move the library into libvncserver/, x11vnc into x11vnc/

1 files changed, 1820 insertions, 0 deletions

diff --git a/libvncserver/tight.c b/libvncserver/tight.c
new file mode 100644
index 0000000..b97adb9
--- /dev/null
+++ b/libvncserver/tight.c
@@ -0,0 +1,1820 @@
+/*
+ * tight.c
+ *
+ * Routines to implement Tight Encoding
+ */
+
+/*
+ *  Copyright (C) 2000, 2001 Const Kaplinsky.  All Rights Reserved.
+ *  Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
+ *
+ *  This is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This software is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this software; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
+ *  USA.
+ */
+
+/*#include <stdio.h>*/
+#include <rfb/rfb.h>
+
+#ifdef WIN32
+#define XMD_H
+#undef FAR
+#define NEEDFAR_POINTERS
+#endif
+
+#include <jpeglib.h>
+
+/* Note: The following constant should not be changed. */
+#define TIGHT_MIN_TO_COMPRESS 12
+
+/* The parameters below may be adjusted. */
+#define MIN_SPLIT_RECT_SIZE     4096
+#define MIN_SOLID_SUBRECT_SIZE  2048
+#define MAX_SPLIT_TILE_SIZE       16
+
+/* May be set to TRUE with "-lazytight" Xvnc option. */
+rfbBool rfbTightDisableGradient = FALSE;
+
+/* This variable is set on every rfbSendRectEncodingTight() call. */
+static rfbBool usePixelFormat24;
+
+
+/* Compression level stuff. The following array contains various
+   encoder parameters for each of 10 compression levels (0..9).
+   Last three parameters correspond to JPEG quality levels (0..9). */
+
+typedef struct TIGHT_CONF_s {
+    int maxRectSize, maxRectWidth;
+    int monoMinRectSize, gradientMinRectSize;
+    int idxZlibLevel, monoZlibLevel, rawZlibLevel, gradientZlibLevel;
+    int gradientThreshold, gradientThreshold24;
+    int idxMaxColorsDivisor;
+    int jpegQuality, jpegThreshold, jpegThreshold24;
+} TIGHT_CONF;
+
+static TIGHT_CONF tightConf[10] = {
+    {   512,   32,   6, 65536, 0, 0, 0, 0,   0,   0,   4,  5, 10000, 23000 },
+    {  2048,  128,   6, 65536, 1, 1, 1, 0,   0,   0,   8, 10,  8000, 18000 },
+    {  6144,  256,   8, 65536, 3, 3, 2, 0,   0,   0,  24, 15,  6500, 15000 },
+    { 10240, 1024,  12, 65536, 5, 5, 3, 0,   0,   0,  32, 25,  5000, 12000 },
+    { 16384, 2048,  12, 65536, 6, 6, 4, 0,   0,   0,  32, 37,  4000, 10000 },
+    { 32768, 2048,  12,  4096, 7, 7, 5, 4, 150, 380,  32, 50,  3000,  8000 },
+    { 65536, 2048,  16,  4096, 7, 7, 6, 4, 170, 420,  48, 60,  2000,  5000 },
+    { 65536, 2048,  16,  4096, 8, 8, 7, 5, 180, 450,  64, 70,  1000,  2500 },
+    { 65536, 2048,  32,  8192, 9, 9, 8, 6, 190, 475,  64, 75,   500,  1200 },
+    { 65536, 2048,  32,  8192, 9, 9, 9, 6, 200, 500,  96, 80,   200,   500 }
+};
+
+static int compressLevel;
+static int qualityLevel;
+
+/* Stuff dealing with palettes. */
+
+typedef struct COLOR_LIST_s {
+    struct COLOR_LIST_s *next;
+    int idx;
+    uint32_t rgb;
+} COLOR_LIST;
+
+typedef struct PALETTE_ENTRY_s {
+    COLOR_LIST *listNode;
+    int numPixels;
+} PALETTE_ENTRY;
+
+typedef struct PALETTE_s {
+    PALETTE_ENTRY entry[256];
+    COLOR_LIST *hash[256];
+    COLOR_LIST list[256];
+} PALETTE;
+
+static int paletteNumColors, paletteMaxColors;
+static uint32_t monoBackground, monoForeground;
+static PALETTE palette;
+
+/* Pointers to dynamically-allocated buffers. */
+
+static int tightBeforeBufSize = 0;
+static char *tightBeforeBuf = NULL;
+
+static int tightAfterBufSize = 0;
+static char *tightAfterBuf = NULL;
+
+static int *prevRowBuf = NULL;
+
+void TightCleanup()
+{
+  if(tightBeforeBufSize) {
+    free(tightBeforeBuf);
+    tightBeforeBufSize=0;
+  }
+  if(tightAfterBufSize) {
+    free(tightAfterBuf);
+    tightAfterBufSize=0;
+  }
+}
+
+/* Prototypes for static functions. */
+
+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,
+                               uint32_t colorValue,
+                               int *x_ptr, int *y_ptr, int *w_ptr, int *h_ptr);
+static rfbBool CheckSolidTile    (rfbClientPtr cl, int x, int y, int w, int h,
+                               uint32_t *colorPtr, rfbBool needSameColor);
+static rfbBool CheckSolidTile8   (rfbClientPtr cl, int x, int y, int w, int h,
+                               uint32_t *colorPtr, rfbBool needSameColor);
+static rfbBool CheckSolidTile16  (rfbClientPtr cl, int x, int y, int w, int h,
+                               uint32_t *colorPtr, rfbBool needSameColor);
+static rfbBool CheckSolidTile32  (rfbClientPtr cl, int x, int y, int w, int h,
+                               uint32_t *colorPtr, rfbBool needSameColor);
+
+static rfbBool SendRectSimple    (rfbClientPtr cl, int x, int y, int w, int h);
+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 CompressData(rfbClientPtr cl, int streamId, int dataLen,
+                         int zlibLevel, int zlibStrategy);
+static rfbBool SendCompressedData(rfbClientPtr cl, int compressedLen);
+
+static void FillPalette8(int count);
+static void FillPalette16(int count);
+static void FillPalette32(int count);
+
+static void PaletteReset(void);
+static int PaletteInsert(uint32_t rgb, int numPixels, int bpp);
+
+static void Pack24(rfbClientPtr cl, char *buf, rfbPixelFormat *fmt, int count);
+
+static void EncodeIndexedRect16(uint8_t *buf, int count);
+static void EncodeIndexedRect32(uint8_t *buf, int count);
+
+static void EncodeMonoRect8(uint8_t *buf, int w, int h);
+static void EncodeMonoRect16(uint8_t *buf, int w, int h);
+static void EncodeMonoRect32(uint8_t *buf, int w, int h);
+
+static void FilterGradient24(rfbClientPtr cl, char *buf, rfbPixelFormat *fmt, int w, int h);
+static void FilterGradient16(rfbClientPtr cl, uint16_t *buf, rfbPixelFormat *fmt, int w, int h);
+static void FilterGradient32(rfbClientPtr cl, uint32_t *buf, rfbPixelFormat *fmt, int w, int h);
+
+static int DetectSmoothImage(rfbClientPtr cl, rfbPixelFormat *fmt, int w, int h);
+static unsigned long DetectSmoothImage24(rfbClientPtr cl, rfbPixelFormat *fmt, int w, int h);
+static unsigned long DetectSmoothImage16(rfbClientPtr cl, rfbPixelFormat *fmt, int w, int h);
+static unsigned long DetectSmoothImage32(rfbClientPtr cl, rfbPixelFormat *fmt, int w, int h);
+
+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 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);
+
+
+/*
+ * Tight encoding implementation.
