class_docstr: Class representing a single plot curve. Instances of this class are created
  automatically as part of :class:`PlotDataItem <pyqtgraph.PlotDataItem>`; 
  these rarely need to be instantiated directly.
  
  Features:
  
    - Fast data update
    - Fill under curve
    - Mouse interaction
  
  =====================  ===============================================
  **Signals:**
  sigPlotChanged(self)   Emitted when the data being plotted has changed
  sigClicked(self, ev)   Emitted when the curve is clicked
  =====================  ===============================================
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code: def pixelPadding(self):
      pen = self.opts["pen"]
      spen = self.opts["shadowPen"]
      w = 0
      if (
          pen is not None
          and pen.isCosmetic()
          and pen.style() != QtCore.Qt.PenStyle.NoPen
      ):
          w += pen.widthF() * 0.7072
      if (
          spen is not None
          and spen.isCosmetic()
          and spen.style() != QtCore.Qt.PenStyle.NoPen
      ):
          w = max(w, spen.widthF() * 0.7072)
      if self.clickable:
          w = max(w, self.opts["mouseWidth"] // 2 + 1)
      return w
  
imports: from ..Qt import QtCore, QtGui, QtWidgets
  import math
  import sys
  import warnings
  import numpy
  from ..None import Qt, debug
  from ..None import functions
  from ..None import getConfigOption
  from .GraphicsObject import GraphicsObject
label_desc: Use image node_id 8 for calling the PlotCurveItem obj's underlying member method code with example usage: obj.pixelPadding() and returns: w