opennurbs_dimensionstyle.h

/* $NoKeywords: $ */
/*
//
// Copyright (c) 1993-2012 Robert McNeel & Associates. All rights reserved.
// OpenNURBS, Rhinoceros, and Rhino3D are registered trademarks of Robert
// McNeel & Associates.
//
// THIS SOFTWARE IS PROVIDED "AS IS" WITHOUT EXPRESS OR IMPLIED WARRANTY.
// ALL IMPLIED WARRANTIES OF FITNESS FOR ANY PARTICULAR PURPOSE AND OF
// MERCHANTABILITY ARE HEREBY DISCLAIMED.
//				
// For complete openNURBS copyright information see <http://www.opennurbs.org>.
//
////////////////////////////////////////////////////////////////
*/

#if !defined(OPENNURBS_DIMENSIONSTYLE_INC_)
#define OPENNURBS_DIMENSIONSTYLE_INC_


class ON_CLASS ON_Arrowhead
{
public:
  ON_Arrowhead() = default;
  ~ON_Arrowhead() = default;
  ON_Arrowhead(const ON_Arrowhead&) = default;
  ON_Arrowhead& operator=(const ON_Arrowhead&) = default;

  bool operator==(const ON_Arrowhead& other) const;
  bool operator!=(const ON_Arrowhead& other) const;


#pragma region RH_C_SHARED_ENUM [ON_Arrowhead::arrow_type] [Rhino.DocObjects.DimensionStyle.ArrowType] [nested:int]
  /// <summary>
  /// Defines enumerated values for arrowhead shapes.
  /// </summary>
  enum class arrow_type : unsigned int
  {
    /// <summary> </summary>
    None = 0,
    /// <summary> </summary>
    UserBlock = 1,
    /// <summary> </summary>
    SolidTriangle = 2,   // 2:1
    /// <summary> </summary>
    Dot = 3,
    /// <summary> </summary>
    Tick = 4,
    /// <summary> </summary>
    ShortTriangle = 5,   // 1:1
    /// <summary> </summary>
    OpenArrow = 6,
    /// <summary> </summary>
    Rectangle = 7,
    /// <summary> </summary>
    LongTriangle = 8,   // 4:1
    /// <summary> </summary>
    LongerTriangle = 9,   // 6:1
  };
#pragma endregion

  static ON_Arrowhead::arrow_type ArrowTypeFromUnsigned(
    unsigned int type_as_unsigned
  );

  arrow_type ArrowheadType() const;
  void SetArrowheadType(arrow_type type);
  ON_UUID ArrowBlockId() const;
  void SetArrowBlockId(ON_UUID id);

  static ON__UINT32 GetPoints(
    arrow_type type,
    const double*& points);

  static ON__UINT32 GetPoints(
    arrow_type type,
    ON_2dPointArray& points);

  static bool GetArrowheadBoundingBox(
    ON_Arrowhead::arrow_type arrow_type,
    ON_UUID arrow_block_id,
    ON_Xform xform,
    ON_BoundingBox& bbox,
    bool grow);

  static
    ON_Arrowhead::arrow_type DefaultArrowType();

private:
  arrow_type       m_arrowhead_type = ON_Arrowhead::arrow_type::SolidTriangle;
  ON_UUID          m_arrow_block_id = ON_nil_uuid;

};

class ON_CLASS ON_TextMask
{
public:

#pragma region RH_C_SHARED_ENUM [ON_TextMask::MaskType] [Rhino.DocObjects.DimensionStyle.MaskType] [nested:byte]
  /// <summary>
  /// Text mask drawn with background color or explicit color
  /// </summary>
  enum class MaskType : unsigned char
  {
    /// <summary>
    /// Text mask drawn with background color
    /// </summary>
    BackgroundColor = 0,
    /// <summary>
    /// Text mask drawn with explicit color
    /// </summary>
    MaskColor = 1,
  };
#pragma endregion

  static ON_TextMask::MaskType MaskTypeFromUnsigned(
    unsigned int mask_type_as_unsigned
  );

public:

  /*
  The default constructor content is idenical to ON_TextMask::None.
  */
  ON_TextMask() = default;
  ~ON_TextMask() = default;
  ON_TextMask(const ON_TextMask& src) = default;
  ON_TextMask& operator=(const ON_TextMask& src) = default;

public:

