fix: inner headlands must not cross outermost one

Do not allow headlands that cross the outermost one
as that means the tool will work outside the field
boundary.

Also, outermost headland must not cross field boundary.

Author: Peter Vaiko

scripts/courseGenerator/FieldworkCourse.lua

@@ -139,10 +139,10 @@ function FieldworkCourse:generateHeadlands()
         if self.nHeadlands > self.nHeadlandsWithRoundCorners and #self.headlands < self.nHeadlands then
             self:generateHeadlandsFromOutside(self.boundary,
                     self:_getHeadlandOffset(self.nHeadlandsWithRoundCorners + 1),
-                    #self.headlands + 1)
+                    #self.headlands + 1, self.headlands[1] and self.headlands[1]:getPolygon())
         end
     elseif self.nHeadlands > 0 then
-        self:generateHeadlandsFromOutside(self.boundary, self:_getHeadlandOffset(1), 1)
+        self:generateHeadlandsFromOutside(self.boundary, self:_getHeadlandOffset(1), 1, self.boundary)
     end
 end
 
@@ -151,12 +151,15 @@ end
 ---@param firstHeadlandWidth number width of the outermost headland to generate, if the boundary is the field boundary,
 --- it will usually be the half working width, if the boundary is another headland, the full working width
 ---@param startIx number index of the first headland to generate
-function FieldworkCourse:generateHeadlandsFromOutside(boundary, firstHeadlandWidth, startIx)
+---@param mustNotCross Polygon|nil polygon which the outermost generated headland must not cross, usually the innermost
+--- headland generated with rounded corners, or the field boundary itself when there are no rounded headlands.
+function FieldworkCourse:generateHeadlandsFromOutside(boundary, firstHeadlandWidth, startIx, mustNotCross)
 
     self.logger:debug('generating %d sharp headlands from the outside, first width %.1f, start at %d, min radius %.1f',
             self.nHeadlands - startIx + 1, firstHeadlandWidth, startIx, self.context.turningRadius)
     -- outermost headland is offset from the field boundary by half width
-    self.headlands[startIx] = CourseGenerator.Headland(boundary, self.context.headlandClockwise, startIx, firstHeadlandWidth, false, nil)
+    self.headlands[startIx] = CourseGenerator.Headland(boundary, self.context.headlandClockwise, startIx,
+            firstHeadlandWidth, false, mustNotCross)
     if not self.headlands[startIx]:isValid() then
         self:_removeHeadland(startIx)
         return