#63 vertical fill bar indicator

graphics/element.lua

@@ -32,6 +32,7 @@ function element.new(args)
     -- get the parent window
     self.p_window = args.window or args.parent.window()
 
+    -- check window
     assert(self.p_window, "graphics.element: no parent window provided")
 
     -- get frame coordinates/size
@@ -48,6 +49,12 @@ function element.new(args)
         protected.frame.h = args.height or h
     end
 
+    -- check frame
+    assert(protected.frame.x >= 1, "graphics.element: frame x not >= 1")
+    assert(protected.frame.y >= 1, "graphics.element: frame y not >= 1")
+    assert(protected.frame.w >= 1, "graphics.element: frame width not >= 1")
+    assert(protected.frame.h >= 1, "graphics.element: frame height not >= 1")
+
     -- create window
     local f = protected.frame
     protected.window = window.create(self.p_window, f.x, f.y, f.w, f.h, true)