  /*
  ON_TextMask::None has no effect on text appearance.
  */
  static const ON_TextMask None;

  /*
  Description:
    ON_TextMask::Compare() compares content in a repeatable
    and well ordered way.
  Returns:
    0: lhs and rhs have identical content.
    <0: lhs content is less than rhs content
    >0: lhs content is greater than rhs content
  */
  static int Compare(
    const ON_TextMask& lhs,
    const ON_TextMask& rhs
    );

  // Specifies whether or not to draw a Text Mask
  bool DrawTextMask() const;
  void SetDrawTextMask(bool bDraw);

  // Determines where to get the color to draw a Text Mask
  // Can be background color or a specific color
  ON_TextMask::MaskType  MaskFillType() const;
  void SetMaskFillType(ON_TextMask::MaskType  source);

  /*
  Returns:
    Mask color.
  Remarks:
    The mask color is applied only when MaskFillType() = ON_TextMask::MaskType::MaskColor
  */
  ON_Color MaskColor() const;

  void SetMaskColor(
    ON_Color color
  );

  /*
  Returns:
    Width of border area around text to be masked. The default value is 0.0.
  */
  double MaskBorder() const;

  void SetMaskBorder(double offset);

  bool Write(
    ON_BinaryArchive& archive
  ) const;

  bool Read(
    ON_BinaryArchive& archive
  );

  /*
  Returns:
    A SHA1 of the values defining the text mask. 
    Two text masks have the same
    content if and only if they have identical content hash values.
  */
  const ON_SHA1_Hash& ContentHash() const;

private:
  bool                   m_bDrawMask = false;
  ON_TextMask::MaskType m_mask_type = ON_TextMask::MaskType::BackgroundColor;
  
  unsigned char m_reserved1 = 0;
  unsigned char m_reserved2 = 0;

  ON_Color               m_mask_color = ON_Color::White;
  double                 m_mask_border = 0.0;

  // At some point, the reserved fields may have the name changed and be
  // used to store additional informtion of how to draw the mask,
  // (feathered edges, rounded corners, etc.).
  unsigned int m_reserved3 = 0;
  mutable ON_SHA1_Hash m_content_hash = ON_SHA1_Hash::ZeroDigest;
};

bool operator==(
  const class ON_TextMask& lhs,
  const class ON_TextMask& rhs
  );

bool operator!=(
  const class ON_TextMask& lhs,
  const class ON_TextMask& rhs
  );


class ON_CLASS ON_DimStyle : public ON_ModelComponent
{
  ON_OBJECT_DECLARE(ON_DimStyle);
private:
  friend class ON_V5x_DimStyle;

public:
  // Predefined default dimension styles always available
  static const ON_DimStyle Unset;                         // index = ON_UNSET_INT_INDEX, id = nil.
  static const ON_DimStyle Default;                       // index = -1, unique and persistent id.
  static const ON_DimStyle DefaultInchDecimal;            // index = -2, unique and persistent id.
  static const ON_DimStyle DefaultInchFractional;         // index = -3, unique and persistent id.
  static const ON_DimStyle DefaultFootInchArchitecture;   // index = -4, unique and persistent id.
  static const ON_DimStyle DefaultMillimeterSmall;        // index = -5, unique and persistent id.
  static const ON_DimStyle DefaultMillimeterLarge;        // index = -6, unique and persistent id.
  static const ON_DimStyle DefaultMillimeterArchitecture; // index = -7, unique and persistent id.

public:
  /*
  Parameters:
    dimstyle - [in]
  Returns:
    If dimstyle not nullptr, then dimstyle is returned.
    Otherwise a non-null pointer to a persistent dimstyle is returned.
    A null pointer is never returned.
  Remarks:
    This function is used when a dimension style is required.
  */
  static const class ON_DimStyle& DimStyleOrDefault(
    const class ON_DimStyle* dimstyle
  );

  /*
  Parameters:
    id - [in]
  Returns:
    If the id is not nil and identifies one of the above system dimstyles, that
    dimstyle is returned. Otherwise, ON_DimStyle::Unset is returned.
  */
  static const ON_DimStyle& SystemDimstyleFromId(
    ON_UUID id
  );

