Package: dash-loading-spinners
Dash Loading SpinnersThis library is designed for use withPlotly Dash. The components have all been
designed to provide functionality similar to Dash's coreLoadingcomponent,
and will display a loading spinner whilst the underlying children are re-rendering.The spinners in it have been adapted for use from a number of other existing
libraries:react-spinnersreact-loader-spinnerreact-css-spinnersThe majority of spinner names have been retained from the originals, but some have
been amended where there were name clashes.More details on the components and usage can be found in ourdocumentation.InstallationDash Loading Spinners is available throughPyPI, and can be installed with pip:pipinstalldash-loading-spinnersBasic UsageOnce installed, you can make use of the components (in their most basic sense) as follows:importdashimportdash_loading_spinnersasdlsapp=dash.Dash()app.layout=dls.Hash()if__name__=="__main__":app.run_server()There are a number of attributes which are common across all spinners. These are:id(string; optional):
The ID of this component, used to identify dash components in
callbacks. The ID needs to be unique across all of the components
in an app.children(a list of or a singular dash component, string or number; optional):
The children of this component.show_initially(boolean; defaultTrue):
Whether the Spinner should show on app start-up before the loading
state has been determined. Default True.debounce(number; default0):
When using the spinner as a loading spinner, add a time delay (in
ms) to the spinner being removed to prevent flickering.fullscreen(boolean; optional):
Boolean that determines if the loading spinner will be displayed
full-screen or not.fullscreenClassName(string; optional):
CSS class names to apply to the container when in fullscreen.fullscreen_style(dict; optional):
Defines CSS styles for the container when in fullscreen.Many spinners additional have properties that can be customised, including colour and size. You
can find these on the individualcomponentpages.Realistically, as part of an application, you will be using them alongside other components and
callbacks. Here is an example of what this might look like:Note:dash-bootstrap-componentsisn't necessary fordash-loading-spinnersto work, but has been included
to improve the layout.# app.pyimportdashimportdash_bootstrap_componentsasdbcimportdash_loading_spinnersasdlsfromdashimportdcc,html,Input,Outputfromhelpersimportget_new_graphapp=dash.Dash(external_stylesheets=[dbc.themes.UNITED])app.layout=html.Div([dbc.Row([dbc.Col(html.Div(dbc.Button("Simulate slow loading component",id="loading-button",className="btn-success",n_clicks=0,)),md=3,),dbc.Col(dls.Hash(dcc.Graph(id="loading-output",),color="#435278",speed_multiplier=2,size=100,),md=9,),],),])@app.callback(Output("loading-output","figure"),[Input("loading-button","n_clicks")],)defload_output(n):# See note belowreturnget_new_graph(n)if__name__=="__main__":app.run_server()The functionget_new_graphin this example is deliberately ambiguous, as it simply acts as a placeholder for any slow-loading component. For completeness, if you wish to use a similar example to the one shown above, you can use the following function:# helpers.pyimportnumpyasnpimportplotly.graph_objectsasgoimporttimedefget_new_graph(n):ifn:# Simulate slow-loading componenttime.sleep(2)# Generate a random scatter plotn=(n+1)*10returngo.Figure(data=go.Scatter(y=np.random.randn(n)*100,mode="markers",marker=dict(size=16,color=np.random.randn(n)*100,colorscale="blues",showscale=True,),),layout=go.Layout(title="This graph takes ages to re-load"),)