flet-printing

Native print dialog / share sheet for Flet apps — wraps the Flutter printing package.

Flet has no built-in printing API. Flutter has a mature one. This extension bridges the gap, the same way official extensions like flet-audio wrap audioplayers.

The demand is documented: flet-dev/flet#894 (Jan 2023) asked for exactly this — PDF printing via the printing package — was closed as "completed" without a shipped solution, and the follow-up question "What's the completed solution for this?" (Feb 2024) was never answered. This package is that answer.

日本語補足: Fletには印刷APIがありません（0.85時点・全API確認済み）。 Flutterのprintingパッケージ（ネイティブ印刷ダイアログ・共有シート）を Flet拡張として包んだものです。ワープロ的なアプリの「ファイル→印刷…」を Fletで実装できます。

Usage

import flet as ft
from flet_printing import Printing

def main(page: ft.Page):
    printing = Printing()
    page.services.append(printing)

    async def print_click(e):
        pdf = open("document.pdf", "rb").read()
        sent = await printing.print_pdf(pdf, name="document")
        # sent=True: 印刷された / False: ダイアログでキャンセル

    page.add(ft.FilledButton("印刷…", on_click=print_click))

ft.run(main)

API:

• await printing.print_pdf(pdf, name="document") — open the platform print dialog (printer selection / copies / duplex / save-as-PDF) for the given PDF bytes. Returns False if the user cancelled.
• await printing.share_pdf(pdf, filename="document.pdf") — open the platform share sheet (mobile) / save dialog (desktop).

PdfPreview — display a PDF with print/share built in

from flet_printing import PdfPreview

page.add(PdfPreview(src=pdf_bytes, pdf_file_name="document.pdf",
                    expand=True))

Renders the PDF pages (scrollable) with an action bar: print and share buttons work out of the box. Properties: src (bytes or base64), allow_printing, allow_sharing, use_actions, pdf_file_name, on_printed/on_shared events. can_change_page_format / can_change_orientation are off by default (the PDF you pass is already laid out).

There is deliberately no HTML-to-PDF here: printing's convertHtml is deprecated. Generate the PDF yourself (e.g. headless Chrome for exact CJK typesetting) and pass the bytes to print_pdf.

Installation

Like every third-party Flet extension, this works with apps compiled via flet build (the prebuilt flet run client only bundles official extensions).

Add to your app's pyproject.toml:

dependencies = [
  "flet-printing",
  "flet>=0.85.3",
]

then flet build linux (or windows / macos / apk / ipa).

A runnable example lives in examples/flet_printing_example (build verified on Linux: extension registers, app launches, print dialog opens from the button).

Platform support

Follows the printing package: Android / iOS / macOS / Windows / Linux (via CUPS) / web. See the printing package docs for details.

License

MIT