  /*
  Parameters:
    index - [in]
  Returns:
    If the id is not nil and identifies one of the above system dimstyles, that
    dimstyle is returned. Otherwise, ON_DimStyle::Unset is returned.
  */
  static const ON_DimStyle& SystemDimstyleFromIndex(
    int index
  );

  /*
  Parameters:
    name_hash - [in]
  Returns:
    If the id is not nil and identifies one of the above system dimstyles, that
    dimstyle is returned. Otherwise, ON_DimStyle::Unset is returned.
  */
  static const ON_DimStyle& SystemDimstyleFromName(
    const ON_NameHash& name_hash
  );

  /*
  Parameters:
    name_hash - [in]
  Returns:
    If the id is not nil and identifies one of the above system dimstyles, that
    dimstyle is returned. Otherwise, ON_DimStyle::Unset is returned.
  */
  static const ON_DimStyle& SystemDimstyleFromContentHash(
    const ON_SHA1_Hash& content_hash
  );

private:
  /*
  Parameters:
    system_dimstyle_list - [out]
  Returns:
    Number of system dimstyles.
  Remarks:
  ON_DimStyle::Unset is not added system_dimstyle_list[].
  */
  static unsigned int Internal_GetSystemDimstyleList(
    ON_SimpleArray<const ON_DimStyle*>& system_dimstyle_list
  );

public:

  /*
  Parameters:
    model_component_reference - [in]
    none_return_value - [in]
      value to return if ON_DimStyle::Cast(model_component_ref.ModelComponent())
      is nullptr
  Returns:
    If ON_DimStyle::Cast(model_component_ref.ModelComponent()) is not nullptr,
    that pointer is returned.  Otherwise, none_return_value is returned. 
  */
  static const ON_DimStyle* FromModelComponentRef(
    const class ON_ModelComponentReference& model_component_reference,
    const ON_DimStyle* none_return_value
    );

  /*
  Description:
    Create a clean dimension style that has the specified font.
    With the exception of the name, the resulting dimension style 
    will have an unset ON_ModelComponent properties (id, index, ...).
  Parameters:
    font_characteristics - [in]
      If nullptr, then &ON_Font::Default is used.
    model_space_text_scale - [in]
      If model_space_text_scale is  > 0.0, then it is used to set
      the DimScale() value.
    dimstyle_settings - [in]
      Setting for non-font dimstyle properties. 
      If nullptr, then &ON_DimStyle::Default is used.
    manifest - [in]
      If manifest is not nullptr, then it is used to generate
      a unique name.
    destination - [in]
      If destination is not nullptr, the result is stored here.
      Otherwise operator new is used to construct an ON_DimStyle on the heap.
  */
  static ON_DimStyle* CreateFromFont(
    const ON_Font* font_characteristics,
    double model_space_text_scale,
    const ON_DimStyle* dimstyle_settings,
    const class ON_ComponentManifest* manifest,
    ON_DimStyle* destination
  );

public:
  // Default constructor result is identical to ON_DimStyle::Unset;
  ON_DimStyle();

  ~ON_DimStyle() = default;
  ON_DimStyle(const ON_DimStyle& src) = default;
  ON_DimStyle& operator=(const ON_DimStyle&) = default;

public:
  // Used when reading V5 and earlier archives
  ON_DimStyle(
    ON::LengthUnitSystem model_length_unit_system,
    const class ON_V5x_DimStyle& src
  );

public:
  ON_DimStyle(const ON_3dmAnnotationSettings& src);

  /*
  Returns:
    True:
      "this" and src have identical names, dimension style appearance attributes,
      and identical atttributes inherited from the same parent dimension style.
    ON_ModelComponent settings other than Name() and ParentId() are
    not compared.
  Remaraks:
    A better name for this function would be EqualForAllPracticalPurposes().
  */
  bool CompareDimstyle(const ON_DimStyle& src) const;

