diff --git a/NodeGraphQt/base/commands.py b/NodeGraphQt/base/commands.py
index 261606a9..184245b6 100644
--- a/NodeGraphQt/base/commands.py
+++ b/NodeGraphQt/base/commands.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python
 from Qt import QtWidgets
 
-from NodeGraphQt.constants import IN_PORT, OUT_PORT
+from NodeGraphQt.constants import PortTypeEnum
 
 
 class PropertyChangedCmd(QtWidgets.QUndoCommand):
@@ -158,7 +158,7 @@ class NodeInputConnectedCmd(QtWidgets.QUndoCommand):
 
     def __init__(self, src_port, trg_port):
         QtWidgets.QUndoCommand.__init__(self)
-        if src_port.type_() == IN_PORT:
+        if src_port.type_() == PortTypeEnum.IN.value:
             self.source = src_port
             self.target = trg_port
         else:
@@ -185,7 +185,7 @@ class NodeInputDisconnectedCmd(QtWidgets.QUndoCommand):
 
     def __init__(self, src_port, trg_port):
         QtWidgets.QUndoCommand.__init__(self)
-        if src_port.type_() == IN_PORT:
+        if src_port.type_() == PortTypeEnum.IN.value:
             self.source = src_port
             self.target = trg_port
         else:
@@ -355,9 +355,9 @@ def set_visible(self, visible):
         self.port.view.setVisible(visible)
         node_view = self.port.node().view
         text_item = None
-        if self.port.type_() == IN_PORT:
+        if self.port.type_() == PortTypeEnum.IN.value:
             text_item = node_view.get_input_text_item(self.port.view)
-        elif self.port.type_() == OUT_PORT:
+        elif self.port.type_() == PortTypeEnum.OUT.value:
             text_item = node_view.get_output_text_item(self.port.view)
         if text_item:
             text_item.setVisible(visible)
diff --git a/NodeGraphQt/base/graph.py b/NodeGraphQt/base/graph.py
index 2654ebb0..caa27ad6 100644
--- a/NodeGraphQt/base/graph.py
+++ b/NodeGraphQt/base/graph.py
@@ -5,7 +5,7 @@
 import os
 import re
 
-from Qt import QtCore, QtWidgets, QtGui
+from Qt import QtCore, QtWidgets
 
 from NodeGraphQt.base.commands import (NodeAddedCmd,
                                        NodeRemovedCmd,
@@ -18,10 +18,10 @@
 from NodeGraphQt.base.port import Port
 from NodeGraphQt.constants import (
     NODE_LAYOUT_DIRECTION, NODE_LAYOUT_HORIZONTAL, NODE_LAYOUT_VERTICAL,
-    PIPE_LAYOUT_CURVED, PIPE_LAYOUT_STRAIGHT, PIPE_LAYOUT_ANGLE,
+    PipeLayoutEnum,
     URI_SCHEME, URN_SCHEME,
-    IN_PORT, OUT_PORT,
-    VIEWER_GRID_LINES
+    PortTypeEnum,
+    ViewerEnum
 )
 from NodeGraphQt.nodes.backdrop_node import BackdropNode
 from NodeGraphQt.nodes.base_node import BaseNode
@@ -369,7 +369,8 @@ def _on_connection_changed(self, disconnected, connected):
             return
 
         label = 'connect node(s)' if connected else 'disconnect node(s)'
-        ptypes = {IN_PORT: 'inputs', OUT_PORT: 'outputs'}
+        ptypes = {PortTypeEnum.IN.value: 'inputs',
+                  PortTypeEnum.OUT.value: 'outputs'}
 
         self._undo_stack.beginMacro(label)
         for p1_view, p2_view in disconnected:
@@ -396,7 +397,8 @@ def _on_connection_sliced(self, ports):
         """
         if not ports:
             return
-        ptypes = {IN_PORT: 'inputs', OUT_PORT: 'outputs'}
+        ptypes = {PortTypeEnum.IN.value: 'inputs',
+                  PortTypeEnum.OUT.value: 'outputs'}
         self._undo_stack.beginMacro('slice connections')
         for p1_view, p2_view in ports:
             node1 = self._model.nodes[p1_view.node.id]
@@ -553,7 +555,7 @@ def set_grid_color(self, r, g, b):
         self.scene().grid_color = (r, g, b)
         self._viewer.force_update()
 
-    def set_grid_mode(self, mode=VIEWER_GRID_LINES):
+    def set_grid_mode(self, mode=None):
         """
         Set node graph grid mode.
 
@@ -562,13 +564,20 @@ def set_grid_mode(self, mode=VIEWER_GRID_LINES):
 
             Node graph background types:
 
-            * :attr:`NodeGraphQt.constants.VIEWER_GRID_NONE`
-            * :attr:`NodeGraphQt.constants.VIEWER_GRID_DOTS`
-            * :attr:`NodeGraphQt.constants.VIEWER_GRID_LINES`
+            * :attr:`NodeGraphQt.constants.ViewerEnum.GRID_DISPLAY_NONE.value`
+            * :attr:`NodeGraphQt.constants.ViewerEnum.GRID_DISPLAY_DOTS.value`
+            * :attr:`NodeGraphQt.constants.ViewerEnum.GRID_DISPLAY_LINES.value`
 
         Args:
             mode (int): background style.
         """
+        display_types = [
+            ViewerEnum.GRID_DISPLAY_NONE.value,
+            ViewerEnum.GRID_DISPLAY_DOTS.value,
+            ViewerEnum.GRID_DISPLAY_LINES.value
+        ]
+        if mode not in display_types:
+            mode = ViewerEnum.GRID_DISPLAY_LINES.value
         self.scene().grid_mode = mode
         self._viewer.force_update()
 
@@ -752,7 +761,7 @@ def set_pipe_collision(self, mode=True):
         self._model.pipe_collision = mode
         self._viewer.pipe_collision = mode
 
-    def set_pipe_style(self, style=PIPE_LAYOUT_CURVED):
+    def set_pipe_style(self, style=PipeLayoutEnum.CURVED.value):
         """
         Set node graph pipes to be drawn as straight, curved or angled.
 
@@ -764,17 +773,17 @@ def set_pipe_style(self, style=PIPE_LAYOUT_CURVED):
 
             Pipe Layout Styles:
 
-            * :attr:`NodeGraphQt.constants.PIPE_LAYOUT_CURVED`
-            * :attr:`NodeGraphQt.constants.PIPE_LAYOUT_STRAIGHT`
-            * :attr:`NodeGraphQt.constants.PIPE_LAYOUT_ANGLE`
+            * :attr:`NodeGraphQt.constants.PipeLayoutEnum.CURVED.value`
+            * :attr:`NodeGraphQt.constants.PipeLayoutEnum.STRAIGHT.value`
+            * :attr:`NodeGraphQt.constants.PipeLayoutEnum.ANGLE.value`
 
         Args:
             style (int): pipe layout style.
         """
-        pipe_max = max([PIPE_LAYOUT_CURVED,
-                        PIPE_LAYOUT_STRAIGHT,
-                        PIPE_LAYOUT_ANGLE])
-        style = style if 0 <= style <= pipe_max else PIPE_LAYOUT_CURVED
+        pipe_max = max([PipeLayoutEnum.CURVED.value,
+                        PipeLayoutEnum.STRAIGHT.value,
+                        PipeLayoutEnum.ANGLE.value])
+        style = style if 0 <= style <= pipe_max else PipeLayoutEnum.CURVED.value
         self._viewer.set_pipe_layout(style)
 
     def fit_to_selection(self):
@@ -1246,16 +1255,20 @@ def _serialize(self, nodes):
             for pname, conn_data in inputs.items():
                 for conn_id, prt_names in conn_data.items():
                     for conn_prt in prt_names:
-                        pipe = {IN_PORT: [n_id, pname],
-                                OUT_PORT: [conn_id, conn_prt]}
+                        pipe = {
+                            PortTypeEnum.IN.value: [n_id, pname],
+                            PortTypeEnum.OUT.value: [conn_id, conn_prt]
+                        }
                         if pipe not in serial_data['connections']:
                             serial_data['connections'].append(pipe)
 
             for pname, conn_data in outputs.items():
                 for conn_id, prt_names in conn_data.items():
                     for conn_prt in prt_names:
-                        pipe = {OUT_PORT: [n_id, pname],
-                                IN_PORT: [conn_id, conn_prt]}
+                        pipe = {
+                            PortTypeEnum.OUT.value: [n_id, pname],
+                            PortTypeEnum.IN.value: [conn_id, conn_prt]
+                        }
                         if pipe not in serial_data['connections']:
                             serial_data['connections'].append(pipe)
 
