ui.py

    def draw_header(self, context):
        cam = context.camera

        self.layout.prop(cam.pov, "dof_enable", text="")

    def draw(self, context):
        layout = self.layout

        cam = context.camera

        layout.active = cam.pov.dof_enable

        layout.prop(cam.pov, "dof_aperture")

        split = layout.split()

        col = split.column()
        col.prop(cam.pov, "dof_samples_min")
        col.prop(cam.pov, "dof_variance")

        col = split.column()
        col.prop(cam.pov, "dof_samples_max")
        col.prop(cam.pov, "dof_confidence")



class CAMERA_PT_povray_cam_nor(CameraDataButtonsPanel, bpy.types.Panel):
    bl_label = "POV-Ray Perturbation"
    COMPAT_ENGINES = {'POVRAY_RENDER'}

    def draw_header(self, context):
        cam = context.camera

        self.layout.prop(cam.pov, "normal_enable", text="")

    def draw(self, context):
        layout = self.layout

        cam = context.camera

        layout.active = cam.pov.normal_enable

        layout.prop(cam.pov,"normal_patterns")
        layout.prop(cam.pov,"cam_normal")
        layout.prop(cam.pov,"turbulence")
        layout.prop(cam.pov,"scale")


class CAMERA_PT_povray_replacement_text(CameraDataButtonsPanel, bpy.types.Panel):
    bl_label = "Custom POV Code"
    COMPAT_ENGINES = {'POVRAY_RENDER'}

    def draw(self, context):
        layout = self.layout

        cam = context.camera

        col = layout.column()
        col.label(text="Replace properties with:")
        col.prop(cam.pov, "replacement_text", text="")

###############################################################################
# Text Povray Settings
###############################################################################

class TEXT_OT_povray_insert(bpy.types.Operator):
    """Tooltip"""
    bl_idname = "text.povray_insert"
    bl_label = "Insert"

    filepath = bpy.props.StringProperty(name="Filepath", subtype='FILE_PATH')

    @classmethod
    def poll(cls, context):
        # context.area.type == 'TEXT_EDITOR'
        return bpy.ops.text.insert.poll()

    def execute(self, context):
        if self.filepath and isfile(self.filepath):
            file = open(self.filepath, "r")
            bpy.ops.text.insert(text=file.read())

            # places the cursor at the end without scrolling -.-
            # context.space_data.text.write(file.read())
            file.close()
        return {'FINISHED'}

def validinsert(ext):
	return ext in {".txt",".inc",".pov"}

class TEXT_MT_insert(bpy.types.Menu):
    bl_label = "Insert"
    bl_idname = "TEXT_MT_insert"

    def draw(self, context):
        pov_documents = locate_docpath()
        prop = self.layout.operator("wm.path_open", text="Open folder", icon='FILE_FOLDER')
        prop.filepath = pov_documents
        self.layout.separator()

        list=[]
        for root,dirs,files in os.walk(pov_documents):
            list.append(root)
        print(list)
        self.path_menu(list,
                       "text.povray_insert",
                       #{"internal": True},
					   filter_ext= validinsert
                       )

class TEXT_PT_povray_custom_code(TextButtonsPanel, bpy.types.Panel):
    bl_label = "POV-Ray"
    COMPAT_ENGINES = {'POVRAY_RENDER'}

    def draw(self, context):
        layout = self.layout

        text = context.space_data.text
            
        pov_documents = locate_docpath()
        if not pov_documents :
            layout.label(text="Please configure ", icon="INFO")
            layout.label(text="default pov include path ")
            layout.label(text="in addon preferences")
            #layout.separator()
            layout.operator("wm.addon_userpref_show",
                         text="Go to Render: POV-Ray addon",
                         icon="PREFERENCES").module = "render_povray"

            #layout.separator()
        else:
            #print(pov_documents)
            layout.menu(TEXT_MT_insert.bl_idname)

        if text:
            box = layout.box()
            box.label('Source to render:', icon='RENDER_STILL')
            row = box.row()
            row.prop(text.pov, "custom_code",expand = True)
            if text.pov.custom_code in {'3dview'}:
                box.operator("render.render", icon='OUTLINER_DATA_POSE')  
            if text.pov.custom_code in {'text'}:
                rtext = bpy.context.space_data.text
                box.operator("text.run", icon='POSE_DATA')
            #layout.prop(text.pov, "custom_code")
            elif text.pov.custom_code in {'both'}:
                box.operator("render.render", icon='POSE_HLT')
                layout.label(text="Please specify declared", icon="INFO")
                layout.label(text="items in properties ")
                #layout.label(text="")                
                layout.label(text="replacement fields")


###############################################
# Text editor templates from header menu

class TEXT_MT_templates_pov(bpy.types.Menu):
    bl_label = "POV-Ray"

    # We list templates on file evaluation, we can assume they are static data,
    # and better avoid running this on every draw call.
    import os
    template_paths = [os.path.join(os.path.dirname(__file__), "templates_pov")]

    def draw(self, context):
        self.path_menu(
            self.template_paths,
            "text.open",
            props_default={"internal": True},
        )

def menu_func_templates(self, context):
    # Do not depend on POV-Ray being active renderer here...
    self.layout.menu("TEXT_MT_templates_pov")