pyweb camera support (#1901)

* add media module

* add Device class to media

* add camera test example

* add snap, download and other convenience methods

* load devices automagically

* add draw method to canvas

* add docstring for download

* add docstrings to draw method

* add docstrings to snap

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* load devices as soon as the page loads

* solve conflict

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* remove display calls listing devices in camera example

* fix typos and other small errors

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* fix typo in docstring

* fix error message typo

* replace setAttribute on JS properties with accessors

* remove debug statement

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* add docstrings

* [pre-commit.ci] auto fixes from pre-commit.com hooks

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* add docstrings to camera example

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---------

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

pyscript.core/src/stdlib/pyweb/media.py

@@ -0,0 +1,95 @@
+from pyodide.ffi import to_js
+from pyscript import window
+
+
+class Device:
+    """Device represents a media input or output device, such as a microphone,
+    camera, or headset.
+    """
+
+    def __init__(self, device):
+        self._js = device
+
+    @property
+    def id(self):
+        return self._js.deviceId
+
+    @property
+    def group(self):
+        return self._js.groupId
+
+    @property
+    def kind(self):
+        return self._js.kind
+
+    @property
+    def label(self):
+        return self._js.label
+
+    def __getitem__(self, key):
+        return getattr(self, key)
+
+    @classmethod
+    async def load(cls, audio=False, video=True):
+        """Load the device stream."""
+        options = window.Object.new()
+        options.audio = audio
+        if isinstance(video, bool):
+            options.video = video
+        else:
+            # TODO: Think this can be simplified but need to check it on the pyodide side
+
+            # TODO: this is pyodide specific. shouldn't be!
+            options.video = window.Object.new()
+            for k in video:
+                setattr(
+                    options.video,
+                    k,
+                    to_js(video[k], dict_converter=window.Object.fromEntries),
+                )
+
+        stream = await window.navigator.mediaDevices.getUserMedia(options)
+        return stream
+
+    async def get_stream(self):
+        key = self.kind.replace("input", "").replace("output", "")
+        options = {key: {"deviceId": {"exact": self.id}}}
+
+        return await self.load(**options)
+
+
+async def list_devices() -> list[dict]:
+    """
+    Return the list of the currently available media input and output devices,
+    such as microphones, cameras, headsets, and so forth.
+
+    Output:
+
+        list(dict) - list of dictionaries representing the available media devices.
+            Each dictionary has the following keys:
+            * deviceId: a string that is an identifier for the represented device
+                that is persisted across sessions. It is un-guessable by other
+                applications and unique to the origin of the calling application.
+                It is reset when the user clears cookies (for Private Browsing, a
+                different identifier is used that is not persisted across sessions).
+
+            * groupId: a string that is a group identifier. Two devices have the same
+                group identifier if they belong to the same physical device — for
+                example a monitor with both a built-in camera and a microphone.
+
+            * kind: an enumerated value that is either "videoinput", "audioinput"
+                or "audiooutput".
+
+            * label: a string describing this device (for example "External USB
+                Webcam").
+
+    Note: the returned list will omit any devices that are blocked by the document
+    Permission Policy: microphone, camera, speaker-selection (for output devices),
+    and so on. Access to particular non-default devices is also gated by the
+    Permissions API, and the list will omit devices for which the user has not
+    granted explicit permission.
+    """
+    # https://developer.mozilla.org/en-US/docs/Web/API/MediaDevices/enumerateDevices
+    return [
+        Device(obj) for obj in await window.navigator.mediaDevices.enumerateDevices()
+    ]