tightPng: Add initial tightPng encoding support.

http://wiki.qemu.org/VNC_Tight_PNG

Signed-off-by: Joel Martin <github@martintribe.org>
Signed-off-by: Christian Beier <dontmind@freeshell.org>

9 files changed, 436 insertions, 62 deletions

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a5425cc..bf17aa3 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -15,6 +15,7 @@ include_directories(${CMAKE_SOURCE_DIR} ${CMAKE_BINARY_DIR} ${CMAKE_SOURCE_DIR}/
 
 find_package(ZLIB)
 find_package(JPEG)
+find_package(PNG)
 find_package(SDL)
 find_package(GnuTLS)
 find_package(Threads)
@@ -30,6 +31,9 @@ endif(ZLIB_FOUND)
 if(JPEG_FOUND)
   set(LIBVNCSERVER_HAVE_LIBJPEG 1)
 endif(JPEG_FOUND)
+if(PNG_FOUND)
+  set(LIBVNCSERVER_HAVE_LIBPNG 1)
+endif(PNG_FOUND)
 option(LIBVNCSERVER_ALLOW24BPP "Allow 24 bpp" ON)
 if(GNUTLS_FOUND)
   set(LIBVNCSERVER_WITH_CLIENT_TLS 1)
@@ -142,12 +146,21 @@ endif(ZLIB_FOUND)
 if(JPEG_FOUND)
   add_definitions(-DLIBVNCSERVER_HAVE_LIBJPEG)
   include_directories(${JPEG_INCLUDE_DIR})
-  set(LIBVNCSERVER_SOURCES
-    ${LIBVNCSERVER_SOURCES}
-    ${LIBVNCSERVER_DIR}/tight.c
-  )
+  set(TIGHT_C ${LIBVNCSERVER_DIR}/tight.c)
 endif(JPEG_FOUND)
 
+if(PNG_FOUND)
+  add_definitions(-DLIBVNCSERVER_HAVE_LIBPNG)
+  include_directories(${PNG_INCLUDE_DIR})
+  set(TIGHT_C ${LIBVNCSERVER_DIR}/tight.c)
+endif(PNG_FOUND)
+
+
+set(LIBVNCSERVER_SOURCES
+    ${LIBVNCSERVER_SOURCES}
+    ${TIGHT_C}
+)
+
 if(TIGHTVNC_FILETRANSFER)
   set(LIBVNCSERVER_SOURCES
     ${LIBVNCSERVER_SOURCES}
@@ -174,6 +187,7 @@ target_link_libraries(vncserver
                       ${ADDITIONAL_LIBS}
                       ${ZLIB_LIBRARIES}
                       ${JPEG_LIBRARIES}
+		      ${PNG_LIBRARIES}
                       ${SDL_LIBRARY}
 )
 
diff --git a/configure.ac b/configure.ac
index 3203d7a..280ea58 100644
--- a/configure.ac
+++ b/configure.ac
@@ -578,6 +578,60 @@ ftp://ftp.uu.net/graphics/jpeg/
 	fi
 fi
 
+AC_ARG_WITH(png,
+[  --without-png           disable support for png]
+[  --with-png=DIR          use png include/library files in DIR],,)
+
+# At this point:
+#	no png on command line    with_png=""
+#	-with-png                 with_png="yes"
+#	-without-png              with_png="no"
+#	-with-png=/foo/dir        with_png="/foo/dir"
+
+if test "x$with_png" != "xno"; then
+	if test ! -z "$with_png" -a "x$with_png" != "xyes"; then
+		# add user supplied directory to flags:
+		saved_CPPFLAGS="$CPPFLAGS"
+		saved_LDFLAGS="$LDFLAGS"
+		CPPFLAGS="$CPPFLAGS -I$with_png/include"
+		LDFLAGS="$LDFLAGS -L$with_png/lib"
+		if test "x$ld_minus_R" = "xno"; then
+			:
+		elif test "x$GCC" = "xyes"; then
+			# this is not complete... in general a rat's nest.
+			LDFLAGS="$LDFLAGS -Xlinker -R$with_png/lib"
+		else
+			LDFLAGS="$LDFLAGS -R$with_png/lib"
+		fi
+	fi
+	AC_CHECK_HEADER(png.h, HAVE_PNGLIB_H="true")
+	if test "x$HAVE_PNGLIB_H" = "xtrue"; then
+		AC_CHECK_LIB(png, png_create_write_struct, , HAVE_PNGLIB_H="")
+	fi
+	if test ! -z "$with_png" -a "x$with_png" != "xyes"; then
+		if test "x$HAVE_PNGLIB_H" != "xtrue"; then
+			# restore old flags on failure:
+			CPPFLAGS="$saved_CPPFLAGS"
+			LDFLAGS="$saved_LDFLAGS"
+		fi
+	fi
+	if test "$build_x11vnc" = "yes"; then
+		if test "x$HAVE_PNGLIB_H" != "xtrue"; then
+			AC_MSG_WARN([
+==========================================================================
+*** The libpng compression library was not found. ***
+This may lead to reduced performance, especially over slow links.
+If libpng is in a non-standard location use --with-png=DIR to
+indicate the header file is in DIR/include/png.h and the library
+in DIR/lib/libpng.a.  A copy of libpng may be obtained from:
+http://www.libpng.org/pub/png/libpng.html
+==========================================================================
+])
+			sleep 5
+		fi
+	fi
+fi
+
 AC_ARG_WITH(libz,
 [  --without-libz          disable support for deflate],,)
 AC_ARG_WITH(zlib,
@@ -654,6 +708,7 @@ AM_CONDITIONAL(WITH_TIGHTVNC_FILETRANSFER, test "$with_tightvnc_filetransfer" =
 
