Production ready: eliminate print statements.

CHANGELOG

@@ -0,0 +1,40 @@
+
+This is a hand generated changelog for versions, not very accurate.
+Use >git log for every commit.
+
+
+Version 0.0.2
+=============
+
+SegmentString, Segment, ControlPoint classes.
+Explicitly model the abstractions of a SegmentString.
+This more cleanly separates freehandTool from what it produces.
+Demonstrates editing a SegmentString by manipulation of its ControlPoints.
+(Although editing is not graphical, just crude demo via keystrokes.)
+
+
+Version 0.0.3
+=============
+
+- Relations between ControlPoints defines actions (behavior of user manipulations.)
+- Cusps known by SegmentString 
+- Actions defined as a Strategy/Policy
+- An API that can be cleanly hooked to a GUI editor.
+
+Version 0.1
+===========
+
+A production version?
+
+Add exception for generated null segments, catch the exception internally, and handle it gracefully.
+I don't expect the algorithm to generate null segments, but if it does they are handled.
+
+Improve ghosting of the head of the generated curve: path instead of straight line.
+
+Clarify use of input, view (int pixel) coords and internal, scene (float) coords.
+Eliminate rounding errors by not converting in the back direction.
+
+Reraise StopIteration.  If the tool fails, it will generate this exception.
+A caller might be able to rescue.
+
+Remove all print statements.

README

@@ -4,8 +4,8 @@
                    Copyright 2012 L. Konneker
                    -------------------------
 
-1. About
-========
+About
+=====
 
 A freehand drawing tool.
 Where a tool is a user interface object, something a user uses.
@@ -34,34 +34,23 @@ References:
 See much more technical discussion in the code.
 
 
-2. Version 0.0.2
-================
-
-SegmentString, Segment, ControlPoint classes.
-Explicitly model the abstractions of a SegmentString.
-This more cleanly separates freehandTool from what it produces.
-Demonstrates editing a SegmentString by manipulation of its ControlPoints.
-(Although editing is not graphical, just crude demo via keystrokes.)
+Versions
+========
 
+See CHANGELOG.
 
-3. Version 0.0.3
-================
 
-- Relations between ControlPoints defines actions (behavior of user manipulations.)
-- Cusps known by SegmentString 
-- Actions defined as a Strategy/Policy
-- An API that can be cleanly hooked to a GUI editor.
+Serialize/Deserialize
+======================
 
+The output SegmentString, a QGraphicsPathItem, does not pickle.
+But QPainterPath implements << for serializing, and it's not hard to do (it's not in this package.)
 
-4. Serialize/Deserialize
-========================
-TODO
-Calculate cuspness geometrically.
 Cuspness is not currently serializable/deserializable, only exists just after SegmentString creation.
 
 
-5. Directory structure and distribution
-=======================================
+Directory structure and distribution
+====================================
 The top directory freehandTool includes a demo app, freehandApp.py.
 It also include other distribution artifacts e.g. setup.py.
 
@@ -74,17 +63,19 @@ The directory freehandTool.freehandTool.generator is a Python package that the t
 The Python distribution (a zipped archive) includes only the package freehandTool.freehandTool and subpackages,
 but not the demo app.
 
-6. The demo app
-===============
+
+The demo app
+============
 
 Draw with the mouse left button down.
 Any key modifies an arbitrary control point (the second one?)
 A key with control key also down modifies said control point while maintaining cuspness.
 
 A real app would have an alternate user interface for editing (dragging?) control points.
 