@@ -2362,8 +2375,10 @@ def get_node_by_port(self, port):
         Returns:
             PortInputNode or PortOutputNode: port node object.
         """
-        func_type = {IN_PORT: self.get_input_port_nodes,
-                     OUT_PORT: self.get_output_port_nodes}
+        func_type = {
+            PortTypeEnum.IN.value: self.get_input_port_nodes,
+            PortTypeEnum.OUT.value: self.get_output_port_nodes
+        }
         for n in func_type.get(port.type_(), []):
             if port == n.parent_port:
                 return n
diff --git a/NodeGraphQt/base/graph_actions.py b/NodeGraphQt/base/graph_actions.py
index 69e2c226..b77fe3d6 100644
--- a/NodeGraphQt/base/graph_actions.py
+++ b/NodeGraphQt/base/graph_actions.py
@@ -256,48 +256,48 @@ def _curved_pipe(graph):
     """
     Set node graph pipes layout as curved.
     """
-    from NodeGraphQt.constants import PIPE_LAYOUT_CURVED
-    graph.set_pipe_style(PIPE_LAYOUT_CURVED)
+    from NodeGraphQt.constants import PipeLayoutEnum
+    graph.set_pipe_style(PipeLayoutEnum.CURVED.value)
 
 
 def _straight_pipe(graph):
     """
     Set node graph pipes layout as straight.
     """
-    from NodeGraphQt.constants import PIPE_LAYOUT_STRAIGHT
-    graph.set_pipe_style(PIPE_LAYOUT_STRAIGHT)
+    from NodeGraphQt.constants import PipeLayoutEnum
+    graph.set_pipe_style(PipeLayoutEnum.STRAIGHT.value)
 
 
 def _angle_pipe(graph):
     """
     Set node graph pipes layout as angled.
     """
-    from NodeGraphQt.constants import PIPE_LAYOUT_ANGLE
-    graph.set_pipe_style(PIPE_LAYOUT_ANGLE)
+    from NodeGraphQt.constants import PipeLayoutEnum
+    graph.set_pipe_style(PipeLayoutEnum.ANGLE.value)
 
 
 def _bg_grid_none(graph):
     """
     Turn off the background patterns.
     """
-    from NodeGraphQt.constants import VIEWER_GRID_NONE
-    graph.set_grid_mode(VIEWER_GRID_NONE)
+    from NodeGraphQt.constants import ViewerEnum
+    graph.set_grid_mode(ViewerEnum.GRID_DISPLAY_NONE.value)
 
 
 def _bg_grid_dots(graph):
     """
     Set background node graph background with grid dots.
     """
-    from NodeGraphQt.constants import VIEWER_GRID_DOTS
-    graph.set_grid_mode(VIEWER_GRID_DOTS)
+    from NodeGraphQt.constants import ViewerEnum
+    graph.set_grid_mode(ViewerEnum.GRID_DISPLAY_DOTS.value)
 
 
 def _bg_grid_lines(graph):
     """
     Set background node graph background with grid lines.
     """
-    from NodeGraphQt.constants import VIEWER_GRID_LINES
-    graph.set_grid_mode(VIEWER_GRID_LINES)
+    from NodeGraphQt.constants import ViewerEnum
+    graph.set_grid_mode(ViewerEnum.GRID_DISPLAY_LINES.value)
 
 
 def _layout_graph_down(graph):
diff --git a/NodeGraphQt/base/port.py b/NodeGraphQt/base/port.py
index e4b7bce2..15896b5a 100644
--- a/NodeGraphQt/base/port.py
+++ b/NodeGraphQt/base/port.py
@@ -9,7 +9,7 @@
     NodeInputDisconnectedCmd
 )
 from NodeGraphQt.base.model import PortModel
-from NodeGraphQt.constants import IN_PORT, OUT_PORT
+from NodeGraphQt.constants import PortTypeEnum
 from NodeGraphQt.errors import PortError
 
 
@@ -196,9 +196,9 @@ def connected_ports(self):
         for node_id, port_names in self.model.connected_ports.items():
             for port_name in port_names:
                 node = graph.get_node_by_id(node_id)
-                if self.type_() == IN_PORT:
+                if self.type_() == PortTypeEnum.IN.value:
                     ports.append(node.outputs()[port_name])
-                elif self.type_() == OUT_PORT:
+                elif self.type_() == PortTypeEnum.OUT.value:
                     ports.append(node.inputs()[port_name])
         return ports
 
@@ -284,7 +284,8 @@ def connect_to(self, port=None, push_undo=True):
 
         # emit "port_connected" signal from the parent graph.
         ports = {p.type_(): p for p in [self, port]}
-        graph.port_connected.emit(ports[IN_PORT], ports[OUT_PORT])
+        graph.port_connected.emit(ports[PortTypeEnum.IN.value],
+                                  ports[PortTypeEnum.OUT.value])
 
     def disconnect_from(self, port=None, push_undo=True):
         """
@@ -315,7 +316,8 @@ def disconnect_from(self, port=None, push_undo=True):
 
         # emit "port_disconnected" signal from the parent graph.
         ports = {p.type_(): p for p in [self, port]}
-        graph.port_disconnected.emit(ports[IN_PORT], ports[OUT_PORT])
+        graph.port_disconnected.emit(ports[PortTypeEnum.IN.value],
+                                     ports[PortTypeEnum.OUT.value])
 
     def clear_connections(self, push_undo=True):
         """
diff --git a/NodeGraphQt/constants.py b/NodeGraphQt/constants.py
index 1159f720..ca70c7be 100644
--- a/NodeGraphQt/constants.py
+++ b/NodeGraphQt/constants.py
@@ -3,110 +3,16 @@
 import os
 
 from Qt import QtWidgets
+from enum import Enum
 
-from .pkg_info import __version__
+from .pkg_info import __version__ as _v
 
 __doc__ = """
-The ``NodeGraphQt.constants`` namespace contains variables used throughout 
-the whole ``NodeGraphQt`` library.
+| The :py:mod:`NodeGraphQt.constants` namespace contains variables and enums 
+ used throughout the NodeGraphQt library.
 """
 
-#: Current version of the NodeGraphQt framework.
-VERSION = __version__
-
-# === PIPE ===
-
-PIPE_WIDTH = 1.2
-PIPE_STYLE_DEFAULT = 0
-PIPE_STYLE_DASHED = 1
-PIPE_STYLE_DOTTED = 2
-PIPE_DEFAULT_COLOR = (175, 95, 30, 255)
-PIPE_DISABLED_COLOR = (190, 20, 20, 255)
-PIPE_ACTIVE_COLOR = (70, 255, 220, 255)
-PIPE_HIGHLIGHT_COLOR = (232, 184, 13, 255)
-PIPE_SLICER_COLOR = (255, 50, 75)
-#: Style to draw the connection pipes as straight lines.
-PIPE_LAYOUT_STRAIGHT = 0
-#: Style to draw the connection pipes as curved lines.
-PIPE_LAYOUT_CURVED = 1
-#: Style to draw the connection pipes as angled lines.
-PIPE_LAYOUT_ANGLE = 2
-
-# === PORT ===
-
-#: Connection type for input ports.
-IN_PORT = 'in'
-#: Connection type for output ports.
-OUT_PORT = 'out'
-
-PORT_DEFAULT_SIZE = 22.0
-PORT_DEFAULT_COLOR = (49, 115, 100, 255)
-PORT_DEFAULT_BORDER_COLOR = (29, 202, 151, 255)
-PORT_ACTIVE_COLOR = (14, 45, 59, 255)
-PORT_ACTIVE_BORDER_COLOR = (107, 166, 193, 255)
-PORT_HOVER_COLOR = (17, 43, 82, 255)
-PORT_HOVER_BORDER_COLOR = (136, 255, 35, 255)
-PORT_FALLOFF = 15.0
-
-# === NODE ===
-
-NODE_WIDTH = 160
-NODE_HEIGHT = 60
-NODE_ICON_SIZE = 18
-NODE_SEL_COLOR = (255, 255, 255, 30)
-NODE_SEL_BORDER_COLOR = (254, 207, 42, 255)
-
-# === NODE PROPERTY ===
-
-#: Property type will hidden in the properties bin (default).
-NODE_PROP = 0
-#: Property type represented with a QLabel widget in the properties bin.
-NODE_PROP_QLABEL = 2
-#: Property type represented with a QLineEdit widget in the properties bin.
-NODE_PROP_QLINEEDIT = 3
-#: Property type represented with a QTextEdit widget in the properties bin.
-NODE_PROP_QTEXTEDIT = 4
-#: Property type represented with a QComboBox widget in the properties bin.
-NODE_PROP_QCOMBO = 5
-#: Property type represented with a QCheckBox widget in the properties bin.
-NODE_PROP_QCHECKBOX = 6
-#: Property type represented with a QSpinBox widget in the properties bin.
-NODE_PROP_QSPINBOX = 7
-#: Property type represented with a ColorPicker widget in the properties bin.
-NODE_PROP_COLORPICKER = 8
-#: Property type represented with a Slider widget in the properties bin.
-NODE_PROP_SLIDER = 9
-#: Property type represented with a file selector widget in the properties bin.
-NODE_PROP_FILE = 10
-#: Property type represented with a file save widget in the properties bin.
-NODE_PROP_FILE_SAVE = 11
-#: Property type represented with a vector2 widget in the properties bin.
-NODE_PROP_VECTOR2 = 12
-#: Property type represented with vector3 widget in the properties bin.
-NODE_PROP_VECTOR3 = 13
-#: Property type represented with vector4 widget in the properties bin.
-NODE_PROP_VECTOR4 = 14
-#: Property type represented with float widget in the properties bin.
-NODE_PROP_FLOAT = 15
-#: Property type represented with int widget in the properties bin.
-NODE_PROP_INT = 16
-#: Property type represented with button widget in the properties bin.
-NODE_PROP_BUTTON = 17
-
-# === NODE VIEWER ===
-
-#: Style to render the node graph background with nothing.
-VIEWER_GRID_NONE = 0
-#: Style to render the node graph background with dots.
-VIEWER_GRID_DOTS = 1
-#: Style to render the node graph background with grid lines.
-VIEWER_GRID_LINES = 2
-
-VIEWER_NAV_BG_COLOR = (25, 25, 25)
-VIEWER_NAV_ITEM_COLOR = (35, 35, 35)
-VIEWER_BG_COLOR = (35, 35, 35)
-VIEWER_GRID_COLOR = (45, 45, 45)
-VIEWER_GRID_SIZE = 50
+# ================================== PRIVATE ===================================
 
