.. _changelog_v4_2_2:

v4.2.2
======

v4.2.2 adds **PNG image support** (decode/encode via lodepng), a table-driven
built-in-model loader, Portenta OV5640 support, an Edge-Impulse TensorFlow
update, and ulab 4.0. The RPC CAN configuration API changed — read the
breaking changes below.

.. contents:: On this page
   :local:
   :depth: 1

Highlights
----------

- **PNG support** — ``Image.to_png()``, ``image.PNG``, and PNG file
  read/write.
- ``tf.load_builtin_model()`` — table-driven built-in models that can be
  replaced or added at build time.
- **Portenta H7** — OV5640 camera support (with autofocus).
- **MicroPython/ulab** — ulab updated to 4.0.0.
- **Breaking:** the RPC CAN configuration API changed — see the breaking
  changes.

New features
------------

- **PNG image format** — a new ``Image.to_png()`` method, an ``image.PNG`` /
  ``PIXFORMAT_PNG`` constant, PNG file load/save (read/write ``.png``), and
  PNG output in ``image.to()`` conversions, via the integrated lodepng codec.
- ``tf.load_builtin_model(path)`` — loads a firmware-built-in model and
  returns a ``(labels, net)`` tuple; built-in models are now table-driven so
  they can be replaced or added at build time.

Other changes and improvements
------------------------------

- **TensorFlow / Edge Impulse** — the bundled inference library was updated to
  Edge Impulse ei-V2.5.0, the ``person_detection`` model moved into the
  built-in model table, and missing TensorFlow operators were added across all
  Cortex-M0+/M4/M7/M55 builds so more Edge Impulse models run.
- **ulab updated to 4.0.0.**
- Opening the USB virtual serial port at 1200 bps now triggers an
  Arduino-style touch reset into the bootloader.
- The WINC1500 WiFi module firmware was updated to 19.7.6 (with the updater
  script), and it now reports the actual host-driver version.
- The RP2 port prints "MPY: soft reboot" and gained UART init/de-init.

Bug fixes
---------

- Fixed the Arduino Nano RP2040 Connect raw frame-buffer size and the Arduino
  Nicla Vision USB Product ID (correct USB enumeration).

Hardware and board support
--------------------------

- **Arduino Portenta H7** — OV5640 camera support (with autofocus); the
  GC2145 is disabled on the Portenta.
- **Arduino Nano RP2040 Connect** — memory configuration and fresh-filesystem
  templates.
- **WiFi Shield (WINC1500)** — firmware updated to 19.7.6.

Breaking API changes
--------------------

User-visible API breaks between v4.2.1 and v4.2.2. Scope: Python C-modules in
``modules/`` and Python libraries in ``scripts/libraries/``.

Each change is tagged with its impact:

- *minor* — narrow API; only affects scripts that used it.
- *behavior* — same API, different results; re-check tuned scripts.

Changes are grouped by impact in that order. Each commit hash links to its
diff on GitHub.

.. _v4_2_2_rpc_can:

RPC CAN configuration API *(minor)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

In the :mod:`rpc` library, the ``rpc_can_master`` / ``rpc_can_slave`` CAN keyword
argument ``sampling_point`` was renamed to ``sample_point`` (to match upstream
MicroPython), and the manual CAN bit-timing helper was removed — the CAN bus
is now configured via ``CAN(..., baudrate=, sample_point=)``. Scripts that
passed ``sampling_point`` or relied on the old bit-timing computation must be
updated.

*Commits:* `b565eca58 <https://github.com/openmv/openmv/commit/b565eca58>`__,
`06d716986 <https://github.com/openmv/openmv/commit/06d716986>`__

.. _v4_2_2_format:

``image.format()`` and compressed images *(behavior)*
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

With the unified compressed-image path added for PNG, ``image.format()`` now
returns ``PIXFORMAT_INVALID`` for an unknown format, and compressed-image
indexing / iteration / printing now covers PNG as well as JPEG. Code that
inspected the previous return value for unknown formats should be re-checked.

*Commit:* `f12a4659c <https://github.com/openmv/openmv/commit/f12a4659c>`__

Migration checklist
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

For a clean port to v4.2.2: rename RPC CAN ``sampling_point`` → ``sample_point``
and drop any manual CAN bit-timing setup
(:ref:`the RPC CAN change <v4_2_2_rpc_can>`), and re-check any code that
inspected ``image.format()`` for unknown formats
(:ref:`the format() change <v4_2_2_format>`).