 AM_CONDITIONAL(HAVE_LIBZ, test ! -z "$HAVE_ZLIB_H")
 AM_CONDITIONAL(HAVE_LIBJPEG, test ! -z "$HAVE_JPEGLIB_H")
+AM_CONDITIONAL(HAVE_LIBPNG, test ! -z "$HAVE_PNGLIB_H")
 
 
 SDLCONFIG="sdl-config"
diff --git a/libvncserver/Makefile.am b/libvncserver/Makefile.am
index 538617f..a685ed1 100644
--- a/libvncserver/Makefile.am
+++ b/libvncserver/Makefile.am
@@ -29,7 +29,11 @@ EXTRA_DIST=tableinit24.c tableinittctemplate.c tabletranstemplate.c \
 if HAVE_LIBZ
 ZLIBSRCS = zlib.c zrle.c zrleoutstream.c zrlepalettehelper.c ../common/zywrletemplate.c
 if HAVE_LIBJPEG
-JPEGSRCS = tight.c
+TIGHTSRCS = tight.c
+else
+if HAVE_LIBPNG
+TIGHTSRCS = tight.c
+endif
 endif
 endif
 
@@ -37,7 +41,7 @@ LIB_SRCS = main.c rfbserver.c rfbregion.c auth.c sockets.c \
 	stats.c corre.c hextile.c rre.c translate.c cutpaste.c \
 	httpd.c cursor.c font.c \
 	draw.c selbox.c ../common/d3des.c ../common/vncauth.c cargs.c ../common/minilzo.c ultra.c scale.c \
-	$(ZLIBSRCS) $(JPEGSRCS) $(TIGHTVNCFILETRANSFERSRCS)
+	$(ZLIBSRCS) $(TIGHTSRCS) $(TIGHTVNCFILETRANSFERSRCS)
 
 libvncserver_la_SOURCES=$(LIB_SRCS)
 
diff --git a/libvncserver/rfbserver.c b/libvncserver/rfbserver.c
index 8f0e390..587a2f0 100644
--- a/libvncserver/rfbserver.c
+++ b/libvncserver/rfbserver.c
@@ -358,10 +358,12 @@ rfbNewTCPOrUDPClient(rfbScreenInfoPtr rfbScreen,
       rfbScreen->clientHead = cl;
       UNLOCK(rfbClientListMutex);
 
-#ifdef LIBVNCSERVER_HAVE_LIBZ
+#if defined(LIBVNCSERVER_HAVE_LIBZ) || defined(LIBVNCSERVER_HAVE_LIBPNG)
       cl->tightQualityLevel = -1;
-#ifdef LIBVNCSERVER_HAVE_LIBJPEG
+#if defined(LIBVNCSERVER_HAVE_LIBJPEG) || defined(LIBVNCSERVER_HAVE_LIBPNG)
       cl->tightCompressLevel = TIGHT_DEFAULT_COMPRESSION;
+#endif
+#ifdef LIBVNCSERVER_HAVE_LIBJPEG
       {
 	int i;
 	for (i = 0; i < 4; i++)
@@ -918,6 +920,9 @@ rfbSendSupportedEncodings(rfbClientPtr cl)
 #ifdef LIBVNCSERVER_HAVE_LIBJPEG
 	rfbEncodingTight,
 #endif
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+	rfbEncodingTightPng,
+#endif
 	rfbEncodingUltra,
 	rfbEncodingUltraZip,
 	rfbEncodingXCursor,
@@ -1938,6 +1943,9 @@ rfbProcessClientNormalMessage(rfbClientPtr cl)
 	    case rfbEncodingTight:
 #endif
 #endif
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+	    case rfbEncodingTightPng:
+#endif
             /* The first supported encoding is the 'preferred' encoding */
                 if (cl->preferredEncoding == -1)
                     cl->preferredEncoding = enc;
@@ -2026,11 +2034,11 @@ rfbProcessClientNormalMessage(rfbClientPtr cl)
 		}
                 break;
             default:
-#ifdef LIBVNCSERVER_HAVE_LIBZ
+#if defined(LIBVNCSERVER_HAVE_LIBZ) || defined(LIBVNCSERVER_HAVE_LIBPNG)
 		if ( enc >= (uint32_t)rfbEncodingCompressLevel0 &&
 		     enc <= (uint32_t)rfbEncodingCompressLevel9 ) {
 		    cl->zlibCompressLevel = enc & 0x0F;
-#ifdef LIBVNCSERVER_HAVE_LIBJPEG
+#if defined(LIBVNCSERVER_HAVE_LIBJPEG) || defined(LIBVNCSERVER_HAVE_LIBPNG)
 		    cl->tightCompressLevel = enc & 0x0F;
 		    rfbLog("Using compression level %d for client %s\n",
 			   cl->tightCompressLevel, cl->host);
@@ -2755,6 +2763,28 @@ rfbSendFramebufferUpdate(rfbClientPtr cl,
 	sraRgnReleaseIterator(i); i=NULL;
 #endif
 #endif
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+    } else if (cl->preferredEncoding == rfbEncodingTightPng) {
+	nUpdateRegionRects = 0;
+
+        for(i = sraRgnGetIterator(updateRegion); sraRgnIteratorNext(i,&rect);){
+            int x = rect.x1;
+            int y = rect.y1;
+            int w = rect.x2 - x;
+            int h = rect.y2 - y;
+            int n;
+            /* We need to count the number of rects in the scaled screen */
+            if (cl->screen!=cl->scaledScreen)
+                rfbScaledCorrection(cl->screen, cl->scaledScreen, &x, &y, &w, &h, "rfbSendFramebufferUpdate");
+	    n = rfbNumCodedRectsTight(cl, x, y, w, h);
+	    if (n == 0) {
+		nUpdateRegionRects = 0xFFFF;
+		break;
+	    }
+	    nUpdateRegionRects += n;
+	}
+	sraRgnReleaseIterator(i); i=NULL;
+#endif
     } else {
         nUpdateRegionRects = sraRgnCountRects(updateRegion);
     }
@@ -2774,6 +2804,10 @@ rfbSendFramebufferUpdate(rfbClientPtr cl,
 	   && cl->preferredEncoding != rfbEncodingTight
 #endif
 #endif
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+	   /* Tight encoding counts the rectangles differently */
+	   && cl->preferredEncoding != rfbEncodingTightPng
+#endif
 	   && nUpdateRegionRects>cl->screen->maxRectsPerUpdate) {
 	    sraRegion* newUpdateRegion = sraRgnBBox(updateRegion);
 	    sraRgnDestroy(updateRegion);
@@ -2868,6 +2902,13 @@ rfbSendFramebufferUpdate(rfbClientPtr cl,
 	    break;
 #endif
 #endif
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+	case rfbEncodingTightPng:
+            /* TODO */
+	    if (!rfbSendRectEncodingTightPng(cl, x, y, w, h))
+	        goto updateFailed;
+	    break;
+#endif
 #ifdef LIBVNCSERVER_HAVE_LIBZ
        case rfbEncodingZRLE:
        case rfbEncodingZYWRLE:
diff --git a/libvncserver/stats.c b/libvncserver/stats.c
index 6dab13b..39de1c6 100644
--- a/libvncserver/stats.c
+++ b/libvncserver/stats.c
@@ -100,6 +100,7 @@ char *encodingName(uint32_t type, char *buf, int len) {
     case rfbEncodingHextile:            snprintf(buf, len, "hextile");     break;
     case rfbEncodingZlib:               snprintf(buf, len, "zlib");        break;
     case rfbEncodingTight:              snprintf(buf, len, "tight");       break;
+    case rfbEncodingTightPng:           snprintf(buf, len, "tightPng");    break;
     case rfbEncodingZlibHex:            snprintf(buf, len, "zlibhex");     break;
     case rfbEncodingUltra:              snprintf(buf, len, "ultra");       break;
     case rfbEncodingZRLE:               snprintf(buf, len, "ZRLE");        break;
diff --git a/libvncserver/tight.c b/libvncserver/tight.c
index bb033c3..83a25e3 100644
--- a/libvncserver/tight.c
+++ b/libvncserver/tight.c
@@ -37,6 +37,9 @@
 #ifdef _RPCNDR_H /* This Windows header typedefs 'boolean', jpeglib has to know */
 #define HAVE_BOOLEAN
 #endif
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+#include <png.h>
+#endif
 #include <jpeglib.h>
 
