diff --git a/common/rfb/CMsgHandler.cxx b/common/rfb/CMsgHandler.cxx
index b89bc18..03e66e8 100644
--- a/common/rfb/CMsgHandler.cxx
+++ b/common/rfb/CMsgHandler.cxx
@@ -34,8 +34,7 @@
 
 void CMsgHandler::setDesktopSize(int width, int height)
 {
-  cp.width = width;
-  cp.height = height;
+  cp.setDimensions(width, height);
 }
 
 void CMsgHandler::setExtendedDesktopSize(unsigned reason, unsigned result,
@@ -47,12 +46,7 @@
   if ((reason == reasonClient) && (result != resultSuccess))
     return;
 
-  if (!layout.validate(width, height))
-    fprintf(stderr, "Server sent us an invalid screen layout\n");
-
-  cp.width = width;
-  cp.height = height;
-  cp.screenLayout = layout;
+  cp.setDimensions(width, height, layout);
 }
 
 void CMsgHandler::setPixelFormat(const PixelFormat& pf)
diff --git a/common/rfb/CMsgReader.cxx b/common/rfb/CMsgReader.cxx
index 1d359d2..7502df6 100644
--- a/common/rfb/CMsgReader.cxx
+++ b/common/rfb/CMsgReader.cxx
@@ -192,10 +192,10 @@
 
 void CMsgReader::readRect(const Rect& r, int encoding)
 {
-  if ((r.br.x > handler->cp.width) || (r.br.y > handler->cp.height)) {
+  if ((r.br.x > handler->cp.width()) || (r.br.y > handler->cp.height())) {
     fprintf(stderr, "Rect too big: %dx%d at %d,%d exceeds %dx%d\n",
 	    r.width(), r.height(), r.tl.x, r.tl.y,
-            handler->cp.width, handler->cp.height);
+            handler->cp.width(), handler->cp.height());
     throw Exception("Rect too big");
   }
 
diff --git a/common/rfb/CMsgWriter.cxx b/common/rfb/CMsgWriter.cxx
index 44b73da..97c3336 100644
--- a/common/rfb/CMsgWriter.cxx
+++ b/common/rfb/CMsgWriter.cxx
@@ -245,8 +245,8 @@
   Point p(pos);
   if (p.x < 0) p.x = 0;
   if (p.y < 0) p.y = 0;
-  if (p.x >= cp->width) p.x = cp->width - 1;
-  if (p.y >= cp->height) p.y = cp->height - 1;
+  if (p.x >= cp->width()) p.x = cp->width() - 1;
+  if (p.y >= cp->height()) p.y = cp->height() - 1;
 
   startMsg(msgTypePointerEvent);
   os->writeU8(buttonMask);
diff --git a/common/rfb/ConnParams.cxx b/common/rfb/ConnParams.cxx
index 405a99c..1fdf8f3 100644
--- a/common/rfb/ConnParams.cxx
+++ b/common/rfb/ConnParams.cxx
@@ -28,7 +28,7 @@
 
 ConnParams::ConnParams()
   : majorVersion(0), minorVersion(0),
-    width(0), height(0), useCopyRect(false),
+    useCopyRect(false),
     supportsLocalCursor(false), supportsLocalXCursor(false),
     supportsLocalCursorWithAlpha(false),
     supportsDesktopResize(false), supportsExtendedDesktopSize(false),
@@ -37,7 +37,8 @@
     supportsSetDesktopSize(false), supportsFence(false),
     supportsContinuousUpdates(false),
     compressLevel(2), qualityLevel(-1), fineQualityLevel(-1),
-    subsampling(subsampleUndefined), name_(0),
+    subsampling(subsampleUndefined),
+    width_(0), height_(0), name_(0),
     ledState_(ledUnknown)
 {
   setName("");
@@ -50,6 +51,23 @@
   delete cursor_;
 }
 
+void ConnParams::setDimensions(int width, int height)
+{
+  ScreenSet layout;
+  layout.add_screen(rfb::Screen(0, 0, 0, width, height, 0));
+  setDimensions(width, height, layout);
+}
+
+void ConnParams::setDimensions(int width, int height, const ScreenSet& layout)
+{
+  if (!layout.validate(width, height))
+    throw Exception("Attempted to configure an invalid screen layout");
+
+  width_ = width;
+  height_ = height;
+  screenLayout_ = layout;
+}
+
 void ConnParams::setPF(const PixelFormat& pf)
 {
   pf_ = pf;
diff --git a/common/rfb/ConnParams.h b/common/rfb/ConnParams.h
index b56c940..1640efc 100644
--- a/common/rfb/ConnParams.h
+++ b/common/rfb/ConnParams.h
@@ -62,9 +62,11 @@
       return !beforeVersion(major,minor+1);
     }
 