-7.  Installing
-==============
+
+Installing
+==========
 
 If you clone the git repository, you can change directory to the project directory and simply execute freehandApp.py.
 

alternatePaintingQGPI.py

@@ -24,7 +24,7 @@ def paint(self, painter, styleOption, widget):
     while True:
       try:
         element = path.elementAt(i)
-        # print type(element), element.type
+        #print type(element), element.type
         if element.isMoveTo():
           pathEnd = QPointF(element.x, element.y)
           i+=1

freehandTool/freehand.py

@@ -331,14 +331,21 @@ def pointerMoveEvent(self, pointerEvent):
       except StopIteration:
         '''
         While user is moving pointer with pointer button down, we don't expect pipe to stop.
-        If programming error stops pipe, quit app so we can see error trace.
+        For debugging, call exitAbnormally().
+        If a component of large app, raise.
+        A caller might catch it and rescue by ending and restarting the tool?
         '''
-        print "Abnormal pointerMoveEvent, exiting"
-        sys.exit()
+        raise
       else:
         self.pathHeadGhost.updateEnd(FreehandPoint(pointerEvent.scenePos))
 
 
+  def exitAbnormally(self):
+    " For debugging: quit app so we can see error trace. "
+    print "Abnormal pointerMoveEvent, exiting"
+    sys.exit()
+
+
   def pointerPressEvent(self, pointerEvent):
     ''' 
     Start freehand drawing. 
@@ -351,7 +358,7 @@ def pointerReleaseEvent(self, pointerEvent):
     self.closeFilterPipe()
     self.pathHeadGhost.hide()
     self._createFinalSegment(pointerEvent)
-    print "Final segment count", self.path.countSegments()
+    #print "Final segment count", self.path.countSegments()
 
 
   def _createFinalSegment(self, pointerEvent):
@@ -374,7 +381,7 @@ def _createFinalSegment(self, pointerEvent):
     # Only create final segment if pointer was NOT released at exact end of current path 
     # For example when ending on a timed cusp??
     if currenPathEnd != currentPointerPos:
-      print "Created final line segment"
+      #print "Created final line segment"
       finalLineSegment = LineSegment(startPoint=currenPathEnd, endPoint=currentPointerPos)
       self.path.appendSegments( [finalLineSegment], segmentCuspness=[False])
 

freehandTool/freehandHead.py

@@ -47,7 +47,7 @@ def __init__(self, **kwargs):
 
 
   def showAt(self, initialPosition):
-    # print "showAt"
+    #print "showAt"
     self.start = initialPosition
     self.end = initialPosition
     self.path.moveTo(initialPosition)
@@ -71,7 +71,7 @@ def updateEnd(self, point):
     '''
     Update current path by appending lineTo new end point.
     '''
-    # print "updateEnd"
+    #print "updateEnd"
     assert isinstance(point, FreehandPoint)
     self.end = point
     self.path.lineTo(point)
@@ -95,7 +95,7 @@ def floatSceneFromIntViewPoint(self, pointVCS):
   def updateStart(self, pointVCS):
     '''
     '''
-    print "updateStart"
+    #print "updateStart"
     # !!! start point from FreehandTool is in View CS. 
     pointViewInt = QPoint(pointVCS.x(), pointVCS.y())
     pointSceneFloat = self.scene().views()[0].mapToScene(pointViewInt)
@@ -120,7 +120,7 @@ def _findFirstElementAt(self, point):
     assert self.path.elementCount() > 1 # moveTo, lineTo
     for elementIndex in range(1, self.path.elementCount()):
       element = self.path.elementAt(elementIndex)
-      print element.x, element.y, point
+      #print element.x, element.y, point
       if element.x == point.x() and element.y == point.y() :
         return elementIndex
     assert False, 'New start point must be on existing path.'

freehandTool/generator/constraints.py

@@ -43,11 +43,11 @@ def update(self, v):
     If you take out turnGenerator, this might make sense.
    
