Widget update in ScrollView

[Tomaz]

Dear all,

I have a question regarding widgets update in ScrollView. 

1) I have a grid (GridLayout)

devices_grid_rows = GridLayout(rows=12, cols=16, row_default_height=58, col_default_width=50, size_hint_y=None)

2) I add widget to every address in this grid (12x16)

devices_grid = devices_grid_rows

        for x in xrange(0, num_devices):

            devices_address[x].reset()

            devices_grid.add_widget(devices_address[x])

3) Since ScrollView accept only one widget, I put all these widgets together

        self.add_widget(devices_grid)

Every widget in a grid (12x16) has a couple of labels (text which is updating). My problem is if I change only one label in one widget in a grid the whole grid refreshes (all elements). If there are not many updates on widgets in a grid, then FPS (frame per second) is suitable, but if there are more updates on separate widgets in a grid, the FPS drops significantly. So for every change in a grid, the whole screen is refreshed (main widget which consists of the grid). Is it possible to refresh only the widget that changes the data and not the entire main widget (grid)? Or is it there any other solution that can fix my problem?

Best regards.

[Elliot Garbus]

If you have a small executable example, it is easier to provide feedback.

 

Here are a few thoughts:

1. The size_hint_x is defaulting to 1, can you fix the size? Ie size_hint: None, None.
2. How are you updating the Labels?  Are you using a Kivyproperty?
3. Is the size causing the layout to recalculate?
4. Profile the code that does the refresh to see where time is being spent.

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[Tomaž - bolha]

Hi Elliot,
Thanks for the feedback. I will try to provide more exact information on how code is working.

1) Yes, I can fix the size, but this does not change anything :)
2) Yes, kivyproperty is used for updating.

The basic code structure is seen in the picture below. FPS drops with a number of 'elements' in the grid even if the update is always the same. So for every single change in the grid, the whole grid update.

class FboGridLayout(GridLayout):
    texture = ObjectProperty(None, allownone=True)

    alpha = NumericProperty(1)

    def __init__(self, **kwargs):
        self.canvas = Canvas()
        self.border = Fbo(size=(kwargs['col_default_width'], kwargs['row_default_height']))
        with self.border:
            Color(0, 0, 1, 1)
            Line(rectangle=(0, 0, kwargs['col_default_width'], kwargs['row_default_height']), width=20)

        with self.canvas:
            self.fbo = Fbo(size=self.size)
            self.fbo_color = Color(1., 1., 1., 1.)
            self.fbo_rect = Rectangle()

        with self.fbo:
            ClearColor(0, 0, 0, 0)
            ClearBuffers()

        # wait that all the instructions are in the canvas to set texture
        self.texture = self.fbo.texture
        super(FboGridLayout, self).__init__(**kwargs)

    def add_widget(self, *largs):
        # trick to attach graphics instruction to fbo instead of canvas
        canvas = self.canvas
        self.canvas = self.fbo
        ret = super(FboGridLayout, self).add_widget(*largs)
        self.canvas = canvas
        return ret

    def remove_widget(self, *largs):
        canvas = self.canvas
        self.canvas = self.fbo
        super(FboGridLayout, self).remove_widget(*largs)
        self.canvas = canvas

    def on_size(self, instance, value):
        self.fbo.size = value
        self.texture = self.fbo.texture
        self.fbo_rect.size = value

    def on_pos(self, instance, value):
        self.fbo_rect.pos = value

    def on_texture(self, instance, value):
        self.fbo_rect.texture = value

    def on_alpha(self, instance, value):
        self.fbo_color.rgba = (1, 1, 1, value)


number_of_devices = 192

devices=[]
add_dev=[]

grid_dev_192 = GridLayout(rows=12, cols=16, row_default_height=58, col_default_width=50, size_hint_y=None)

class DItem(RelativeLayout):
    sqr_n = NumericProperty(0)

    def __init__(self, **kwargs):
        super(DItem, self).__init__(**kwargs)
        app = App.get_running_app()
        self.dev_lay = app.devices_view
        self.large_view = app.large_view