 /* Note: The following constant should not be changed. */
@@ -91,6 +94,25 @@ static TIGHT_CONF tightConf[10] = {
     { 65536, 2048,  32,  8192, 9, 9, 9, 6, 200, 500,  96, 80,   200,   500 }
 };
 
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+typedef struct TIGHT_PNG_CONF_s {
+    int png_zlib_level, png_filters;
+} TIGHT_PNG_CONF;
+
+static TIGHT_PNG_CONF tightPngConf[10] = {
+    { 0, PNG_NO_FILTERS },
+    { 1, PNG_NO_FILTERS },
+    { 2, PNG_NO_FILTERS },
+    { 3, PNG_NO_FILTERS },
+    { 4, PNG_NO_FILTERS },
+    { 5, PNG_ALL_FILTERS },
+    { 6, PNG_ALL_FILTERS },
+    { 7, PNG_ALL_FILTERS },
+    { 8, PNG_ALL_FILTERS },
+    { 9, PNG_ALL_FILTERS },
+};
+#endif
+
 static TLS int compressLevel = 0;
 static TLS int qualityLevel = 0;
 
@@ -146,6 +168,8 @@ void rfbTightCleanup(rfbScreenInfoPtr screen)
 
 /* Prototypes for static functions. */
 
+static rfbBool SendRectEncodingTight(rfbClientPtr cl, int x, int y,
+                                     int w, int h);
 static void FindBestSolidArea (rfbClientPtr cl, int x, int y, int w, int h,
                                uint32_t colorValue, int *w_ptr, int *h_ptr);
 static void ExtendSolidArea   (rfbClientPtr cl, int x, int y, int w, int h,
@@ -165,10 +189,10 @@ static rfbBool SendSubrect       (rfbClientPtr cl, int x, int y, int w, int h);
 static rfbBool SendTightHeader   (rfbClientPtr cl, int x, int y, int w, int h);
 
 static rfbBool SendSolidRect     (rfbClientPtr cl);
-static rfbBool SendMonoRect      (rfbClientPtr cl, int w, int h);
-static rfbBool SendIndexedRect   (rfbClientPtr cl, int w, int h);
-static rfbBool SendFullColorRect (rfbClientPtr cl, int w, int h);
-static rfbBool SendGradientRect  (rfbClientPtr cl, int w, int h);
+static rfbBool SendMonoRect      (rfbClientPtr cl, int x, int y, int w, int h);
+static rfbBool SendIndexedRect   (rfbClientPtr cl, int x, int y, int w, int h);
+static rfbBool SendFullColorRect (rfbClientPtr cl, int x, int y, int w, int h);
+static rfbBool SendGradientRect  (rfbClientPtr cl, int x, int y, int w, int h);
 
 static rfbBool CompressData(rfbClientPtr cl, int streamId, int dataLen,
                          int zlibLevel, int zlibStrategy);
@@ -201,16 +225,20 @@ static unsigned long DetectSmoothImage32(rfbClientPtr cl, rfbPixelFormat *fmt, i
 