     if abs(v.x())<=1 and abs(v.y())<=1 :
-      print "No constraints."
+      #print "No constraints."
       pass
     else:
     '''
-    # print "Updating constraints"
+    #print "Updating constraints"
     offset = PointerPoint( v.x() + (1 if v.y() >= 0 and (v.y()>0 or v.x()<0) else -1 ),
                       v.y() + (1 if v.x() <= 0 and (v.x()<0 or v.y()<0) else -1 ) )
     if self.constraintLeft.crossProduct(offset) >= 0 :

freehandTool/generator/curveGenerator.py

@@ -80,7 +80,8 @@ def CurveGenerator(self, startLine):
       GeneratorExit exception is still in effect after finally, but caller does not see it,
       and Python does NOT allow it to return a value.
       '''
-      print "closed curve generator"
+      #print "closed curve generator"
+      pass
 
 
 
@@ -142,7 +143,7 @@ def segmentsFromLineMidToEnd(self, line1, line2):
     '''
     midToMidsegments, endOfMidToMid, cuspness = self.segmentsFromLineMidToMid(line1, line2)
     finalEndPoint = FreehandPoint(self.mapFromDeviceToScene(line2.p2()))  # line2.p2()
-    print "Mid to end"
+    #print "Mid to end"
     midToEnd = LineSegment(endOfMidToMid, finalEndPoint)
     return midToMidsegments + [midToEnd], finalEndPoint, cuspness + [True]
 
@@ -160,7 +161,7 @@ def segmentsForCusp(self, cuspPoint, endPoint):
     Note we already generated segment to first midpoint,
     and will subsequently generate segment from second midpoint.
     '''
-    print "cusp <<<"
+    #print "cusp <<<"
     try:
       # !!! Here is where we use cache
       firstSegment = LineSegment(self.lastEndPointGenerated, cuspPoint)

freehandTool/generator/lineGenerator.py

@@ -36,7 +36,7 @@ def LineGenerator(self, startPosition):
       while True:
         turn, positionElapsedTime = (yield)
         #turnElapsedTime = turnClock.restart()
-        # print "Turn elapsed", turnElapsedTime
+        #print "Turn elapsed", turnElapsedTime
         #line = self.smallestLineFromPath(previousTurn, turn) # TEST 
         line = self._lineFromPath(startTurn, previousTurn, turn, constraints) # ,directions)
         if line is not None:  # if turn not satisfied by vector
@@ -54,24 +54,25 @@ def LineGenerator(self, startPosition):
             startTurn = previousTurn  # !!! current turn is part of next PathLine
             didLastEmitCusp = True
           else:
-            print "Skipping consecutive cusps"
+            #print "Skipping consecutive cusps"
+            pass
         # else current path (all turns) still satisfied by a PathLine: wait
 
         previousTurn = turn  # Roll forward  !!! Every turn, not just on send()
     except Exception:
       # !!! GeneratorExit is a BaseException, not an Exception
       # Unexpected programming errors, which are obscured unless caught
-      print "Exception in LineGenerator"
+      #print "Exception in LineGenerator"
       traceback.print_exc()
       raise
     except GeneratorExit:
-      print "closing line generator"
+      #print "closing line generator"
       if previousTurn != startTurn:
-        print "closing line generator"
+        #print "closing line generator"
         #print "startTurn, previousTurn", startTurn, previousTurn
         ''' Have turn not sent. Fabricate a PathLine and send() it now. '''
         self.curveGenerator.send((PathLine(startTurn, previousTurn), False))
-      print "closed line generator"
+      #print "closed line generator"
 
 
 
@@ -112,7 +113,7 @@ def _lineFromPath(self, startTurn, previousTurn, currentTurn, constraints, direc
     if len(directions) > 3:
       # a path with four directions can't be approximated with one vector
       # end point is starting pixel of segment ???
-      print "Four directions"
+      #print "Four directions"
       self.resetLineFittingFilter()
       # Note end is previousTurn, not current Turn
       return PathLine(startTurn, previousTurn)
@@ -122,7 +123,7 @@ def _lineFromPath(self, startTurn, previousTurn, currentTurn, constraints, direc
     vectorViaAllTurns = currentTurn - startTurn
 
