- added in CNCJob preferences new preferences that allow compensation for the CNC bed skew/tilt (axes not being square one to another)

- all pre-processors are altered such they can adjust the gcode to use the compensation values set in Preferences -> CNC-Job section

preprocessors/hpgl.py

@@ -64,8 +64,20 @@ class hpgl(PreProc):
         if y >= 32768:
             y = 32768
 
+        # formula for skewing on x for example is:
+        # x_fin = x_init + y_init/slope where slope = p._bed_limit_y / p._bed_skew_x (a.k.a tangent)
+        if p._bed_skew_x == 0:
+            x_pos = x + p._bed_offset_x
+        else:
+            x_pos = (x + p._bed_offset_x) + ((y / p._bed_limit_y) * p._bed_skew_x)
+
+        if p._bed_skew_y == 0:
+            y_pos = y + p._bed_offset_y
+        else:
+            y_pos = (y + p._bed_offset_y) + ((x / p._bed_limit_x) * p._bed_skew_y)
+
         return ('PA' + self.coordinate_format + ',' + self.coordinate_format + ';') % \
-               (p.coords_decimals, x, p.coords_decimals, y)
+               (p.coords_decimals, x_pos, p.coords_decimals, y_pos)
 
     def rapid_code(self, p):
         return self.position_code(p).format(**p)