 static rfbBool SendJpegRect(rfbClientPtr cl, int x, int y, int w, int h,
                          int quality);
-static void PrepareRowForJpeg(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
-static void PrepareRowForJpeg24(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
-static void PrepareRowForJpeg16(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
-static void PrepareRowForJpeg32(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
+static void PrepareRowForImg(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
+static void PrepareRowForImg24(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
+static void PrepareRowForImg16(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
+static void PrepareRowForImg32(rfbClientPtr cl, uint8_t *dst, int x, int y, int count);
 
 static void JpegInitDestination(j_compress_ptr cinfo);
 static boolean JpegEmptyOutputBuffer(j_compress_ptr cinfo);
 static void JpegTermDestination(j_compress_ptr cinfo);
 static void JpegSetDstManager(j_compress_ptr cinfo);
 
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+static rfbBool SendPngRect(rfbClientPtr cl, int x, int y, int w, int h);
+static rfbBool CanSendPngRect(rfbClientPtr cl, int w, int h);
+#endif
 
 /*
  * Tight encoding implementation.
@@ -251,6 +279,29 @@ rfbSendRectEncodingTight(rfbClientPtr cl,
                          int w,
                          int h)
 {
+    cl->tightEncoding = rfbEncodingTight;
+    return SendRectEncodingTight(cl, x, y, w, h);
+}
+
+rfbBool
+rfbSendRectEncodingTightPng(rfbClientPtr cl,
+                         int x,
+                         int y,
+                         int w,
+                         int h)
+{
+    cl->tightEncoding = rfbEncodingTightPng;
+    return SendRectEncodingTight(cl, x, y, w, h);
+}
+
+
+rfbBool
+SendRectEncodingTight(rfbClientPtr cl,
+                         int x,
+                         int y,
+                         int w,
+                         int h)
+{
     int nMaxRows;
     uint32_t colorValue;
     int dx, dy, dw, dh;
@@ -341,7 +392,7 @@ rfbSendRectEncodingTight(rfbClientPtr cl,
                      !SendRectSimple(cl, x, y, w, y_best-y) )
                     return FALSE;
                 if ( x_best != x &&
-                     !rfbSendRectEncodingTight(cl, x, y_best,
+                     !SendRectEncodingTight(cl, x, y_best,
                                                x_best-x, h_best) )
                     return FALSE;
 
@@ -364,11 +415,11 @@ rfbSendRectEncodingTight(rfbClientPtr cl,
                 /* Send remaining rectangles (at right and bottom). */
 
                 if ( x_best + w_best != x + w &&
-                     !rfbSendRectEncodingTight(cl, x_best+w_best, y_best,
+                     !SendRectEncodingTight(cl, x_best+w_best, y_best,
                                                w-(x_best-x)-w_best, h_best) )
                     return FALSE;
                 if ( y_best + h_best != y + h &&
-                     !rfbSendRectEncodingTight(cl, x, y_best+h_best,
+                     !SendRectEncodingTight(cl, x, y_best+h_best,
                                                w, h-(y_best-y)-h_best) )
                     return FALSE;
 
@@ -629,10 +680,10 @@ SendSubrect(rfbClientPtr cl,
                 success = SendJpegRect(cl, x, y, w, h,
                                        tightConf[qualityLevel].jpegQuality);
             } else {
-                success = SendGradientRect(cl, w, h);
+                success = SendGradientRect(cl, x, y, w, h);
             }
         } else {
-            success = SendFullColorRect(cl, w, h);
+            success = SendFullColorRect(cl, x, y, w, h);
         }
         break;
     case 1:
@@ -641,7 +692,7 @@ SendSubrect(rfbClientPtr cl,
         break;
     case 2:
         /* Two-color rectangle */
-        success = SendMonoRect(cl, w, h);
+        success = SendMonoRect(cl, x, y, w, h);
         break;
     default:
         /* Up to 256 different colors */
@@ -651,7 +702,7 @@ SendSubrect(rfbClientPtr cl,
             success = SendJpegRect(cl, x, y, w, h,
                                    tightConf[qualityLevel].jpegQuality);
         } else {
-            success = SendIndexedRect(cl, w, h);
+            success = SendIndexedRect(cl, x, y, w, h);
         }
     }
     return success;
@@ -675,13 +726,13 @@ SendTightHeader(rfbClientPtr cl,
     rect.r.y = Swap16IfLE(y);
     rect.r.w = Swap16IfLE(w);
     rect.r.h = Swap16IfLE(h);
-    rect.encoding = Swap32IfLE(rfbEncodingTight);
+    rect.encoding = Swap32IfLE(cl->tightEncoding);
 
     memcpy(&cl->updateBuf[cl->ublen], (char *)&rect,
            sz_rfbFramebufferUpdateRectHeader);
     cl->ublen += sz_rfbFramebufferUpdateRectHeader;
 
-    rfbStatRecordEncodingSent(cl, rfbEncodingTight, sz_rfbFramebufferUpdateRectHeader,
+    rfbStatRecordEncodingSent(cl, cl->tightEncoding, sz_rfbFramebufferUpdateRectHeader,
                               sz_rfbFramebufferUpdateRectHeader + w * (cl->format.bitsPerPixel / 8) * h);
 
     return TRUE;
@@ -711,19 +762,29 @@ SendSolidRect(rfbClientPtr cl)
     memcpy (&cl->updateBuf[cl->ublen], tightBeforeBuf, len);
     cl->ublen += len;
 
-    rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, len+1);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, len+1);
 
     return TRUE;
 }
 
 static rfbBool
 SendMonoRect(rfbClientPtr cl,
+             int x,
+             int y,
              int w,
              int h)
 {
     int streamId = 1;
     int paletteLen, dataLen;
 
