Replace busy waiting.

Rendering/OpenGL2/vtkXOpenGLRenderWindow.cxx

@@ -425,16 +425,16 @@ void vtkXOpenGLRenderWindow::SetShowWindow(bool val)
       vtkDebugMacro(" Mapping the xwindow\n");
       XMapWindow(this->DisplayId, this->WindowId);
       XSync(this->DisplayId,False);
-      XWindowAttributes winattr;
-      XGetWindowAttributes(this->DisplayId,
-                           this->WindowId,&winattr);
       // guarantee that the window is mapped before the program continues
       // on to do the OpenGL rendering.
-      while (winattr.map_state == IsUnmapped)
+      while(true)
       {
-        XGetWindowAttributes(this->DisplayId,
-                             this->WindowId,&winattr);
-        XSync(this->DisplayId,False);
+        XEvent e;
+        XNextEvent(this->DisplayId, &e);
+        if (e.type == MapNotify)
+        {
+          break;
+        }
       }
       this->Mapped = 1;
     }
@@ -443,16 +443,14 @@ void vtkXOpenGLRenderWindow::SetShowWindow(bool val)
       vtkDebugMacro(" UnMapping the xwindow\n");
       XUnmapWindow(this->DisplayId, this->WindowId);
       XSync(this->DisplayId,False);
-      XWindowAttributes winattr;
-      XGetWindowAttributes(this->DisplayId,
-                           this->WindowId,&winattr);
-      // guarantee that the window is mapped before the program continues
-      // on to do the OpenGL rendering.
-      while (winattr.map_state != IsUnmapped)
+      while(true)
       {
-        XGetWindowAttributes(this->DisplayId,
-                             this->WindowId,&winattr);
-        XSync(this->DisplayId,False);
+        XEvent e;
+        XNextEvent(this->DisplayId, &e);
+        if (e.type == UnmapNotify)
+        {
+          break;
+        }
       }
       this->Mapped = 0;
     }
@@ -1004,23 +1002,15 @@ void vtkXOpenGLRenderWindow::SetSize(int width,int height)
                     static_cast<unsigned int>(width),
                     static_cast<unsigned int>(height));
       // this is an async call so we wait until we
-      // know it has been resized. To avoid infinite
-      // loops we put in a count limit just to be safe
-      XWindowAttributes attribs;
-      int count = 20000;
-      do
+      // know it has been resized.
+      while(true)
       {
-        XSync(this->DisplayId,False);
-
-        //  Find the current window size
-        XGetWindowAttributes(this->DisplayId,
-                             this->WindowId, &attribs);
-        count--;
-      }
-      while (count && (attribs.width != width || attribs.height != height));
-      if (!count)
-      {
-        vtkWarningMacro("warning window did not resize in the allotted time");
+        XEvent e;
+        XNextEvent(this->DisplayId, &e);
+        if (e.type == ConfigureNotify)
+        {
+          break;
+        }
       }
     }