libvncclient: add functionality to set what a client is requesting

With this new API, the caller can tell the client to only request a
subset of the remote framebuffer during incremental framebuffer
requests.

Author: bk138

include/rfb/rfbclient.h

@@ -486,6 +486,9 @@ typedef struct _rfbClient {
 	 * Callback fired when "Extended Clipboard" UTF-8 text data is received.
 	 */
         GotXCutTextUTF8Proc GotXCutTextUTF8;
+
+        /* flag to indicate wheter updateRect is managed by lib or user */
+        rfbBool isUpdateRectManagedByLib;
 } rfbClient;
 
 /* cursor.c */
@@ -672,6 +675,26 @@ extern void PrintPixelFormat(rfbPixelFormat *format);
 extern rfbBool SupportsClient2Server(rfbClient* client, int messageType);
 extern rfbBool SupportsServer2Client(rfbClient* client, int messageType);
 
+/**
+ * Set the rectangle the client is interested in. If set, the client will
+ * ask only for the given rectangle in incremental framebuffer requests.
+ * @param client The client on which to set the rectangle
+ * @param rect The rectangle the client is interested in. The function does
+ *             not take ownership of 'rect'. Set to NULL to have the library
+ *             manage this, which means always request the full remote
+ *             framebuffer.
+ */
+extern void rfbClientSetUpdateRect(rfbClient *client, rfbRectangle *rect);
+
+/**
+ * Get the rectangle the client asks for in incremental framebuffer
+ * requests.
+ * @param client The client for which to get the rectangle
+ * @param rect Will be filled with what's currently set for the given client
+ * @param isManagedbylib Will be set to TRUE if client is using the default
+ */
+extern void rfbClientGetUpdateRect(rfbClient *client, rfbRectangle *rect, rfbBool *isManagedByLib);
+
 /* client data */
 
 /**

src/libvncclient/rfbclient.c

@@ -1684,9 +1684,12 @@ ResizeClientBuffer(rfbClient* client, int width, int height)
 {
   client->width = width;
   client->height = height;
-  client->updateRect.x = client->updateRect.y = 0;
-  client->updateRect.w = client->width;
-  client->updateRect.h = client->height;
+  /* Only adadpt updateRect to new dimensions if managed by lib */
+  if (client->isUpdateRectManagedByLib) {
+      client->updateRect.x = client->updateRect.y = 0;
+      client->updateRect.w = client->width;
+      client->updateRect.h = client->height;
+  }
   return client->MallocFrameBuffer(client);
 }
 
@@ -1972,6 +1975,29 @@ rfbClientProcessExtServerCutText(rfbClient* client, char *data, int len)
 }
 #endif
 
+void rfbClientSetUpdateRect(rfbClient *client, rfbRectangle *rect) {
+    if (rect) {
+	client->updateRect.x = rect->x;
+	client->updateRect.y = rect->y;
+	client->updateRect.w = rect->w;
+	client->updateRect.h = rect->h;
+	client->isUpdateRectManagedByLib = FALSE;
+    } else {
+	/* rect NULL, reset to defaults */
+	client->updateRect.x = client->updateRect.y = 0;
+	client->updateRect.w = client->width;
+	client->updateRect.h = client->height;
+	client->isUpdateRectManagedByLib = TRUE;
+    }
+}
+
+void rfbClientGetUpdateRect(rfbClient *client, rfbRectangle *rect, rfbBool *isManagedByLib) {
+    rect->x = client->updateRect.x;
+    rect->y = client->updateRect.y;
+    rect->w = client->updateRect.w;
+    rect->h = client->updateRect.h;
+    *isManagedByLib = client->isUpdateRectManagedByLib;
+}
 
 /*
  * HandleRFBServerMessage.

src/libvncclient/vncviewer.c

@@ -403,6 +403,7 @@ static rfbBool rfbInitConnection(rfbClient* client)
     client->updateRect.x = client->updateRect.y = 0;
     client->updateRect.w = client->width;
     client->updateRect.h = client->height;
+    client->isUpdateRectManagedByLib = TRUE;
   }
 
   if (client->appData.scaleSetting>1)