 URI_SCHEME = 'nodegraphqt://'
 URN_SCHEME = 'nodegraphqt::'
@@ -142,3 +48,194 @@
 #: Variable for setting the node layout direction.
 # NODE_LAYOUT_DIRECTION = NODE_LAYOUT_VERTICAL
 NODE_LAYOUT_DIRECTION = NODE_LAYOUT_HORIZONTAL
+
+# =================================== GLOBAL ===================================
+
+
+class VersionEnum(Enum):
+    """
+    Current framework version.
+    :py:mod:`NodeGraphQt.constants.VersionEnum`
+    """
+    #:
+    VERSION = _v
+    #:
+    MAJOR = int(_v.split('.')[0])
+    #:
+    MINOR = int(_v.split('.')[1])
+    #:
+    PATCH = int(_v.split('.')[2])
+
+# =================================== VIEWER ===================================
+
+
+class ViewerEnum(Enum):
+    """
+    Node graph viewer styling layout:
+    :py:mod:`NodeGraphQt.constants.ViewerEnum`
+    """
+    #: default background color for the node graph.
+    BACKGROUND_COLOR = (35, 35, 35)
+    #: style node graph background with no grid or dots.
+    GRID_DISPLAY_NONE = 0
+    #: style node graph background with dots.
+    GRID_DISPLAY_DOTS = 1
+    #: style node graph background with grid lines.
+    GRID_DISPLAY_LINES = 2
+    #: grid size when styled with grid lines.
+    GRID_SIZE = 50
+    #: grid line color.
+    GRID_COLOR = (45, 45, 45)
+
+
+class ViewerNavEnum(Enum):
+    """
+    Node graph viewer navigation styling layout:
+    :py:mod:`NodeGraphQt.constants.ViewerNavEnum`
+    """
+    #: default background color.
+    BACKGROUND_COLOR = (25, 25, 25)
+    #: default item color.
+    ITEM_COLOR = (35, 35, 35)
+
+# ==================================== NODE ====================================
+
+
+class NodeEnum(Enum):
+    """
+    Node styling layout:
+    :py:mod:`NodeGraphQt.constants.NodeEnum`
+    """
+    #: default node width.
+    WIDTH = 160
+    #: default node height.
+    HEIGHT = 60
+    #: default node icon size (WxH).
+    ICON_SIZE = 18
+    #: default node overlay color when selected.
+    SELECTED_COLOR = (255, 255, 255, 30)
+    #: default node border color when selected.
+    SELECTED_BORDER_COLOR = (254, 207, 42, 255)
+
+# ==================================== PORT ====================================
+
+
+class PortEnum(Enum):
+    """
+    Port styling layout:
+    :py:mod:`NodeGraphQt.constants.PortEnum`
+    """
+    #: default port size.
+    SIZE = 22.0
+    #: default port color. (r, g, b, a)
+    COLOR = (49, 115, 100, 255)
+    #: default port border color.
+    BORDER_COLOR = (29, 202, 151, 255)
+    #: port color when selected.
+    ACTIVE_COLOR = (14, 45, 59, 255)
+    #: port border color when selected.
+    ACTIVE_BORDER_COLOR = (107, 166, 193, 255)
+    #: port color on mouse over.
+    HOVER_COLOR = (17, 43, 82, 255)
+    #: port border color on mouse over.
+    HOVER_BORDER_COLOR = (136, 255, 35, 255)
+    #: threshold for selecting a port.
+    CLICK_FALLOFF = 15.0
+
+
+class PortTypeEnum(Enum):
+    """
+    Port connection types:
+    :py:mod:`NodeGraphQt.constants.PortTypeEnum`
+    """
+    #: Connection type for input ports.
+    IN = 'in'
+    #: Connection type for output ports.
+    OUT = 'out'
+
+# ==================================== PIPE ====================================
+
+
+class PipeEnum(Enum):
+    """
+    Pipe styling layout:
+    :py:mod:`NodeGraphQt.constants.PipeEnum`
+    """
+    #: default width.
+    WIDTH = 1.2
+    #: default color.
+    COLOR = (175, 95, 30, 255)
+    #: pipe color to a node when it's disabled.
+    DISABLED_COLOR = (190, 20, 20, 255)
+    #: pipe color when selected or mouse over.
+    ACTIVE_COLOR = (70, 255, 220, 255)
+    #: pipe color to a node when it's selected.
+    HIGHLIGHT_COLOR = (232, 184, 13, 255)
+    #: draw connection as a line.
+    DRAW_TYPE_DEFAULT = 0
+    #: draw connection as dashed lines.
+    DRAW_TYPE_DASHED = 1
+    #: draw connection as a dotted line.
+    DRAW_TYPE_DOTTED = 2
+
+
+class PipeSlicerEnum(Enum):
+    """
+    Slicer Pipe styling layout:
+    :py:mod:`NodeGraphQt.constants.PipeSlicerEnum`
+    """
+    #: default width.
+    WIDTH = 1.5
+    #: default color.
+    COLOR = (255, 50, 75)
+
+
+class PipeLayoutEnum(Enum):
+    """
+    Pipe connection drawing layout:
+    :py:mod:`NodeGraphQt.constants.PipeLayoutEnum`
+    """
+    #: draw straight lines for pipe connections.
+    STRAIGHT = 0
+    #: draw curved lines for pipe connections.
+    CURVED = 1
+    #: draw angled lines for pipe connections.
+    ANGLE = 2
+
+
+# === PROPERTY BIN WIDGET ===
+
+#: Property type will hidden in the properties bin (default).
+NODE_PROP = 0
+#: Property type represented with a QLabel widget in the properties bin.
+NODE_PROP_QLABEL = 2
+#: Property type represented with a QLineEdit widget in the properties bin.
+NODE_PROP_QLINEEDIT = 3
+#: Property type represented with a QTextEdit widget in the properties bin.
+NODE_PROP_QTEXTEDIT = 4
+#: Property type represented with a QComboBox widget in the properties bin.
+NODE_PROP_QCOMBO = 5
+#: Property type represented with a QCheckBox widget in the properties bin.
+NODE_PROP_QCHECKBOX = 6
+#: Property type represented with a QSpinBox widget in the properties bin.
+NODE_PROP_QSPINBOX = 7
+#: Property type represented with a ColorPicker widget in the properties bin.
+NODE_PROP_COLORPICKER = 8
+#: Property type represented with a Slider widget in the properties bin.
+NODE_PROP_SLIDER = 9
+#: Property type represented with a file selector widget in the properties bin.
+NODE_PROP_FILE = 10
+#: Property type represented with a file save widget in the properties bin.
+NODE_PROP_FILE_SAVE = 11
+#: Property type represented with a vector2 widget in the properties bin.
+NODE_PROP_VECTOR2 = 12
+#: Property type represented with vector3 widget in the properties bin.
+NODE_PROP_VECTOR3 = 13
+#: Property type represented with vector4 widget in the properties bin.
+NODE_PROP_VECTOR4 = 14
+#: Property type represented with float widget in the properties bin.
+NODE_PROP_FLOAT = 15
+#: Property type represented with int widget in the properties bin.
+NODE_PROP_INT = 16
+#: Property type represented with button widget in the properties bin.
+NODE_PROP_BUTTON = 17
diff --git a/NodeGraphQt/nodes/base_node.py b/NodeGraphQt/nodes/base_node.py
index cef3d184..8ad5a84e 100644
--- a/NodeGraphQt/nodes/base_node.py
+++ b/NodeGraphQt/nodes/base_node.py
@@ -7,7 +7,7 @@
                                    NODE_PROP_QLINEEDIT,
                                    NODE_PROP_QCOMBO,
                                    NODE_PROP_QCHECKBOX,
-                                   IN_PORT, OUT_PORT,
+                                   PortTypeEnum,
                                    NODE_LAYOUT_VERTICAL,
                                    NODE_LAYOUT_HORIZONTAL)
 from NodeGraphQt.errors import (PortError,
@@ -261,7 +261,7 @@ def add_input(self, name='input', multi_input=False, display_name=True,
             view.border_color = [min([255, max([0, i + 80])]) for i in color]
 
         port = Port(self, view)
-        port.model.type_ = IN_PORT
+        port.model.type_ = PortTypeEnum.IN.value
         port.model.name = name
         port.model.display_name = display_name
         port.model.multi_connection = multi_input
@@ -303,7 +303,7 @@ def add_output(self, name='output', multi_output=True, display_name=True,
             view.color = color
             view.border_color = [min([255, max([0, i + 80])]) for i in color]
         port = Port(self, view)
-        port.model.type_ = OUT_PORT
+        port.model.type_ = PortTypeEnum.OUT.value
         port.model.name = name
         port.model.display_name = display_name
         port.model.multi_connection = multi_output
@@ -632,4 +632,3 @@ def on_input_disconnected(self, in_port, out_port):
             out_port (NodeGraphQt.Port): output port that was disconnected.
         """
         return
-
diff --git a/NodeGraphQt/qgraphics/node_abstract.py b/NodeGraphQt/qgraphics/node_abstract.py
index 2241f4bd..ca996da3 100644
--- a/NodeGraphQt/qgraphics/node_abstract.py
+++ b/NodeGraphQt/qgraphics/node_abstract.py
@@ -1,10 +1,7 @@
 #!/usr/bin/python
 from Qt import QtCore, QtWidgets
 
-from NodeGraphQt.constants import (Z_VAL_NODE,
-                                   NODE_WIDTH,
-                                   NODE_HEIGHT,
-                                   ITEM_CACHE_MODE)
+from NodeGraphQt.constants import Z_VAL_NODE, NodeEnum, ITEM_CACHE_MODE
 
 
 class AbstractNodeItem(QtWidgets.QGraphicsItem):
@@ -28,8 +25,8 @@ def __init__(self, name='node', parent=None):
             'disabled': False,
             'visible': False,
         }
-        self._width = NODE_WIDTH
-        self._height = NODE_HEIGHT
+        self._width = NodeEnum.WIDTH.value
+        self._height = NodeEnum.HEIGHT.value
 
     def __repr__(self):
         return '{}.{}(\'{}\')'.format(
diff --git a/NodeGraphQt/qgraphics/node_backdrop.py b/NodeGraphQt/qgraphics/node_backdrop.py
index 7d3f2d8e..4e806653 100644
--- a/NodeGraphQt/qgraphics/node_backdrop.py
+++ b/NodeGraphQt/qgraphics/node_backdrop.py
@@ -1,9 +1,7 @@
 #!/usr/bin/python
 from Qt import QtGui, QtCore, QtWidgets
 