+ */
+
+int
+rfbNumCodedRectsTight(cl, x, y, w, h)
+    rfbClientPtr cl;
+    int x, y, w, h;
+{
+    int maxRectSize, maxRectWidth;
+    int subrectMaxWidth, subrectMaxHeight;
+
+    /* No matter how many rectangles we will send if LastRect markers
+       are used to terminate rectangle stream. */
+    if (cl->enableLastRectEncoding && w * h >= MIN_SPLIT_RECT_SIZE)
+      return 0;
+
+    maxRectSize = tightConf[cl->tightCompressLevel].maxRectSize;
+    maxRectWidth = tightConf[cl->tightCompressLevel].maxRectWidth;
+
+    if (w > maxRectWidth || w * h > maxRectSize) {
+        subrectMaxWidth = (w > maxRectWidth) ? maxRectWidth : w;
+        subrectMaxHeight = maxRectSize / subrectMaxWidth;
+        return (((w - 1) / maxRectWidth + 1) *
+                ((h - 1) / subrectMaxHeight + 1));
+    } else {
+        return 1;
+    }
+}
+
+rfbBool
+rfbSendRectEncodingTight(cl, x, y, w, h)
+    rfbClientPtr cl;
+    int x, y, w, h;
+{
+    int nMaxRows;
+    uint32_t colorValue;
+    int dx, dy, dw, dh;
+    int x_best, y_best, w_best, h_best;
+    char *fbptr;
+
+    rfbSendUpdateBuf(cl);
+
+    compressLevel = cl->tightCompressLevel;
+    qualityLevel = cl->tightQualityLevel;
+
+    if ( cl->format.depth == 24 && cl->format.redMax == 0xFF &&
+         cl->format.greenMax == 0xFF && cl->format.blueMax == 0xFF ) {
+        usePixelFormat24 = TRUE;
+    } else {
+        usePixelFormat24 = FALSE;
+    }
+
+    if (!cl->enableLastRectEncoding || w * h < MIN_SPLIT_RECT_SIZE)
+        return SendRectSimple(cl, x, y, w, h);
+
+    /* Make sure we can write at least one pixel into tightBeforeBuf. */
+
+    if (tightBeforeBufSize < 4) {
+        tightBeforeBufSize = 4;
+        if (tightBeforeBuf == NULL)
+            tightBeforeBuf = (char *)malloc(tightBeforeBufSize);
+        else
+            tightBeforeBuf = (char *)realloc(tightBeforeBuf,
+                                              tightBeforeBufSize);
+    }
+
+    /* Calculate maximum number of rows in one non-solid rectangle. */
+
+    {
+        int maxRectSize, maxRectWidth, nMaxWidth;
+
+        maxRectSize = tightConf[compressLevel].maxRectSize;
+        maxRectWidth = tightConf[compressLevel].maxRectWidth;
+        nMaxWidth = (w > maxRectWidth) ? maxRectWidth : w;
+        nMaxRows = maxRectSize / nMaxWidth;
+    }
+
+    /* Try to find large solid-color areas and send them separately. */
+
+    for (dy = y; dy < y + h; dy += MAX_SPLIT_TILE_SIZE) {
+
+        /* If a rectangle becomes too large, send its upper part now. */
+
+        if (dy - y >= nMaxRows) {
+            if (!SendRectSimple(cl, x, y, w, nMaxRows))
+                return 0;
+            y += nMaxRows;
+            h -= nMaxRows;
+        }
+
+        dh = (dy + MAX_SPLIT_TILE_SIZE <= y + h) ?
+            MAX_SPLIT_TILE_SIZE : (y + h - dy);
+
+        for (dx = x; dx < x + w; dx += MAX_SPLIT_TILE_SIZE) {
+
+            dw = (dx + MAX_SPLIT_TILE_SIZE <= x + w) ?
+                MAX_SPLIT_TILE_SIZE : (x + w - dx);
+
+            if (CheckSolidTile(cl, dx, dy, dw, dh, &colorValue, FALSE)) {
+
+                /* Get dimensions of solid-color area. */
+
+                FindBestSolidArea(cl, dx, dy, w - (dx - x), h - (dy - y),
+				  colorValue, &w_best, &h_best);
+
+                /* Make sure a solid rectangle is large enough
+                   (or the whole rectangle is of the same color). */
+
+                if ( w_best * h_best != w * h &&
+                     w_best * h_best < MIN_SOLID_SUBRECT_SIZE )
+                    continue;
+
+                /* Try to extend solid rectangle to maximum size. */
+
+                x_best = dx; y_best = dy;
+                ExtendSolidArea(cl, x, y, w, h, colorValue,
+                                &x_best, &y_best, &w_best, &h_best);
+
+                /* Send rectangles at top and left to solid-color area. */
+
+                if ( y_best != y &&
+                     !SendRectSimple(cl, x, y, w, y_best-y) )
+                    return FALSE;
+                if ( x_best != x &&
+                     !rfbSendRectEncodingTight(cl, x, y_best,
+                                               x_best-x, h_best) )
+                    return FALSE;
+
+                /* Send solid-color rectangle. */
+
+                if (!SendTightHeader(cl, x_best, y_best, w_best, h_best))
+                    return FALSE;
+
+                fbptr = (cl->screen->frameBuffer +
+                         (cl->screen->paddedWidthInBytes * y_best) +
+                         (x_best * (cl->screen->bitsPerPixel / 8)));
+
+                (*cl->translateFn)(cl->translateLookupTable, &cl->screen->rfbServerFormat,
+                                   &cl->format, fbptr, tightBeforeBuf,
+                                   cl->screen->paddedWidthInBytes, 1, 1);
+
+                if (!SendSolidRect(cl))
+                    return FALSE;
+
+                /* Send remaining rectangles (at right and bottom). */
+
+                if ( x_best + w_best != x + w &&
+                     !rfbSendRectEncodingTight(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,
+                                               w, h-(y_best-y)-h_best) )
+                    return FALSE;
+
+                /* Return after all recursive calls are done. */
+
+                return TRUE;
+            }
+
+        }
+
+    }
+
+    /* No suitable solid-color rectangles found. */
+
+    return SendRectSimple(cl, x, y, w, h);
+}
+
+static void
+FindBestSolidArea(cl, x, y, w, h, colorValue, w_ptr, h_ptr)
+    rfbClientPtr cl;
+    int x, y, w, h;
+    uint32_t colorValue;
+    int *w_ptr, *h_ptr;
+{
+    int dx, dy, dw, dh;
+    int w_prev;
+    int w_best = 0, h_best = 0;
+
+    w_prev = w;
+
+    for (dy = y; dy < y + h; dy += MAX_SPLIT_TILE_SIZE) {
+
+        dh = (dy + MAX_SPLIT_TILE_SIZE <= y + h) ?
+            MAX_SPLIT_TILE_SIZE : (y + h - dy);
+        dw = (w_prev > MAX_SPLIT_TILE_SIZE) ?
+            MAX_SPLIT_TILE_SIZE : w_prev;
+
+        if (!CheckSolidTile(cl, x, dy, dw, dh, &colorValue, TRUE))
+            break;
+
+        for (dx = x + dw; dx < x + w_prev;) {
+            dw = (dx + MAX_SPLIT_TILE_SIZE <= x + w_prev) ?
+                MAX_SPLIT_TILE_SIZE : (x + w_prev - dx);
+            if (!CheckSolidTile(cl, dx, dy, dw, dh, &colorValue, TRUE))
+                break;
+	    dx += dw;
+        }
+
+        w_prev = dx - x;
+        if (w_prev * (dy + dh - y) > w_best * h_best) {
+            w_best = w_prev;
+            h_best = dy + dh - y;
+        }
+    }
+
+    *w_ptr = w_best;
+    *h_ptr = h_best;
+}
+
+static void
+ExtendSolidArea(cl, x, y, w, h, colorValue, x_ptr, y_ptr, w_ptr, h_ptr)
+    rfbClientPtr cl;
+    int x, y, w, h;
+    uint32_t colorValue;
+    int *x_ptr, *y_ptr, *w_ptr, *h_ptr;
+{
+    int cx, cy;
+
+    /* Try to extend the area upwards. */
+    for ( cy = *y_ptr - 1;
+          cy >= y && CheckSolidTile(cl, *x_ptr, cy, *w_ptr, 1, &colorValue, TRUE);
+          cy-- );
+    *h_ptr += *y_ptr - (cy + 1);
+    *y_ptr = cy + 1;
+
+    /* ... downwards. */
+    for ( cy = *y_ptr + *h_ptr;
+          cy < y + h &&
+              CheckSolidTile(cl, *x_ptr, cy, *w_ptr, 1, &colorValue, TRUE);
+          cy++ );
+    *h_ptr += cy - (*y_ptr + *h_ptr);
+
+    /* ... to the left. */
+    for ( cx = *x_ptr - 1;
+          cx >= x && CheckSolidTile(cl, cx, *y_ptr, 1, *h_ptr, &colorValue, TRUE);
+          cx-- );
+    *w_ptr += *x_ptr - (cx + 1);
+    *x_ptr = cx + 1;
+
+    /* ... to the right. */
+    for ( cx = *x_ptr + *w_ptr;
+          cx < x + w &&
+              CheckSolidTile(cl, cx, *y_ptr, 1, *h_ptr, &colorValue, TRUE);
+          cx++ );
+    *w_ptr += cx - (*x_ptr + *w_ptr);
+}
+
+/*
+ * Check if a rectangle is all of the same color. If needSameColor is
+ * set to non-zero, then also check that its color equals to the
+ * *colorPtr value. The result is 1 if the test is successfull, and in
+ * that case new color will be stored in *colorPtr.