    def on_touch_down(self, touch):
        if (self.collide_point(*touch.pos) and not touch.is_mouse_scrolling
                and self.parent.parent.parent.parent.parent.parent._anim_progress <= 0.1):
            touch.grab(self)
            whole_view = App.get_running_app().whole_view
            self.parent.parent.singlesqr_n.sqr_n = self.sqr_n
            whole_view.selection_pl_start = self.sqr_n
            whole_view.selection_pl = False
            Clock.schedule_once(whole_view.selection_st, .5)
            return True

    def on_touch_move(self, touch):
        if self.collide_point(*touch.pos):
            whole_view = App.get_running_app().whole_view
            if whole_view.selection_pl:
                whole_view.update_poll_ran_sqr_n(self.sqr_n)
                return True
            elif self.parent.parent.singlesqr_n.sqr_n <> self.sqr_n:
                Clock.unschedule(whole_view.selection_st)

    def on_touch_up(self, touch, *args):
        whole_view = App.get_running_app().whole_view

        touch.ungrab(self)
        whole_view.prevent_selection_pl()

        if not touch.ud.get('ignore-up', False):
            if self.collide_point(*touch.pos) and not touch.is_mouse_scrolling:

                time = touch.time_end - touch.time_start
                if (time < 0.3 and self.parent.parent.singlesqr_n.sqr_n == self.sqr_n
                        and self.parent.parent.parent.parent.parent.parent._anim_progress <= 0.1
                        and self.parent.parent.parent.parent._anim_progress <= 0.1
                        and abs(touch.oy - touch.y) < 30):
                    touch.ud['ignore-up'] = True
                    if self.polling:
                        self.on_touch_up_action()
                    else:
                        whole_view.reset_poll_ran()
                    return True


class Devicesqr_n(DItem):
    data = DictProperty({'pre_em': True, 'double_err': False, 'series': '', 'type': '', 'value_a': -1})
    bg_color = ListProperty([.2, .2, .2, .1])

    def __init__(self, **kwargs):
        super(Devicesqr_n, self).__init__(**kwargs)
        self.sqr_n_label_white = CoreLabel(text=str(self.sqr_n),
                                             font_size=12, bold=True,
                                             color=(1., 1., 1., 1.))

        self.sqr_n_label_white.refresh()
        self.sqr_n_label_black = CoreLabel(text=str(self.sqr_n),
                                             font_size=12, color=(0., 0., 0., 1.))
        self.sqr_n_label_black.refresh()
        self.series_label = CoreLabel(text='', font_size=10,
                                      color=(0., 0., 0., 1.), bold=self.large_view)
        self.series_label.refresh()
        self.type_label = CoreLabel(text='', font_size=17,
                                    color=(0., 0., 0., 1.), bold=self.large_view)
        self.type_label.refresh()
        with self.canvas:
            Color(1, 1, 1, 1)
            self.sqr_n_rect = Rectangle(pos=((2, 40)),
                                          texture=self.sqr_n_label_white.texture,
                                          size=self.sqr_n_label_white.texture.size)

    def on_touch_up_action(self):
        self.dev_lay.singlesqr_n.pre_open()

    def reset(self):
        self.parent = None
        self.data = {'pre_em': True, 'double_err': False, 'series': '', 'type': '', 'value_a': -1}
        self.bg_color = (.2, .2, .2, 1.)
        self.series_label.text = ''
        self.series_label.refresh()
        self.type_label.text = ''
        self.type_label.refresh()
        self.canvas.clear()
        with self.canvas:
            Color(1, 1, 1, 1)
            self.sqr_n_rect = Rectangle(pos=((2, 40)),
                                          texture=self.sqr_n_label_white.texture,
                                          size=self.sqr_n_label_white.texture.size)

    # @mainthread
    def update(self, data):

        App.get_running_app().devices_updated[self.sqr_n - 1] = True
        change = False
        bg_color = self.bg_color

        if data['pre_em'] <> self.data['pre_em'] or data['double_err'] <> self.data['double_err']:
            change = True
            if data['pre_em']:
                bg_color = [.2, .2, .2, 1.]
            elif data['pre_em'] == None:
                bg_color = [.0, .0, .0, 1.]
            elif data['double_err']:
                bg_color = [.65, .3, 1., 1.]
            else:
                bg_color = [1., 1., 1., 1.]