-from NodeGraphQt.constants import (Z_VAL_PIPE,
-                                   NODE_SEL_COLOR,
-                                   NODE_SEL_BORDER_COLOR)
+from NodeGraphQt.constants import Z_VAL_PIPE, NodeEnum
 from NodeGraphQt.qgraphics.node_abstract import AbstractNodeItem
 from NodeGraphQt.qgraphics.pipe import PipeItem
 from NodeGraphQt.qgraphics.port import PortItem
@@ -88,7 +86,7 @@ def paint(self, painter, option, widget):
 
         item = self.parentItem()
         if item and item.selected:
-            color = QtGui.QColor(*NODE_SEL_BORDER_COLOR)
+            color = QtGui.QColor(*NodeEnum.SELECTED_BORDER_COLOR.value)
         else:
             color = QtGui.QColor(*item.color)
             color = color.darker(110)
@@ -221,7 +219,7 @@ def paint(self, painter, option, widget):
                              self.backdrop_text)
 
         if self.selected:
-            sel_color = [x for x in NODE_SEL_COLOR]
+            sel_color = [x for x in NodeEnum.SELECTED_COLOR.value]
             sel_color[-1] = 15
             painter.setBrush(QtGui.QColor(*sel_color))
             painter.setPen(QtCore.Qt.NoPen)
@@ -234,9 +232,9 @@ def paint(self, painter, option, widget):
 
         border = 0.8
         border_color = self.color
-        if self.selected and NODE_SEL_BORDER_COLOR:
+        if self.selected and NodeEnum.SELECTED_BORDER_COLOR.value:
             border = 1.0
-            border_color = NODE_SEL_BORDER_COLOR
+            border_color = NodeEnum.SELECTED_BORDER_COLOR.value
         painter.setBrush(QtCore.Qt.NoBrush)
         painter.setPen(QtGui.QPen(QtGui.QColor(*border_color), border))
         painter.drawRoundedRect(rect, radius, radius)
diff --git a/NodeGraphQt/qgraphics/node_base.py b/NodeGraphQt/qgraphics/node_base.py
index 41ddf02e..9bb8dc4c 100644
--- a/NodeGraphQt/qgraphics/node_base.py
+++ b/NodeGraphQt/qgraphics/node_base.py
@@ -3,12 +3,14 @@
 
 from Qt import QtGui, QtCore, QtWidgets
 
-from NodeGraphQt.constants import (IN_PORT, OUT_PORT,
-                                   NODE_WIDTH, NODE_HEIGHT,
-                                   NODE_ICON_SIZE, ICON_NODE_BASE,
-                                   NODE_SEL_COLOR, NODE_SEL_BORDER_COLOR,
-                                   PORT_FALLOFF, Z_VAL_NODE,
-                                   ITEM_CACHE_MODE)
+from NodeGraphQt.constants import (
+    ITEM_CACHE_MODE,
+    ICON_NODE_BASE,
+    NodeEnum,
+    PortEnum,
+    PortTypeEnum,
+    Z_VAL_NODE
+)
 from NodeGraphQt.errors import NodeWidgetError
 from NodeGraphQt.qgraphics.node_abstract import AbstractNodeItem
 from NodeGraphQt.qgraphics.node_overlay_disabled import XDisabledItem
@@ -28,9 +30,10 @@ class NodeItem(AbstractNodeItem):
     def __init__(self, name='node', parent=None):
         super(NodeItem, self).__init__(name, parent)
         pixmap = QtGui.QPixmap(ICON_NODE_BASE)
-        if pixmap.size().height() > NODE_ICON_SIZE:
+        if pixmap.size().height() > NodeEnum.ICON_SIZE.value:
             pixmap = pixmap.scaledToHeight(
-                NODE_ICON_SIZE, QtCore.Qt.SmoothTransformation
+                NodeEnum.ICON_SIZE.value,
+                QtCore.Qt.SmoothTransformation
             )
         self._properties['icon'] = ICON_NODE_BASE
         self._icon_item = QtWidgets.QGraphicsPixmapItem(pixmap, self)
@@ -73,7 +76,7 @@ def paint(self, painter, option, widget):
 
         # light overlay on background when selected.
         if self.selected:
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
             painter.drawRoundedRect(rect, radius, radius)
 
         # node name background.
@@ -84,7 +87,7 @@ def paint(self, painter, option, widget):
                                   rect.width() - padding[0] - margin,
                                   text_rect.height() - (padding[1] * 2))
         if self.selected:
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             painter.setBrush(QtGui.QColor(0, 0, 0, 80))
         painter.drawRoundedRect(text_rect, 3.0, 3.0)
@@ -92,7 +95,9 @@ def paint(self, painter, option, widget):
         # node border
         if self.selected:
             border_width = 1.2
-            border_color = QtGui.QColor(*NODE_SEL_BORDER_COLOR)
+            border_color = QtGui.QColor(
+                *NodeEnum.SELECTED_BORDER_COLOR.value
+            )
         else:
             border_width = 0.8
             border_color = QtGui.QColor(*self.border_color)
@@ -202,10 +207,10 @@ def _set_base_size(self, add_w=0.0, add_h=0.0):
             add_h (float): add additional height.
         """
         self._width, self._height = self.calc_size(add_w, add_h)
-        if self._width < NODE_WIDTH:
-            self._width = NODE_WIDTH
-        if self._height < NODE_HEIGHT:
-            self._height = NODE_HEIGHT
+        if self._width < NodeEnum.WIDTH.value:
+            self._width = NodeEnum.WIDTH.value
+        if self._height < NodeEnum.HEIGHT.value:
+            self._height = NodeEnum.HEIGHT.value
 
     def _set_text_color(self, color):
         """
@@ -384,7 +389,7 @@ def align_ports(self, v_offset=0.0):
             v_offset (float): port vertical offset.
         """
         width = self._width
-        txt_offset = PORT_FALLOFF - 2
+        txt_offset = PortEnum.CLICK_FALLOFF.value - 2
         spacing = 1
 
         # adjust input position
@@ -524,9 +529,11 @@ def icon(self, path=None):
         self._properties['icon'] = path
         path = path or ICON_NODE_BASE
         pixmap = QtGui.QPixmap(path)
-        if pixmap.size().height() > NODE_ICON_SIZE:
-            pixmap = pixmap.scaledToHeight(NODE_ICON_SIZE,
-                                           QtCore.Qt.SmoothTransformation)
+        if pixmap.size().height() > NodeEnum.ICON_SIZE.value:
+            pixmap = pixmap.scaledToHeight(
+                NodeEnum.ICON_SIZE.value,
+                QtCore.Qt.SmoothTransformation
+            )
         self._icon_item.setPixmap(pixmap)
         if self.scene():
             self.post_init()
@@ -624,9 +631,9 @@ def _add_port(self, port):
         text.setFont(text.font())
         text.setVisible(port.display_name)
         text.setCacheMode(ITEM_CACHE_MODE)
-        if port.port_type == IN_PORT:
+        if port.port_type == PortTypeEnum.IN.value:
             self._input_items[port] = text
-        elif port.port_type == OUT_PORT:
+        elif port.port_type == PortTypeEnum.OUT.value:
             self._output_items[port] = text
         if self.scene():
             self.post_init()
@@ -653,7 +660,7 @@ def add_input(self, name='input', multi_port=False, display_name=True,
         else:
             port = PortItem(self)
         port.name = name
-        port.port_type = IN_PORT
+        port.port_type = PortTypeEnum.IN.value
         port.multi_connection = multi_port
         port.display_name = display_name
         port.locked = locked
@@ -680,7 +687,7 @@ def add_output(self, name='output', multi_port=False, display_name=True,
         else:
             port = PortItem(self)
         port.name = name
-        port.port_type = OUT_PORT
+        port.port_type = PortTypeEnum.OUT.value
         port.multi_connection = multi_port
         port.display_name = display_name
         port.locked = locked
@@ -808,14 +815,16 @@ def paint(self, painter, option, widget):
 
         # light overlay on background when selected.
         if self.selected:
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(
+                QtGui.QColor(*NodeEnum.SELECTED_COLOR.value)
+            )
             painter.drawRoundedRect(rect, radius, radius)
 
         # top & bottom edge background.
         padding = 2.0
         height = 10
         if self.selected:
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             painter.setBrush(QtGui.QColor(0, 0, 0, 80))
         for y in [rect.y() + padding, rect.height() - height - 1]:
@@ -828,7 +837,9 @@ def paint(self, painter, option, widget):
         border_color = QtGui.QColor(*self.border_color)
         if self.selected:
             border_width = 1.2
-            border_color = QtGui.QColor(*NODE_SEL_BORDER_COLOR)
+            border_color = QtGui.QColor(
+                *NodeEnum.SELECTED_BORDER_COLOR.value
+            )
         border_rect = QtCore.QRectF(rect.left(), rect.top(),
                                     rect.width(), rect.height())
 
diff --git a/NodeGraphQt/qgraphics/node_group.py b/NodeGraphQt/qgraphics/node_group.py
index 26f4298b..fa4e91dd 100644
--- a/NodeGraphQt/qgraphics/node_group.py
+++ b/NodeGraphQt/qgraphics/node_group.py
@@ -1,9 +1,7 @@
 #!/usr/bin/python
 from Qt import QtCore, QtGui, QtWidgets
 
-from NodeGraphQt.constants import (NODE_SEL_BORDER_COLOR,
-                                   NODE_SEL_COLOR,
-                                   PORT_FALLOFF)
+from NodeGraphQt.constants import NodeEnum, PortEnum
 from NodeGraphQt.qgraphics.node_base import NodeItem
 
