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+=====================================================================
+Clipper Change Log
+=====================================================================
+v6.4.2 (27 February 2017) Rev 512
+* Several minor bugfixes: #152 #160 #161 #162 
+
+v6.4 (2 July 2015) Rev 495
+* Numerous generally minor bugfixes 
+
+v6.2.1 (31 October 2014) Rev 482
+* Bugfix in ClipperOffset.Execute where the Polytree.IsHole property 
+  was returning incorrect values with negative offsets
+* Very minor improvement to join rounding in ClipperOffset
+* Fixed CPP OpenGL demo.
+
+v6.2.0 (17 October 2014) Rev 477
+* Numerous minor bugfixes, too many to list. 
+  (See revisions 454-475 in Sourceforge Repository)
+* The ZFillFunction (custom callback function) has had its parameters 
+  changed. 
+* Curves demo removed (temporarily).
+* Deprecated functions have been removed. 
+
+v6.1.5 (26 February 2014) Rev 460
+* Improved the joining of output polygons sharing a common edge 
+  when those common edges are horizontal.
+* Fixed a bug in ClipperOffset.AddPath() which would produce
+  incorrect solutions when open paths were added before closed paths.
+* Minor code tidy and performance improvement
+
+v6.1.4 (6 February 2014)
+* Fixed bugs in MinkowskiSum
+* Fixed minor bug when using Clipper.ForceSimplify.
+* Modified use_xyz callback so that all 4 vertices around an
+  intersection point are now passed to the callback function.
+
+v6.1.3a (22 January 2014) Rev 453
+* Fixed buggy PointInPolygon function (C++ and C# only). 
+  Note this bug only affected the newly exported function, the 
+  internal PointInPolygon function used by Clipper was OK.
+ 
+v6.1.3 (19 January 2014) Rev 452
+* Fixed potential endless loop condition when adding open 
+  paths to Clipper.
+* Fixed missing implementation of SimplifyPolygon function 
+  in C++ code.
+* Fixed incorrect upper range constant for polygon coordinates 
+  in Delphi code.
+* Added PointInPolygon function. 
+* Overloaded MinkowskiSum function to accommodate multi-contour 
+  paths.  
+
+v6.1.2 (15 December 2013) Rev 444
+* Fixed broken C++ header file.
+* Minor improvement to joining polygons.
+
+v6.1.1 (13 December 2013) Rev 441
+* Fixed a couple of bugs affecting open paths that could 
+  raise unhandled exceptions.
+  
+v6.1.0 (12 December 2013)
+* Deleted: Previously deprecated code has been removed. 
+* Modified: The OffsetPaths function is now deprecated as it has 
+  been replaced by the ClipperOffset class which is much more 
+  flexible. 
+* Bugfixes: Several minor bugs have been fixed including 
+  occasionally an incorrect nesting within the PolyTree structure.
+
+v6.0.0 (30 October 2013)
+* Added: Open path (polyline) clipping. A new 'Curves' demo 
+  application showcases this (see the 'Curves' directory). 
+* Update: Major improvement in the merging of 
+  shared/collinear edges in clip solutions (see Execute). 
+* Added: The IntPoint structure now has an optional 'Z' member. 
+  (See the precompiler directive use_xyz.) 
+* Added: Users can now force Clipper to use 32bit integers 
+  (via the precompiler directive use_int32) instead of using 
+  64bit integers.
+* Modified: To accommodate open paths, the Polygon and Polygons 
+  structures have been renamed Path and Paths respectively. The 
+  AddPolygon and AddPolygons methods of the ClipperBase class 
+  have been renamed AddPath and AddPaths respectively. Several 
+  other functions have been similarly renamed. 
+* Modified: The PolyNode Class has a new IsOpen property. 
+* Modified: The Clipper class has a new ZFillFunction property. 
+* Added: MinkowskiSum and MinkowskiDiff functions added. 
+* Added: Several other new functions have been added including 
+  PolyTreeToPaths, OpenPathsFromPolyTree and ClosedPathsFromPolyTree. 
+* Added: The Clipper constructor now accepts an optional InitOptions 
+  parameter to simplify setting properties. 
+* Bugfixes: Numerous minor bugs have been fixed. 
+* Deprecated: Version 6 is a major upgrade from previous versions 
+  and quite a number of changes have been made to exposed structures 
+  and functions. To minimize inconvenience to existing library users, 
+  some code has been retained and some added to maintain backward 
+  compatibility. However, because this code will be removed in a 
+  future update, it has been marked as deprecated and a precompiler 
+  directive use_deprecated has been defined.