  /*
  Returns:
    True if this and src have identical dimension style appearance attributes
    and the same parent dimension style id.
    CompareFields() ignores Name, Index, Id() values.
    CompareFields() ignores differences in IsOverride(field_id) values.
  Remaraks:
    A better name for this function would be EqualAppearanceSettings().
  */
  bool CompareFields(const ON_DimStyle& src) const;

private:
  /*
  Returns:
    True:
      If a.IsFieldOverride(field_id) == b.IsFieldOverride(field_id)
      for all ON_DimStyle::field enum values.
  */
  static bool Internal_EqualOverrideParentFields(
    const ON_DimStyle& a,
    const ON_DimStyle& b
  );
public:

  //////////////////////////////////////////////////////////////////////
  //
  // ON_Object overrides

  // virtual
  bool IsValid( class ON_TextLog* text_log = nullptr ) const override;

  // virtual
  void Dump(ON_TextLog&) const override; // for debugging

  // virtual
  bool Write(
    ON_BinaryArchive&  // serialize definition to binary archive
    ) const override;

  // virtual
  bool Read(
    ON_BinaryArchive&  // restore definition from binary archive
    ) override;

  //////////////////////////////////////////////////////////////////////
  // Interface

  void EmergencyDestroy();

  //////////////////////////////////////////////////////////////////////
  // Interface

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::LengthDisplay] [Rhino.DocObjects.DimensionStyle.LengthDisplay] [nested:int]
  /// <summary>
  /// Dimension display length unit system and style
  /// </summary>
  enum class LengthDisplay : unsigned int
  {
    /// <summary>
    /// Decimal current model units
    /// </summary>
    ModelUnits = 0,

    /// <summary>
    /// Decimal Millimeters
    /// </summary>
    Millmeters = 3,

    /// <summary>
    /// Decimal Centimeters
    /// </summary>
    Centimeters = 4,

    /// <summary>
    /// Decimal Meters
    /// </summary>
    Meters = 5,

    /// <summary>
    /// Decimal Kilometers
    /// </summary>
    Kilometers = 6,

    /// <summary>
    /// Decimal Inches
    /// </summary>
    InchesDecimal = 7,

    /// <summary>
    /// Fractional Inches ( 1.75 inches displays as 1-3/4 )
    /// </summary>
    InchesFractional = 1,

    /// <summary>
    /// Decimal Feet
    /// </summary>
    FeetDecimal = 8,

    /// <summary>
    /// Feet and Inches ( 14.75 inches displays as 1&apos;-2-3/4&quot; )
    /// </summary>
    FeetAndInches = 2,

    /// <summary>
    /// Decimal Miles
    /// </summary>
    Miles = 9
  };

#pragma endregion

  static ON_DimStyle::LengthDisplay LengthDisplayFromUnsigned(
    unsigned int length_display_as_unsigned
  );

  /*
  Returns:
    true if length_display selects a decimal format.
    false if length_display is ON_DimStyle::LengthDisplay::FeetAndInches 
    or ON_DimStyle::LengthDisplay::InchesFractional.
  */
  static bool LengthDisplayIsDecimal(
    ON_DimStyle::LengthDisplay dimension_length_display
  );

 static ON::LengthUnitSystem LengthUnitSystemFromLengthDisplay(
    ON_DimStyle::LengthDisplay dimension_length_display
  );


#pragma region RH_C_SHARED_ENUM [ON_DimStyle::tolerance_format] [Rhino.DocObjects.DimensionStyle.ToleranceDisplayFormat] [nested:byte]
  /// <summary>
  /// Style of tolerance display for dimensions
  /// </summary>
  enum class tolerance_format : unsigned char
  {
    /// <summary>
    /// No tolerance display
    /// </summary>
    None = 0,
    /// <summary>
    /// Symmetrical +/- tolerance
    /// </summary>
    Symmetrical = 1,
    /// <summary>
    /// Distance +tol, -tol
    /// </summary>
    Deviation = 2,
    /// <summary>
    /// Distance upper and lower limits
    /// </summary>
    Limits = 3,
  };
#pragma endregion

  static ON_DimStyle::tolerance_format ToleranceFormatFromUnsigned(
    unsigned int format_as_unsigned
  );