 
@@ -65,9 +63,11 @@ def paint(self, painter, option, widget):
         painter.drawRect(rect_2)
 
         if self.selected:
-            border_color = QtGui.QColor(*NODE_SEL_BORDER_COLOR)
+            border_color = QtGui.QColor(
+                *NodeEnum.SELECTED_BORDER_COLOR.value
+            )
             # light overlay on background when selected.
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
             painter.drawRect(rect_2)
         else:
             border_color = QtGui.QColor(*self.border_color)
@@ -80,7 +80,7 @@ def paint(self, painter, option, widget):
                                   rect.right() - (padding[0] * 2) - margin,
                                   text_rect.height() - (padding[1] * 2))
         if self.selected:
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             painter.setBrush(QtGui.QColor(0, 0, 0, 80))
         painter.setPen(QtCore.Qt.NoPen)
@@ -114,7 +114,7 @@ def align_ports(self, v_offset=0.0):
             v_offset (float): port vertical offset.
         """
         width = self._width
-        txt_offset = PORT_FALLOFF - 2
+        txt_offset = PortEnum.CLICK_FALLOFF.value - 2
         spacing = 1
 
         # adjust input position
@@ -242,9 +242,11 @@ def paint(self, painter, option, widget):
         painter.drawRect(rect_2)
 
         if self.selected:
-            border_color = QtGui.QColor(*NODE_SEL_BORDER_COLOR)
+            border_color = QtGui.QColor(
+                *NodeEnum.SELECTED_BORDER_COLOR.value
+            )
             # light overlay on background when selected.
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
             painter.drawRect(rect_2)
         else:
             border_color = QtGui.QColor(*self.border_color)
@@ -253,7 +255,7 @@ def paint(self, painter, option, widget):
         padding = 2.0
         height = 10
         if self.selected:
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             painter.setBrush(QtGui.QColor(0, 0, 0, 80))
 
diff --git a/NodeGraphQt/qgraphics/node_port_in.py b/NodeGraphQt/qgraphics/node_port_in.py
index 6a981246..e76e5d73 100644
--- a/NodeGraphQt/qgraphics/node_port_in.py
+++ b/NodeGraphQt/qgraphics/node_port_in.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python
 from Qt import QtCore, QtGui, QtWidgets
 
-from NodeGraphQt.constants import (NODE_SEL_BORDER_COLOR, NODE_SEL_COLOR)
+from NodeGraphQt.constants import NodeEnum
 from NodeGraphQt.qgraphics.node_base import NodeItem, NodeItemVertical
 
 
@@ -74,8 +74,10 @@ def paint(self, painter, option, widget):
         poly = transform.map(triangle)
 
         if self.selected:
-            pen = QtGui.QPen(QtGui.QColor(*NODE_SEL_BORDER_COLOR), 1.3)
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            pen = QtGui.QPen(
+                QtGui.QColor(*NodeEnum.SELECTED_BORDER_COLOR.value), 1.3
+            )
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             pen = QtGui.QPen(QtGui.QColor(*self.border_color), 1.2)
             painter.setBrush(QtGui.QColor(0, 0, 0, 50))
@@ -220,8 +222,10 @@ def paint(self, painter, option, widget):
         poly = transform.map(triangle)
 
         if self.selected:
-            pen = QtGui.QPen(QtGui.QColor(*NODE_SEL_BORDER_COLOR), 1.3)
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            pen = QtGui.QPen(
+                QtGui.QColor(*NodeEnum.SELECTED_BORDER_COLOR.value), 1.3
+            )
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             pen = QtGui.QPen(QtGui.QColor(*self.border_color), 1.2)
             painter.setBrush(QtGui.QColor(0, 0, 0, 50))
diff --git a/NodeGraphQt/qgraphics/node_port_out.py b/NodeGraphQt/qgraphics/node_port_out.py
index c834c7ea..a692c74a 100644
--- a/NodeGraphQt/qgraphics/node_port_out.py
+++ b/NodeGraphQt/qgraphics/node_port_out.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python
 from Qt import QtCore, QtGui, QtWidgets
 
-from NodeGraphQt.constants import (NODE_SEL_BORDER_COLOR, NODE_SEL_COLOR)
+from NodeGraphQt.constants import NodeEnum
 from NodeGraphQt.qgraphics.node_base import NodeItem, NodeItemVertical
 
 
@@ -74,8 +74,10 @@ def paint(self, painter, option, widget):
         poly = transform.map(triangle)
 
         if self.selected:
-            pen = QtGui.QPen(QtGui.QColor(*NODE_SEL_BORDER_COLOR), 1.3)
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            pen = QtGui.QPen(
+                QtGui.QColor(*NodeEnum.SELECTED_BORDER_COLOR.value), 1.3
+            )
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             pen = QtGui.QPen(QtGui.QColor(*self.border_color), 1.2)
             painter.setBrush(QtGui.QColor(0, 0, 0, 50))
@@ -229,8 +231,10 @@ def paint(self, painter, option, widget):
         poly = transform.map(triangle)
 
         if self.selected:
-            pen = QtGui.QPen(QtGui.QColor(*NODE_SEL_BORDER_COLOR), 1.3)
-            painter.setBrush(QtGui.QColor(*NODE_SEL_COLOR))
+            pen = QtGui.QPen(
+                QtGui.QColor(*NodeEnum.SELECTED_BORDER_COLOR.value), 1.3
+            )
+            painter.setBrush(QtGui.QColor(*NodeEnum.SELECTED_COLOR.value))
         else:
             pen = QtGui.QPen(QtGui.QColor(*self.border_color), 1.2)
             painter.setBrush(QtGui.QColor(0, 0, 0, 50))
diff --git a/NodeGraphQt/qgraphics/pipe.py b/NodeGraphQt/qgraphics/pipe.py
index b2b48c12..29beada0 100644
--- a/NodeGraphQt/qgraphics/pipe.py
+++ b/NodeGraphQt/qgraphics/pipe.py
@@ -4,21 +4,18 @@
 from Qt import QtCore, QtGui, QtWidgets
 
 from NodeGraphQt.constants import (
-    PIPE_DEFAULT_COLOR, PIPE_ACTIVE_COLOR,
-    PIPE_HIGHLIGHT_COLOR, PIPE_DISABLED_COLOR,
-    PIPE_STYLE_DASHED, PIPE_STYLE_DEFAULT, PIPE_STYLE_DOTTED,
-    PIPE_LAYOUT_STRAIGHT, PIPE_WIDTH, IN_PORT, OUT_PORT, Z_VAL_PIPE,
+    PipeEnum, PipeLayoutEnum, PortTypeEnum, Z_VAL_PIPE,
     Z_VAL_NODE_WIDGET,
-    PIPE_LAYOUT_ANGLE, PIPE_LAYOUT_CURVED,
     ITEM_CACHE_MODE,
     NODE_LAYOUT_VERTICAL, NODE_LAYOUT_HORIZONTAL,
-    NODE_LAYOUT_DIRECTION)
+    NODE_LAYOUT_DIRECTION
+)
 from NodeGraphQt.qgraphics.port import PortItem
 
 PIPE_STYLES = {
-    PIPE_STYLE_DEFAULT: QtCore.Qt.SolidLine,
-    PIPE_STYLE_DASHED: QtCore.Qt.DashLine,
-    PIPE_STYLE_DOTTED: QtCore.Qt.DotLine
+    PipeEnum.DRAW_TYPE_DEFAULT.value: QtCore.Qt.SolidLine,
+    PipeEnum.DRAW_TYPE_DASHED.value: QtCore.Qt.DashLine,
+    PipeEnum.DRAW_TYPE_DOTTED.value: QtCore.Qt.DotLine
 }
 
 
@@ -32,8 +29,8 @@ def __init__(self, input_port=None, output_port=None):
         self.setZValue(Z_VAL_PIPE)
         self.setAcceptHoverEvents(True)
         self.setFlag(QtWidgets.QGraphicsItem.ItemIsSelectable)
-        self._color = PIPE_DEFAULT_COLOR
-        self._style = PIPE_STYLE_DEFAULT
+        self._color = PipeEnum.COLOR.value
+        self._style = PipeEnum.DRAW_TYPE_DEFAULT.value
         self._active = False
         self._highlight = False
         self._input_port = input_port
@@ -76,22 +73,22 @@ def paint(self, painter, option, widget):
         """
         color = QtGui.QColor(*self._color)
         pen_style = PIPE_STYLES.get(self.style)
-        pen_width = PIPE_WIDTH
+        pen_width = PipeEnum.WIDTH.value
         if self._active:
-            color = QtGui.QColor(*PIPE_ACTIVE_COLOR)
+            color = QtGui.QColor(*PipeEnum.ACTIVE_COLOR.value)
             if pen_style == QtCore.Qt.DashDotDotLine:
                 pen_width += 1
             else:
                 pen_width += 0.35
         elif self._highlight:
-            color = QtGui.QColor(*PIPE_HIGHLIGHT_COLOR)
-            pen_style = PIPE_STYLES.get(PIPE_STYLE_DEFAULT)
+            color = QtGui.QColor(*PipeEnum.HIGHLIGHT_COLOR.value)
+            pen_style = PIPE_STYLES.get(PipeEnum.DRAW_TYPE_DEFAULT.value)
 
         if self.disabled():
             if not self._active:
-                color = QtGui.QColor(*PIPE_DISABLED_COLOR)
+                color = QtGui.QColor(*PipeEnum.DISABLED_COLOR.value)
             pen_width += 0.2
-            pen_style = PIPE_STYLES.get(PIPE_STYLE_DOTTED)
+            pen_style = PIPE_STYLES.get(PipeEnum.DRAW_TYPE_DOTTED.value)
 