+
+v5.1.6 (23 May 2013)
+* BugFix: CleanPolygon function was buggy.
+* Changed: The behaviour of the 'miter' JoinType has been 
+  changed so that when squaring occurs, it's no longer 
+  extended up to the miter limit but is squared off at 
+  exactly 'delta' units. (This improves the look of mitering 
+  with larger limits at acute angles.) 
+* Added: New OffsetPolyLines function
+* Update: Minor code refactoring and optimisations
+
+v5.1.5 (5 May 2013)
+* Added: ForceSimple property to Clipper class
+* Update: Improved documentation  
+
+v5.1.4 (24 March 2013)
+* Update: CleanPolygon function enhanced.
+* Update: Documentation improved.  
+
+v5.1.3 (14 March 2013)
+* Bugfix: Minor bugfixes.
+* Update: Documentation significantly improved.  
+
+v5.1.2 (26 February 2013)
+* Bugfix: PolyNode class was missing a constructor. 
+* Update: The MiterLimit parameter in the OffsetPolygons 
+  function has been renamed Limit and can now also be used to 
+  limit the number of vertices used to construct arcs when 
+  JoinType is set to jtRound.
+
+v5.1.0 (17 February 2013)
+* Update: ExPolygons has been replaced with the PolyTree & 
+  PolyNode classes to more fully represent the parent-child 
+  relationships of the polygons returned by Clipper. 
+* Added: New CleanPolygon and CleanPolygons functions. 
+* Bugfix: Another orientation bug fixed.
+
+v5.0.2 - 30 December 2012
+* Bugfix: Significant fixes in and tidy of the internal 
+  Int128 class (which is used only when polygon coordinate 
+  values are greater than ą0x3FFFFFFF (~1.07e9)). 
+* Update: The Area algorithm has been updated and is faster. 
+* Update: Documentation updates. The newish but undocumented 
+  'CheckInputs' parameter of the OffsetPolygons function has been 
+  renamed 'AutoFix' and documented too. The comments on rounding 
+  have also been improved (ie clearer and expanded).
+
+v4.10.0 - 25 December 2012
+* Bugfix: Orientation bugs should now be resolved (finally!).
+* Bugfix: Bug in Int128 class
+
+v4.9.8 - 2 December 2012
+* Bugfix: Further fixes to rare Orientation bug.
+
+v4.9.7 - 29 November 2012
+* Bugfix: Bug that very rarely returned the wrong polygon 
+  orientation.
+* Bugfix: Obscure bug affecting OffsetPolygons when using 
+  jtRound for the JoinType parameter and when polygons also
+  contain very large coordinate values (> +/-100000000000).
+
+v4.9.6 - 9 November 2012
+* Bugfix: Another obscure bug related to joining polygons.
+
+v4.9.4 - 2 November 2012
+* Bugfix: Bugs in Int128 class occasionally causing 
+  wrong orientations.
+* Bugfix: Further fixes related to joining polygons.
+
+v4.9.0 - 9 October 2012
+* Bugfix: Obscure bug related to joining polygons.
+
+v4.8.9 - 25 September 2012
+* Bugfix: Obscure bug related to precision of intersections.
+          
+v4.8.8 - 30 August 2012
+* Bugfix: Fixed bug in OffsetPolygons function introduced in 
+  version 4.8.5.
+
+v4.8.7 - 24 August 2012
+* Bugfix: ReversePolygon function in C++ translation was broken.
+* Bugfix: Two obscure bugs affecting orientation fixed too.
+
+v4.8.6 - 11 August 2012
+* Bugfix: Potential for memory overflow errors when using 
+  ExPolygons structure.
+* Bugfix: The polygon coordinate range has been reduced to 
+  +/- 0x3FFFFFFFFFFFFFFF (4.6e18).
+* Update: ReversePolygons function was misnamed ReversePoints in C++.
+* Update: SimplifyPolygon function now takes a PolyFillType parameter.
+          
+v4.8.5 - 15 July 2012
+* Bugfix: Potential for memory overflow errors in OffsetPolygons().
+
+v4.8.4 - 1 June 2012
+* Bugfix: Another obscure bug affecting ExPolygons structure.
+
+v4.8.3 - 27 May 2012
+* Bugfix: Obscure bug causing incorrect removal of a vertex.
+
+v4.8.2 - 21 May 2012
+* Bugfix: Obscure bug could cause an exception when using 
+  ExPolygon structure.
+
+v4.8.1 - 12 May 2012
+* Update: Cody tidy and minor bug fixes.