+ */
+
+static rfbBool CheckSolidTile(rfbClientPtr cl, int x, int y, int w, int h, uint32_t* colorPtr, rfbBool needSameColor)
+{
+    switch(cl->screen->rfbServerFormat.bitsPerPixel) {
+    case 32:
+        return CheckSolidTile32(cl, x, y, w, h, colorPtr, needSameColor);
+    case 16:
+        return CheckSolidTile16(cl, x, y, w, h, colorPtr, needSameColor);
+    default:
+        return CheckSolidTile8(cl, x, y, w, h, colorPtr, needSameColor);
+    }
+}
+
+#define DEFINE_CHECK_SOLID_FUNCTION(bpp)                                      \
+                                                                              \
+static rfbBool                                                                   \
+CheckSolidTile##bpp(rfbClientPtr cl, int x, int y, int w, int h, uint32_t* colorPtr, rfbBool needSameColor) \
+{                                                                             \
+    uint##bpp##_t *fbptr;                                                         \
+    uint##bpp##_t colorValue;                                                     \
+    int dx, dy;                                                               \
+                                                                              \
+    fbptr = (uint##bpp##_t *)                                                     \
+        &cl->screen->frameBuffer[y * cl->screen->paddedWidthInBytes + x * (bpp/8)]; \
+                                                                              \
+    colorValue = *fbptr;                                                      \
+    if (needSameColor && (uint32_t)colorValue != *colorPtr)                     \
+        return FALSE;                                                         \
+                                                                              \
+    for (dy = 0; dy < h; dy++) {                                              \
+        for (dx = 0; dx < w; dx++) {                                          \
+            if (colorValue != fbptr[dx])                                      \
+                return FALSE;                                                 \
+        }                                                                     \
+        fbptr = (uint##bpp##_t *)((uint8_t *)fbptr + cl->screen->paddedWidthInBytes); \
+    }                                                                         \
+                                                                              \
+    *colorPtr = (uint32_t)colorValue;                                           \
+    return TRUE;                                                              \
+}
+
+DEFINE_CHECK_SOLID_FUNCTION(8)
+DEFINE_CHECK_SOLID_FUNCTION(16)
+DEFINE_CHECK_SOLID_FUNCTION(32)
+
+static rfbBool
+SendRectSimple(cl, x, y, w, h)
+    rfbClientPtr cl;
+    int x, y, w, h;
+{
+    int maxBeforeSize, maxAfterSize;
+    int maxRectSize, maxRectWidth;
+    int subrectMaxWidth, subrectMaxHeight;
+    int dx, dy;
+    int rw, rh;
+
+    maxRectSize = tightConf[compressLevel].maxRectSize;
+    maxRectWidth = tightConf[compressLevel].maxRectWidth;
+
+    maxBeforeSize = maxRectSize * (cl->format.bitsPerPixel / 8);
+    maxAfterSize = maxBeforeSize + (maxBeforeSize + 99) / 100 + 12;
+
+    if (tightBeforeBufSize < maxBeforeSize) {
+        tightBeforeBufSize = maxBeforeSize;
+        if (tightBeforeBuf == NULL)
+            tightBeforeBuf = (char *)malloc(tightBeforeBufSize);
+        else
+            tightBeforeBuf = (char *)realloc(tightBeforeBuf,
+                                              tightBeforeBufSize);
+    }
+
+    if (tightAfterBufSize < maxAfterSize) {
+        tightAfterBufSize = maxAfterSize;
+        if (tightAfterBuf == NULL)
+            tightAfterBuf = (char *)malloc(tightAfterBufSize);
+        else
+            tightAfterBuf = (char *)realloc(tightAfterBuf,
+                                             tightAfterBufSize);
+    }
+
+    if (w > maxRectWidth || w * h > maxRectSize) {
+        subrectMaxWidth = (w > maxRectWidth) ? maxRectWidth : w;
+        subrectMaxHeight = maxRectSize / subrectMaxWidth;
+
+        for (dy = 0; dy < h; dy += subrectMaxHeight) {
+            for (dx = 0; dx < w; dx += maxRectWidth) {
+                rw = (dx + maxRectWidth < w) ? maxRectWidth : w - dx;
+                rh = (dy + subrectMaxHeight < h) ? subrectMaxHeight : h - dy;
+                if (!SendSubrect(cl, x+dx, y+dy, rw, rh))
+                    return FALSE;
+            }
+        }
+    } else {
+        if (!SendSubrect(cl, x, y, w, h))
+            return FALSE;
+    }
+
+    return TRUE;
+}
+
+static rfbBool
+SendSubrect(cl, x, y, w, h)
+    rfbClientPtr cl;
+    int x, y, w, h;
+{
+    char *fbptr;
+    rfbBool success = FALSE;
+
+    /* Send pending data if there is more than 128 bytes. */
+    if (cl->ublen > 128) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    if (!SendTightHeader(cl, x, y, w, h))
+        return FALSE;
+
+    fbptr = (cl->screen->frameBuffer + (cl->screen->paddedWidthInBytes * y)
+             + (x * (cl->screen->bitsPerPixel / 8)));
+
+    (*cl->translateFn)(cl->translateLookupTable, &cl->screen->rfbServerFormat,
+                       &cl->format, fbptr, tightBeforeBuf,
+                       cl->screen->paddedWidthInBytes, w, h);
+
+    paletteMaxColors = w * h / tightConf[compressLevel].idxMaxColorsDivisor;
+    if ( paletteMaxColors < 2 &&
+         w * h >= tightConf[compressLevel].monoMinRectSize ) {
+        paletteMaxColors = 2;
+    }
+    switch (cl->format.bitsPerPixel) {
+    case 8:
+        FillPalette8(w * h);
+        break;
+    case 16:
+        FillPalette16(w * h);
+        break;
+    default:
+        FillPalette32(w * h);
+    }
+
+    switch (paletteNumColors) {
+    case 0:
+        /* Truecolor image */
+        if (DetectSmoothImage(cl, &cl->format, w, h)) {
+            if (qualityLevel != -1) {
+                success = SendJpegRect(cl, x, y, w, h,
+                                       tightConf[qualityLevel].jpegQuality);
+            } else {
+                success = SendGradientRect(cl, w, h);
+            }
+        } else {
+            success = SendFullColorRect(cl, w, h);
+        }
+        break;
+    case 1:
+        /* Solid rectangle */
+        success = SendSolidRect(cl);
+        break;
+    case 2:
+        /* Two-color rectangle */
+        success = SendMonoRect(cl, w, h);
+        break;
+    default:
+        /* Up to 256 different colors */
+        if ( paletteNumColors > 96 &&
+             qualityLevel != -1 && qualityLevel <= 3 &&
+             DetectSmoothImage(cl, &cl->format, w, h) ) {
+            success = SendJpegRect(cl, x, y, w, h,
+                                   tightConf[qualityLevel].jpegQuality);
+        } else {
+            success = SendIndexedRect(cl, w, h);
+        }
+    }
+    return success;
+}
+
+static rfbBool
+SendTightHeader(cl, x, y, w, h)
+    rfbClientPtr cl;
+    int x, y, w, h;
+{
+    rfbFramebufferUpdateRectHeader rect;
+
+    if (cl->ublen + sz_rfbFramebufferUpdateRectHeader > UPDATE_BUF_SIZE) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    rect.r.x = Swap16IfLE(x);
+    rect.r.y = Swap16IfLE(y);
+    rect.r.w = Swap16IfLE(w);
+    rect.r.h = Swap16IfLE(h);
+    rect.encoding = Swap32IfLE(rfbEncodingTight);
+
+    memcpy(&cl->updateBuf[cl->ublen], (char *)&rect,
+           sz_rfbFramebufferUpdateRectHeader);
+    cl->ublen += sz_rfbFramebufferUpdateRectHeader;
+
+    cl->rfbRectanglesSent[rfbEncodingTight]++;
+    cl->rfbBytesSent[rfbEncodingTight] += sz_rfbFramebufferUpdateRectHeader;
+
+    return TRUE;
+}
+
+/*
+ * Subencoding implementations.