         pen = QtGui.QPen(color, pen_width, pen_style)
         pen.setCapStyle(QtCore.Qt.RoundCap)
@@ -154,13 +151,13 @@ def __draw_path_vertical(self, start_port, pos1, pos2, path):
             pos2 (QPointF): end port position.
             path (QPainterPath): path to draw.
         """
-        if self.viewer_pipe_layout() == PIPE_LAYOUT_CURVED:
+        if self.viewer_pipe_layout() == PipeLayoutEnum.CURVED.value:
             ctr_offset_y1, ctr_offset_y2 = pos1.y(), pos2.y()
             tangent = abs(ctr_offset_y1 - ctr_offset_y2)
 
             max_height = start_port.node.boundingRect().height()
             tangent = min(tangent, max_height)
-            if start_port.port_type == IN_PORT:
+            if start_port.port_type == PortTypeEnum.IN.value:
                 ctr_offset_y1 -= tangent
                 ctr_offset_y2 += tangent
             else:
@@ -171,10 +168,10 @@ def __draw_path_vertical(self, start_port, pos1, pos2, path):
             ctr_point2 = QtCore.QPointF(pos2.x(), ctr_offset_y2)
             path.cubicTo(ctr_point1, ctr_point2, pos2)
             self.setPath(path)
-        elif self.viewer_pipe_layout() == PIPE_LAYOUT_ANGLE:
+        elif self.viewer_pipe_layout() == PipeLayoutEnum.ANGLE.value:
             ctr_offset_y1, ctr_offset_y2 = pos1.y(), pos2.y()
             distance = abs(ctr_offset_y1 - ctr_offset_y2)/2
-            if start_port.port_type == IN_PORT:
+            if start_port.port_type == PortTypeEnum.IN.value:
                 ctr_offset_y1 -= distance
                 ctr_offset_y2 += distance
             else:
@@ -198,13 +195,13 @@ def __draw_path_horizontal(self, start_port, pos1, pos2, path):
             pos2 (QPointF): end port position.
             path (QPainterPath): path to draw.
         """
-        if self.viewer_pipe_layout() == PIPE_LAYOUT_CURVED:
+        if self.viewer_pipe_layout() == PipeLayoutEnum.CURVED.value:
             ctr_offset_x1, ctr_offset_x2 = pos1.x(), pos2.x()
             tangent = abs(ctr_offset_x1 - ctr_offset_x2)
 
             max_width = start_port.node.boundingRect().width()
             tangent = min(tangent, max_width)
-            if start_port.port_type == IN_PORT:
+            if start_port.port_type == PortTypeEnum.IN.value:
                 ctr_offset_x1 -= tangent
                 ctr_offset_x2 += tangent
             else:
@@ -215,10 +212,10 @@ def __draw_path_horizontal(self, start_port, pos1, pos2, path):
             ctr_point2 = QtCore.QPointF(ctr_offset_x2, pos2.y())
             path.cubicTo(ctr_point1, ctr_point2, pos2)
             self.setPath(path)
-        elif self.viewer_pipe_layout() == PIPE_LAYOUT_ANGLE:
+        elif self.viewer_pipe_layout() == PipeLayoutEnum.ANGLE.value:
             ctr_offset_x1, ctr_offset_x2 = pos1.x(), pos2.x()
             distance = abs(ctr_offset_x1 - ctr_offset_x2) / 2
-            if start_port.port_type == IN_PORT:
+            if start_port.port_type == PortTypeEnum.IN.value:
                 ctr_offset_x1 -= distance
                 ctr_offset_x2 += distance
             else:
@@ -260,7 +257,7 @@ def draw_path(self, start_port, end_port=None, cursor_pos=None):
         path = QtGui.QPainterPath()
         path.moveTo(line.x1(), line.y1())
 
-        if self.viewer_pipe_layout() == PIPE_LAYOUT_STRAIGHT:
+        if self.viewer_pipe_layout() == PipeLayoutEnum.STRAIGHT.value:
             path.lineTo(pos2)
             self.setPath(path)
             return
@@ -298,8 +295,10 @@ def viewer_pipe_layout(self):
 
     def activate(self):
         self._active = True
-        color = QtGui.QColor(*PIPE_ACTIVE_COLOR)
-        pen = QtGui.QPen(color, 2.5, PIPE_STYLES.get(PIPE_STYLE_DEFAULT))
+        color = QtGui.QColor(*PipeEnum.ACTIVE_COLOR.value)
+        pen = QtGui.QPen(
+            color, 2.5, PIPE_STYLES.get(PipeEnum.DRAW_TYPE_DEFAULT.value)
+        )
         self.setPen(pen)
 
     def active(self):
@@ -307,8 +306,10 @@ def active(self):
 
     def highlight(self):
         self._highlight = True
-        color = QtGui.QColor(*PIPE_HIGHLIGHT_COLOR)
-        pen = QtGui.QPen(color, 2, PIPE_STYLES.get(PIPE_STYLE_DEFAULT))
+        color = QtGui.QColor(*PipeEnum.HIGHLIGHT_COLOR.value)
+        pen = QtGui.QPen(
+            color, 2, PIPE_STYLES.get(PipeEnum.DRAW_TYPE_DEFAULT.value)
+        )
         self.setPen(pen)
 
     def highlighted(self):
@@ -326,10 +327,10 @@ def set_connections(self, port1, port2):
             port1.port_type: port1,
             port2.port_type: port2
         }
-        self.input_port = ports[IN_PORT]
-        self.output_port = ports[OUT_PORT]
-        ports[IN_PORT].add_pipe(self)
-        ports[OUT_PORT].add_pipe(self)
+        self.input_port = ports[PortTypeEnum.IN.value]
+        self.output_port = ports[PortTypeEnum.OUT.value]
+        ports[PortTypeEnum.IN.value].add_pipe(self)
+        ports[PortTypeEnum.OUT.value].add_pipe(self)
 
     def disabled(self):
         if self.input_port and self.input_port.node.disabled:
@@ -409,9 +410,9 @@ def paint(self, painter, option, widget):
                 used to describe the parameters needed to draw.
             widget (QtWidgets.QWidget): not used.
         """
-        color = QtGui.QColor(*PIPE_ACTIVE_COLOR)
-        pen_style = PIPE_STYLES.get(PIPE_STYLE_DASHED)
-        pen_width = PIPE_WIDTH + 0.35
+        color = QtGui.QColor(*PipeEnum.ACTIVE_COLOR.value)
+        pen_style = PIPE_STYLES.get(PipeEnum.DRAW_TYPE_DASHED.value)
+        pen_width = PipeEnum.WIDTH.value + 0.35
 
         pen = QtGui.QPen(color, pen_width)
         pen.setStyle(pen_style)
diff --git a/NodeGraphQt/qgraphics/port.py b/NodeGraphQt/qgraphics/port.py
index 2c723980..78c8a0ad 100644
--- a/NodeGraphQt/qgraphics/port.py
+++ b/NodeGraphQt/qgraphics/port.py
@@ -2,15 +2,7 @@
 from Qt import QtGui, QtCore, QtWidgets
 
 from NodeGraphQt.constants import (
-    IN_PORT, OUT_PORT,
-    PORT_DEFAULT_COLOR,
-    PORT_DEFAULT_BORDER_COLOR,
-    PORT_DEFAULT_SIZE,
-    PORT_FALLOFF,
-    PORT_HOVER_COLOR,
-    PORT_HOVER_BORDER_COLOR,
-    PORT_ACTIVE_COLOR,
-    PORT_ACTIVE_BORDER_COLOR,
+    PortTypeEnum, PortEnum,
     Z_VAL_PORT,
     ITEM_CACHE_MODE)
 
@@ -28,13 +20,13 @@ def __init__(self, parent=None):
         self.setFlag(self.ItemSendsScenePositionChanges, True)
         self.setZValue(Z_VAL_PORT)
         self._pipes = []
-        self._width = PORT_DEFAULT_SIZE
-        self._height = PORT_DEFAULT_SIZE
+        self._width = PortEnum.SIZE.value
+        self._height = PortEnum.SIZE.value
         self._hovered = False
         self._name = 'port'
         self._display_name = True
-        self._color = PORT_DEFAULT_COLOR
-        self._border_color = PORT_DEFAULT_BORDER_COLOR
+        self._color = PortEnum.COLOR.value
+        self._border_color = PortEnum.BORDER_COLOR.value
         self._border_size = 1
         self._port_type = None
         self._multi_connection = False
@@ -47,7 +39,9 @@ def __repr__(self):
         return '{}.PortItem("{}")'.format(self.__module__, self.name)
 
     def boundingRect(self):
-        return QtCore.QRectF(0.0, 0.0, self._width + PORT_FALLOFF, self._height)
+        return QtCore.QRectF(0.0, 0.0,
+                             self._width + PortEnum.CLICK_FALLOFF.value,
+                             self._height)
 
     def paint(self, painter, option, widget):
         """
@@ -76,11 +70,11 @@ def paint(self, painter, option, widget):
         port_rect = QtCore.QRectF(rect_x, rect_y, rect_w, rect_h)
 
         if self._hovered:
-            color = QtGui.QColor(*PORT_HOVER_COLOR)
-            border_color = QtGui.QColor(*PORT_HOVER_BORDER_COLOR)
+            color = QtGui.QColor(*PortEnum.HOVER_COLOR.value)
+            border_color = QtGui.QColor(*PortEnum.HOVER_BORDER_COLOR.value)
         elif self.connected_pipes:
-            color = QtGui.QColor(*PORT_ACTIVE_COLOR)
-            border_color = QtGui.QColor(*PORT_ACTIVE_BORDER_COLOR)
+            color = QtGui.QColor(*PortEnum.ACTIVE_COLOR.value)
+            border_color = QtGui.QColor(*PortEnum.ACTIVE_BORDER_COLOR.value)
         else:
             color = QtGui.QColor(*self.color)
             border_color = QtGui.QColor(*self.border_color)
@@ -146,9 +140,9 @@ def redraw_connected_pipes(self):
         if not self.connected_pipes:
             return
         for pipe in self.connected_pipes:
-            if self.port_type == IN_PORT:
+            if self.port_type == PortTypeEnum.IN.value:
                 pipe.draw_path(self, pipe.output_port)
-            elif self.port_type == OUT_PORT:
+            elif self.port_type == PortTypeEnum.OUT.value:
                 pipe.draw_path(pipe.input_port, self)
 
