Fixes issue nallath#55.

The extruder absolute position is reset to the value it had at te
begining of the first layer redone.

scripts/PauseAtHeight.py

@@ -147,6 +147,9 @@ def execute(self, data: list):
                             prevLayer = data[index - 1]
                             prevLines = prevLayer.split("\n")
                             current_e = 0.
+
+                            # Access last layer, browse it backwards to find
+                            # last extruder absolute position
                             for prevLine in reversed(prevLines):
                                 current_e = self.getValue(prevLine, 'E', -1)
                                 if current_e >= 0:
@@ -157,6 +160,19 @@ def execute(self, data: list):
                                 prevLayer = data[index - i]
                                 layer = prevLayer + layer
 
+                                # Get extruder's absolute position at the
+                                # begining of the first layer redone
+                                # see https://github.com/nallath/PostProcessingPlugin/issues/55
+                                if i == redo_layers:
+                                    prevLines = prevLayer.split("\n")
+                                    for line in prevLines:
+                                        new_e = self.getValue(line, 'E',
+                                                              current_e)
+
+                                        if new_e != current_e:
+                                            current_e = new_e
+                                            break
+
                             prepend_gcode = ";TYPE:CUSTOM\n"
                             prepend_gcode += ";added code by post processing\n"
                             prepend_gcode += ";script: PauseAtHeight.py\n"