vnc: add basic tight support

Add support for tight encoding [1]. This patch only add support
for "basic" tight compression without any filter.

[1] http://tigervnc.org/cgi-bin/rfbproto#tight-encoding.

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>

7 files changed, 498 insertions, 4 deletions

diff --git a/Makefile b/Makefile
index 7986bf6922..9deb0f7cce 100644
--- a/Makefile
+++ b/Makefile
@@ -124,6 +124,8 @@ vnc-encoding-zlib.o: vnc.h
 
 vnc-encoding-hextile.o: vnc.h
 
+vnc-encoding-tight.o: vnc.h vnc-encoding-tight.h
+
 curses.o: curses.c keymaps.h curses_keys.h
 
 bt-host.o: QEMU_CFLAGS += $(BLUEZ_CFLAGS)
diff --git a/Makefile.objs b/Makefile.objs
index 1a942e5e74..9796dcbd16 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -105,6 +105,7 @@ common-obj-$(CONFIG_SDL) += sdl.o sdl_zoom.o x_keymap.o
 common-obj-$(CONFIG_CURSES) += curses.o
 common-obj-y += vnc.o acl.o d3des.o
 common-obj-y += vnc-encoding-zlib.o vnc-encoding-hextile.o
+common-obj-y += vnc-encoding-tight.o
 common-obj-y += iov.o
 common-obj-$(CONFIG_VNC_TLS) += vnc-tls.o vnc-auth-vencrypt.o
 common-obj-$(CONFIG_VNC_SASL) += vnc-auth-sasl.o
diff --git a/vnc-encoding-tight.c b/vnc-encoding-tight.c
new file mode 100644
index 0000000000..ce9cc496a8
--- /dev/null
+++ b/vnc-encoding-tight.c
@@ -0,0 +1,295 @@
+/*
+ * QEMU VNC display driver: tight encoding
+ *
+ * From libvncserver/libvncserver/tight.c
+ * Copyright (C) 2000, 2001 Const Kaplinsky.  All Rights Reserved.
+ * Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
+ *
+ * Copyright (C) 2010 Corentin Chary <corentin.chary@gmail.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include <stdbool.h>
+
+#include "vnc.h"
+#include "vnc-encoding-tight.h"
+
+/* 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). */
+
+static const struct {
+    int max_rect_size, max_rect_width;
+    int mono_min_rect_size, gradient_min_rect_size;
+    int idx_zlib_level, mono_zlib_level, raw_zlib_level, gradient_zlib_level;
+    int gradient_threshold, gradient_threshold24;
+    int idx_max_colors_divisor;
+    int jpeg_quality, jpeg_threshold, jpeg_threshold24;
+} tight_conf[] = {
+    {   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 tight_init_stream(VncState *vs, int stream_id,
+                             int level, int strategy)
+{
+    z_streamp zstream = &vs->tight_stream[stream_id];
+
+    if (zstream->opaque == NULL) {
+        int err;
+
+        VNC_DEBUG("VNC: TIGHT: initializing zlib stream %d\n", stream_id);
+        VNC_DEBUG("VNC: TIGHT: opaque = %p | vs = %p\n", zstream->opaque, vs);
+        zstream->zalloc = vnc_zlib_zalloc;
+        zstream->zfree = vnc_zlib_zfree;
+
+        err = deflateInit2(zstream, level, Z_DEFLATED, MAX_WBITS,
+                           MAX_MEM_LEVEL, strategy);
+
+        if (err != Z_OK) {
+            fprintf(stderr, "VNC: error initializing zlib\n");
+            return -1;
+        }
+
+        vs->tight_levels[stream_id] = level;
+        zstream->opaque = vs;
+    }
+
+    if (vs->tight_levels[stream_id] != level) {
+        if (deflateParams(zstream, level, strategy) != Z_OK) {
+            return -1;
+        }
+        vs->tight_levels[stream_id] = level;
+    }
+    return 0;
+}
+
+static void tight_send_compact_size(VncState *vs, size_t len)
+{
+    int lpc = 0;
+    int bytes = 0;
+    char buf[3] = {0, 0, 0};
+
+    buf[bytes++] = len & 0x7F;
+    if (len > 0x7F) {
+        buf[bytes-1] |= 0x80;
+        buf[bytes++] = (len >> 7) & 0x7F;
+        if (len > 0x3FFF) {
+            buf[bytes-1] |= 0x80;
+            buf[bytes++] = (len >> 14) & 0xFF;
+        }
+    }
+    for(lpc = 0; lpc < bytes; lpc++) {
+        vnc_write_u8(vs, buf[lpc]);
+    }
+}
+
+static int tight_compress_data(VncState *vs, int stream_id, size_t bytes,
+                               int level, int strategy)
+{
+    z_streamp zstream = &vs->tight_stream[stream_id];