     def add_pipe(self, pipe):
@@ -164,7 +158,10 @@ def connected_pipes(self):
     @property
     def connected_ports(self):
         ports = []
-        port_types = {IN_PORT: 'output_port', OUT_PORT: 'input_port'}
+        port_types = {
+            PortTypeEnum.IN.value: 'output_port',
+            PortTypeEnum.OUT.value: 'input_port'
+        }
         for pipe in self.connected_pipes:
             ports.append(getattr(pipe, port_types[self.port_type]))
         return ports
@@ -266,7 +263,10 @@ def connect_to(self, port):
         self.update()
 
     def disconnect_from(self, port):
-        port_types = {IN_PORT: 'output_port', OUT_PORT: 'input_port'}
+        port_types = {
+            PortTypeEnum.IN.value: 'output_port',
+            PortTypeEnum.OUT.value: 'input_port'
+        }
         for pipe in self.connected_pipes:
             connected_port = getattr(pipe, port_types[self.port_type])
             if connected_port == port:
diff --git a/NodeGraphQt/qgraphics/slicer.py b/NodeGraphQt/qgraphics/slicer.py
index 11c480f9..08282840 100644
--- a/NodeGraphQt/qgraphics/slicer.py
+++ b/NodeGraphQt/qgraphics/slicer.py
@@ -3,7 +3,7 @@
 
 from Qt import QtCore, QtGui, QtWidgets
 
-from NodeGraphQt.constants import Z_VAL_NODE_WIDGET, PIPE_SLICER_COLOR
+from NodeGraphQt.constants import Z_VAL_NODE_WIDGET, PipeSlicerEnum
 
 
 class SlicerPipeItem(QtWidgets.QGraphicsPathItem):
@@ -25,7 +25,7 @@ def paint(self, painter, option, widget):
                 used to describe the parameters needed to draw.
             widget (QtWidgets.QWidget): not used.
         """
-        color = QtGui.QColor(*PIPE_SLICER_COLOR)
+        color = QtGui.QColor(*PipeSlicerEnum.COLOR.value)
         p1 = self.path().pointAtPercent(0)
         p2 = self.path().pointAtPercent(1)
         size = 6.0
@@ -42,15 +42,21 @@ def paint(self, painter, option, widget):
         text_x = painter.fontMetrics().width(text) / 2
         text_y = painter.fontMetrics().height() / 1.5
         text_pos = QtCore.QPointF(p1.x() - text_x, p1.y() - text_y)
-        text_color = QtGui.QColor(*PIPE_SLICER_COLOR)
+        text_color = QtGui.QColor(*PipeSlicerEnum.COLOR.value)
         text_color.setAlpha(80)
-        painter.setPen(QtGui.QPen(text_color, 1.5, QtCore.Qt.SolidLine))
+        painter.setPen(QtGui.QPen(
+            text_color, PipeSlicerEnum.WIDTH.value, QtCore.Qt.SolidLine
+        ))
         painter.drawText(text_pos, text)
 
-        painter.setPen(QtGui.QPen(color, 1.5, QtCore.Qt.DashDotLine))
+        painter.setPen(QtGui.QPen(
+            color, PipeSlicerEnum.WIDTH.value, QtCore.Qt.DashDotLine
+        ))
         painter.drawPath(self.path())
 
-        pen = QtGui.QPen(color, 1.5, QtCore.Qt.SolidLine)
+        pen = QtGui.QPen(
+            color, PipeSlicerEnum.WIDTH.value, QtCore.Qt.SolidLine
+        )
         pen.setCapStyle(QtCore.Qt.RoundCap)
         pen.setJoinStyle(QtCore.Qt.MiterJoin)
         painter.setPen(pen)
diff --git a/NodeGraphQt/widgets/actions.py b/NodeGraphQt/widgets/actions.py
index 0f9b1784..4ec9ce1d 100644
--- a/NodeGraphQt/widgets/actions.py
+++ b/NodeGraphQt/widgets/actions.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python
 from Qt import QtCore, QtWidgets
 
-from NodeGraphQt.constants import VIEWER_BG_COLOR
+from NodeGraphQt.constants import ViewerEnum
 
 
 class BaseMenu(QtWidgets.QMenu):
@@ -13,7 +13,9 @@ def __init__(self, *args, **kwargs):
         style_dict = {
             'QMenu': {
                 'color': 'rgb({0},{1},{2})'.format(*text_color),
-                'background-color': 'rgb({0},{1},{2})'.format(*VIEWER_BG_COLOR),
+                'background-color': 'rgb({0},{1},{2})'.format(
+                    *ViewerEnum.BACKGROUND_COLOR.value
+                ),
                 'border': '1px solid rgba({0},{1},{2},30)'.format(*text_color),
                 'border-radius': '3px',
             },
diff --git a/NodeGraphQt/widgets/node_graph.py b/NodeGraphQt/widgets/node_graph.py
index 786e746b..7998ad02 100644
--- a/NodeGraphQt/widgets/node_graph.py
+++ b/NodeGraphQt/widgets/node_graph.py
@@ -1,10 +1,9 @@
 from Qt import QtWidgets, QtGui
 
 from NodeGraphQt.constants import (
-    NODE_SEL_BORDER_COLOR,
-    VIEWER_BG_COLOR,
-    VIEWER_NAV_BG_COLOR
+    NodeEnum, ViewerEnum, ViewerNavEnum
 )
+
 from NodeGraphQt.widgets.viewer_nav import NodeNavigationWidget
 
 
@@ -15,13 +14,18 @@ def __init__(self, parent=None):
         self.setTabsClosable(True)
         self.setTabBarAutoHide(True)
         text_color = self.palette().text().color().toTuple()
-        bg_color = QtGui.QColor(*VIEWER_BG_COLOR).darker(120).toTuple()
+        bg_color = QtGui.QColor(
+            *ViewerEnum.BACKGROUND_COLOR.value).darker(120).toTuple()
         style_dict = {
             'QWidget': {
-                'background-color': 'rgb({0},{1},{2})'.format(*VIEWER_BG_COLOR),
+                'background-color': 'rgb({0},{1},{2})'.format(
+                    *ViewerEnum.BACKGROUND_COLOR.value
+                ),
             },
             'QTabWidget::pane': {
-                'background': 'rgb({0},{1},{2})'.format(*VIEWER_BG_COLOR),
+                'background': 'rgb({0},{1},{2})'.format(
+                    *ViewerEnum.BACKGROUND_COLOR.value
+                ),
                 'border': '0px',
                 'border-top': '0px solid rgb({0},{1},{2})'.format(*bg_color),
             },
@@ -34,14 +38,16 @@ def __init__(self, parent=None):
             },
             'QTabBar::tab:selected': {
                 'color': 'rgb({0},{1},{2})'.format(*text_color),
-                'background': 'rgb({0},{1},{2})'.format(*VIEWER_NAV_BG_COLOR),
+                'background': 'rgb({0},{1},{2})'.format(
+                    *ViewerNavEnum.BACKGROUND_COLOR.value
+                ),
                 'border-top': '1px solid rgb({0},{1},{2})'
-                              .format(*NODE_SEL_BORDER_COLOR),
+                              .format(*NodeEnum.SELECTED_BORDER_COLOR.value),
             },
             'QTabBar::tab:hover': {
                 'color': 'rgb({0},{1},{2})'.format(*text_color),
                 'border-top': '1px solid rgb({0},{1},{2})'
-                              .format(*NODE_SEL_BORDER_COLOR),
+                              .format(*NodeEnum.SELECTED_BORDER_COLOR.value),
             }
         }
         stylesheet = ''
diff --git a/NodeGraphQt/widgets/node_widgets.py b/NodeGraphQt/widgets/node_widgets.py
index 8fa8e257..e2bf29f2 100644
--- a/NodeGraphQt/widgets/node_widgets.py
+++ b/NodeGraphQt/widgets/node_widgets.py
@@ -1,7 +1,7 @@
 #!/usr/bin/python
 from Qt import QtCore, QtWidgets
 
-from NodeGraphQt.constants import VIEWER_GRID_COLOR, Z_VAL_NODE_WIDGET
+from NodeGraphQt.constants import ViewerEnum, Z_VAL_NODE_WIDGET
 from NodeGraphQt.errors import NodeWidgetError
 
 
@@ -329,7 +329,7 @@ def __init__(self, parent=None, name='', label='', text=''):
             'QLineEdit': {
                 'background': 'rgba({0},{1},{2},20)'.format(*bg_color),
                 'border': '1px solid rgb({0},{1},{2})'
-                          .format(*VIEWER_GRID_COLOR),
+                          .format(*ViewerEnum.GRID_COLOR.value),
                 'border-radius': '3px',
                 'color': 'rgba({0},{1},{2},150)'.format(*text_color),
                 'selection-background-color': 'rgba({0},{1},{2},100)'
diff --git a/NodeGraphQt/widgets/scene.py b/NodeGraphQt/widgets/scene.py
index 54309ea7..91e7ccfa 100644
--- a/NodeGraphQt/widgets/scene.py
+++ b/NodeGraphQt/widgets/scene.py
@@ -1,20 +1,16 @@
 #!/usr/bin/python
 from Qt import QtGui, QtCore, QtWidgets
 
