fps

import time

import bpy
import bgl
import blf


def draw_callback_px(self, context):
    bgl.glColor4f(1.0, 1.0, 1.0, 1.0)
    blf.position(0, 15, context.region.height - 60, 0)
    blf.size(0, 20, 72)
    blf.draw(0, '{0:06.2f} fps'.format(1.0 / self.timer.time_delta))
    bgl.glColor4f(0.0, 0.0, 0.0, 1.0)


class ModalDrawOperator(bpy.types.Operator):
    bl_idname = 'view3d.fps'
    bl_label = 'fps'

    def modal(self, context, event):
        #print(event.type, self.timer.time_delta, self.timer.time_duration, self.timer.time_step)
        if self._handle is None:
            for sa in context.screen.areas:
                if sa.type == 'VIEW_3D':
                    for ar in sa.regions:
                        if ar.type == 'WINDOW':
                            self._handle = ar.callback_add(draw_callback_px, (self, context), 'POST_PIXEL')
                            self._region = ar
                    break
        if event.type == 'IINBETWEEN_MOUSEMOVE':
            return {'PASS_THROUGH'}
        elif event.type == 'ESC':
            if self._handle is not None:
                self._region.callback_remove(self._handle)
            context.window_manager.event_timer_remove(self.timer)
        for sa in context.screen.areas:
            if sa.type == 'VIEW_3D':
                sa.tag_redraw()
        if event.type == 'ESC':
            return {'CANCELLED'}
        return {'PASS_THROUGH'}


    def invoke(self, context, event):
        self.timer = context.window_manager.event_timer_add(0.01, context.window)
        context.window_manager.modal_handler_add(self)

        if context.area.type == 'VIEW_3D':
            self._handle = context.region.callback_add(draw_callback_px, (self, context), 'POST_PIXEL')
            self._region = context.region
        else:
            self._handle = None

        return {'RUNNING_MODAL'}


def register():
    bpy.utils.register_class(ModalDrawOperator)


def unregister():
    bpy.utils.unregister_class(ModalDrawOperator)


if __name__ == '__main__':
    register()
    bpy.ops.view3d.fps('INVOKE_DEFAULT')