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+    if (CanSendPngRect(cl, w, h)) {
+        /* TODO: setup palette maybe */
+        return SendPngRect(cl, x, y, w, h);
+        /* TODO: destroy palette maybe */
+    }
+#endif
+
     if ( cl->ublen + TIGHT_MIN_TO_COMPRESS + 6 +
 	 2 * cl->format.bitsPerPixel / 8 > UPDATE_BUF_SIZE ) {
         if (!rfbSendUpdateBuf(cl))
@@ -754,7 +815,7 @@ SendMonoRect(rfbClientPtr cl,
 
         memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, paletteLen);
         cl->ublen += paletteLen;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 3 + paletteLen);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 3 + paletteLen);
         break;
 
     case 16:
@@ -765,7 +826,7 @@ SendMonoRect(rfbClientPtr cl,
 
         memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, 4);
         cl->ublen += 4;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 7);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 7);
         break;
 
     default:
@@ -773,7 +834,7 @@ SendMonoRect(rfbClientPtr cl,
 
         cl->updateBuf[cl->ublen++] = (char)monoBackground;
         cl->updateBuf[cl->ublen++] = (char)monoForeground;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 5);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 5);
     }
 
     return CompressData(cl, streamId, dataLen,
@@ -783,12 +844,20 @@ SendMonoRect(rfbClientPtr cl,
 
 static rfbBool
 SendIndexedRect(rfbClientPtr cl,
+                int x,
+                int y,
                 int w,
                 int h)
 {
     int streamId = 2;
     int i, entryLen;
 
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+    if (CanSendPngRect(cl, w, h)) {
+        return SendPngRect(cl, x, y, w, h);
+    }
+#endif
+
     if ( cl->ublen + TIGHT_MIN_TO_COMPRESS + 6 +
 	 paletteNumColors * cl->format.bitsPerPixel / 8 >
          UPDATE_BUF_SIZE ) {
@@ -819,7 +888,7 @@ SendIndexedRect(rfbClientPtr cl,
 
         memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, paletteNumColors * entryLen);
         cl->ublen += paletteNumColors * entryLen;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 3 + paletteNumColors * entryLen);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 3 + paletteNumColors * entryLen);
         break;
 
     case 16:
@@ -832,7 +901,7 @@ SendIndexedRect(rfbClientPtr cl,
 
         memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, paletteNumColors * 2);
         cl->ublen += paletteNumColors * 2;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 3 + paletteNumColors * 2);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 3 + paletteNumColors * 2);
         break;
 
     default:
@@ -846,19 +915,27 @@ SendIndexedRect(rfbClientPtr cl,
 
 static rfbBool
 SendFullColorRect(rfbClientPtr cl,
+                  int x,
+                  int y,
                   int w,
                   int h)
 {
     int streamId = 0;
     int len;
 
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+    if (CanSendPngRect(cl, w, h)) {
+        return SendPngRect(cl, x, y, w, h);
+    }
+#endif
+
     if (cl->ublen + TIGHT_MIN_TO_COMPRESS + 1 > UPDATE_BUF_SIZE) {
         if (!rfbSendUpdateBuf(cl))
             return FALSE;
     }
 
     cl->updateBuf[cl->ublen++] = 0x00;  /* stream id = 0, no flushing, no filter */
-    rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 1);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 1);
 
     if (usePixelFormat24) {
         Pack24(cl, tightBeforeBuf, &cl->format, w * h);
@@ -873,6 +950,8 @@ SendFullColorRect(rfbClientPtr cl,
 
 static rfbBool
 SendGradientRect(rfbClientPtr cl,
+                 int x,
+                 int y,
                  int w,
                  int h)
 {
@@ -880,7 +959,7 @@ SendGradientRect(rfbClientPtr cl,
     int len;
 
     if (cl->format.bitsPerPixel == 8)
-        return SendFullColorRect(cl, w, h);
+        return SendFullColorRect(cl, x, y, w, h);
 
     if (cl->ublen + TIGHT_MIN_TO_COMPRESS + 2 > UPDATE_BUF_SIZE) {
         if (!rfbSendUpdateBuf(cl))
@@ -892,7 +971,7 @@ SendGradientRect(rfbClientPtr cl,
 
     cl->updateBuf[cl->ublen++] = (streamId | rfbTightExplicitFilter) << 4;
     cl->updateBuf[cl->ublen++] = rfbTightFilterGradient;
-    rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 2);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 2);
 
     if (usePixelFormat24) {
         FilterGradient24(cl, tightBeforeBuf, &cl->format, w, h);
@@ -923,7 +1002,7 @@ CompressData(rfbClientPtr cl,
     if (dataLen < TIGHT_MIN_TO_COMPRESS) {
         memcpy(&cl->updateBuf[cl->ublen], tightBeforeBuf, dataLen);
         cl->ublen += dataLen;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, dataLen);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, dataLen);
         return TRUE;
     }
 
@@ -973,15 +1052,15 @@ static rfbBool SendCompressedData(rfbClientPtr cl,
     int i, portionLen;
 
     cl->updateBuf[cl->ublen++] = compressedLen & 0x7F;
-    rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 1);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 1);
     if (compressedLen > 0x7F) {
         cl->updateBuf[cl->ublen-1] |= 0x80;
         cl->updateBuf[cl->ublen++] = compressedLen >> 7 & 0x7F;
-        rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 1);
+        rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 1);
         if (compressedLen > 0x3FFF) {
             cl->updateBuf[cl->ublen-1] |= 0x80;
             cl->updateBuf[cl->ublen++] = compressedLen >> 14 & 0xFF;
-            rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 1);
+            rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 1);
         }
     }
 