        try:
            if data['series'] <> self.data['series']:
                change = True
                self.series_label.text = data['series']
                self.series_label.refresh()
            if data['type'] <> self.data['type']:
                change = True
                self.type_label.text = data['type']
                self.type_label.refresh()
            if data['value_a'] <> self.data['value_a']:
                if data['value_a'] > -1:
                    value_a = data['value_a']
                    if value_a < 8:
                        bg_color = [.594, .594, 1., 1.]
                    elif value_a < 45:
                        bg_color = [.414, .829, .414, 1.]
                    elif value_a < 55:
                        bg_color = [.72, .72, .36, 1.]
                    else:
                        bg_color = [1., .5, .5, 1.]

            if self.bg_color <> bg_color:
                change = True
                self.bg_color = bg_color

            if change:
                self.data = data
                self.canvas.clear()
                with self.canvas:
                    Color(1, 1, 1, 1)
                    if data['pre_em']:
                        self.sqr_n_rect = Rectangle(pos=((5, 48) if self.large_view else (2, 40)),
                                                      texture=self.sqr_n_label_white.texture,
                                                      size=self.sqr_n_label_white.texture.size)
                    elif data['pre_em'] == None:
                        self.sqr_n_rect = Rectangle(pos=((5, 48) if self.large_view else (2, 40)),
                                                      texture=self.sqr_n_label_white.texture,
                                                      size=self.sqr_n_label_white.texture.size)
                    else:
                        self.sqr_n_rect = Rectangle(pos=((5, 48) if self.large_view else (2, 40)),
                                                      texture=self.sqr_n_label_black.texture,
                                                      size=self.sqr_n_label_black.texture.size)
                        Rectangle(pos=((95 if self.large_view else 47) - self.series_label.texture.size[0],
                                       (47 if self.large_view else 42)),
                                  texture=self.series_label.texture, size=self.series_label.texture.size)
                        Rectangle(pos=((49 if self.large_view else 24) - self.type_label.texture.size[0] / 2,
                                       5 if self.large_view else 10),
                                  texture=self.type_label.texture, size=self.type_label.texture.size)
                    self.previous_sqr_n_rect = self.sqr_n_rect
            if data['pre_em'] != None:
                if not self.selected:
                    if data['pre_em']:
                        self.sqr_n_rect.texture = self.sqr_n_label_black.texture
                        self.sqr_n_rect.size = self.sqr_n_label_black.texture.size
                    else:
                        self.sqr_n_rect.texture = self.sqr_n_label_white.texture
                        self.sqr_n_rect.size = self.sqr_n_label_white.texture.size
                    self.selected = True
                else:
                    if self.data['pre_em']:
                        self.sqr_n_rect.texture = self.sqr_n_label_white.texture
                        self.sqr_n_rect.size = self.sqr_n_label_white.texture.size
                    else:
                        self.sqr_n_rect.texture = self.sqr_n_label_black.texture
                        self.sqr_n_rect.size = self.sqr_n_label_black.texture.size
        except KeyError:
            print 'File: %s; Line: %s -> I got a KeyError - ' % (
            os.path.basename(sys.argv[0]), lineno())

    def deselect(self, data):
        if data['pre_em'] != None:
            if data['pre_em']:
                self.sqr_n_rect.texture = self.sqr_n_label_white.texture
                self.sqr_n_rect.size = self.sqr_n_label_white.texture.size
            else:
                self.sqr_n_rect.texture = self.sqr_n_label_black.texture
                self.sqr_n_rect.size = self.sqr_n_label_black.texture.size
            self.selected = False

class DevView(ScrollView):
    current_view = 'Basic1 view'

    def __init__(self, **kwargs):
        super(DevView, self).__init__(**kwargs)
        app = App.get_running_app()

    def start_operation_b(self, *args):
        global devices
        global add_dev
        app = App.get_running_app()
        self.current_view = 'operation_b'
        app.info_overlay = self.operation_b_info_overlay
        whole_view = app.whole_view
        whole_view.close_navigation_drawer_scheduler()
        whole_view.title.text = tr._('operation_b')

        self.clear_widgets()

        grid_dev = grid_dev_192
        grid_dev.clear_widgets()
        grid_dev.parent = None

        self.scroll_y = 1
        for x in xrange(0, number_of_devices):
            add_dev[x].reset()
            add_dev[x].selected = False
            grid_dev.add_widget(add_dev[x])
        self.add_widget(grid_dev)
        whole_view.loop_index = number_of_devices
        devices = add_dev
        app.disable_updates = False

        whole_view.update_poll_ran()

