Fade effect of text/image widgets

fade_on_click.lua

local fade_widget = wibox.widget {
    {
        id = 'icon',
        image = '/usr/share/icons/Yaru/24x24/apps/org.gnome.PowerStats.png',
        widget = wibox.widget.imagebox
    },
    {
        id = 'text',
        text = 'Click to fade',
        widget = wibox.widget.textbox
    },
    spacing = 4,
    layout = wibox.layout.fixed.horizontal,
    toggle_fade = function(self, is_fade)
        self:get_children_by_id('icon')[1]:set_opacity(is_fade and 0.2 or 1)
        self:get_children_by_id('icon')[1]:emit_signal('widget::redraw_needed')
        self:get_children_by_id('text')[1]:set_opacity(is_fade and 0.2 or 1)
        self:get_children_by_id('text')[1]:emit_signal('widget::redraw_needed')
    end
}

-- on click
local faded = true
fade_widget:connect_signal('button::press', function(c)
    faded = not faded
    c:toggle_fade(not faded)
end)

-- on hover
fade_widget:toggle_fade(true)
fade_widget:connect_signal('mouse::enter', function(c) c:toggle_fade(false) end)
fade_widget:connect_signal('mouse::leave', function(c) c:toggle_fade(true) end)