docstr: internal: read more image data
docstr_tok: ["internal",":","read","more","image","data"]
code: def load_read(self, read_bytes):
      """internal: read more image data"""
  
      while self.__idat == 0:
          # end of chunk, skip forward to next one
  
          self.fp.read(4)  # CRC
  
          cid, pos, length = self.png.read()
  
          if cid not in [b"IDAT", b"DDAT"]:
              self.png.push(cid, pos, length)
              return b""
  
          self.__idat = length  # empty chunks are allowed
  
      # read more data from this chunk
      if read_bytes <= 0:
          read_bytes = self.__idat
      else:
          read_bytes = min(read_bytes, self.__idat)
  
      self.__idat = self.__idat - read_bytes
  
      return self.fp.read(read_bytes)
  
imports: import logging
  import re
  import struct
  import zlib
  from .None import Image, ImageFile, ImagePalette
  from ._binary import i8, i16be, i32be, o16be, o32be
  from ._util import py3
label_desc: Use image node_id 5 for calling the PngImageFile obj's underlying member method code with example usage: obj.load_read(read_bytes) and returns: self, bytes