feat: Added detrending by a polynomial function of given degree

	HeightMap save and load function to save to file and reload
	computation results

heightmap.py

@@ -40,7 +40,7 @@ import ZygoXYZ
 import ZygoDatx
 from processing import *
 from activefigure import *
-
+import pickle
 
 class HeightMap(object):
     '''! @brief The HeightMap object-
@@ -57,9 +57,9 @@ class HeightMap(object):
     ## the class  constructor
     #
     # All public variables of the class are defined in this function
-    def __init__(self):
-
+    def __init__(self,*,file=None):
 
+        self.filepath=''
 
         ## (float,float) The pixel dimension [x,y] (in m).
         self.pixel=[0,0]
@@ -86,7 +86,7 @@ class HeightMap(object):
         ## the fit parameter (rx, pitch, ry, roll, z0)  [unused]
         self.fitpars = None
 
-        ## slope rms
+        ## slope rms CPSD
         self.srms = None
 
         ## slope PSD frequency array
@@ -129,6 +129,7 @@ class HeightMap(object):
             print("Unknown file type:", Path(filename).suffix)
             return False
         if datfile.openFile(filename):      #if false invalid file message is printed
+            self.filepath=filename
             self.rawZ=self.z=np.ma.masked_invalid( datfile.getHeight())
             if self.z.size==0:
                 return False
@@ -276,6 +277,17 @@ class HeightMap(object):
               format(rx, pitch, ry, roll, Z0))
 #end remove_toroid
 
+    def detrend_poly2D(self,powers, rot=0):
+        """! Detrend the height data by removing a best fit polynomial in X and Y  
+        @param powers the list of X and Y powers of the polynomial this list can be created by processing::makePowerList
+        @param rot an optional roration angle if the polynomial function in rad
+        the function will print the fit coefficients and return the fit residual in self.ze
+        """
+        (coefficients, self.ze)=fit2D_poly(self.x,self.y,self.z, powers, rot)
+        print( "coefficients")
+        for index,(i,j) in enumerate(powers):
+            print("x^",i,"y^",j," x  ",coefficients[index])
+            
 
     def compute_x_slope(self) :
         """!  @brief Calculate on the ROI, the slope in the x direction, from the height data.
@@ -522,6 +534,14 @@ class HeightMap(object):
         plt.title('Cumulated RMS tangential slopes {}'.format(comment))
 # end plot_slope_rms
 
+    def save(self, filepath=''):
+        if not Path(filepath).parent.is_dir():
+            tkinter.Tk().withdraw()
+            filepath=filedialog.asksavefilename(title="open a hmap file", filetypes=(("superflat hmap","*.hmap"), ("all","*.*") ) )
+        print("writing to", filepath)
+        with open(filepath, 'wb') as f:
+            pickle.dump(self, f)
+
 
     def testplot(self, data, scale=1, percent=5):
         uu=data*scale
@@ -550,3 +570,15 @@ class HeightMap(object):
         plt.xlabel('x (mm)')
         plt.ylabel('y (mm)')
         plt.title("testplot")
+
+
+#  this function return a HeightMap object from a previously saved .hmap file
+def load(self, filepath=''):
+    if not Path(filepath).is_file():
+        tkinter.Tk().withdraw()
+        filepath=filedialog.askopenfilename(title="open a hmap file", filetypes=(("superflat hmap","*.hmap"), ("all","*.*") ) )
+        if  filepath=='' :
+            return None
+    print("loading from", filepath)
+    with open(filepath, 'rb') as f:
+        return pickle.load(f)

processing.py

@@ -228,3 +228,18 @@ def spline_interpolate(data, window=('tukey', 0.2) ):
     print ("percent of invalid data=", 100*invalids/(data.shape[0]*data.shape[1]) )
     print("output shape", outdata.shape)
     return outdata
+    
+def makePowerList(nx,ny, N):
+    """! Create a power list suitable for use with fit2D_poly where
+    @param nx is the maximum degree in X
+    @param ny is the maximum degree in Y
+    @param N is the maximum  total degree in  X and Y
+    """
+    plist=[]
+    for npow in range(N+1):
+        for ix in range(min(npow,nx),-1,-1):
+            iy=npow-ix
+            if iy>ny :
+                break
+            plist.append((ix,iy))
+    return plist