+    int previous_out;
+
+    if (bytes < VNC_TIGHT_MIN_TO_COMPRESS) {
+        vnc_write(vs, vs->tight.buffer, vs->tight.offset);
+        return bytes;
+    }
+
+    if (tight_init_stream(vs, stream_id, level, strategy)) {
+        return -1;
+    }
+
+    /* reserve memory in output buffer */
+    buffer_reserve(&vs->tight_zlib, bytes + 64);
+
+    /* set pointers */
+    zstream->next_in = vs->tight.buffer;
+    zstream->avail_in = vs->tight.offset;
+    zstream->next_out = vs->tight_zlib.buffer + vs->tight_zlib.offset;
+    zstream->avail_out = vs->tight_zlib.capacity - vs->tight_zlib.offset;
+    zstream->data_type = Z_BINARY;
+    previous_out = zstream->total_out;
+
+    /* start encoding */
+    if (deflate(zstream, Z_SYNC_FLUSH) != Z_OK) {
+        fprintf(stderr, "VNC: error during tight compression\n");
+        return -1;
+    }
+
+    vs->tight_zlib.offset = vs->tight_zlib.capacity - zstream->avail_out;
+    bytes = zstream->total_out - previous_out;
+
+    tight_send_compact_size(vs, bytes);
+    vnc_write(vs, vs->tight_zlib.buffer, bytes);
+
+    buffer_reset(&vs->tight_zlib);
+
+    return bytes;
+}
+
+/*
+ * Subencoding implementations.
+ */
+static void tight_pack24(VncState *vs, size_t count)
+{
+    unsigned char *buf;
+    uint32_t *buf32;
+    uint32_t pix;
+    int rshift, gshift, bshift;
+
+    buf = vs->tight.buffer;
+    buf32 = (uint32_t *)buf;
+
+    if ((vs->clientds.flags & QEMU_BIG_ENDIAN_FLAG) ==
+        (vs->ds->surface->flags & QEMU_BIG_ENDIAN_FLAG)) {
+        rshift = vs->clientds.pf.rshift;
+        gshift = vs->clientds.pf.gshift;
+        bshift = vs->clientds.pf.bshift;
+    } else {
+        rshift = 24 - vs->clientds.pf.rshift;
+        gshift = 24 - vs->clientds.pf.gshift;
+        bshift = 24 - vs->clientds.pf.bshift;
+    }
+
+    vs->tight.offset = count * 3;
+
+    while (count--) {
+        pix = *buf32++;
+        *buf++ = (char)(pix >> rshift);
+        *buf++ = (char)(pix >> gshift);
+        *buf++ = (char)(pix >> bshift);
+    }
+}
+
+static int send_full_color_rect(VncState *vs, int w, int h)
+{
+    int stream = 0;
+    size_t bytes;
+
+    vnc_write_u8(vs, stream << 4); /* no flushing, no filter */
+
+    if (vs->tight_pixel24) {
+        tight_pack24(vs, w * h);
+        bytes = 3;
+    } else {
+        bytes = vs->clientds.pf.bytes_per_pixel;
+    }
+
+    bytes = tight_compress_data(vs, stream, w * h * bytes,
+                                tight_conf[vs->tight_compression].raw_zlib_level,
+                                Z_DEFAULT_STRATEGY);
+
+    return (bytes >= 0);
+}
+
+static void vnc_tight_start(VncState *vs)
+{
+    buffer_reset(&vs->tight);
+
+    // make the output buffer be the zlib buffer, so we can compress it later
+    vs->tight_tmp = vs->output;
+    vs->output = vs->tight;
+}
+
+static void vnc_tight_stop(VncState *vs)
+{
+    // switch back to normal output/zlib buffers
+    vs->tight = vs->output;
+    vs->output = vs->tight_tmp;
+}
+
+static int send_sub_rect(VncState *vs, int x, int y, int w, int h)
+{
+    vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_TIGHT);
+
+    /*
+     * Convert pixels and store them in vs->tight
+     * We will probably rework that later, probably
+     * when adding other sub-encodings
+     */
+    vnc_tight_start(vs);
+    vnc_raw_send_framebuffer_update(vs, x, y, w, h);
+    vnc_tight_stop(vs);
+
+    return send_full_color_rect(vs, w, h);
+}
+
+static int send_rect_simple(VncState *vs, int x, int y, int w, int h)
+{
+    int max_size, max_width;
+    int max_sub_width, max_sub_height;
+    int dx, dy;
+    int rw, rh;
+    int n = 0;
+
+    max_size = tight_conf[vs->tight_compression].max_rect_size;
+    max_width = tight_conf[vs->tight_compression].max_rect_width;
+
+    if (w > max_width || w * h > max_size) {
+        max_sub_width = (w > max_width) ? max_width : w;
+        max_sub_height = max_size / max_sub_width;