-    int width;
-    int height;
-    ScreenSet screenLayout;
+    const int width() const { return width_; }
+    const int height() const { return height_; }
+    const ScreenSet& screenLayout() const { return screenLayout_; }
+    void setDimensions(int width, int height);
+    void setDimensions(int width, int height, const ScreenSet& layout);
 
     const PixelFormat& pf() const { return pf_; }
     void setPF(const PixelFormat& pf);
@@ -105,6 +107,10 @@
 
   private:
 
+    int width_;
+    int height_;
+    ScreenSet screenLayout_;
+
     PixelFormat pf_;
     char* name_;
     Cursor* cursor_;
diff --git a/common/rfb/SMsgHandler.cxx b/common/rfb/SMsgHandler.cxx
index c38458c..137734b 100644
--- a/common/rfb/SMsgHandler.cxx
+++ b/common/rfb/SMsgHandler.cxx
@@ -86,8 +86,6 @@
 void SMsgHandler::setDesktopSize(int fb_width, int fb_height,
                                  const ScreenSet& layout)
 {
-  cp.width = fb_width;
-  cp.height = fb_height;
-  cp.screenLayout = layout;
+  cp.setDimensions(fb_width, fb_height, layout);
 }
 
diff --git a/common/rfb/SMsgWriter.cxx b/common/rfb/SMsgWriter.cxx
index 3da9413..96df653 100644
--- a/common/rfb/SMsgWriter.cxx
+++ b/common/rfb/SMsgWriter.cxx
@@ -49,8 +49,8 @@
 
 void SMsgWriter::writeServerInit()
 {
-  os->writeU16(cp->width);
-  os->writeU16(cp->height);
+  os->writeU16(cp->width());
+  os->writeU16(cp->height());
   cp->pf().write(os);
   os->writeString(cp->name());
   endMsg();
@@ -422,15 +422,15 @@
 
   // Send this before SetDesktopSize to make life easier on the clients
   if (needExtendedDesktopSize) {
-    writeExtendedDesktopSizeRect(0, 0, cp->width, cp->height,
-                                 cp->screenLayout);
+    writeExtendedDesktopSizeRect(0, 0, cp->width(), cp->height(),
+                                 cp->screenLayout());
     needExtendedDesktopSize = false;
   }
 
   // Some clients assume this is the last rectangle so don't send anything
   // more after this
   if (needSetDesktopSize) {
-    writeSetDesktopSizeRect(cp->width, cp->height);
+    writeSetDesktopSizeRect(cp->width(), cp->height());
     needSetDesktopSize = false;
   }
 }
diff --git a/common/rfb/VNCSConnectionST.cxx b/common/rfb/VNCSConnectionST.cxx
index f1591f4..4dd0035 100644
--- a/common/rfb/VNCSConnectionST.cxx
+++ b/common/rfb/VNCSConnectionST.cxx
@@ -192,8 +192,9 @@
 {
   try {
     if (!authenticated()) return;
-    if (cp.width && cp.height && (server->pb->width() != cp.width ||
-                                  server->pb->height() != cp.height))
+    if (cp.width() && cp.height() &&
+        (server->pb->width() != cp.width() ||
+         server->pb->height() != cp.height()))
     {
       // We need to clip the next update to the new size, but also add any
       // extra bits if it's bigger.  If we wanted to do this exactly, something
@@ -203,18 +204,17 @@
 
       //updates.intersect(server->pb->getRect());
       //
-      //if (server->pb->width() > cp.width)
-      //  updates.add_changed(Rect(cp.width, 0, server->pb->width(),
+      //if (server->pb->width() > cp.width())
+      //  updates.add_changed(Rect(cp.width(), 0, server->pb->width(),
       //                           server->pb->height()));
-      //if (server->pb->height() > cp.height)
-      //  updates.add_changed(Rect(0, cp.height, cp.width,
+      //if (server->pb->height() > cp.height())
+      //  updates.add_changed(Rect(0, cp.height(), client.width(),
       //                           server->pb->height()));
 
       damagedCursorRegion.assign_intersect(server->pb->getRect());
 