+ */
+
+static rfbBool
+SendSolidRect(cl)
+    rfbClientPtr cl;
+{
+    int len;
+
+    if (usePixelFormat24) {
+        Pack24(cl, tightBeforeBuf, &cl->format, 1);
+        len = 3;
+    } else
+        len = cl->format.bitsPerPixel / 8;
+
+    if (cl->ublen + 1 + len > UPDATE_BUF_SIZE) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    cl->updateBuf[cl->ublen++] = (char)(rfbTightFill << 4);
+    memcpy (&cl->updateBuf[cl->ublen], tightBeforeBuf, len);
+    cl->ublen += len;
+
+    cl->rfbBytesSent[rfbEncodingTight] += len + 1;
+
+    return TRUE;
+}
+
+static rfbBool
+SendMonoRect(cl, w, h)
+    rfbClientPtr cl;
+    int w, h;
+{
+    int streamId = 1;
+    int paletteLen, dataLen;
+
+    if ( cl->ublen + TIGHT_MIN_TO_COMPRESS + 6 +
+	 2 * cl->format.bitsPerPixel / 8 > UPDATE_BUF_SIZE ) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    /* Prepare tight encoding header. */
+    dataLen = (w + 7) / 8;
+    dataLen *= h;
+
+    cl->updateBuf[cl->ublen++] = (streamId | rfbTightExplicitFilter) << 4;
+    cl->updateBuf[cl->ublen++] = rfbTightFilterPalette;
+    cl->updateBuf[cl->ublen++] = 1;
+
+    /* Prepare palette, convert image. */
+    switch (cl->format.bitsPerPixel) {
+
+    case 32:
+        EncodeMonoRect32((uint8_t *)tightBeforeBuf, w, h);
+
+        ((uint32_t *)tightAfterBuf)[0] = monoBackground;
+        ((uint32_t *)tightAfterBuf)[1] = monoForeground;
+        if (usePixelFormat24) {
+            Pack24(cl, tightAfterBuf, &cl->format, 2);
+            paletteLen = 6;
+        } else
+            paletteLen = 8;
+
+        memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, paletteLen);
+        cl->ublen += paletteLen;
+        cl->rfbBytesSent[rfbEncodingTight] += 3 + paletteLen;
+        break;
+
+    case 16:
+        EncodeMonoRect16((uint8_t *)tightBeforeBuf, w, h);
+
+        ((uint16_t *)tightAfterBuf)[0] = (uint16_t)monoBackground;
+        ((uint16_t *)tightAfterBuf)[1] = (uint16_t)monoForeground;
+
+        memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, 4);
+        cl->ublen += 4;
+        cl->rfbBytesSent[rfbEncodingTight] += 7;
+        break;
+
+    default:
+        EncodeMonoRect8((uint8_t *)tightBeforeBuf, w, h);
+
+        cl->updateBuf[cl->ublen++] = (char)monoBackground;
+        cl->updateBuf[cl->ublen++] = (char)monoForeground;
+        cl->rfbBytesSent[rfbEncodingTight] += 5;
+    }
+
+    return CompressData(cl, streamId, dataLen,
+                        tightConf[compressLevel].monoZlibLevel,
+                        Z_DEFAULT_STRATEGY);
+}
+
+static rfbBool
+SendIndexedRect(cl, w, h)
+    rfbClientPtr cl;
+    int w, h;
+{
+    int streamId = 2;
+    int i, entryLen;
+
+    if ( cl->ublen + TIGHT_MIN_TO_COMPRESS + 6 +
+	 paletteNumColors * cl->format.bitsPerPixel / 8 >
+         UPDATE_BUF_SIZE ) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    /* Prepare tight encoding header. */
+    cl->updateBuf[cl->ublen++] = (streamId | rfbTightExplicitFilter) << 4;
+    cl->updateBuf[cl->ublen++] = rfbTightFilterPalette;
+    cl->updateBuf[cl->ublen++] = (char)(paletteNumColors - 1);
+
+    /* Prepare palette, convert image. */
+    switch (cl->format.bitsPerPixel) {
+
+    case 32:
+        EncodeIndexedRect32((uint8_t *)tightBeforeBuf, w * h);
+
+        for (i = 0; i < paletteNumColors; i++) {
+            ((uint32_t *)tightAfterBuf)[i] =
+                palette.entry[i].listNode->rgb;
+        }
+        if (usePixelFormat24) {
+            Pack24(cl, tightAfterBuf, &cl->format, paletteNumColors);
+            entryLen = 3;
+        } else
+            entryLen = 4;
+
+        memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, paletteNumColors * entryLen);
+        cl->ublen += paletteNumColors * entryLen;
+        cl->rfbBytesSent[rfbEncodingTight] += 3 + paletteNumColors * entryLen;
+        break;
+
+    case 16:
+        EncodeIndexedRect16((uint8_t *)tightBeforeBuf, w * h);
+
+        for (i = 0; i < paletteNumColors; i++) {
+            ((uint16_t *)tightAfterBuf)[i] =
+                (uint16_t)palette.entry[i].listNode->rgb;
+        }
+
+        memcpy(&cl->updateBuf[cl->ublen], tightAfterBuf, paletteNumColors * 2);
+        cl->ublen += paletteNumColors * 2;
+        cl->rfbBytesSent[rfbEncodingTight] += 3 + paletteNumColors * 2;
+        break;
+
+    default:
+        return FALSE;           /* Should never happen. */
+    }
+
+    return CompressData(cl, streamId, w * h,
+                        tightConf[compressLevel].idxZlibLevel,
+                        Z_DEFAULT_STRATEGY);
+}
+
+static rfbBool
+SendFullColorRect(cl, w, h)
+    rfbClientPtr cl;
+    int w, h;
+{
+    int streamId = 0;
+    int len;
+
+    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 */
+    cl->rfbBytesSent[rfbEncodingTight]++;
+
+    if (usePixelFormat24) {
+        Pack24(cl, tightBeforeBuf, &cl->format, w * h);
+        len = 3;
+    } else
+        len = cl->format.bitsPerPixel / 8;
+
+    return CompressData(cl, streamId, w * h * len,
+                        tightConf[compressLevel].rawZlibLevel,
+                        Z_DEFAULT_STRATEGY);
+}
+
+static rfbBool
+SendGradientRect(cl, w, h)
+    rfbClientPtr cl;
+    int w, h;
+{
+    int streamId = 3;
+    int len;
+
+    if (cl->format.bitsPerPixel == 8)
+        return SendFullColorRect(cl, w, h);
+
+    if (cl->ublen + TIGHT_MIN_TO_COMPRESS + 2 > UPDATE_BUF_SIZE) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    if (prevRowBuf == NULL)
+        prevRowBuf = (int *)malloc(2048 * 3 * sizeof(int));
+
+    cl->updateBuf[cl->ublen++] = (streamId | rfbTightExplicitFilter) << 4;
+    cl->updateBuf[cl->ublen++] = rfbTightFilterGradient;
+    cl->rfbBytesSent[rfbEncodingTight] += 2;
+
+    if (usePixelFormat24) {
+        FilterGradient24(cl, tightBeforeBuf, &cl->format, w, h);
+        len = 3;
+    } else if (cl->format.bitsPerPixel == 32) {
+        FilterGradient32(cl, (uint32_t *)tightBeforeBuf, &cl->format, w, h);
+        len = 4;
+    } else {
+        FilterGradient16(cl, (uint16_t *)tightBeforeBuf, &cl->format, w, h);
+        len = 2;
+    }
+
+    return CompressData(cl, streamId, w * h * len,
+                        tightConf[compressLevel].gradientZlibLevel,
+                        Z_FILTERED);
+}
+
+static rfbBool
+CompressData(cl, streamId, dataLen, zlibLevel, zlibStrategy)
+    rfbClientPtr cl;
+    int streamId, dataLen, zlibLevel, zlibStrategy;
+{
+    z_streamp pz;
+    int err;
+
+    if (dataLen < TIGHT_MIN_TO_COMPRESS) {
+        memcpy(&cl->updateBuf[cl->ublen], tightBeforeBuf, dataLen);
+        cl->ublen += dataLen;
+        cl->rfbBytesSent[rfbEncodingTight] += dataLen;
+        return TRUE;
+    }
+
+    pz = &cl->zsStruct[streamId];
+
+    /* Initialize compression stream if needed. */
+    if (!cl->zsActive[streamId]) {
+        pz->zalloc = Z_NULL;
+        pz->zfree = Z_NULL;
+        pz->opaque = Z_NULL;
+
+        err = deflateInit2 (pz, zlibLevel, Z_DEFLATED, MAX_WBITS,
+                            MAX_MEM_LEVEL, zlibStrategy);
+        if (err != Z_OK)
+            return FALSE;
+
+        cl->zsActive[streamId] = TRUE;
+        cl->zsLevel[streamId] = zlibLevel;
+    }
+
+    /* Prepare buffer pointers. */
+    pz->next_in = (Bytef *)tightBeforeBuf;
+    pz->avail_in = dataLen;
+    pz->next_out = (Bytef *)tightAfterBuf;
+    pz->avail_out = tightAfterBufSize;
+
+    /* Change compression parameters if needed. */
+    if (zlibLevel != cl->zsLevel[streamId]) {
+        if (deflateParams (pz, zlibLevel, zlibStrategy) != Z_OK) {
+            return FALSE;
+        }
+        cl->zsLevel[streamId] = zlibLevel;
+    }
+
+    /* Actual compression. */
+    if ( deflate (pz, Z_SYNC_FLUSH) != Z_OK ||
+         pz->avail_in != 0 || pz->avail_out == 0 ) {
+        return FALSE;
+    }
+
+    return SendCompressedData(cl, tightAfterBufSize - pz->avail_out);
+}
+
+static rfbBool SendCompressedData(cl, compressedLen)
+    rfbClientPtr cl;
+    int compressedLen;
+{
+    int i, portionLen;
+
+    cl->updateBuf[cl->ublen++] = compressedLen & 0x7F;
+    cl->rfbBytesSent[rfbEncodingTight]++;
+    if (compressedLen > 0x7F) {
+        cl->updateBuf[cl->ublen-1] |= 0x80;
+        cl->updateBuf[cl->ublen++] = compressedLen >> 7 & 0x7F;
+        cl->rfbBytesSent[rfbEncodingTight]++;
+        if (compressedLen > 0x3FFF) {
+            cl->updateBuf[cl->ublen-1] |= 0x80;
+            cl->updateBuf[cl->ublen++] = compressedLen >> 14 & 0xFF;
+            cl->rfbBytesSent[rfbEncodingTight]++;
+        }
+    }
+
+    portionLen = UPDATE_BUF_SIZE;
+    for (i = 0; i < compressedLen; i += portionLen) {
+        if (i + portionLen > compressedLen) {
+            portionLen = compressedLen - i;
+        }
+        if (cl->ublen + portionLen > UPDATE_BUF_SIZE) {
+            if (!rfbSendUpdateBuf(cl))
+                return FALSE;
+        }
+        memcpy(&cl->updateBuf[cl->ublen], &tightAfterBuf[i], portionLen);
+        cl->ublen += portionLen;
+    }
+    cl->rfbBytesSent[rfbEncodingTight] += compressedLen;
+
+    return TRUE;
+}
+
+/*
+ * Code to determine how many different colors used in rectangle.