+
+        for (dy = 0; dy < h; dy += max_sub_height) {
+            for (dx = 0; dx < w; dx += max_width) {
+                rw = MIN(max_sub_width, w - dx);
+                rh = MIN(max_sub_height, h - dy);
+                n += send_sub_rect(vs, x+dx, y+dy, rw, rh);
+            }
+        }
+    } else {
+        n += send_sub_rect(vs, x, y, w, h);
+    }
+
+    return n;
+}
+
+int vnc_tight_send_framebuffer_update(VncState *vs, int x, int y,
+                                      int w, int h)
+{
+    if (vs->clientds.pf.bytes_per_pixel == 4 && vs->clientds.pf.rmax == 0xFF &&
+        vs->clientds.pf.bmax == 0xFF && vs->clientds.pf.gmax == 0xFF) {
+        vs->tight_pixel24 = true;
+    } else {
+        vs->tight_pixel24 = false;
+    }
+
+    return send_rect_simple(vs, x, y, w, h);
+}
+
+void vnc_tight_clear(VncState *vs)
+{
+    int i;
+    for (i=0; i<ARRAY_SIZE(vs->tight_stream); i++) {
+        if (vs->tight_stream[i].opaque) {
+            deflateEnd(&vs->tight_stream[i]);
+        }
+    }
+
+    buffer_free(&vs->tight);
+    buffer_free(&vs->tight_zlib);
+}
diff --git a/vnc-encoding-tight.h b/vnc-encoding-tight.h
new file mode 100644
index 0000000000..64d10625fe
--- /dev/null
+++ b/vnc-encoding-tight.h
@@ -0,0 +1,176 @@
+/*
+ * QEMU VNC display driver: tight encoding
+ *
+ * From libvncserver/rfb/rfbproto.h
+ * Copyright (C) 2005 Rohit Kumar, Johannes E. Schindelin
+ * Copyright (C) 2000-2002 Constantin Kaplinsky.  All Rights Reserved.
+ * Copyright (C) 2000 Tridia Corporation.  All Rights Reserved.
+ * Copyright (C) 1999 AT&T Laboratories Cambridge.  All Rights Reserved.
+ *
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#ifndef VNC_ENCODING_TIGHT_H
+#define VNC_ENCODING_TIGHT_H
+
+/*- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+ * Tight Encoding.
+ *
+ *-- 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):
+ *
+ *   bit 0:    if 1, then compression stream 0 should be reset;
+ *   bit 1:    if 1, then compression stream 1 should be reset;
+ *   bit 2:    if 1, then compression stream 2 should be reset;
+ *   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 0xxx, then the compression type is "basic",
+ *             values greater than 1001 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:
+ *
+ *   bits 5-4:  decimal representation is the index of a particular zlib
+ *              stream which should be used for decompressing the data;
+ *   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").
+ *
+ *-- 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:
+ *
+ *   1..3 bytes:  data size (N) in compact representation;
+ *   N bytes:     JPEG image.
+ *
+ * Data size is compactly represented in one, two or three bytes, according
+ * to the following scheme:
+ *
+ *  0xxxxxxx                    (for values 0..127)
+ *  1xxxxxxx 0yyyyyyy           (for values 128..16383)
+ *  1xxxxxxx 1yyyyyyy zzzzzzzz  (for values 16384..4194303)
+ *
+ * Here each character denotes one bit, xxxxxxx are the least significant 7
+ * bits of the value (bits 0-6), yyyyyyy are bits 7-13, and zzzzzzzz are the
+ * most significant 8 bits (bits 14-21). For example, decimal value 10000
+ * should be represented as two bytes: binary 10010000 01001110, or
+ * hexadecimal 90 4E.
+ *
+ *-- If the compression type is "basic" and bit 6 of the compression control
+ * byte was set to 1, then the next (second) byte specifies "filter id" which
+ * tells the decoder what filter type was used by the encoder to pre-process
+ * pixel data before the compression. The "filter id" byte can be one of the
+ * following:
+ *
+ *   0:  no filter ("copy" filter);
+ *   1:  "palette" filter;
+ *   2:  "gradient" filter.
+ *
+ *-- If bit 6 of the compression control byte is set to 0 (no "filter id"
+ * byte), or if the filter id is 0, then raw pixel values in the client
+ * format (see NOTE 1) will be compressed. See below details on the
