pages/001 link demo.py

### A link to download Qrcode

# this is demo is based on the topic discussed on stackoverflow
# https://stackoverflow.com/questions/78045476/streamlit-re-runs-app-on-button-click-delaying-download/79008691#79008691

import simplestart as ss

ss.md('''
#### In this demo, you can change the URL in the input to generate a QR code image. Click the link below to download it.
---
''')

import qrcode
from io import BytesIO
from PIL import Image

#api
def generate_qr_code(link):  # Generate QR Code
    qr = qrcode.QRCode(
        version=1.00,
        error_correction=qrcode.constants.ERROR_CORRECT_L,
        box_size=10,
        border=2,
    )
    qr.add_data(link)
    qr.make(fit=True)
    img = qr.make_image(fill_color="black", back_color="white")
    return img


def download_qr_code(img):  # Convert PIL image to bytes
    img_bytes = BytesIO()
    img.save(img_bytes, format='PNG')
    img_bytes.seek(0)
    return img_bytes

#event handler
def text_change(event):
    generate_img()
    
def generate_img():
    link = link_text.value
    qr_img = generate_qr_code(link)
    img = download_qr_code(qr_img)
    myimg.image = img
    
#ui
ss.write("# QR Code Generator")
link_text = ss.text_input("http://www.simplestart.cc", label = "Enter a link:", onchange = text_change, max_width = 600)
myimg = ss.image("", title='Generated QR Code', width=300, border= True)

generate_img()

ss.link("Download QR Code", myimg.image, file_name = "qr_code.png", mime = "image/png")


ss.space()
ss.md('''
---
### Related References:
[Streamlit Re-runs App on Button Click, Delaying Download](https://stackoverflow.com/questions/78045476/streamlit-re-runs-app-on-button-click-delaying-download) (stackoverflow)

[source code of this demo](https://github.com/readever/simplestart/tree/main/demo/stackoverflow/a%20link%20to%20download%20qrcode) (github)
''')