@@ -997,7 +1076,7 @@ static rfbBool SendCompressedData(rfbClientPtr cl,
         memcpy(&cl->updateBuf[cl->ublen], &tightAfterBuf[i], portionLen);
         cl->ublen += portionLen;
     }
-    rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, compressedLen);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, compressedLen);
 
     return TRUE;
 }
@@ -1659,11 +1738,11 @@ SendJpegRect(rfbClientPtr cl, int x, int y, int w, int h, int quality)
     int dy;
 
     if (cl->screen->serverFormat.bitsPerPixel == 8)
-        return SendFullColorRect(cl, w, h);
+        return SendFullColorRect(cl, x, y, w, h);
 
     srcBuf = (uint8_t *)malloc(w * 3);
     if (srcBuf == NULL) {
-        return SendFullColorRect(cl, w, h);
+        return SendFullColorRect(cl, x, y, w, h);
     }
     rowPointer[0] = srcBuf;
 
@@ -1683,7 +1762,7 @@ SendJpegRect(rfbClientPtr cl, int x, int y, int w, int h, int quality)
     jpeg_start_compress(&cinfo, TRUE);
 
     for (dy = 0; dy < h; dy++) {
-        PrepareRowForJpeg(cl, srcBuf, x, y + dy, w);
+        PrepareRowForImg(cl, srcBuf, x, y + dy, w);
         jpeg_write_scanlines(&cinfo, rowPointer, 1);
         if (jpegError)
             break;
@@ -1696,7 +1775,7 @@ SendJpegRect(rfbClientPtr cl, int x, int y, int w, int h, int quality)
     free(srcBuf);
 
     if (jpegError)
-        return SendFullColorRect(cl, w, h);
+        return SendFullColorRect(cl, x, y, w, h);
 
     if (cl->ublen + TIGHT_MIN_TO_COMPRESS + 1 > UPDATE_BUF_SIZE) {
         if (!rfbSendUpdateBuf(cl))
@@ -1704,13 +1783,13 @@ SendJpegRect(rfbClientPtr cl, int x, int y, int w, int h, int quality)
     }
 
     cl->updateBuf[cl->ublen++] = (char)(rfbTightJpeg << 4);
-    rfbStatRecordEncodingSentAdd(cl, rfbEncodingTight, 1);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 1);
 
     return SendCompressedData(cl, jpegDstDataLen);
 }
 
 static void
-PrepareRowForJpeg(rfbClientPtr cl,
+PrepareRowForImg(rfbClientPtr cl,
                   uint8_t *dst,
                   int x,
                   int y,
@@ -1720,18 +1799,18 @@ PrepareRowForJpeg(rfbClientPtr cl,
         if ( cl->screen->serverFormat.redMax == 0xFF &&
              cl->screen->serverFormat.greenMax == 0xFF &&
              cl->screen->serverFormat.blueMax == 0xFF ) {
-            PrepareRowForJpeg24(cl, dst, x, y, count);
+            PrepareRowForImg24(cl, dst, x, y, count);
         } else {
-            PrepareRowForJpeg32(cl, dst, x, y, count);
+            PrepareRowForImg32(cl, dst, x, y, count);
         }
     } else {
         /* 16 bpp assumed. */
-        PrepareRowForJpeg16(cl, dst, x, y, count);
+        PrepareRowForImg16(cl, dst, x, y, count);
     }
 }
 
 static void
-PrepareRowForJpeg24(rfbClientPtr cl,
+PrepareRowForImg24(rfbClientPtr cl,
                     uint8_t *dst,
                     int x,
                     int y,
@@ -1754,7 +1833,7 @@ PrepareRowForJpeg24(rfbClientPtr cl,
 #define DEFINE_JPEG_GET_ROW_FUNCTION(bpp)                                   \
                                                                             \
 static void                                                                 \
-PrepareRowForJpeg##bpp(rfbClientPtr cl, uint8_t *dst, int x, int y, int count) { \
+PrepareRowForImg##bpp(rfbClientPtr cl, uint8_t *dst, int x, int y, int count) { \
     uint##bpp##_t *fbptr;                                                   \
     uint##bpp##_t pix;                                                      \
     int inRed, inGreen, inBlue;                                             \
@@ -1822,3 +1901,161 @@ JpegSetDstManager(j_compress_ptr cinfo)
     cinfo->dest = &jpegDstManager;
 }
 