+ */
+
+static void
+FillPalette8(count)
+    int count;
+{
+    uint8_t *data = (uint8_t *)tightBeforeBuf;
+    uint8_t c0, c1;
+    int i, n0, n1;
+
+    paletteNumColors = 0;
+
+    c0 = data[0];
+    for (i = 1; i < count && data[i] == c0; i++);
+    if (i == count) {
+        paletteNumColors = 1;
+        return;                 /* Solid rectangle */
+    }
+
+    if (paletteMaxColors < 2)
+        return;
+
+    n0 = i;
+    c1 = data[i];
+    n1 = 0;
+    for (i++; i < count; i++) {
+        if (data[i] == c0) {
+            n0++;
+        } else if (data[i] == c1) {
+            n1++;
+        } else
+            break;
+    }
+    if (i == count) {
+        if (n0 > n1) {
+            monoBackground = (uint32_t)c0;
+            monoForeground = (uint32_t)c1;
+        } else {
+            monoBackground = (uint32_t)c1;
+            monoForeground = (uint32_t)c0;
+        }
+        paletteNumColors = 2;   /* Two colors */
+    }
+}
+
+#define DEFINE_FILL_PALETTE_FUNCTION(bpp)                               \
+                                                                        \
+static void                                                             \
+FillPalette##bpp(count)                                                 \
+    int count;                                                          \
+{                                                                       \
+    uint##bpp##_t *data = (uint##bpp##_t *)tightBeforeBuf;                      \
+    uint##bpp##_t c0, c1, ci;                                               \
+    int i, n0, n1, ni;                                                  \
+                                                                        \
+    c0 = data[0];                                                       \
+    for (i = 1; i < count && data[i] == c0; i++);                       \
+    if (i >= count) {                                                   \
+        paletteNumColors = 1;   /* Solid rectangle */                   \
+        return;                                                         \
+    }                                                                   \
+                                                                        \
+    if (paletteMaxColors < 2) {                                         \
+        paletteNumColors = 0;   /* Full-color encoding preferred */     \
+        return;                                                         \
+    }                                                                   \
+                                                                        \
+    n0 = i;                                                             \
+    c1 = data[i];                                                       \
+    n1 = 0;                                                             \
+    for (i++; i < count; i++) {                                         \
+        ci = data[i];                                                   \
+        if (ci == c0) {                                                 \
+            n0++;                                                       \
+        } else if (ci == c1) {                                          \
+            n1++;                                                       \
+        } else                                                          \
+            break;                                                      \
+    }                                                                   \
+    if (i >= count) {                                                   \
+        if (n0 > n1) {                                                  \
+            monoBackground = (uint32_t)c0;                                \
+            monoForeground = (uint32_t)c1;                                \
+        } else {                                                        \
+            monoBackground = (uint32_t)c1;                                \
+            monoForeground = (uint32_t)c0;                                \
+        }                                                               \
+        paletteNumColors = 2;   /* Two colors */                        \
+        return;                                                         \
+    }                                                                   \
+                                                                        \
+    PaletteReset();                                                     \
+    PaletteInsert (c0, (uint32_t)n0, bpp);                                \
+    PaletteInsert (c1, (uint32_t)n1, bpp);                                \
+                                                                        \
+    ni = 1;                                                             \
+    for (i++; i < count; i++) {                                         \
+        if (data[i] == ci) {                                            \
+            ni++;                                                       \
+        } else {                                                        \
+            if (!PaletteInsert (ci, (uint32_t)ni, bpp))                   \
+                return;                                                 \
+            ci = data[i];                                               \
+            ni = 1;                                                     \
+        }                                                               \
+    }                                                                   \
+    PaletteInsert (ci, (uint32_t)ni, bpp);                                \
+}
+
+DEFINE_FILL_PALETTE_FUNCTION(16)
+DEFINE_FILL_PALETTE_FUNCTION(32)
+
+
+/*
+ * Functions to operate with palette structures.
+ */
+
+#define HASH_FUNC16(rgb) ((int)(((rgb >> 8) + rgb) & 0xFF))
+#define HASH_FUNC32(rgb) ((int)(((rgb >> 16) + (rgb >> 8)) & 0xFF))
+
+static void
+PaletteReset(void)
+{
+    paletteNumColors = 0;
+    memset(palette.hash, 0, 256 * sizeof(COLOR_LIST *));
+}
+
+static int
+PaletteInsert(rgb, numPixels, bpp)
+    uint32_t rgb;
+    int numPixels;
+    int bpp;
+{
+    COLOR_LIST *pnode;
+    COLOR_LIST *prev_pnode = NULL;
+    int hash_key, idx, new_idx, count;
+
+    hash_key = (bpp == 16) ? HASH_FUNC16(rgb) : HASH_FUNC32(rgb);
+
+    pnode = palette.hash[hash_key];
+
+    while (pnode != NULL) {
+        if (pnode->rgb == rgb) {
+            /* Such palette entry already exists. */
+            new_idx = idx = pnode->idx;
+            count = palette.entry[idx].numPixels + numPixels;
+            if (new_idx && palette.entry[new_idx-1].numPixels < count) {
+                do {
+                    palette.entry[new_idx] = palette.entry[new_idx-1];
+                    palette.entry[new_idx].listNode->idx = new_idx;
+                    new_idx--;
+                }
+                while (new_idx && palette.entry[new_idx-1].numPixels < count);
+                palette.entry[new_idx].listNode = pnode;
+                pnode->idx = new_idx;
+            }
+            palette.entry[new_idx].numPixels = count;
+            return paletteNumColors;
+        }
+        prev_pnode = pnode;
+        pnode = pnode->next;
+    }
+
+    /* Check if palette is full. */
+    if (paletteNumColors == 256 || paletteNumColors == paletteMaxColors) {
+        paletteNumColors = 0;
+        return 0;
+    }
+
+    /* Move palette entries with lesser pixel counts. */
+    for ( idx = paletteNumColors;
+          idx > 0 && palette.entry[idx-1].numPixels < numPixels;
+          idx-- ) {
+        palette.entry[idx] = palette.entry[idx-1];
+        palette.entry[idx].listNode->idx = idx;
+    }
+
+    /* Add new palette entry into the freed slot. */
+    pnode = &palette.list[paletteNumColors];
+    if (prev_pnode != NULL) {
+        prev_pnode->next = pnode;
+    } else {
+        palette.hash[hash_key] = pnode;
+    }
+    pnode->next = NULL;
+    pnode->idx = idx;
+    pnode->rgb = rgb;
+    palette.entry[idx].listNode = pnode;
+    palette.entry[idx].numPixels = numPixels;
+
+    return (++paletteNumColors);
+}
+
+
+/*
+ * Converting 32-bit color samples into 24-bit colors.
