Method rows_from_interlace

_plotly_utils/png.py:1821–1833

Yield each row from an interlaced PNG.

()

        if self.interlace:

            def rows_from_interlace():
                """Yield each row from an interlaced PNG."""
                # It's important that this iterator doesn't read
                # IDAT chunks until it yields the first row.
                bs = bytearray(itertools.chain(*raw))
                arraycode = "BH"[self.bitdepth > 8]
                # Like :meth:`group` but
                # producing an array.array object for each row.
                values = self._deinterlace(bs)
                vpr = self.width * self.planes
                for i in range(0, len(values), vpr):
                    row = array(arraycode, values[i : i + vpr])
                    yield row

            rows = rows_from_interlace()
        else: