Add resolution member to client info struct. Interpret new third parameter for screen size.

src/guacd/daemon.c

@@ -202,6 +202,14 @@ void guacd_handle_connection(guac_socket* socket) {
     client->info.optimal_width  = atoi(size->argv[0]);
     client->info.optimal_height = atoi(size->argv[1]);
 
+    /* If DPI given, set the client resolution */
+    if (size->argc >= 3)
+        client->info.optimal_resolution = atoi(size->argv[2]);
+
+    /* Otherwise, use a safe default for rough backwards compatibility */
+    else
+        client->info.optimal_resolution = 96;
+
     /* Store audio mimetypes */
     client->info.audio_mimetypes = malloc(sizeof(char*) * (audio->argc+1));
     memcpy(client->info.audio_mimetypes, audio->argv,

src/libguac/guacamole/client.h

@@ -238,6 +238,15 @@ typedef struct guac_client_info {
      */
     const char** video_mimetypes;
 
+    /**
+     * The DPI of the physical remote display if configured for the optimal
+     * width/height combination described here. This need not be honored by
+     * a client plugin implementation, but if the underlying protocol of the
+     * client plugin supports dynamic sizing of the screen, honoring the
+     * stated resolution of the display size request is recommended.
+     */
+    int optimal_resolution;
+
 } guac_client_info;
 
 /**