-from NodeGraphQt.constants import (VIEWER_BG_COLOR,
-                                   VIEWER_GRID_SIZE,
-                                   VIEWER_GRID_COLOR,
-                                   VIEWER_GRID_DOTS,
-                                   VIEWER_GRID_LINES)
+from NodeGraphQt.constants import ViewerEnum
 
 
 class NodeScene(QtWidgets.QGraphicsScene):
 
     def __init__(self, parent=None):
         super(NodeScene, self).__init__(parent)
-        self._grid_mode = VIEWER_GRID_LINES
-        self._grid_color = VIEWER_GRID_COLOR
-        self._bg_color = VIEWER_BG_COLOR
+        self._grid_mode = ViewerEnum.GRID_DISPLAY_LINES.value
+        self._grid_color = ViewerEnum.GRID_COLOR.value
+        self._bg_color = ViewerEnum.BACKGROUND_COLOR.value
         self.setBackgroundBrush(QtGui.QColor(*self._bg_color))
 
     def __repr__(self):
@@ -98,21 +94,25 @@ def drawBackground(self, painter, rect):
         painter.setRenderHint(QtGui.QPainter.Antialiasing, False)
         painter.setBrush(self.backgroundBrush())
 
-        if self._grid_mode is VIEWER_GRID_DOTS:
+        if self._grid_mode is ViewerEnum.GRID_DISPLAY_DOTS.value:
             pen = QtGui.QPen(QtGui.QColor(*self.grid_color), 0.65)
-            self._draw_dots(painter, rect, pen, VIEWER_GRID_SIZE)
+            self._draw_dots(painter, rect, pen, ViewerEnum.GRID_SIZE.value)
 
-        elif self._grid_mode is VIEWER_GRID_LINES:
+        elif self._grid_mode is ViewerEnum.GRID_DISPLAY_LINES.value:
             zoom = self.viewer().get_zoom()
             if zoom > -0.5:
                 pen = QtGui.QPen(QtGui.QColor(*self.grid_color), 0.65)
-                self._draw_grid(painter, rect, pen, VIEWER_GRID_SIZE)
+                self._draw_grid(
+                    painter, rect, pen, ViewerEnum.GRID_SIZE.value
+                )
 
             color = QtGui.QColor(*self._bg_color).darker(150)
             if zoom < -0.0:
                 color = color.darker(100 - int(zoom * 110))
             pen = QtGui.QPen(color, 0.65)
-            self._draw_grid(painter, rect, pen, VIEWER_GRID_SIZE * 8)
+            self._draw_grid(
+                painter, rect, pen, ViewerEnum.GRID_SIZE.value * 8
+            )
 
         painter.restore()
 
@@ -148,7 +148,9 @@ def grid_mode(self):
         return self._grid_mode
 
     @grid_mode.setter
-    def grid_mode(self, mode=VIEWER_GRID_LINES):
+    def grid_mode(self, mode=None):
+        if mode is None:
+            mode = ViewerEnum.GRID_DISPLAY_LINES.value
         self._grid_mode = mode
 
     @property
diff --git a/NodeGraphQt/widgets/tab_search.py b/NodeGraphQt/widgets/tab_search.py
index 5500c226..1e80af3f 100644
--- a/NodeGraphQt/widgets/tab_search.py
+++ b/NodeGraphQt/widgets/tab_search.py
@@ -4,7 +4,7 @@
 
 from Qt import QtCore, QtWidgets, QtGui
 
-from NodeGraphQt.constants import VIEWER_BG_COLOR, VIEWER_NAV_BG_COLOR
+from NodeGraphQt.constants import ViewerEnum, ViewerNavEnum
 
 
 class TabSearchCompleter(QtWidgets.QCompleter):
@@ -62,12 +62,15 @@ def __init__(self, parent=None):
         style_dict = {
             'QLineEdit': {
                 'color': 'rgb({0},{1},{2})'.format(*text_color),
-                'border': '1px solid rgb({0},{1},{2})'
-                          .format(*selected_color),
+                'border': '1px solid rgb({0},{1},{2})'.format(
+                    *selected_color
+                ),
                 'border-radius': '3px',
                 'padding': '2px 4px',
                 'margin': '2px 4px 8px 4px',
-                'background': 'rgb({0},{1},{2})'.format(*VIEWER_NAV_BG_COLOR),
+                'background': 'rgb({0},{1},{2})'.format(
+                    *ViewerNavEnum.BACKGROUND_COLOR.value
+                ),
                 'selection-background-color': 'rgba({0},{1},{2},200)'
                                               .format(*selected_color),
             }
@@ -110,7 +113,9 @@ def __init__(self, node_dict=None):
         style_dict = {
             'QMenu': {
                 'color': 'rgb({0},{1},{2})'.format(*text_color),
-                'background-color': 'rgb({0},{1},{2})'.format(*VIEWER_BG_COLOR),
+                'background-color': 'rgb({0},{1},{2})'.format(
+                    *ViewerEnum.BACKGROUND_COLOR.value
+                ),
                 'border': '1px solid rgba({0},{1},{2},30)'.format(*text_color),
                 'border-radius': '3px',
             },
diff --git a/NodeGraphQt/widgets/viewer.py b/NodeGraphQt/widgets/viewer.py
index f575b8ae..6fc3e744 100644
--- a/NodeGraphQt/widgets/viewer.py
+++ b/NodeGraphQt/widgets/viewer.py
@@ -6,7 +6,7 @@
 from Qt import QtGui, QtCore, QtWidgets
 
 from NodeGraphQt.base.menu import BaseMenu
-from NodeGraphQt.constants import IN_PORT, OUT_PORT, PIPE_LAYOUT_CURVED
+from NodeGraphQt.constants import PortTypeEnum, PipeLayoutEnum
 from NodeGraphQt.qgraphics.node_abstract import AbstractNodeItem
 from NodeGraphQt.qgraphics.node_backdrop import BackdropNodeItem
 from NodeGraphQt.qgraphics.pipe import PipeItem, LivePipeItem
@@ -71,7 +71,7 @@ def __init__(self, parent=None, undo_stack=None):
         self._update_scene()
         self._last_size = self.size()
 
-        self._pipe_layout = PIPE_LAYOUT_CURVED
+        self._pipe_layout = PipeLayoutEnum.CURVED.value
         self._detached_port = None
         self._start_port = None
         self._origin_pos = None
@@ -696,7 +696,10 @@ def sceneMousePressEvent(self, event):
 
             from_port.hovered = True
 
-            attr = {IN_PORT: 'output_port', OUT_PORT: 'input_port'}
+            attr = {
+                PortTypeEnum.IN.value: 'output_port',
+                PortTypeEnum.OUT.value: 'input_port'
+            }
             self._detached_port = getattr(pipe, attr[from_port.port_type])
             self.start_live_connection(from_port)
             self._LIVE_PIPE.draw_path(self._start_port, cursor_pos=pos)
@@ -829,9 +832,9 @@ def start_live_connection(self, selected_port):
         if not selected_port:
             return
         self._start_port = selected_port
-        if self._start_port.type == IN_PORT:
+        if self._start_port.type == PortTypeEnum.IN.value:
             self._LIVE_PIPE.input_port = self._start_port
-        elif self._start_port == OUT_PORT:
+        elif self._start_port == PortTypeEnum.OUT.value:
             self._LIVE_PIPE.output_port = self._start_port
         self._LIVE_PIPE.setVisible(True)
 
@@ -873,7 +876,10 @@ def acyclic_check(start_port, end_port):
         """
         start_node = start_port.node
         check_nodes = [end_port.node]
-        io_types = {IN_PORT: 'outputs', OUT_PORT: 'inputs'}
+        io_types = {
+            PortTypeEnum.IN.value: 'outputs',
+            PortTypeEnum.OUT.value: 'inputs'
+        }
         while check_nodes:
             check_node = check_nodes.pop(0)
             for check_port in getattr(check_node, io_types[end_port.port_type]):
diff --git a/NodeGraphQt/widgets/viewer_nav.py b/NodeGraphQt/widgets/viewer_nav.py
index 89bacab9..573d611f 100644
--- a/NodeGraphQt/widgets/viewer_nav.py
+++ b/NodeGraphQt/widgets/viewer_nav.py
@@ -1,10 +1,6 @@
 from Qt import QtWidgets, QtCore, QtGui
 
-from NodeGraphQt.constants import (
-    NODE_SEL_BORDER_COLOR,
-    VIEWER_NAV_BG_COLOR,
-    VIEWER_NAV_ITEM_COLOR
-)
+from NodeGraphQt.constants import NodeEnum, ViewerNavEnum
 
 
 class NodeNavigationDelagate(QtWidgets.QStyledItemDelegate):
@@ -36,11 +32,11 @@ def paint(self, painter, option, index):
         painter.setRenderHint(QtGui.QPainter.Antialiasing, True)
 
         # background.
-        bg_color = QtGui.QColor(*VIEWER_NAV_ITEM_COLOR)
+        bg_color = QtGui.QColor(*ViewerNavEnum.ITEM_COLOR.value)
         itm_color = QtGui.QColor(80, 128, 123)
         if option.state & QtWidgets.QStyle.State_Selected:
             bg_color = bg_color.lighter(120)
-            itm_color = QtGui.QColor(*NODE_SEL_BORDER_COLOR)
+            itm_color = QtGui.QColor(*NodeEnum.SELECTED_BORDER_COLOR.value)
 
         roundness = 2.0
         painter.setBrush(bg_color)
@@ -109,7 +105,7 @@ def __init__(self, parent=None):
         # self.viewport().setAutoFillBackground(False)
         self.setStyleSheet(
             'QListView {{border: 0px;background-color: rgb({0},{1},{2});}}'
-            .format(*VIEWER_NAV_BG_COLOR)
+            .format(*ViewerNavEnum.BACKGROUND_COLOR.value)
         )
 
         self.setItemDelegate(NodeNavigationDelagate(self))