-      cp.width = server->pb->width();
-      cp.height = server->pb->height();
-      cp.screenLayout = server->screenLayout;
+      cp.setDimensions(server->pb->width(), server->pb->height(),
+                       server->screenLayout);
       if (state() == RFBSTATE_NORMAL) {
         // We should only send EDS to client asking for both
         if (!writer()->writeExtendedDesktopSize()) {
@@ -417,9 +417,8 @@
   server->startDesktop();
 
   // - Set the connection parameters appropriately
-  cp.width = server->pb->width();
-  cp.height = server->pb->height();
-  cp.screenLayout = server->screenLayout;
+  cp.setDimensions(server->pb->width(), server->pb->height(),
+                   server->screenLayout);
   cp.setName(server->getName());
   cp.setLEDState(server->ledState);
   
@@ -678,10 +677,11 @@
   SConnection::framebufferUpdateRequest(r, incremental);
 
   // Check that the client isn't sending crappy requests
-  if (!r.enclosed_by(Rect(0, 0, cp.width, cp.height))) {
+  if (!r.enclosed_by(Rect(0, 0, cp.width(), cp.height()))) {
     vlog.error("FramebufferUpdateRequest %dx%d at %d,%d exceeds framebuffer %dx%d",
-               r.width(), r.height(), r.tl.x, r.tl.y, cp.width, cp.height);
-    safeRect = r.intersect(Rect(0, 0, cp.width, cp.height));
+               r.width(), r.height(), r.tl.x, r.tl.y,
+               cp.width(), cp.height());
+    safeRect = r.intersect(Rect(0, 0, cp.width(), cp.height()));
   } else {
     safeRect = r;
   }
@@ -1124,13 +1124,15 @@
   if (!authenticated())
     return;
 
-  cp.screenLayout = server->screenLayout;
+  cp.setDimensions(cp.width(), cp.height(),
+                   server->screenLayout);
 
   if (state() != RFBSTATE_NORMAL)
     return;
 
-  writer()->writeExtendedDesktopSize(reason, 0, cp.width, cp.height,
-                                     cp.screenLayout);
+  writer()->writeExtendedDesktopSize(reason, 0,
+                                     cp.width(), cp.height(),
+                                     cp.screenLayout());
 }
 
 
diff --git a/tests/decperf.cxx b/tests/decperf.cxx
index 9061cb5..24f6604 100644
--- a/tests/decperf.cxx
+++ b/tests/decperf.cxx
@@ -85,7 +85,7 @@
 {
   CConnection::setDesktopSize(w, h);
 
-  setFramebuffer(new rfb::ManagedPixelBuffer(filePF, cp.width, cp.height));
+  setFramebuffer(new rfb::ManagedPixelBuffer(filePF, cp.width(), cp.height()));
 }
 
 void CConn::setPixelFormat(const rfb::PixelFormat& pf)
diff --git a/tests/encperf.cxx b/tests/encperf.cxx
index 4e7038f..a232fb9 100644
--- a/tests/encperf.cxx
+++ b/tests/encperf.cxx
@@ -203,7 +203,7 @@
   CConnection::setDesktopSize(w, h);
 
   pb = new rfb::ManagedPixelBuffer((bool)translate ? fbPF : cp.pf(),
-                                   cp.width, cp.height);
+                                   cp.width(), cp.height());
   setFramebuffer(pb);
 }
 
diff --git a/vncviewer/CConn.cxx b/vncviewer/CConn.cxx
index 69186c5..e87ebcd 100644
--- a/vncviewer/CConn.cxx
+++ b/vncviewer/CConn.cxx
@@ -191,7 +191,7 @@
   strcat(infoText, "\n");
 
   snprintf(scratch, sizeof(scratch),
-           _("Size: %d x %d"), cp.width, cp.height);
+           _("Size: %d x %d"), cp.width(), cp.height());
   strcat(infoText, scratch);
   strcat(infoText, "\n");
 
@@ -324,7 +324,8 @@
 
   serverPF = cp.pf();
 
-  desktop = new DesktopWindow(cp.width, cp.height, cp.name(), serverPF, this);
+  desktop = new DesktopWindow(cp.width(), cp.height(),
+                              cp.name(), serverPF, this);
   fullColourPF = desktop->getPreferredPF();
 
