How to download matplotlib graphs generated in a Streamlit app-CodePudding

Is there any way to allow users to download a graph made using matplotlib/seaborn in a Streamlit app? I managed to get a download button working to download a dataframe as a csv, but I can't figure out how to allow users to download a graph. I have provided a code snippet below of the graph code.

Thank you for your help!

fig_RFC_scatter, ax = plt.subplots(1,1, figsize = (5,4))
ax = sns.scatterplot(data = RFC_results_df_subset, x = X_Element_RM, y = Y_Element_RM, hue = "F_sil_remaining", edgecolor = "k", legend = "full")
ax = sns.scatterplot(data = RFC_results_df_subset, x = X_Element_CM, y = Y_Element_CM, hue = "F_sil_remaining", edgecolor = "k", legend = None, marker = "s")
ax = plt.xlabel(X_Element_RM)
ax = plt.ylabel(Y_Element_RM)
ax = plt.xlim(x_min, x_max)
ax = plt.ylim(y_min, y_max)
ax = plt.xscale(x_scale)
ax = plt.yscale(y_scale)
ax = plt.axhline(y = 1, color = "grey", linewidth = 0.5, linestyle = "--")
ax = plt.axvline(x = 1, color = "grey", linewidth = 0.5, linestyle = "--")
ax = plt.legend(bbox_to_anchor = (1, 0.87), frameon = False, title = "% Sil. Remaining")
st.write(fig_RFC_scatter)

CodePudding user response：

Two approaches first save the image to file and offer for download and second save image to memory (no clutter on disk) and offer for download.

First

"""
Ref: https://docs.streamlit.io/library/api-reference/widgets/st.download_button
"""

import io

import matplotlib.pyplot as plt
import seaborn as sns
import streamlit as st 


X = [1, 2, 3, 4, 5, 6, 7, 8]
Y = [1500, 1550, 1600, 1640, 1680, 1700, 1760, 1800]
sns.scatterplot(x=X, y=Y)

# Save to file first or an image file has already existed.
fn = 'scatter.png'
plt.savefig(fn)
with open(fn, "rb") as img:
    btn = st.download_button(
        label="Download image",
        data=img,
        file_name=fn,
        mime="image/png"
    )

Second
Save to memory first.

fn = 'scatter.png'
img = io.BytesIO()
plt.savefig(img, format='png')
 
btn = st.download_button(
   label="Download image",
   data=img,
   file_name=fn,
   mime="image/png"
)

Downloaded file output