GUACAMOLE-1760: Add guacd support for setting VNC compression and quality.

src/protocols/vnc/settings.c

@@ -95,6 +95,8 @@ const char* GUAC_VNC_CLIENT_ARGS[] = {
     "wol-wait-time",
 
     "force-lossless",
+    "compress-level",
+    "quality-level",
     NULL
 };
 
@@ -389,6 +391,18 @@ enum VNC_ARGS_IDX {
      */
     IDX_FORCE_LOSSLESS,
 
+    /**
+     * The level of compression, on a scale of 0 (no compression) to 9 (maximum
+     * compression), that the connection will be configured for.
+     */
+    IDX_COMPRESS_LEVEL,
+
+    /**
+     * The level of display quality, on a scale of 0 (worst quality) to 9 (best
+     * quality), that the connection will be configured for.
+     */
+    IDX_QUALITY_LEVEL,
+
     VNC_ARGS_COUNT
 };
 
@@ -453,6 +467,16 @@ guac_vnc_settings* guac_vnc_parse_args(guac_user* user,
         guac_user_parse_args_boolean(user, GUAC_VNC_CLIENT_ARGS, argv,
                 IDX_FORCE_LOSSLESS, false);
 
+    /* Compression level */
+    settings->compress_level =
+        guac_user_parse_args_int(user, GUAC_VNC_CLIENT_ARGS, argv,
+                IDX_COMPRESS_LEVEL, -1);
+
+    /* Display quality */
+    settings->quality_level =
+        guac_user_parse_args_int(user, GUAC_VNC_CLIENT_ARGS, argv,
+                IDX_QUALITY_LEVEL, -1);
+
 #ifdef ENABLE_VNC_REPEATER
     /* Set repeater parameters if specified */
     settings->dest_host =

src/protocols/vnc/settings.h

@@ -82,6 +82,16 @@ typedef struct guac_vnc_settings {
      */
     bool lossless;
 
+    /**
+     * The level of compression to ask the VNC client library to perform.
+     */
+    int compress_level;
+
+     /**
+      * The quality level to ask the VNC client library to maintain.
+      */
+    int quality_level;
+
 #ifdef ENABLE_VNC_REPEATER
     /**
      * The VNC host to connect to, if using a repeater.

src/protocols/vnc/vnc.c

@@ -440,6 +440,13 @@ void* guac_vnc_client_thread(void* data) {
      * heuristics) */
     guac_common_display_set_lossless(vnc_client->display, settings->lossless);
 
+    /* If compression and display quality have been configured, set those. */
+    if (settings->compress_level >= 0 && settings->compress_level <= 9)
+        rfb_client->appData.compressLevel = settings->compress_level;
+
+    if (settings->quality_level >= 0 && settings->quality_level <= 9)
+        rfb_client->appData.qualityLevel = settings->quality_level;
+
     /* If not read-only, set an appropriate cursor */
     if (settings->read_only == 0) {
         if (settings->remote_cursor)