+ * compression.
+ *
+ *-- The "gradient" filter pre-processes pixel data with a simple algorithm
+ * which converts each color component to a difference between a "predicted"
+ * intensity and the actual intensity. Such a technique does not affect
+ * uncompressed data size, but helps to compress photo-like images better.
+ * Pseudo-code for converting intensities to differences is the following:
+ *
+ *   P[i,j] := V[i-1,j] + V[i,j-1] - V[i-1,j-1];
+ *   if (P[i,j] < 0) then P[i,j] := 0;
+ *   if (P[i,j] > MAX) then P[i,j] := MAX;
+ *   D[i,j] := V[i,j] - P[i,j];
+ *
+ * Here V[i,j] is the intensity of a color component for a pixel at
+ * coordinates (i,j). MAX is the maximum value of intensity for a color
+ * component.
+ *
+ *-- The "palette" filter converts true-color pixel data to indexed colors
+ * and a palette which can consist of 2..256 colors. If the number of colors
+ * is 2, then each pixel is encoded in 1 bit, otherwise 8 bits is used to
+ * encode one pixel. 1-bit encoding is performed such way that the most
+ * significant bits correspond to the leftmost pixels, and each raw of pixels
+ * is aligned to the byte boundary. When "palette" filter is used, the
+ * palette is sent before the pixel data. The palette begins with an unsigned
+ * byte which value is the number of colors in the palette minus 1 (i.e. 1
+ * means 2 colors, 255 means 256 colors in the palette). Then follows the
+ * palette itself which consist of pixel values in client pixel format (see
+ * NOTE 1).
+ *
+ *-- The pixel data is compressed using the zlib library. But if the data
+ * size after applying the filter but before the compression is less then 12,
+ * then the data is sent as is, uncompressed. Four separate zlib streams
+ * (0..3) can be used and the decoder should read the actual stream id from
+ * the compression control byte (see NOTE 2).
+ *
+ * If the compression is not used, then the pixel data is sent as is,
+ * otherwise the data stream looks like this:
+ *
+ *   1..3 bytes:  data size (N) in compact representation;
+ *   N bytes:     zlib-compressed data.
+ *
+ * Data size is compactly represented in one, two or three bytes, just like
+ * in the "jpeg" compression method (see above).
+ *
+ *-- NOTE 1. If the color depth is 24, and all three color components are
+ * 8-bit wide, then one pixel in Tight encoding is always represented by
+ * three bytes, where the first byte is red component, the second byte is
+ * green component, and the third byte is blue component of the pixel color
+ * value. This applies to colors in palettes as well.
+ *
+ *-- 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".
+ *
+ *-- NOTE 3. The "gradient" filter and "jpeg" compression may be used only
+ * when bits-per-pixel value is either 16 or 32, not 8.
+ *
+ *-- NOTE 4. The width of any Tight-encoded rectangle cannot exceed 2048
+ * pixels. If a rectangle is wider, it must be split into several rectangles
+ * and each one should be encoded separately.
+ *
+ */
+
+#define VNC_TIGHT_EXPLICIT_FILTER       0x04
+#define VNC_TIGHT_FILL                  0x08
+#define VNC_TIGHT_JPEG                  0x09
+#define VNC_TIGHT_MAX_SUBENCODING       0x09
+
+/* Filters to improve compression efficiency */
+#define VNC_TIGHT_FILTER_COPY             0x00
+#define VNC_TIGHT_FILTER_PALETTE          0x01
+#define VNC_TIGHT_FILTER_GRADIENT         0x02
+
+/* Note: The following constant should not be changed. */
+#define VNC_TIGHT_MIN_TO_COMPRESS 12
+
+/* The parameters below may be adjusted. */
+#define VNC_TIGHT_MIN_SPLIT_RECT_SIZE     4096
+#define VNC_TIGHT_MIN_SOLID_SUBRECT_SIZE  2048
+#define VNC_TIGHT_MAX_SPLIT_TILE_SIZE       16
+
+#endif /* VNC_ENCODING_TIGHT_H */
diff --git a/vnc-encoding-zlib.c b/vnc-encoding-zlib.c
index 88ac863a53..a99bc387dc 100644
--- a/vnc-encoding-zlib.c
+++ b/vnc-encoding-zlib.c
@@ -28,7 +28,7 @@
 
