Show images inline in jupyter notebook

[gerritholl]

Feature Request

Is your feature request related to a problem? Please describe.

I don't know if this is the correct place to report this, because I don't know how inline visualisation in jupyter works.

When I use satpy's sc.show(...), the result is displayed inline in a jupyter notebook.

When I use trollimages xrimage.show(...), a popup window appears.

The second command results in a popup window.

Describe the solution you'd like

I would like that im.show() shows the image in-line in a jupyter notebook.

Describe any changes to existing user workflow

Users may see a change in behaviour when using trollimage through a jupyter notebook.

Additional context

[djhoese]

Perhaps counter-intuitively Satpy's Scene returns the Pillow Image object when in a notebook which is then displayed inline. If it is not in a notebook then it calls Image.show():

https://github.com/pytroll/satpy/blob/930d8fc60f1e6f0066d5babf8685001702328b92/satpy/scene.py#L1034-L1037

        img = get_enhanced_image(self[dataset_id].squeeze(), overlay=overlay)
        if not in_ipynb():
            img.show()
        return img

Even more interesting, I think if you just do im (as in "show me the representation of the value of the XRImage") then it should also show it inline as a PNG:

trollimage/trollimage/xrimage.py

Lines 1658 to 1662 in 19697c4

	def _repr_png_(self):
	import io
	b = io.BytesIO()
	self.pil_image().save(b, format='png')
	return b.getvalue()

[djhoese]

We should probably take a page out of Pillow's book and implement all these _repr_ methods:

    def __repr__(self) -> str:
        return (
            f"<{self.__class__.__module__}.{self.__class__.__name__} "
            f"image mode={self.mode} size={self.size[0]}x{self.size[1]} "
            f"at 0x{id(self):X}>"
        )

    def _repr_pretty_(self, p: PrettyPrinter, cycle: bool) -> None:
        """IPython plain text display support"""

        # Same as __repr__ but without unpredictable id(self),
        # to keep Jupyter notebook `text/plain` output stable.
        p.text(
            f"<{self.__class__.__module__}.{self.__class__.__name__} "
            f"image mode={self.mode} size={self.size[0]}x{self.size[1]}>"
        )

    def _repr_image(self, image_format: str, **kwargs: Any) -> bytes | None:
        """Helper function for iPython display hook.

        :param image_format: Image format.
        :returns: image as bytes, saved into the given format.
        """
        b = io.BytesIO()
        try:
            self.save(b, image_format, **kwargs)
        except Exception:
            return None
        return b.getvalue()

    def _repr_png_(self) -> bytes | None:
        """iPython display hook support for PNG format.

        :returns: PNG version of the image as bytes
        """
        return self._repr_image("PNG", compress_level=1)

    def _repr_jpeg_(self) -> bytes | None:
        """iPython display hook support for JPEG format.

        :returns: JPEG version of the image as bytes
        """
        return self._repr_image("JPEG")

[gerritholl]

Even more interesting, I think if you just do im (as in "show me the representation of the value of the XRImage") then it should also show it inline as a PNG.

Ah, indeed. Replacing im.show() by im does show me the image inline.

[djhoese]

Pull requests welcome on making .show work as expected.