+ * Should be called only when redMax, greenMax and blueMax are 255.
+ * Color components assumed to be byte-aligned.
+ */
+
+static void Pack24(cl, buf, fmt, count)
+    rfbClientPtr cl;
+    char *buf;
+    rfbPixelFormat *fmt;
+    int count;
+{
+    uint32_t *buf32;
+    uint32_t pix;
+    int r_shift, g_shift, b_shift;
+
+    buf32 = (uint32_t *)buf;
+
+    if (!cl->screen->rfbServerFormat.bigEndian == !fmt->bigEndian) {
+        r_shift = fmt->redShift;
+        g_shift = fmt->greenShift;
+        b_shift = fmt->blueShift;
+    } else {
+        r_shift = 24 - fmt->redShift;
+        g_shift = 24 - fmt->greenShift;
+        b_shift = 24 - fmt->blueShift;
+    }
+
+    while (count--) {
+        pix = *buf32++;
+        *buf++ = (char)(pix >> r_shift);
+        *buf++ = (char)(pix >> g_shift);
+        *buf++ = (char)(pix >> b_shift);
+    }
+}
+
+
+/*
+ * Converting truecolor samples into palette indices.
+ */
+
+#define DEFINE_IDX_ENCODE_FUNCTION(bpp)                                 \
+                                                                        \
+static void                                                             \
+EncodeIndexedRect##bpp(buf, count)                                      \
+    uint8_t *buf;                                                         \
+    int count;                                                          \
+{                                                                       \
+    COLOR_LIST *pnode;                                                  \
+    uint##bpp##_t *src;                                                     \
+    uint##bpp##_t rgb;                                                      \
+    int rep = 0;                                                        \
+                                                                        \
+    src = (uint##bpp##_t *) buf;                                            \
+                                                                        \
+    while (count--) {                                                   \
+        rgb = *src++;                                                   \
+        while (count && *src == rgb) {                                  \
+            rep++, src++, count--;                                      \
+        }                                                               \
+        pnode = palette.hash[HASH_FUNC##bpp(rgb)];                      \
+        while (pnode != NULL) {                                         \
+            if ((uint##bpp##_t)pnode->rgb == rgb) {                         \
+                *buf++ = (uint8_t)pnode->idx;                             \
+                while (rep) {                                           \
+                    *buf++ = (uint8_t)pnode->idx;                         \
+                    rep--;                                              \
+                }                                                       \
+                break;                                                  \
+            }                                                           \
+            pnode = pnode->next;                                        \
+        }                                                               \
+    }                                                                   \
+}
+
+DEFINE_IDX_ENCODE_FUNCTION(16)
+DEFINE_IDX_ENCODE_FUNCTION(32)
+
+#define DEFINE_MONO_ENCODE_FUNCTION(bpp)                                \
+                                                                        \
+static void                                                             \
+EncodeMonoRect##bpp(buf, w, h)                                          \
+    uint8_t *buf;                                                         \
+    int w, h;                                                           \
+{                                                                       \
+    uint##bpp##_t *ptr;                                                     \
+    uint##bpp##_t bg;                                                       \
+    unsigned int value, mask;                                           \
+    int aligned_width;                                                  \
+    int x, y, bg_bits;                                                  \
+                                                                        \
+    ptr = (uint##bpp##_t *) buf;                                            \
+    bg = (uint##bpp##_t) monoBackground;                                    \
+    aligned_width = w - w % 8;                                          \
+                                                                        \
+    for (y = 0; y < h; y++) {                                           \
+        for (x = 0; x < aligned_width; x += 8) {                        \
+            for (bg_bits = 0; bg_bits < 8; bg_bits++) {                 \
+                if (*ptr++ != bg)                                       \
+                    break;                                              \
+            }                                                           \
+            if (bg_bits == 8) {                                         \
+                *buf++ = 0;                                             \
+                continue;                                               \
+            }                                                           \
+            mask = 0x80 >> bg_bits;                                     \
+            value = mask;                                               \
+            for (bg_bits++; bg_bits < 8; bg_bits++) {                   \
+                mask >>= 1;                                             \
+                if (*ptr++ != bg) {                                     \
+                    value |= mask;                                      \
+                }                                                       \
+            }                                                           \
+            *buf++ = (uint8_t)value;                                      \
+        }                                                               \
+                                                                        \
+        mask = 0x80;                                                    \
+        value = 0;                                                      \
+        if (x >= w)                                                     \
+            continue;                                                   \
+                                                                        \
+        for (; x < w; x++) {                                            \
+            if (*ptr++ != bg) {                                         \
+                value |= mask;                                          \
+            }                                                           \
+            mask >>= 1;                                                 \
+        }                                                               \
+        *buf++ = (uint8_t)value;                                          \
+    }                                                                   \
+}
+
+DEFINE_MONO_ENCODE_FUNCTION(8)
+DEFINE_MONO_ENCODE_FUNCTION(16)
+DEFINE_MONO_ENCODE_FUNCTION(32)
+
+
+/*
+ * ``Gradient'' filter for 24-bit color samples.
+ * Should be called only when redMax, greenMax and blueMax are 255.
+ * Color components assumed to be byte-aligned.
+ */
+
+static void
+FilterGradient24(cl, buf, fmt, w, h)
+    rfbClientPtr cl;
+    char *buf;
+    rfbPixelFormat *fmt;
+    int w, h;
+{
+    uint32_t *buf32;
+    uint32_t pix32;
+    int *prevRowPtr;
+    int shiftBits[3];
+    int pixHere[3], pixUpper[3], pixLeft[3], pixUpperLeft[3];
+    int prediction;
+    int x, y, c;
+
+    buf32 = (uint32_t *)buf;
+    memset (prevRowBuf, 0, w * 3 * sizeof(int));
+
+    if (!cl->screen->rfbServerFormat.bigEndian == !fmt->bigEndian) {
+        shiftBits[0] = fmt->redShift;
+        shiftBits[1] = fmt->greenShift;
+        shiftBits[2] = fmt->blueShift;
+    } else {
+        shiftBits[0] = 24 - fmt->redShift;
+        shiftBits[1] = 24 - fmt->greenShift;
+        shiftBits[2] = 24 - fmt->blueShift;
+    }
+
+    for (y = 0; y < h; y++) {
+        for (c = 0; c < 3; c++) {
+            pixUpper[c] = 0;
+            pixHere[c] = 0;
+        }
+        prevRowPtr = prevRowBuf;
+        for (x = 0; x < w; x++) {
+            pix32 = *buf32++;
+            for (c = 0; c < 3; c++) {
+                pixUpperLeft[c] = pixUpper[c];
+                pixLeft[c] = pixHere[c];
+                pixUpper[c] = *prevRowPtr;
+                pixHere[c] = (int)(pix32 >> shiftBits[c] & 0xFF);
+                *prevRowPtr++ = pixHere[c];
+
+                prediction = pixLeft[c] + pixUpper[c] - pixUpperLeft[c];
+                if (prediction < 0) {
+                    prediction = 0;
+                } else if (prediction > 0xFF) {
+                    prediction = 0xFF;
+                }
+                *buf++ = (char)(pixHere[c] - prediction);
+            }
+        }
+    }
+}
+
+
+/*
+ * ``Gradient'' filter for other color depths.