#pragma region RH_C_SHARED_ENUM [ON_DimStyle::ContentAngleStyle] [Rhino.DocObjects.DimensionStyle.LeaderContentAngleStyle] [nested:byte]
  /// <summary>
  /// Angle for text or other leader or dimension content
  /// </summary>
  enum class ContentAngleStyle : unsigned char
  {
    /// <summary>
    /// Annotation text is horizontal in annotation object's plane
    /// </summary>
    Horizontal = 0,   
    /// <summary>
    /// Aligned with last leader direction or dimension line
    /// </summary>
    Aligned = 1,   
    /// <summary>
    /// Explicit angle
    /// </summary>
    Rotated = 2,
  };
#pragma endregion

  static ON_DimStyle::ContentAngleStyle ContentAngleStyleFromUnsigned(
    unsigned int alignment_as_unsigned
  );

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::leader_curve_type] [Rhino.DocObjects.DimensionStyle.LeaderCurveStyle] [nested:byte]
  /// <summary>
  /// Type of leader curve
  /// </summary>
  enum class leader_curve_type : unsigned char
  {
    /// <summary>
    ///
    /// </summary>
    None = 0,
    /// <summary>
    ///
    /// </summary>
    Polyline = 1,
    /// <summary>
    ///
    /// </summary>
    Spline = 2
  };
#pragma endregion
  
  static ON_DimStyle::leader_curve_type LeaderCurveTypeFromUnsigned(
    unsigned int type_as_unsigned
  );

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::field] [Rhino.DocObjects.DimensionStyle.Field] [nested:int]
  // Don't change these enum values. They are used in file reading and writing.
  /// <summary>
  /// Field identifiers used for file i/o and getting/setting values
  /// </summary>
  enum class field : unsigned int
  {
    /// <summary></summary>
    Unset                          = 0,

    /// <summary>Dimension style Name property. Cannot be inherited from parent.</summary>
    Name                           = 1,

    /// <summary>Dimension style runtime model component index property. Cannot be inherited from parent.</summary>
    Index                          = 2,

    /// <summary></summary>
    ExtensionLineExtension         = 3,
    /// <summary></summary>
    ExtensionLineOffset            = 4,
    /// <summary></summary>
    Arrowsize                      = 5,
    /// <summary></summary>
    LeaderArrowsize                = 6,
    /// <summary></summary>
    Centermark                     = 7,
    /// <summary></summary>
    TextGap                        = 8,
    /// <summary></summary>
    TextHeight                     = 9,
    /// <summary>Linear, angular, and ordinate dimension text location above/in/below</summary>
    DimTextLocation                = 10,
 
     //OBSOLETE_LengthFormat_                   = 11,

    /// <summary></summary>
    LengthResolution               = 12,
    /// <summary></summary>
    AngleFormat                    = 13,
    /// <summary></summary>
    AngleResolution                = 14,
    /// <summary></summary>
    Font                           = 15,
    
    /// <summary>
    /// LengthFactor is a rarely used. It applies when a model is being
    /// drawn to a scale and the dimension length values should be
    /// reverse scaled. For example, if a model is drawn at 1/4 scale,
    /// a line 5 units long indicates the real world line is 20 units
    /// long. In this case setting LengthFactor to 4 would cause
    /// a linear dimension applied to that line to display a value of 20.
    ///</summary>
    LengthFactor                   = 16,

    /// <summary></summary>
    Alternate                      = 17,

    /// <summary>
    /// AlternateLengthFactor is a rarely used. See Length factor for
    /// a discription of this property.
    ///</summary>
    AlternateLengthFactor          = 18,