   // Force a switch to the format and encoding we'd like
@@ -478,7 +479,8 @@
       if (cp.supportsContinuousUpdates) {
         vlog.info(_("Enabling continuous updates"));
         continuousUpdates = true;
-        writer()->writeEnableContinuousUpdates(true, 0, 0, cp.width, cp.height);
+        writer()->writeEnableContinuousUpdates(true, 0, 0,
+                                               cp.width(), cp.height());
       }
     }
   } else {
@@ -508,9 +510,10 @@
     return;
 
   if (continuousUpdates)
-    writer()->writeEnableContinuousUpdates(true, 0, 0, cp.width, cp.height);
+    writer()->writeEnableContinuousUpdates(true, 0, 0,
+                                           cp.width(), cp.height());
 
-  desktop->resizeFramebuffer(cp.width, cp.height);
+  desktop->resizeFramebuffer(cp.width(), cp.height());
 }
 
 // autoSelectFormatAndEncoding() chooses the format and encoding appropriate
@@ -647,7 +650,7 @@
 
   if (forceNonincremental || !continuousUpdates) {
     pendingUpdate = true;
-    writer()->writeFramebufferUpdateRequest(Rect(0, 0, cp.width, cp.height),
+    writer()->writeFramebufferUpdateRequest(Rect(0, 0, cp.width(), cp.height()),
                                             !forceNonincremental);
   }
  
diff --git a/vncviewer/DesktopWindow.cxx b/vncviewer/DesktopWindow.cxx
index d070b64..e6d0ca7 100644
--- a/vncviewer/DesktopWindow.cxx
+++ b/vncviewer/DesktopWindow.cxx
@@ -1014,14 +1014,14 @@
 void DesktopWindow::remoteResize(int width, int height)
 {
   ScreenSet layout;
-  ScreenSet::iterator iter;
+  ScreenSet::const_iterator iter;
 
   if (!fullscreen_active() || (width > w()) || (height > h())) {
     // In windowed mode (or the framebuffer is so large that we need
     // to scroll) we just report a single virtual screen that covers
     // the entire framebuffer.
 
-    layout = cc->cp.screenLayout;
+    layout = cc->cp.screenLayout();
 
     // Not sure why we have no screens, but adding a new one should be
     // safe as there is nothing to conflict with...
@@ -1077,8 +1077,8 @@
       sy -= viewport_rect.tl.y;
 
       // Look for perfectly matching existing screen...
-      for (iter = cc->cp.screenLayout.begin();
-           iter != cc->cp.screenLayout.end(); ++iter) {
+      for (iter = cc->cp.screenLayout().begin();
+           iter != cc->cp.screenLayout().end(); ++iter) {
         if ((iter->dimensions.tl.x == sx) &&
             (iter->dimensions.tl.y == sy) &&
             (iter->dimensions.width() == sw) &&
@@ -1087,7 +1087,7 @@
       }
 
       // Found it?
-      if (iter != cc->cp.screenLayout.end()) {
+      if (iter != cc->cp.screenLayout().end()) {
         layout.add_screen(*iter);
         continue;
       }
@@ -1095,13 +1095,13 @@
       // Need to add a new one, which means we need to find an unused id
       while (true) {
         id = rand();
-        for (iter = cc->cp.screenLayout.begin();
-             iter != cc->cp.screenLayout.end(); ++iter) {
+        for (iter = cc->cp.screenLayout().begin();
+             iter != cc->cp.screenLayout().end(); ++iter) {
           if (iter->id == id)
             break;
         }
 
-        if (iter == cc->cp.screenLayout.end())
+        if (iter == cc->cp.screenLayout().end())
           break;
       }
 
@@ -1115,14 +1115,14 @@
   }
 
   // Do we actually change anything?
-  if ((width == cc->cp.width) &&
-      (height == cc->cp.height) &&
-      (layout == cc->cp.screenLayout))
+  if ((width == cc->cp.width()) &&
+      (height == cc->cp.height()) &&
+      (layout == cc->cp.screenLayout()))
     return;
 
   char buffer[2048];
   vlog.debug("Requesting framebuffer resize from %dx%d to %dx%d",
-             cc->cp.width, cc->cp.height, width, height);
+             cc->cp.width(), cc->cp.height(), width, height);
   layout.print(buffer, sizeof(buffer));
   vlog.debug("%s", buffer);