+/*
+ * PNG compression stuff.
+ */
+
+#ifdef LIBVNCSERVER_HAVE_LIBPNG
+
+static TLS int pngDstDataLen = 0;
+
+static rfbBool CanSendPngRect(rfbClientPtr cl, int w, int h) {
+    if (cl->tightEncoding != rfbEncodingTightPng) {
+        return FALSE;
+    }
+
+    if ( cl->screen->serverFormat.bitsPerPixel == 8 ||
+         cl->format.bitsPerPixel == 8) {
+        return FALSE;
+    }
+
+    return TRUE;
+}
+
+static void pngWriteData(png_structp png_ptr, png_bytep data,
+                           png_size_t length)
+{
+#if 0
+    rfbClientPtr cl = png_get_io_ptr(png_ptr);
+
+    buffer_reserve(&vs->tight.png, vs->tight.png.offset + length);
+    memcpy(vs->tight.png.buffer + vs->tight.png.offset, data, length);
+#endif
+    memcpy(tightAfterBuf + pngDstDataLen, data, length);
+
+    pngDstDataLen += length;
+}
+
+static void pngFlushData(png_structp png_ptr)
+{
+}
+
+
+static void *pngMalloc(png_structp png_ptr, png_size_t size)
+{
+    return malloc(size);
+}
+
+static void pngFree(png_structp png_ptr, png_voidp ptr)
+{
+    free(ptr);
+}
+
+static rfbBool SendPngRect(rfbClientPtr cl, int x, int y, int w, int h) {
+    /* rfbLog(">> SendPngRect x:%d, y:%d, w:%d, h:%d\n", x, y, w, h); */
+
+    png_byte color_type;
+    png_structp png_ptr;
+    png_infop info_ptr;
+    png_colorp png_palette = NULL;
+    int level = tightPngConf[cl->tightCompressLevel].png_zlib_level;
+    int filters = tightPngConf[cl->tightCompressLevel].png_filters;
+    uint8_t *buf;
+    int dy;
+
+    pngDstDataLen = 0;
+
+    png_ptr = png_create_write_struct_2(PNG_LIBPNG_VER_STRING, NULL, NULL, NULL,
+                                        NULL, pngMalloc, pngFree);
+
+    if (png_ptr == NULL)
+        return FALSE;
+
+    info_ptr = png_create_info_struct(png_ptr);
+
+    if (info_ptr == NULL) {
+        png_destroy_write_struct(&png_ptr, NULL);
+        return FALSE;
+    }
+
+    png_set_write_fn(png_ptr, (void *) cl, pngWriteData, pngFlushData);
+    png_set_compression_level(png_ptr, level);
+    png_set_filter(png_ptr, PNG_FILTER_TYPE_DEFAULT, filters);
+
+#if 0
+    /* TODO: */
+    if (palette) {
+        color_type = PNG_COLOR_TYPE_PALETTE;
+    } else {
+        color_type = PNG_COLOR_TYPE_RGB;
+    }
+#else
+    color_type = PNG_COLOR_TYPE_RGB;
+#endif
+    png_set_IHDR(png_ptr, info_ptr, w, h,
+                 8, color_type, PNG_INTERLACE_NONE,
+                 PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
+
+#if 0
+    if (color_type == PNG_COLOR_TYPE_PALETTE) {
+        struct palette_cb_priv priv;
+
+        png_palette = pngMalloc(png_ptr, sizeof(*png_palette) *
+                                 palette_size(palette));
+
+        priv.vs = vs;
+        priv.png_palette = png_palette;
+        palette_iter(palette, write_png_palette, &priv);
+
+        png_set_PLTE(png_ptr, info_ptr, png_palette, palette_size(palette));
+
+        offset = vs->tight.tight.offset;
+        if (vs->clientds.pf.bytes_per_pixel == 4) {
+            tight_encode_indexed_rect32(vs->tight.tight.buffer, w * h, palette);
+        } else {
+            tight_encode_indexed_rect16(vs->tight.tight.buffer, w * h, palette);
+        }
+    }
+
+    buffer_reserve(&vs->tight.png, 2048);
+#endif
+
+    png_write_info(png_ptr, info_ptr);
+    buf = malloc(w * 3);
+    for (dy = 0; dy < h; dy++)
+    {
+#if 0
+        if (color_type == PNG_COLOR_TYPE_PALETTE) {
+            memcpy(buf, vs->tight.tight.buffer + (dy * w), w);
+        } else {
+            PrepareRowForImg(cl, buf, x, y + dy, w);
+        }
+#else
+        PrepareRowForImg(cl, buf, x, y + dy, w);
+#endif
+        png_write_row(png_ptr, buf);
+    }
+    free(buf);
+
+    png_write_end(png_ptr, NULL);
+
+    if (color_type == PNG_COLOR_TYPE_PALETTE) {
+        pngFree(png_ptr, png_palette);
+    }
+
+    png_destroy_write_struct(&png_ptr, &info_ptr);
+
+    /* done v */
+
+    if (cl->ublen + TIGHT_MIN_TO_COMPRESS + 1 > UPDATE_BUF_SIZE) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    cl->updateBuf[cl->ublen++] = (char)(rfbTightPng << 4);
+    rfbStatRecordEncodingSentAdd(cl, cl->tightEncoding, 1);
+
+    /* rfbLog("<< SendPngRect\n"); */
+    return SendCompressedData(cl, pngDstDataLen);
+}
+#endif
diff --git a/rfb/rfb.h b/rfb/rfb.h
index c16336d..e79b68b 100644
--- a/rfb/rfb.h
+++ b/rfb/rfb.h
@@ -542,7 +542,9 @@ typedef struct _rfbClientRec {
     struct z_stream_s compStream;
     rfbBool compStreamInited;
     uint32_t zlibCompressLevel;
-    /** the quality level is also used by ZYWRLE */
+#endif
+#if defined(LIBVNCSERVER_HAVE_LIBZ) || defined(LIBVNCSERVER_HAVE_LIBPNG)
+    /** the quality level is also used by ZYWRLE and TightPng */
     int tightQualityLevel;
 
 #ifdef LIBVNCSERVER_HAVE_LIBJPEG
@@ -550,6 +552,8 @@ typedef struct _rfbClientRec {
     z_stream zsStruct[4];
     rfbBool zsActive[4];
     int zsLevel[4];
+#endif
+#if defined(LIBVNCSERVER_HAVE_LIBJPEG) || defined(LIBVNCSERVER_HAVE_LIBPNG)
     int tightCompressLevel;
 #endif
 #endif
@@ -624,6 +628,9 @@ typedef struct _rfbClientRec {
   char *afterEncBuf;
   int afterEncBufSize;
   int afterEncBufLen;
+#if defined(LIBVNCSERVER_HAVE_LIBZ) || defined(LIBVNCSERVER_HAVE_LIBPNG)
+    uint32_t tightEncoding;  /* rfbEncodingTight or rfbEncodingTightPng */
+#endif
 } rfbClientRec, *rfbClientPtr;
 