    //OBSOLETE_AlternateLengthFormat_          = 19,

    /// <summary></summary>
    AlternateLengthResolution      = 20,
    /// <summary></summary>
    Prefix                         = 21,
    /// <summary></summary>
    Suffix                         = 22,
    /// <summary></summary>
    AlternatePrefix                = 23,
    /// <summary></summary>
    AlternateSuffix                = 24,
    /// <summary></summary>
    DimensionLineExtension         = 25,
    /// <summary></summary>
    SuppressExtension1             = 26,
    /// <summary></summary>
    SuppressExtension2             = 27,
    /// <summary></summary>
    ExtLineColorSource             = 28,
    /// <summary></summary>
    DimLineColorSource             = 29,
    /// <summary></summary>
    ArrowColorSource               = 30,
    /// <summary></summary>
    TextColorSource                = 31,
    /// <summary></summary>
    ExtLineColor                   = 32,
    /// <summary></summary>
    DimLineColor                   = 33,
    /// <summary></summary>
    ArrowColor                     = 34,
    /// <summary></summary>
    TextColor                      = 35,
    /// <summary></summary>
    ExtLinePlotColorSource         = 36,
    /// <summary></summary>
    DimLinePlotColorSource         = 37,
    /// <summary></summary>
    ArrowPlotColorSource           = 38,
    /// <summary></summary>
    TextPlotColorSource            = 39,
    /// <summary></summary>
    ExtLinePlotColor               = 40,
    /// <summary></summary>
    DimLinePlotColor               = 41,
    /// <summary></summary>
    ArrowPlotColor                 = 42,
    /// <summary></summary>
    TextPlotColor                  = 43,
    /// <summary></summary>
    ExtLinePlotWeightSource        = 44,
    /// <summary></summary>
    DimLinePlotWeightSource        = 45,
    /// <summary></summary>
    ExtLinePlotWeight_mm           = 46,
    /// <summary></summary>
    DimLinePlotWeight_mm           = 47,
    /// <summary></summary>
    ToleranceFormat                = 48,
    /// <summary></summary>
    ToleranceResolution            = 49,
    /// <summary></summary>
    ToleranceUpperValue            = 50,
    /// <summary></summary>
    ToleranceLowerValue            = 51,
    /// <summary></summary>
    AltToleranceResolution         = 52,
    /// <summary></summary>
    ToleranceHeightScale           = 53,
    /// <summary></summary>
    BaselineSpacing                = 54,
    /// <summary></summary>
    DrawMask                       = 55,
    /// <summary></summary>
    MaskColorSource                = 56,
    /// <summary></summary>
    MaskColor                      = 57,
    /// <summary></summary>
    MaskBorder                     = 58,
    /// <summary></summary>
    DimensionScale                 = 59,
    /// <summary></summary>
    DimscaleSource                 = 60,
    /// <summary></summary>
    FixedExtensionLength           = 61,
    /// <summary></summary>
    FixedExtensionOn               = 62,
    /// <summary></summary>
    TextRotation                   = 63,
    /// <summary></summary>
    SuppressArrow1                 = 64,
    /// <summary></summary>
    SuppressArrow2                 = 65,
    /// <summary></summary>
    TextmoveLeader                 = 66,
    /// <summary></summary>
    ArclengthSymbol                = 67,
    /// <summary></summary>
    StackTextheightScale           = 68,
    /// <summary></summary>
    StackFormat                    = 69,
    /// <summary></summary>
    AltRound                       = 70,
    /// <summary></summary>
    Round                          = 71,
    /// <summary></summary>
    AngularRound                   = 72,
    /// <summary></summary>
    AltZeroSuppress                = 73,

    //OBSOLETE ToleranceZeroSuppress          = 74,

    /// <summary></summary>
    AngleZeroSuppress              = 75,
    /// <summary></summary>
    ZeroSuppress                   = 76,
    /// <summary></summary>
    AltBelow                       = 77,
    /// <summary></summary>
    ArrowType1                     = 78,
    /// <summary></summary>
    ArrowType2                     = 79,
    /// <summary></summary>
    LeaderArrowType                = 80,
    /// <summary></summary>
    ArrowBlockId1                  = 81,
    /// <summary></summary>
    ArrowBlockId2                  = 82,
    /// <summary></summary>
    LeaderArrowBlock               = 83,
    /// <summary>Radial dimension text location above/in/below</summary>
    DimRadialTextLocation          = 84,
    /// <summary></summary>
    TextVerticalAlignment          = 85,
    /// <summary></summary>
    LeaderTextVerticalAlignment    = 86,
    /// <summary></summary>
    LeaderContentAngleStyle        = 87,
    /// <summary></summary>
    LeaderCurveType                = 88,
    /// <summary></summary>
    LeaderContentAngle             = 89,
    /// <summary></summary>
    LeaderHasLanding               = 90,
    /// <summary></summary>
    LeaderLandingLength            = 91,
    /// <summary></summary>
    MaskFlags                      = 92,
    /// <summary></summary>
    CentermarkStyle                = 93,
    /// <summary></summary>
    TextHorizontalAlignment        = 94,
    /// <summary></summary>
    LeaderTextHorizontalAlignment  = 95,
    /// <summary></summary>
    DrawForward                    = 96,
    /// <summary></summary>
    SignedOrdinate                 = 97,
    
