Can I load an image from bytes?

[pudo]

It seems to me like setImage() basically just calls Pillow's save method and then loads the resulting byte stream into tesseract. Is there a way of loading a bytes object directly into Tesseract, without opening it in Pillow first?

[sirfz]

There's the SetImageBytes API method.

[pudo]

Sorry my ticket was very badly phrased. I saw that method, but the additional arguments it takes would require me to open the image first to inspect its metadata, anyway. Yet I saw that the setImage method internally just stuffs the saved image data into a pix, which seems much simpler. Can this be exposed, rather than the full signature of setImageBytes? Or can I pass stub defaults into setImageBytes, like -1?

[sirfz]

So basically you want a method which sets an image directly from a given bytes buffer. PRs are welcome.

[bertsky]

That cannot work. Tesseract's image datastructure pix (from Leptonica) needs to know what format the input is in. Either it's a full byte stream of some standard image format (recognizable by its header) – that's the alley SetImage() / PIL.Image.save() / pixReadMem() is taking –, or it's a raw byte stream and you pass its format (height, width, depth) explicitly – that's where SetImageBytes() will take you.

I recommend closing.

[nadirpajaro]

I'm interested too. could something like this work?

def SetImageMem(self, buffer):
    """Set image from buffer for Tesserac to recognize.

    Args:
        buffer (bytes): Buffer.

    Raises:
        :exc:`RuntimeError`: If for any reason the api failed
            to load the given image.
    """
    cdef:
        bytes raw = _b(buffer)
    with nogil:
        self._destroy_pix()
        self._pix = pixReadMem(raw, len(raw))
        if self._pix == NULL:
            with gil:
                raise RuntimeError('Error reading image')
        self._baseapi.SetImage(self._pix)