    # r - currently selected menu (1-disable updates, 2-operation_b, 3-mode and polling LED, etc.)
    previous_sqr_n = -1

    @mainthread
    def update_sqr_n(self, sqr_n, data):
        if self.update_block and sqr_n != 1:
            print "operation_b - update block"
        else:
            self.update_block = False
            global number_of_devices
            if App.get_running_app().disable_updates:
                self.r = 1
                return
        
            device = add_dev[sqr_n - 1]
            if self.r != 1:
                if self.previous_sqr_n > -1:
                    if self.r not in [3, 4, 5, 6, 7]:  # deselect only if current menu is used
                        previous_device = add_dev[self.previous_sqr_n]
                        previous_device.deselect(self.previous_data)
                    else:  # otherwise just change to current menu
                        self.previous_sqr_n = 0
                        self.r = 2
                device.update(data)
                self.previous_sqr_n = sqr_n - 1
                self.previous_data = data
            else:  # if update is not available do not use deselect option
                device.update(data)
                self.previous_sqr_n = sqr_n - 1
                self.previous_data = data
                self.r = 2

#kivy#
< Devicesqr_n >:
polling: True
selected: False
size_hint: 1, 1
opacity: 1 if self.polling else .3
canvas.before:
    Color:
        rgba: self.bg_color
    Rectangle:
        pos: 0, 1
        size: (self.width - 1, self.height - 1)

V V čet., 30. jul. 2020 ob 18:44 je oseba Elliot Garbus <elli...@cox.net> napisala:

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[Elliot Garbus]

Taking a look at your code I see something that could be an issue.  I don’t think you are canceling the schedule. This could cause a significant performance issue.  In the code:

 

def on_touch_down(self, touch):
    if (self.collide_point(*touch.pos) and not touch.is_mouse_scrolling
            and self.parent.parent.parent.parent.parent.parent._anim_progress <= 0.1):
        touch.grab(self)
        whole_view = App.get_running_app().whole_view
        self.parent.parent.singlesqr_n.sqr_n = self.sqr_n
        whole_view.selection_pl_start = self.sqr_n
        whole_view.selection_pl = False
        Clock.schedule_once(whole_view.selection_st, .5)
        return True

def on_touch_move(self, touch):
    if self.collide_point(*touch.pos):
        whole_view = App.get_running_app().whole_view
        if whole_view.selection_pl:
            whole_view.update_poll_ran_sqr_n(self.sqr_n)
            return True
        elif self.parent.parent.singlesqr_n.sqr_n <> self.sqr_n:
            Clock.unschedule(whole_view.selection_st)

 

Add self.schedule to the __init__()

Change:

Clock.schedule_once(whole_view.selection_st, .5)

To:

self.schedule = Clock.schedule_once(whole_view.selection_st, .5)

 

and Change:

Clock.unschedule(whole_view.selection_st)

self.schedule.cancel()

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[Tomaž - bolha]

Elliot,
thank you for your reply. I try it, but it does not see that scheduler causes the problem. When I was testing different scenarios, it seems like every additional element in the grid causes fps drop. So the scroll view main widget (whole grid) is updated with every change on the widget inside one element of this grid. Is it possible to update only one part of the main widget and not the whole one?

V V pet., 31. jul. 2020 ob 15:44 je oseba Elliot Garbus <elli...@cox.net> napisala:

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[Elliot Garbus]

Profile to code to see where time is being spent.

https://kivy.org/doc/stable/api-kivy.app.html#profiling-with-on-start-and-on-stop

 

Or provide an executable example.  It’s tough to see what is going on just looking at a code sample.

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[Tomaž - bolha]

Thanks Elliot,

I will try to prepare an executable example and I will also try the first option. Based on my today's testing I found this...

If I comment part of the code below (texture change) I get FPS which is enough for my application. Is any option of how texture can be changed in a more elegant manner?

V V ned., 2. avg. 2020 ob 15:27 je oseba Elliot Garbus <elli...@cox.net> napisala:

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