+
+v4.8.0 - 30 April 2012
+* Bugfix: Occasional errors in orientation fixed. 
+* Update: Added notes on rounding to the documentation. 
+
+v4.7.6 - 11 April 2012
+* Fixed a bug in Orientation function (affecting C# translations only).
+* Minor documentation update.
+
+v4.7.5 - 28 March 2012
+* Bugfix: Fixed a recently introduced bug that occasionally caused an 
+  unhandled exception in C++ and C# translations. 
+
+v4.7.4 - 15 March 2012
+* Bugfix: Another minor bugfix.
+
+v4.7.2 - 4 March 2012
+* Bugfix: Fixed bug introduced in ver 4.7 which sometimes caused 
+  an exception if ExPolygon structure was passed to Clipper's 
+  Execute method. 
+
+v4.7.1 - 3 March 2012
+* Bugfix: Rare crash when JoinCommonEdges joined polygons that 
+  'cancelled' each other. 
+* Bugfix: Clipper's internal Orientation method occasionally 
+  returned wrong result. 
+* Update: Improved C# code (thanks to numerous excellent suggestions 
+  from David Piepgrass) 
+
+v4.7 - 10 February 2012
+* Improved the joining of output polygons sharing a common edge.
+
+v4.6.6 - 3 February 2012
+* Bugfix: Another obscure bug occasionally causing incorrect 
+  polygon orientation. 
+
+v4.6.5 - 17 January 2012
+* Bugfix: Obscure bug occasionally causing incorrect hole 
+  assignment in ExPolygon structure. 
+
+v4.6.4 - 8 November 2011
+* Added: SimplifyPolygon and SimplifyPolygons functions.
+
+v4.6.3 - 11 November 2011
+* Bugfix: Fixed another minor mitering bug in OffsetPolygons.
+
+v4.6.2 - 10 November 2011
+* Bugfix: Fixed a rare bug in the orientation of polygons 
+  returned by Clipper's Execute() method.
+* Bugfix: Previous update introduced a mitering bug in the
+  OffsetPolygons function.
+
+v4.6 - 29 October 2011
+* Added: Support for Positive and Negative polygon fill 
+  types (in addition to the EvenOdd and NonZero fill types).
+* Bugfix: The OffsetPolygons function was generating the 
+  occasional artefact when 'shrinking' polygons.
+
+v4.5.5 - 8 October 2011
+* Bugfix: Fixed an obscure bug in Clipper's JoinCommonEdges 
+  method. 
+* Update: Replaced IsClockwise function with Orientation 
+  function. The orientation issues affecting OffsetPolygons 
+  should now be finally resolved.
+* Change: The Area function once again returns a signed value.
+ 
+v4.5.1 - 28 September 2011
+* Deleted: The UseFullCoordinateRange property has been 
+  deleted since integer range is now managed implicitly. 
+* BugFix: Minor bug in OffsetPolygon mitering. 
+* Change: C# JoinType enum moved from Clipper class to 
+  ClipperLib namespace. 
+* Change: The Area function now returns the absolute area 
+  (irrespective of orientation). 
+* Change: The IsClockwise function now requires a second 
+  parameter - YAxisPositiveUpward - to accommodate displays 
+  with Y-axis oriented in either direction
+
+v4.4.4 - 10 September 2011
+* Change: Deleted jtButt from JoinType (used by the 
+  OffsetPolygons function). 
+* BugFix: Fixed another minor bug in OffsetPolygons function. 
+* Update: Further improvements to the help file
+
+v4.4.3 - 29 August 2011
+* BugFix: fixed a minor rounding issue in OffsetPolygons 
+  function (affected C++ & C# translations). 
+* BugFix: fixed a minor bug in OffsetPolygons' function 
+  declaration (affected C++ translation only). 
+* Change: 'clipper' namespace changed to 'ClipperLib' 
+  namespace in both C++ and C# code to remove the ambiguity 
+  between the Clipper class and the namespace. (This also 
+  required numerous updates to the accompanying demos.)
+
+v4.4.2 - 26 August 2011
+* BugFix: minor bugfixes in Clipper. 
+* Update: the OffsetPolygons function has been significantly 
+  improved by offering 4 different join styles. 
+
+v4.4.0 - 6 August 2011
+* BugFix: A number of minor bugs have been fixed that mostly 
+  affected the new ExPolygons structure. 
+
+v4.3.0 - 17 June 2011
+* New: ExPolygons structure that explicitly associates 'hole' 
+  polygons with their 'outer' container polygons.