     if constraints.isViolatedBy(vector=vectorViaAllTurns):
-      # print "Constraint violation", constraints, "vector", vectorViaAllTurns
+      #print "Constraint violation", constraints, "vector", vectorViaAllTurns
       result = self._interpolateConstraintViolating(startTurn=startTurn,
          lastSatisfyingTurn=previousTurn,
          firstNonsatisfingTurn=currentTurn)
@@ -144,11 +145,11 @@ def _forceLineFromPath(self, startTurn, previousTurn, currentTurn, constraints,
 
     if startTurn == currentTurn:
       ''' A reversal. A line from start to current would be Null. '''
-      print "Reversal"
+      #print "Reversal"
       assert previousTurn != startTurn
       return PathLine(startTurn, previousTurn)
     else:
-      ## print "Force PathLine", startTurn, currentTurn
+      ##print "Force PathLine", startTurn, currentTurn
       return PathLine(startTurn, currentTurn)
 
 

freehandTool/generator/turnGenerator.py

@@ -35,7 +35,7 @@ def TurnGenerator(self, startPosition):
     positionClock = QTime.currentTime()  # note restart returns elapsed
     positionClock.restart()
     # I also tried countPositionsSinceTurn to solve lag for cusp-like
-    # print "init turn"
+    #print "init turn"
 
     try:
       while True:
@@ -49,12 +49,12 @@ def TurnGenerator(self, startPosition):
           pass
     # Not catching general exceptions, have not found a need for it.
     except GeneratorExit:
-      print "Closing turn generator"
+      #print "Closing turn generator"
       # assert position is defined
       if previousPosition != position:
         ''' Have position not sent. Fabricate a turn (equal to position) and send() '''
         self.lineGenerator.send((position, 0))
-      print "Closed turn generator"
+      #print "Closed turn generator"
 
 
 

freehandTool/segmentString/segment.py

@@ -62,7 +62,7 @@ def isNull(self):
     Float equality a problem?
     '''
     result = self.controlPoints[0] == self.controlPoints[3]
-    # print "isNull", result
+    #print "isNull", result
     return result
 
 

freehandTool/segmentString/segmentActions.py

@@ -59,7 +59,7 @@ def _dispatchMoveRelated(self, relations, controlPoint, deltaCoordinate, alterna
     if self.isRoleAnchorAtCusp(controlPoint):
       if not alternateMode:
         # default is : make cusps more cuspy or possibly take out cusp
-        print "Moving cusp anchor"
+        #print "Moving cusp anchor"
         self.moveAnchorSetNotMaintainingCuspness(relations, controlPoint, deltaCoordinate, alternateMode, visitor)
       else:
         # alternate is weaker: don't remove the cusp, only move it as a three ControlPoint unit

freehandTool/segmentString/segmentString.py

@@ -374,7 +374,7 @@ def appendInternalRepr(self, path, pointsLCS):
     !!! and cubicTo has 3 points of Segment's 4 points.
     '''
     assert len(pointsLCS) == SegmentString.ELEMENTS_PER_SEGMENT
-    # print "appendInternalRep", pointsLCS
+    #print "appendInternalRep", pointsLCS
     path.cubicTo(*pointsLCS[1:])
 
 
@@ -383,7 +383,7 @@ def segmentChanged(self, segment, indexOfSegmentInString):
     User changed control points of segment (i.e. model.)
     Propagate change to path (i.e. view.) 
     '''
-    ## print "Segment changed"
+    ##print "Segment changed"
     self.updateSegment(segment, indexOfSegmentInString)
 
 
@@ -526,7 +526,7 @@ def _getSegmentAt(self, segmentIndex):
     (last point of previous segment shared with first point of next segment.)
     E.G. CurveSegment requires four points from three in the path.
     '''
-    # print "SegmentIndex", segmentIndex
+    #print "SegmentIndex", segmentIndex
     assert segmentIndex >= 0 and segmentIndex <= self._indexOfLastSegment()
     assert self.countSegments() > 0