 #define ZALLOC_ALIGNMENT 16
 
-static void *zalloc(void *x, unsigned items, unsigned size)
+void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size)
 {
     void *p;
 
@@ -40,7 +40,7 @@ static void *zalloc(void *x, unsigned items, unsigned size)
     return (p);
 }
 
-static void zfree(void *x, void *addr)
+void vnc_zlib_zfree(void *x, void *addr)
 {
     qemu_free(addr);
 }
@@ -72,8 +72,8 @@ static int vnc_zlib_stop(VncState *vs)
 
         VNC_DEBUG("VNC: initializing zlib stream\n");
         VNC_DEBUG("VNC: opaque = %p | vs = %p\n", zstream->opaque, vs);
-        zstream->zalloc = zalloc;
-        zstream->zfree = zfree;
+        zstream->zalloc = vnc_zlib_zalloc;
+        zstream->zfree = vnc_zlib_zfree;
 
         err = deflateInit2(zstream, vs->tight_compression, Z_DEFLATED, MAX_WBITS,
                            MAX_MEM_LEVEL, Z_DEFAULT_STRATEGY);
diff --git a/vnc.c b/vnc.c
index 626f17317e..046bd3849c 100644
--- a/vnc.c
+++ b/vnc.c
@@ -678,6 +678,9 @@ static int send_framebuffer_update(VncState *vs, int x, int y, int w, int h)
             vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_HEXTILE);
             n = vnc_hextile_send_framebuffer_update(vs, x, y, w, h);
             break;
+        case VNC_ENCODING_TIGHT:
+            n = vnc_tight_send_framebuffer_update(vs, x, y, w, h);
+            break;
         default:
             vnc_framebuffer_update(vs, x, y, w, h, VNC_ENCODING_RAW);
             n = vnc_raw_send_framebuffer_update(vs, x, y, w, h);
@@ -982,6 +985,7 @@ static void vnc_disconnect_finish(VncState *vs)
     qobject_decref(vs->info);
 
     vnc_zlib_clear(vs);
+    vnc_tight_clear(vs);
 
 #ifdef CONFIG_VNC_TLS
     vnc_tls_client_cleanup(vs);
@@ -1677,6 +1681,10 @@ static void set_encodings(VncState *vs, int32_t *encodings, size_t n_encodings)
             vs->features |= VNC_FEATURE_HEXTILE_MASK;
             vs->vnc_encoding = enc;
             break;
+        case VNC_ENCODING_TIGHT:
+            vs->features |= VNC_FEATURE_TIGHT_MASK;
+            vs->vnc_encoding = enc;
+            break;
         case VNC_ENCODING_ZLIB:
             vs->features |= VNC_FEATURE_ZLIB_MASK;
             vs->vnc_encoding = enc;
diff --git a/vnc.h b/vnc.h
index cd6495f345..51595e6eb9 100644
--- a/vnc.h
+++ b/vnc.h
@@ -170,6 +170,12 @@ struct VncState
     /* Tight */
     uint8_t tight_quality;
     uint8_t tight_compression;
+    uint8_t tight_pixel24;
+    Buffer tight;
+    Buffer tight_tmp;
+    Buffer tight_zlib;
+    int tight_levels[4];
+    z_stream tight_stream[4];
 
     /* Hextile */
     VncSendHextileTile *send_hextile_tile;
@@ -404,7 +410,13 @@ int vnc_hextile_send_framebuffer_update(VncState *vs, int x,
                                          int y, int w, int h);
 void vnc_hextile_set_pixel_conversion(VncState *vs, int generic);
 
+void *vnc_zlib_zalloc(void *x, unsigned items, unsigned size);
+void vnc_zlib_zfree(void *x, void *addr);
 int vnc_zlib_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
 void vnc_zlib_clear(VncState *vs);
 
+
+int vnc_tight_send_framebuffer_update(VncState *vs, int x, int y, int w, int h);
+void vnc_tight_clear(VncState *vs);
+
 #endif /* __QEMU_VNC_H */