+ */
+
+#define DEFINE_GRADIENT_FILTER_FUNCTION(bpp)                             \
+                                                                         \
+static void                                                              \
+FilterGradient##bpp(cl, buf, fmt, w, h)                                      \
+    rfbClientPtr cl; \
+    uint##bpp##_t *buf;                                                      \
+    rfbPixelFormat *fmt;                                                 \
+    int w, h;                                                            \
+{                                                                        \
+    uint##bpp##_t pix, diff;                                                 \
+    rfbBool endianMismatch;                                                 \
+    int *prevRowPtr;                                                     \
+    int maxColor[3], shiftBits[3];                                       \
+    int pixHere[3], pixUpper[3], pixLeft[3], pixUpperLeft[3];            \
+    int prediction;                                                      \
+    int x, y, c;                                                         \
+                                                                         \
+    memset (prevRowBuf, 0, w * 3 * sizeof(int));                         \
+                                                                         \
+    endianMismatch = (!cl->screen->rfbServerFormat.bigEndian != !fmt->bigEndian);    \
+                                                                         \
+    maxColor[0] = fmt->redMax;                                           \
+    maxColor[1] = fmt->greenMax;                                         \
+    maxColor[2] = fmt->blueMax;                                          \
+    shiftBits[0] = fmt->redShift;                                        \
+    shiftBits[1] = fmt->greenShift;                                      \
+    shiftBits[2] = fmt->blueShift;                                       \
+                                                                         \
+    for (y = 0; y < h; y++) {                                            \
+        for (c = 0; c < 3; c++) {                                        \
+            pixUpper[c] = 0;                                             \
+            pixHere[c] = 0;                                              \
+        }                                                                \
+        prevRowPtr = prevRowBuf;                                         \
+        for (x = 0; x < w; x++) {                                        \
+            pix = *buf;                                                  \
+            if (endianMismatch) {                                        \
+                pix = Swap##bpp(pix);                                    \
+            }                                                            \
+            diff = 0;                                                    \
+            for (c = 0; c < 3; c++) {                                    \
+                pixUpperLeft[c] = pixUpper[c];                           \
+                pixLeft[c] = pixHere[c];                                 \
+                pixUpper[c] = *prevRowPtr;                               \
+                pixHere[c] = (int)(pix >> shiftBits[c] & maxColor[c]);   \
+                *prevRowPtr++ = pixHere[c];                              \
+                                                                         \
+                prediction = pixLeft[c] + pixUpper[c] - pixUpperLeft[c]; \
+                if (prediction < 0) {                                    \
+                    prediction = 0;                                      \
+                } else if (prediction > maxColor[c]) {                   \
+                    prediction = maxColor[c];                            \
+                }                                                        \
+                diff |= ((pixHere[c] - prediction) & maxColor[c])        \
+                    << shiftBits[c];                                     \
+            }                                                            \
+            if (endianMismatch) {                                        \
+                diff = Swap##bpp(diff);                                  \
+            }                                                            \
+            *buf++ = diff;                                               \
+        }                                                                \
+    }                                                                    \
+}
+
+DEFINE_GRADIENT_FILTER_FUNCTION(16)
+DEFINE_GRADIENT_FILTER_FUNCTION(32)
+
+
+/*
+ * Code to guess if given rectangle is suitable for smooth image
+ * compression (by applying "gradient" filter or JPEG coder).
+ */
+
+#define JPEG_MIN_RECT_SIZE  4096
+
+#define DETECT_SUBROW_WIDTH    7
+#define DETECT_MIN_WIDTH       8
+#define DETECT_MIN_HEIGHT      8
+
+static int
+DetectSmoothImage (cl, fmt, w, h)
+    rfbClientPtr cl;
+    rfbPixelFormat *fmt;
+    int w, h;
+{
+    long avgError;
+
+    if ( cl->screen->rfbServerFormat.bitsPerPixel == 8 || fmt->bitsPerPixel == 8 ||
+         w < DETECT_MIN_WIDTH || h < DETECT_MIN_HEIGHT ) {
+        return 0;
+    }
+
+    if (qualityLevel != -1) {
+        if (w * h < JPEG_MIN_RECT_SIZE) {
+            return 0;
+        }
+    } else {
+        if ( rfbTightDisableGradient ||
+             w * h < tightConf[compressLevel].gradientMinRectSize ) {
+            return 0;
+        }
+    }
+
+    if (fmt->bitsPerPixel == 32) {
+        if (usePixelFormat24) {
+            avgError = DetectSmoothImage24(cl, fmt, w, h);
+            if (qualityLevel != -1) {
+                return (avgError < tightConf[qualityLevel].jpegThreshold24);
+            }
+            return (avgError < tightConf[compressLevel].gradientThreshold24);
+        } else {
+            avgError = DetectSmoothImage32(cl, fmt, w, h);
+        }
+    } else {
+        avgError = DetectSmoothImage16(cl, fmt, w, h);
+    }
+    if (qualityLevel != -1) {
+        return (avgError < tightConf[qualityLevel].jpegThreshold);
+    }
+    return (avgError < tightConf[compressLevel].gradientThreshold);
+}
+
+static unsigned long
+DetectSmoothImage24 (cl, fmt, w, h)
+    rfbClientPtr cl;
+    rfbPixelFormat *fmt;
+    int w, h;
+{
+    int off;
+    int x, y, d, dx, c;
+    int diffStat[256];
+    int pixelCount = 0;
+    int pix, left[3];
+    unsigned long avgError;
+
+    /* If client is big-endian, color samples begin from the second
+       byte (offset 1) of a 32-bit pixel value. */
+    off = (fmt->bigEndian != 0);
+
+    memset(diffStat, 0, 256*sizeof(int));
+
+    y = 0, x = 0;
+    while (y < h && x < w) {
+        for (d = 0; d < h - y && d < w - x - DETECT_SUBROW_WIDTH; d++) {
+            for (c = 0; c < 3; c++) {
+                left[c] = (int)tightBeforeBuf[((y+d)*w+x+d)*4+off+c] & 0xFF;
+            }
+            for (dx = 1; dx <= DETECT_SUBROW_WIDTH; dx++) {
+                for (c = 0; c < 3; c++) {
+                    pix = (int)tightBeforeBuf[((y+d)*w+x+d+dx)*4+off+c] & 0xFF;
+                    diffStat[abs(pix - left[c])]++;
+                    left[c] = pix;
+                }
+                pixelCount++;
+            }
+        }
+        if (w > h) {
+            x += h;
+            y = 0;
+        } else {
+            x = 0;
+            y += w;
+        }
+    }
+
+    if (diffStat[0] * 33 / pixelCount >= 95)
+        return 0;
+
+    avgError = 0;
+    for (c = 1; c < 8; c++) {
+        avgError += (unsigned long)diffStat[c] * (unsigned long)(c * c);
+        if (diffStat[c] == 0 || diffStat[c] > diffStat[c-1] * 2)
+            return 0;
+    }
+    for (; c < 256; c++) {
+        avgError += (unsigned long)diffStat[c] * (unsigned long)(c * c);
+    }
+    avgError /= (pixelCount * 3 - diffStat[0]);
+
+    return avgError;
+}
+
+#define DEFINE_DETECT_FUNCTION(bpp)                                          \
+                                                                             \
+static unsigned long                                                         \
+DetectSmoothImage##bpp (cl, fmt, w, h)                                           \
+    rfbClientPtr cl; \
+    rfbPixelFormat *fmt;                                                     \
+    int w, h;                                                                \
+{                                                                            \
+    rfbBool endianMismatch;                                                     \
+    uint##bpp##_t pix;                                                           \
+    int maxColor[3], shiftBits[3];                                           \
+    int x, y, d, dx, c;                                                      \
+    int diffStat[256];                                                       \
+    int pixelCount = 0;                                                      \
+    int sample, sum, left[3];                                                \
+    unsigned long avgError;                                                  \
+                                                                             \
+    endianMismatch = (!cl->screen->rfbServerFormat.bigEndian != !fmt->bigEndian);        \
+                                                                             \
+    maxColor[0] = fmt->redMax;                                               \
+    maxColor[1] = fmt->greenMax;                                             \
+    maxColor[2] = fmt->blueMax;                                              \
+    shiftBits[0] = fmt->redShift;                                            \
+    shiftBits[1] = fmt->greenShift;                                          \
+    shiftBits[2] = fmt->blueShift;                                           \
+                                                                             \
+    memset(diffStat, 0, 256*sizeof(int));                                    \
+                                                                             \
+    y = 0, x = 0;                                                            \
+    while (y < h && x < w) {                                                 \
+        for (d = 0; d < h - y && d < w - x - DETECT_SUBROW_WIDTH; d++) {     \
+            pix = ((uint##bpp##_t *)tightBeforeBuf)[(y+d)*w+x+d];                \
+            if (endianMismatch) {                                            \
+                pix = Swap##bpp(pix);                                        \
+            }                                                                \
+            for (c = 0; c < 3; c++) {                                        \
+                left[c] = (int)(pix >> shiftBits[c] & maxColor[c]);          \
+            }                                                                \
+            for (dx = 1; dx <= DETECT_SUBROW_WIDTH; dx++) {                  \
+                pix = ((uint##bpp##_t *)tightBeforeBuf)[(y+d)*w+x+d+dx];         \
+                if (endianMismatch) {                                        \
+                    pix = Swap##bpp(pix);                                    \
+                }                                                            \
+                sum = 0;                                                     \
+                for (c = 0; c < 3; c++) {                                    \
+                    sample = (int)(pix >> shiftBits[c] & maxColor[c]);       \
+                    sum += abs(sample - left[c]);                            \
+                    left[c] = sample;                                        \
+                }                                                            \
+                if (sum > 255)                                               \
+                    sum = 255;                                               \
+                diffStat[sum]++;                                             \
+                pixelCount++;                                                \
+            }                                                                \
+        }                                                                    \
+        if (w > h) {                                                         \
+            x += h;                                                          \
+            y = 0;                                                           \
+        } else {                                                             \
+            x = 0;                                                           \
+            y += w;                                                          \
+        }                                                                    \
+    }                                                                        \
+                                                                             \
+    if ((diffStat[0] + diffStat[1]) * 100 / pixelCount >= 90)                \
+        return 0;                                                            \
+                                                                             \
+    avgError = 0;                                                            \
+    for (c = 1; c < 8; c++) {                                                \
+        avgError += (unsigned long)diffStat[c] * (unsigned long)(c * c);     \
+        if (diffStat[c] == 0 || diffStat[c] > diffStat[c-1] * 2)             \
+            return 0;                                                        \
+    }                                                                        \
+    for (; c < 256; c++) {                                                   \
+        avgError += (unsigned long)diffStat[c] * (unsigned long)(c * c);     \
+    }                                                                        \
+    avgError /= (pixelCount - diffStat[0]);                                  \
+                                                                             \
+    return avgError;                                                         \
+}
+
+DEFINE_DETECT_FUNCTION(16)
+DEFINE_DETECT_FUNCTION(32)
+
+
+/*
+ * JPEG compression stuff.
