Linking desktop PyQt with the layers backend

[cudmore]

Here are some ideas on the needed functions in the backend layer API so we can get up and running with it in the desktop PyQt app.

For a viewer, all we need is point and line dataframes.

Moving on to editing, we need a few more functions that are probably in the API and we can conform to what is already there.

Let me know what you think @Suhayb-A and @jtle00

import enum
import pandas as pd

class layerTypes(enum.Enum):
 # image = 'image'
 points = 'points'
 lines = 'lines'
 roi = 'roi'

class addToLayerAPI():

 def getPointAnnotations(self) -> pd.DataFrame:
 """Get the current point annotations as a pandas DataFrame.
 
 Notes
 -----
 The dataframe should have
 - One row per point
 - Columns names corresponding to columns in the original csv file.
 """
 pass

 def getLineAnnotations(self) -> pd.DataFrame:
 """Get the current line annotation as a pandas DataFrame.

 Notes
 -----
 The dataframe should have
 - One row per point in the tracing
 - Columns names corresponding to columns in the original csv file.
 """

 def getROIs(self, spineID : int) -> dict:
 """Get the x and y spine ROIs for the specified spine.
 
 Returns
 -------
 dict with the following keys:
 "xSpineRoi": list of x coordinates in the spine ROI
 "ySpineRoi": list of y coordinates in the spine ROI
 "xSegmentRoi": ...
 "ySegmentRoi": ...
 "xBackgroundSpineRoi": ...
 "yBackgroundSpineRoiRoi": ...
 "xBackgroundSegmentRoi": ...
 "yBackgroundSegmentRoi": ...
 """
 #
 # editing points
 # each time we call an edit (mutate) function, the backend point/line dataframe should be updated
 # 
 
 def addPoint(self, x : int, y : int, z : int, roiType):
 """Add a point annotation.
 """

 def addSpine(self, x : int, y : int, z : int, segmentID : int):
 """Add a spine point annotation.
 """

 def deletePoint(self, layerType : layerTypes, idx : int):
 """Delete a point/line annotation.
 """

 def setValue(self, layerType : layerTypes, pnt : int, col : str, value):
 """Set a property (column name) of an individual line/point annotation.
 """

 #
 # editing/tracing line segments
 # 
 # COMING SOON, API might need a few more functions