 /**
@@ -800,7 +807,7 @@ extern rfbBool rfbSendRectEncodingUltra(rfbClientPtr cl, int x,int y,int w,int h
 extern rfbBool rfbSendRectEncodingZlib(rfbClientPtr cl, int x, int y, int w,
 				    int h);
 
-#ifdef LIBVNCSERVER_HAVE_LIBJPEG
+#if defined(LIBVNCSERVER_HAVE_LIBJPEG) || defined(LIBVNCSERVER_HAVE_LIBPNG)
 /* tight.c */
 
 #define TIGHT_DEFAULT_COMPRESSION  6
@@ -808,7 +815,13 @@ extern rfbBool rfbSendRectEncodingZlib(rfbClientPtr cl, int x, int y, int w,
 extern rfbBool rfbTightDisableGradient;
 
 extern int rfbNumCodedRectsTight(rfbClientPtr cl, int x,int y,int w,int h);
+
+#if defined(LIBVNCSERVER_HAVE_LIBJPEG)
 extern rfbBool rfbSendRectEncodingTight(rfbClientPtr cl, int x,int y,int w,int h);
+#endif
+#if defined(LIBVNCSERVER_HAVE_LIBPNG)
+extern rfbBool rfbSendRectEncodingTightPng(rfbClientPtr cl, int x,int y,int w,int h);
+#endif
 
 #endif
 #endif
diff --git a/rfb/rfbconfig.h.cmake b/rfb/rfbconfig.h.cmake
index de898fc..b7f225c 100644
--- a/rfb/rfbconfig.h.cmake
+++ b/rfb/rfbconfig.h.cmake
@@ -18,6 +18,9 @@
 /* Define to 1 if you have the `jpeg' library (-ljpeg). */
 #cmakedefine LIBVNCSERVER_HAVE_LIBJPEG  1 
 
+/* Define if you have the `png' library (-lpng). */
+#cmakedefine LIBVNCSERVER_HAVE_LIBPNG  1
+
 /* Define to 1 if you have the `pthread' library (-lpthread). */
 #cmakedefine LIBVNCSERVER_HAVE_LIBPTHREAD  1 
 
diff --git a/rfb/rfbproto.h b/rfb/rfbproto.h
index 73d200a..c6dfd2c 100644
--- a/rfb/rfbproto.h
+++ b/rfb/rfbproto.h
@@ -434,6 +434,7 @@ typedef struct {
 #define rfbEncodingHextile 5
 #define rfbEncodingZlib 6
 #define rfbEncodingTight 7
+#define rfbEncodingTightPng 0xFFFFFEFC /* -260 */
 #define rfbEncodingZlibHex 8
 #define rfbEncodingUltra 9
 #define rfbEncodingZRLE 16
@@ -704,7 +705,10 @@ typedef struct {
 #ifdef LIBVNCSERVER_HAVE_LIBZ
 
 /*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
- * Tight Encoding.
+ * Tight and TightPng Encoding.
+ *
+ *-- TightPng is like Tight but basic compression is not used, instead PNG
+ *   data is sent.
  *
  *-- The first byte of each Tight-encoded rectangle is a "compression control
  *   byte". Its format is as follows (bit 0 is the least significant one):
@@ -715,8 +719,9 @@ typedef struct {
  *   bit 3:    if 1, then compression stream 3 should be reset;
  *   bits 7-4: if 1000 (0x08), then the compression type is "fill",
  *             if 1001 (0x09), then the compression type is "jpeg",
+ *             if 1001 (0x0A), then the compression type is "png",
  *             if 0xxx, then the compression type is "basic",
- *             values greater than 1001 are not valid.
+ *             values greater than 1010 are not valid.
  *
  * If the compression type is "basic", then bits 6..4 of the
  * compression control byte (those xxx in 0xxx) specify the following:
@@ -726,17 +731,17 @@ typedef struct {
  *   bit 6:     if 1, then a "filter id" byte is following this byte.
  *
  *-- The data that follows after the compression control byte described
- * above depends on the compression type ("fill", "jpeg" or "basic").
+ * above depends on the compression type ("fill", "jpeg", "png" or "basic").
  *
  *-- If the compression type is "fill", then the only pixel value follows, in
  * client pixel format (see NOTE 1). This value applies to all pixels of the
  * rectangle.
  *
- *-- If the compression type is "jpeg", the following data stream looks like
- * this:
+ *-- If the compression type is "jpeg" or "png", the following data stream
+ * looks like this:
  *
  *   1..3 bytes:  data size (N) in compact representation;
- *   N bytes:     JPEG image.
+ *   N bytes:     JPEG or PNG image.
  *
  * Data size is compactly represented in one, two or three bytes, according
  * to the following scheme:
@@ -817,7 +822,7 @@ typedef struct {
  *-- NOTE 2. The decoder must reset compression streams' states before
  * decoding the rectangle, if some of bits 0,1,2,3 in the compression control
  * byte are set to 1. Note that the decoder must reset zlib streams even if
- * the compression type is "fill" or "jpeg".
+ * the compression type is "fill", "jpeg" or "png".
  *
  *-- NOTE 3. The "gradient" filter and "jpeg" compression may be used only
  * when bits-per-pixel value is either 16 or 32, not 8.
@@ -831,7 +836,8 @@ typedef struct {
 #define rfbTightExplicitFilter         0x04
 #define rfbTightFill                   0x08
 #define rfbTightJpeg                   0x09
-#define rfbTightMaxSubencoding         0x09
+#define rfbTightPng                    0x0A
+#define rfbTightMaxSubencoding         0x0A
 
 /* Filters to improve compression efficiency */
 #define rfbTightFilterCopy             0x00