+ */
+
+static struct jpeg_destination_mgr jpegDstManager;
+static rfbBool jpegError;
+static int jpegDstDataLen;
+
+static rfbBool
+SendJpegRect(cl, x, y, w, h, quality)
+    rfbClientPtr cl;
+    int x, y, w, h;
+    int quality;
+{
+    struct jpeg_compress_struct cinfo;
+    struct jpeg_error_mgr jerr;
+    uint8_t *srcBuf;
+    JSAMPROW rowPointer[1];
+    int dy;
+
+    if (cl->screen->rfbServerFormat.bitsPerPixel == 8)
+        return SendFullColorRect(cl, w, h);
+
+    srcBuf = (uint8_t *)malloc(w * 3);
+    if (srcBuf == NULL) {
+        return SendFullColorRect(cl, w, h);
+    }
+    rowPointer[0] = srcBuf;
+
+    cinfo.err = jpeg_std_error(&jerr);
+    jpeg_create_compress(&cinfo);
+
+    cinfo.image_width = w;
+    cinfo.image_height = h;
+    cinfo.input_components = 3;
+    cinfo.in_color_space = JCS_RGB;
+
+    jpeg_set_defaults(&cinfo);
+    jpeg_set_quality(&cinfo, quality, TRUE);
+
+    JpegSetDstManager (&cinfo);
+
+    jpeg_start_compress(&cinfo, TRUE);
+
+    for (dy = 0; dy < h; dy++) {
+        PrepareRowForJpeg(cl, srcBuf, x, y + dy, w);
+        jpeg_write_scanlines(&cinfo, rowPointer, 1);
+        if (jpegError)
+            break;
+    }
+
+    if (!jpegError)
+        jpeg_finish_compress(&cinfo);
+
+    jpeg_destroy_compress(&cinfo);
+    free(srcBuf);
+
+    if (jpegError)
+        return SendFullColorRect(cl, w, h);
+
+    if (cl->ublen + TIGHT_MIN_TO_COMPRESS + 1 > UPDATE_BUF_SIZE) {
+        if (!rfbSendUpdateBuf(cl))
+            return FALSE;
+    }
+
+    cl->updateBuf[cl->ublen++] = (char)(rfbTightJpeg << 4);
+    cl->rfbBytesSent[rfbEncodingTight]++;
+
+    return SendCompressedData(cl, jpegDstDataLen);
+}
+
+static void
+PrepareRowForJpeg(cl, dst, x, y, count)
+    rfbClientPtr cl;
+    uint8_t *dst;
+    int x, y, count;
+{
+    if (cl->screen->rfbServerFormat.bitsPerPixel == 32) {
+        if ( cl->screen->rfbServerFormat.redMax == 0xFF &&
+             cl->screen->rfbServerFormat.greenMax == 0xFF &&
+             cl->screen->rfbServerFormat.blueMax == 0xFF ) {
+            PrepareRowForJpeg24(cl, dst, x, y, count);
+        } else {
+            PrepareRowForJpeg32(cl, dst, x, y, count);
+        }
+    } else {
+        /* 16 bpp assumed. */
+        PrepareRowForJpeg16(cl, dst, x, y, count);
+    }
+}
+
+static void
+PrepareRowForJpeg24(cl, dst, x, y, count)
+    rfbClientPtr cl;
+    uint8_t *dst;
+    int x, y, count;
+{
+    uint32_t *fbptr;
+    uint32_t pix;
+
+    fbptr = (uint32_t *)
+        &cl->screen->frameBuffer[y * cl->screen->paddedWidthInBytes + x * 4];
+
+    while (count--) {
+        pix = *fbptr++;
+        *dst++ = (uint8_t)(pix >> cl->screen->rfbServerFormat.redShift);
+        *dst++ = (uint8_t)(pix >> cl->screen->rfbServerFormat.greenShift);
+        *dst++ = (uint8_t)(pix >> cl->screen->rfbServerFormat.blueShift);
+    }
+}
+
+#define DEFINE_JPEG_GET_ROW_FUNCTION(bpp)                                   \
+                                                                            \
+static void                                                                 \
+PrepareRowForJpeg##bpp(cl, dst, x, y, count)                                    \
+    rfbClientPtr cl; \
+    uint8_t *dst;                                                             \
+    int x, y, count;                                                        \
+{                                                                           \
+    uint##bpp##_t *fbptr;                                                       \
+    uint##bpp##_t pix;                                                          \
+    int inRed, inGreen, inBlue;                                             \
+                                                                            \
+    fbptr = (uint##bpp##_t *)                                                   \
+        &cl->screen->frameBuffer[y * cl->screen->paddedWidthInBytes +             \
+                             x * (bpp / 8)];                                \
+                                                                            \
+    while (count--) {                                                       \
+        pix = *fbptr++;                                                     \
+                                                                            \
+        inRed = (int)                                                       \
+            (pix >> cl->screen->rfbServerFormat.redShift   & cl->screen->rfbServerFormat.redMax);   \
+        inGreen = (int)                                                     \
+            (pix >> cl->screen->rfbServerFormat.greenShift & cl->screen->rfbServerFormat.greenMax); \
+        inBlue  = (int)                                                     \
+            (pix >> cl->screen->rfbServerFormat.blueShift  & cl->screen->rfbServerFormat.blueMax);  \
+                                                                            \
+	*dst++ = (uint8_t)((inRed   * 255 + cl->screen->rfbServerFormat.redMax / 2) /     \
+                         cl->screen->rfbServerFormat.redMax);                           \
+	*dst++ = (uint8_t)((inGreen * 255 + cl->screen->rfbServerFormat.greenMax / 2) /   \
+                         cl->screen->rfbServerFormat.greenMax);                         \
+	*dst++ = (uint8_t)((inBlue  * 255 + cl->screen->rfbServerFormat.blueMax / 2) /    \
+                         cl->screen->rfbServerFormat.blueMax);                          \
+    }                                                                       \
+}
+
+DEFINE_JPEG_GET_ROW_FUNCTION(16)
+DEFINE_JPEG_GET_ROW_FUNCTION(32)
+
+/*
+ * Destination manager implementation for JPEG library.
+ */
+
+static void
+JpegInitDestination(j_compress_ptr cinfo)
+{
+    jpegError = FALSE;
+    jpegDstManager.next_output_byte = (JOCTET *)tightAfterBuf;
+    jpegDstManager.free_in_buffer = (size_t)tightAfterBufSize;
+}
+
+static boolean
+JpegEmptyOutputBuffer(j_compress_ptr cinfo)
+{
+    jpegError = TRUE;
+    jpegDstManager.next_output_byte = (JOCTET *)tightAfterBuf;
+    jpegDstManager.free_in_buffer = (size_t)tightAfterBufSize;
+
+    return TRUE;
+}
+
+static void
+JpegTermDestination(j_compress_ptr cinfo)
+{
+    jpegDstDataLen = tightAfterBufSize - jpegDstManager.free_in_buffer;
+}
+
+static void
+JpegSetDstManager(j_compress_ptr cinfo)
+{
+    jpegDstManager.init_destination = JpegInitDestination;
+    jpegDstManager.empty_output_buffer = JpegEmptyOutputBuffer;
+    jpegDstManager.term_destination = JpegTermDestination;
+    cinfo->dest = &jpegDstManager;
+}
+