    /// <summary>
    /// Unit system for dimension rendering sizes like  TextHeight, TextGap, ArrowSize, ExtOffset,
    /// and dozens of other properties that control the appearance and placement of the components
    /// used to render a dimension.
    ///</summary>
    UnitSystem                     = 98,

    /// <summary></summary>
    TextMask                       = 99,
    /// <summary></summary>
    TextOrientation                = 100,
    /// <summary></summary>        
    LeaderTextOrientation          = 101,
    /// <summary></summary>
    DimTextOrientation             = 102,
    /// <summary></summary>
    DimRadialTextOrientation       = 103,
    /// <summary></summary>
    DimTextAngleStyle              = 104,
    /// <summary></summary>
    DimRadialTextAngleStyle        = 105,
    /// <summary></summary>
    TextUnderlined                 = 106,

    //OBSOLETE_DimensionUnitSystem_            = 107,
    //OBSOLETE_AlternateDimensionUnitSystem_   = 108,

    /// <summary>
    /// Dimension length display. See ON_DimStyle::DimensionLengthDisplay() for a descpription of this parameter.
    /// </summary>
    DimensionLengthDisplay = 109,

    /// <summary>
    /// Alternate dimension length display. See ON_DimStyle::AlternateDimensionLengthDisplay() for a descpription of this parameter.
    /// </summary>
    AlternateDimensionLengthDisplay = 110,

    /// <summary>Every enum UINT value that identifies a valid dimension style property is less than the UINT value of Count.</summary>
    Count = 111
  };
  
#pragma endregion

  enum : unsigned int
  {
    // must be 1 + the maximum value of an ON_DimStyle::field enum value.
    FieldCount = (unsigned int)field::Count
  };

  static ON_DimStyle::field FieldFromUnsigned(
    unsigned int field_as_unsigned
  );
  

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::angle_format] [Rhino.DocObjects.DimensionStyle.AngleDisplayFormat] [nested:byte]
  /// <summary>
  /// Display format for angles
  /// </summary>
  enum class angle_format : unsigned char
  {
    /// <summary> Decimal Degrees </summary>
    DecimalDegrees   = 0,
    /// <summary> Degrees Minutes Seconds </summary>
    DegMinSec        = 1,
    /// <summary> Decimal Radians </summary>
    Radians          = 2,
    /// <summary> Decimal Gradians </summary>
    Grads            = 3
  };
#pragma endregion

  static ON_DimStyle::angle_format AngleFormatFromUnsigned(
    unsigned int format_as_unsigned
  );

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::OBSOLETE_length_format] [Rhino.DocObjects.DimensionStyle.LengthDisplayFormat] [nested:byte]
  /// <summary>
  /// Obsolete format for length display - use ON_DimStyle::DimensionLengthDisplay instead
  /// </summary>
  enum class OBSOLETE_length_format : unsigned char
  {
    /// <summary>Obsolete - use ON_DimStyle::DimensionLengthDisplay::ModelUnits.</summary>
    Decimal       = 0,

    /// <summary>Obsolete - use ON_DimStyle::DimensionLengthDisplay::InchesFractional</summary>
    Fractional    = 1,

    /// <summary>Obsolete - use ON_DimStyle::DimensionLengthDisplay::FeetAndInches</summary>
    FeetInches = 2,

    /// <summary>Obsolete - use ON_DimStyle::DimensionLengthDisplay::FeetAndInches enum.</summary>
    FeetDecimalInches = 3
  };
#pragma endregion


  static ON_DimStyle::OBSOLETE_length_format OBSOLETE_LengthFormatFromUnsigned(
    unsigned int format_as_unsigned
  );

