Dear Dash Python Community,
I created a Plotly subplot figure within my DashApp. I’m able to change the number of subplots by the help of the selection within a dropdown menu.
That works fine so far.
I have to ensure a square aspect ratio for all subplots.
The positioning and scaling of my subplots gets disturbed as soon as I’m using the update_xaxes function and fix the “scaleanchor” to the corresponding y axis.
The layout and the size of my individual subplot now depends on the number of subplots in the initial callback. I can change the inital number of subplot from my dropdown menu as I simply prevent the initial call. I have to reload my webbrowser/ DashApp to be able to change this behavior.
Is there a way to “reload” the initial state of the Callback function or is there any other way to ensure a square aspect ratio?
I highly appreciate any comments and help!
Plotly Version: 5.16.1
Dash Version: 2.12.1
Here comes the code:
app = Dash(__name__)
app.layout = html.Div([
dcc.Dropdown(
id='subplot-dropdown',
options=[
{'label': '1 Subplot', 'value': 1},
{'label': '2 Subplots', 'value': 2},
{'label': '3 Subplots', 'value': 3},
{'label': '4 Subplots', 'value': 4}
],
value = 1
),
dcc.Graph(id='subplot-fig', style = {'width' : '80vw','height' : '80vh'},
config= {'responsive' : True} )
])
@app.callback(
Output('subplot-fig', 'figure'),
Input('subplot-dropdown', 'value'),
prevent_initial_call=True
)
def update_subplot_figure(selected_value):
# Define a dictionary to map selected_value to rows and cols
subplots_mapping = {
1: (1, 1,),
2: (1, 2,),
3: (2, 2,),
4: (2, 2,)
}
rowsi, colsi = subplots_mapping[selected_value]
subplots_position = {
0: (1, 1),
1: (1, 2),
2: (2, 1),
3: (2, 2)
}
fig = make_subplots(rows = rowsi, cols = colsi)
# add traces to the subplot, dependend on the dropdwon value
for i in range(selected_value):
# defien the row and col for the subplot
rowi, coli = subplots_position[i]
fig.add_trace(go.Scatter(name = f'Legendtext {i}',
x = [0,1,1,0,0,1,1,2,2,3,3,2,2,3], y = [0,0,1,1,3,3,2,2,3,3,1,1,0,0] ),
row= rowi,
col= coli,
)
# force a square aspect ratio for every subplot (could also do this in a loop)...here comes the problem
fig.update_xaxes(scaleanchor = 'y1', scaleratio = 1, row = 1, col =1)
fig.update_xaxes(scaleanchor = 'y2', scaleratio = 1, row = 1, col =2)
fig.update_xaxes(scaleanchor = 'y3', scaleratio = 1, row = 2, col =1)
fig.update_xaxes(scaleanchor = 'y4', scaleratio = 1, row = 2, col =2)
return fig
if __name__ == '__main__':
app.run_server(debug=True)