+* New: Execute method overloaded so the solution parameter 
+  can now be either Polygons or ExPolygons.  
+* BugFix: Fixed a rare bug in solution polygons orientation. 
+
+v4.2.8 - 21 May 2011
+* Update: JoinCommonEdges() improved once more. 
+* BugFix: Several minor bugs fixed. 
+
+v4.2.6 - 1 May 2011
+* Bugfix: minor bug in SlopesEqual function.
+* Update: Merging of output polygons sharing common edges 
+  has been significantly inproved
+
+v4.2.4 - 26 April 2011
+  Input polygon coordinates can now contain the full range of 
+  signed 64bit integers (ie +/-9,223,372,036,854,775,807). This 
+  means that floating point values can be converted to and from 
+  Clipper's 64bit integer coordinates structure (IntPoint) and  
+  still retain a precision of up to 18 decimal places. However, 
+  since the large-integer math that supports this expanded range 
+  imposes a small cost on performance (~15%), a new property 
+  UseFullCoordinateRange has been added to the Clipper class to 
+  allow users the choice of whether or not to use this expanded 
+  coordinate range. If this property is disabled, coordinate values 
+  are restricted to +/-1,500,000,000.
+
+v4.2 - 12 April 2011
+  JoinCommonEdges() code significantly improved plus other minor 
+  improvements.
+
+v4.1.2 - 9 April 2011
+* Update: Minor code tidy. 
+* Bugfix: Possible endless loop in JoinCommonEdges() in clipper.pas.
+
+v4.1.1 - 8 April 2011
+* Update: All polygon coordinates are now stored as 64bit integers
+  (though they're still restricted to range -1.5e9 to +1.5e9 pending 
+  the inclusion of code supporting 64bit math).
+* Change: AddPolygon and AddPolygons methods now return boolean 
+  values. 
+* Bugfix: Bug in JoinCommonEdges() caused potential endless loop. 
+* Bugfix: Bug in IsClockwise(). (C++ code only)
+
+v4.0 - 5 April 2011
+* Clipper 4 is a major rewrite of earlier versions. The biggest 
+  change is that floating point values are no longer used, 
+  except for the storing of edge slope values. The main benefit 
+  of this is the issue of numerical robustness has been 
+  addressed. Due to other major code improvements Clipper v4 
+  is approximately 40% faster than Clipper v3. 
+* The AddPolyPolygon method has been renamed to AddPolygons. 
+* The IgnoreOrientation property has been removed. 
+* The clipper_misc library has been merged back into the 
+  main clipper library.
+  
+v3.1.0 - 17 February 2011
+* Bugfix: Obscure bug in TClipperBase.SetDx method that caused 
+  problems with very small edges ( edges <1/1000th pixel in size).
+  
+v3.0.3 - 9 February 2011
+* Bugfix: Significant bug, but only in C# code.
+* Update: Minor refactoring.
+
+v3.0 - 31 January 2011
+* Update: Major rewrite of the portion of code that calculates 
+  the output polygons' orientation.
+* Update: Help file significantly improved.
+* Change: Renamed ForceOrientation property to IgnoreOrientation. 
+  If the orientation of output polygons is not important, or can 
+  be managed separately, clipping routines can be sped up by about 
+  60% by setting IgnoreOrientation to true. Defaults to false.
+* Change: The OffsetPolygon and Area functions have been moved to 
+  the new unit - clipper_misc. 
+
+2.99 - 15 January 2011
+* Bugfix: Obscure bug in AddPolygon method could cause an endless loop. 
+
+2.8 - 20 November 2010
+* Updated: Output polygons which previously shared a common 
+  edge are now merged. 
+* Changed: The orientation of outer polygons is now clockwise 
+  when the display's Y axis is positive downwards (as is 
+  typical for most Windows applications). Inner polygons 
+  (holes) have the opposite orientation.
+* Added: Support module for Cairo Graphics Library (with demo). 
+* Updated: C# and C++ demos.
+
+2.522 - 15 October 2010
+* Added C# translation (thanks to Olivier Lejeune) and 
+  a link to Ruby bindings (thanks to Mike Owens).
+
+2.0 - 30 July 2010
+* Clipper now clips using both the Even-Odd (alternate) and 
+  Non-Zero (winding) polygon filling rules. (Previously Clipper 
+  assumed the Even-Odd rule for polygon filling.)
+  
+1.4c - 16 June 2010
+* Added C++ support for AGG graphics library 
+  
+1.2s - 2 June 2010
+* Added C++ translation of clipper.pas
+
+1.0 - 9 May 2010
+\ No newline at end of file