -errcode;
+                    }
+
+                  DEBUGASSERT(nsent <= size);
+                  src  += nsent;
+                  size -= nsent;
+                }
+              while (size > 0);
+            }
+        }
+    }
+
+  return OK;
+}

graphics/vnc/server/vnc_server.h

@@ -240,6 +240,22 @@ struct fb_startup_s
   int16_t result;               /* OK: successfully initialized */
 };
 
+/* The size of the color type in the local framebuffer */
+
+#if defined(CONFIG_VNCSERVER_COLORFMT_RGB16)
+typedef uint16_t lfb_color_t;
+#elif defined(CONFIG_VNCSERVER_COLORFMT_RGB32)
+typedef uint32_t lfb_color_t;
+#else
+#  error Unspecified/unsupported color format
+#endif
+
+/* Color conversion function pointer types */
+
+typedef CODE uint8_t  (*vnc_convert8_t) (lfb_color_t rgb);
+typedef CODE uint16_t (*vnc_convert16_t)(lfb_color_t rgb);
+typedef CODE uint32_t (*vnc_convert32_t)(lfb_color_t rgb);
+
 /****************************************************************************
  * Public Data
  ****************************************************************************/
@@ -388,6 +404,26 @@ int vnc_update_rectangle(FAR struct vnc_session_s *session,
 
 int vnc_receiver(FAR struct vnc_session_s *session);
 
+/****************************************************************************
+ * Name: vnc_raw
+ *
+ * Description:
+ *  As a fallback, send the framebuffer update using the RAW encoding which
+ *  must be supported by all VNC clients.
+ *
+ * Input Parameters:
+ *   pixel - The src color in local framebuffer format.
+ *   rect  - Describes the rectangle in the local framebuffer.
+ *
+ * Returned Value:
+ *   Zero (OK) on success; A negated errno value is returned on failure that
+ *   indicates the the natture of the failure.  A failure is only returned
+ *   in cases of a network failure and unexpected internal failures.
+ *
+ ****************************************************************************/
+
+int vnc_raw(FAR struct vnc_session_s *session, FAR struct nxgl_rect_s *rect);
+
 /****************************************************************************
  * Name: vnc_key_map
  *
@@ -428,6 +464,28 @@ void vnc_key_map(FAR struct vnc_session_s *session, uint16_t keysym,
 
 FAR struct vnc_session_s *vnc_find_session(int display);
 
+/****************************************************************************
+ * Name: vnc_convert_rgbNN
+ *
+ * Description:
+ *  Convert the native framebuffer color format (either RGB16 5:6:5 or RGB32
+ *  8:8:8) to the remote framebuffer color format (either RGB16 5:6:5,
+ *  RGB16 5:5:5, or RGB32 8:8:)
+ *
+ * Input Parameters:
+ *   rgb - The RGB src color in local framebuffer color format.
+ *
+ * Returned Value:
+ *   The pixel in the remote framebuffer color format.
+ *
+ ****************************************************************************/
+
+uint8_t  vnc_convert_rgb8_222(lfb_color_t rgb);
+uint8_t  vnc_convert_rgb8_332(lfb_color_t rgb);
+uint16_t vnc_convert_rgb16_555(lfb_color_t rgb);
+uint16_t vnc_convert_rgb16_565(lfb_color_t rgb);
+uint32_t vnc_convert_rgb32_888(lfb_color_t rgb);
+
 #undef EXTERN
 #ifdef __cplusplus
 }