mesh_snap_utilities_line.py

                if "bl_rna" in panel.__dict__:
                    bpy.utils.unregister_class(panel)

                panel.bl_category = addon_prefs.category
                bpy.utils.register_class(panel)

    except Exception as e:
        print("\n[{}]\n{}\n\nError:\n{}".format(__name__, message, e))
        pass


class SnapAddonPreferences(AddonPreferences):
    # this must match the addon name, use '__package__'
    # when defining this in a submodule of a python package.
    bl_idname = __name__

    intersect = BoolProperty(
            name="Intersect",
            description="Intersects created line with the existing edges, "
                        "even if the lines do not intersect",
            default=True
            )
    create_new_obj = BoolProperty(
            name="Create a new object",
            description="If have not a active object, or the active object "
                        "is not in edit mode, it creates a new object",
            default=False
            )
    create_face = BoolProperty(
            name="Create faces",
            description="Create faces defined by enclosed edges",
            default=False
            )
    outer_verts = BoolProperty(
            name="Snap to outer vertices",
            description="The vertices of the objects are not activated also snapped",
            default=True
            )
    expand_snap_settings = BoolProperty(
            name="Expand",
            description="Expand, to display the settings",
            default=False
            )
    expand_color_settings = BoolProperty(
            name="Color Settings",
            description="Expand, to display the color settings",
            default=False
            )
    increments_grid = BoolProperty(
            name="Increments of Grid",
            description="Snap to increments of grid",
            default=False
            )
    category = StringProperty(
            name="Category",
            description="Choose a name for the category of the panel",
            default="Snap Utilities",
            update=update_panel
            )
    incremental = FloatProperty(
            name="Incremental",
            description="Snap in defined increments",
            default=0,
            min=0,
            step=1,
            precision=3
            )
    relative_scale = FloatProperty(
            name="Relative Scale",
            description="Value that divides the global scale",
            default=1,
            min=0,
            step=1,
            precision=3
            )
    out_color = FloatVectorProperty(
            name="OUT",
            default=(0.0, 0.0, 0.0, 0.5),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )
    face_color = FloatVectorProperty(
            name="FACE",
            default=(1.0, 0.8, 0.0, 1.0),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )
    edge_color = FloatVectorProperty(
            name="EDGE",
            default=(0.0, 0.8, 1.0, 1.0),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )
    vert_color = FloatVectorProperty(
            name="VERT",
            default=(1.0, 0.5, 0.0, 1.0),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )
    center_color = FloatVectorProperty(
            name="CENTER",
            default=(1.0, 0.0, 1.0, 1.0),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )
    perpendicular_color = FloatVectorProperty(
            name="PERPENDICULAR",
            default=(0.1, 0.5, 0.5, 1.0),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )
    constrain_shift_color = FloatVectorProperty(
            name="SHIFT CONSTRAIN",
            default=(0.8, 0.5, 0.4, 1.0),
            size=4,
            subtype="COLOR",
            min=0, max=1
            )

    def draw(self, context):
        layout = self.layout
        icon = "TRIA_DOWN" if self.expand_color_settings else "TRIA_RIGHT"

        box = layout.box()
        box.prop(self, "expand_color_settings", icon=icon, toggle=True, emboss=False)
        if self.expand_color_settings:
            split = box.split()

            col = split.column()
            col.prop(self, "out_color")
            col.prop(self, "constrain_shift_color")
            col = split.column()
            col.prop(self, "face_color")
            col.prop(self, "center_color")
            col = split.column()
            col.prop(self, "edge_color")
            col.prop(self, "perpendicular_color")
            col = split.column()
            col.prop(self, "vert_color")

        row = layout.row()

        col = row.column(align=True)
        box = col.box()
        box.label(text="Snap Items:")
        box.prop(self, "incremental")
        box.prop(self, "outer_verts")
        box.prop(self, "increments_grid")
        if self.increments_grid:
            box.prop(self, "relative_scale")
        else:
            box.separator()
            box.separator()

        col = row.column(align=True)
        box = col.box()
        box.label(text="Line Tool:")
        box.prop(self, "intersect")
        box.prop(self, "create_face")
        box.prop(self, "create_new_obj")
        box.separator()
        box.separator()

        row = layout.row()
        col = row.column()
        col.label(text="Tab Category:")
        col.prop(self, "category", text="")


def register():
    bpy.utils.register_class(SnapAddonPreferences)
    bpy.utils.register_class(SnapUtilitiesLine)
    bpy.utils.register_class(PanelSnapUtilities)
    update_panel(None, bpy.context)


def unregister():
    bpy.utils.unregister_class(PanelSnapUtilities)
    bpy.utils.unregister_class(SnapUtilitiesLine)
    bpy.utils.unregister_class(SnapAddonPreferences)


if __name__ == "__main__":
    __name__ = "mesh_snap_utilities_line"
    register()