class_docstr: **Bases:** :class:`GraphicsObject <pyqtgraph.GraphicsObject>`
class_docstr_tok: ["*","*","Bases",":","*","*",":","class",":","`","GraphicsObject","<","pyqtgraph.GraphicsObject",">","`"]
docstr: Estimates the min/max values of the image data by subsampling.
  Subsampling is performed at regular strides chosen to evaluate a number of samples
  equal to or less than `targetSize`.
  
  Returns (`min`, `max`).
docstr_tok: ["Estimates","the","min\/max","values","of","the","image","data","by","subsampling",".","Subsampling","is","performed","at","regular","strides","chosen","to","evaluate","a","number","of","samples","equal","to","or","less","than","`","targetSize","`",".","Returns","(","`","min","`",",","`","max","`",")","."]
code: def quickMinMax(self, targetSize=1e6):
      """
      Estimates the min/max values of the image data by subsampling.
      Subsampling is performed at regular strides chosen to evaluate a number of samples
      equal to or less than `targetSize`.
  
      Returns (`min`, `max`).
      """
      data = self.image
      if targetSize < 2:  # keep at least two pixels
          targetSize = 2
      while True:
          h, w = data.shape[:2]
          if h * w <= targetSize:
              break
          if h > w:
              data = data[::2, ::]  # downsample first axis
          else:
              data = data[::, ::2]  # downsample second axis
      return self._xp.nanmin(data), self._xp.nanmax(data)
  
imports: import warnings
  from collections.abc import Callable
  import numpy
  from ..None import colormap
  from ..None import debug
  from ..None import functions
  from ..None import getConfigOption
  from ..Point import Point
  from ..Qt import QtCore, QtGui, QtWidgets
  from ..util.cupy_helper import getCupy
  from .GraphicsObject import GraphicsObject
label_desc: Use image node_id 25 for calling the ImageItem obj's underlying member method code with example usage: obj.quickMinMax(targetSize) and returns: self,  self