  /*
  Parameters:
    dimension_length_display - [in]
    model_serial_number - [in]
      0: Ignore model settings
      >0: dimstyle.ModelSerialNumber()
  */
  static ON_DimStyle::OBSOLETE_length_format OBSOLETE_LengthFormatFromLengthDisplay(
    ON_DimStyle::LengthDisplay dimension_length_display,
    unsigned int model_serial_number
  );

  static ON_DimStyle::OBSOLETE_length_format OBSOLETE_LengthFormatFromLengthDisplay(
    ON_DimStyle::LengthDisplay dimension_length_display,
    ON::LengthUnitSystem model_unit_system
  );

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::TextLocation] [Rhino.DocObjects.DimensionStyle.TextLocation] [nested:byte]
  /// <summary>
  /// The location of text in linear, angular, radial, and ordinate dimensions.
  /// </summary>
  enum class TextLocation : unsigned char
  {
    /// <summary>Text is above dimension line.</summary>
    AboveDimLine = 0,
    /// <summary>Text is centered in dimension line.</summary>
    InDimLine = 1,
    /// <summary>Text is below dimension line.</summary>
    BelowDimLine = 2
  };
#pragma endregion

  static ON_DimStyle::TextLocation TextLocationFromUnsigned(
    unsigned int dim_text_location_as_unsigned
    );  
  
  // convert ON_DimStyle::OBSOLETE_length_format enum to ON::OBSOLETE_DistanceDisplayMode enum
  static ON::OBSOLETE_DistanceDisplayMode DistanceDisplayModeFromLengthFormat(
    ON_DimStyle::OBSOLETE_length_format
    );

  // convert ON::OBSOLETE_DistanceDisplayMode enum to ON_DimStyle::OBSOLETE_length_format enum
  static ON_DimStyle::OBSOLETE_length_format LengthFormatFromDistanceDisplayMode(
    ON::OBSOLETE_DistanceDisplayMode
    );


#pragma region RH_C_SHARED_ENUM [ON_DimStyle::suppress_zero] [Rhino.DocObjects.DimensionStyle.ZeroSuppression] [nested:byte]
  /// <summary>
  /// Marks leading and trailing zeros for removal.
  /// </summary>
  enum class suppress_zero : unsigned char
  {
    /// <summary>No zero suppression.</summary>
    None                          = 0,
    /// <summary>Suppress leading zeros.</summary>
    SuppressLeading               = 1,
    /// <summary>Suppress trailing zeros.</summary>
    SuppressTrailing              = 2,
    /// <summary>Suppress leading and trailing zeros.</summary>
    SuppressLeadingAndTrailing    = 3,
    /// <summary>Suppress zero feet.</summary>
    SuppressZeroFeet              = 4,
    /// <summary>Suppress zero inches.</summary>
    SuppressZeroInches            = 8,
    /// <summary>Suppress zero feet and zero inches.</summary>
    SuppressZeroFeetAndZeroInches = 12
  };
#pragma endregion

  static ON_DimStyle::suppress_zero ZeroSuppressFromUnsigned(
    unsigned int suppress_ero_as_unsigned
  );

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::stack_format] [Rhino.DocObjects.DimensionStyle.StackDisplayFormat] [nested:byte]
  /// <summary>
  /// Format of stacked fractions
  /// </summary>
  enum class stack_format : unsigned char
  {
    /// <summary> No stacking </summary>
    None               = 0,
    /// <summary> Stack with horizontal line </summary>
    StackHorizontal    = 1,
    /// <summary> Stack with angled line </summary>
    StackDiagonal      = 2,
  };
#pragma endregion

  static ON_DimStyle::stack_format StackFormatFromUnsigned(
    unsigned int format_as_unsigned
  );

#pragma region RH_C_SHARED_ENUM [ON_DimStyle::centermark_style] [Rhino.DocObjects.DimensionStyle.CenterMarkStyle] [nested:byte]
  /// <summary>
  /// Style for drawing centermark for Radial dimensions and Centermark objects
  /// </summary>
  enum class centermark_style : unsigned char
  {
    /// <summary>
    /// No centermark display
    /// </summary>
    None = 0,
    /// <summary>
    /// + mark only
    /// </summary>
    Mark = 1,
    /// <summary>
    /// + mark and lines to radius
    /// </summary>
    MarkAndLines = 2,
  };
#pragma endregion

  static ON_DimStyle::centermark_style CentermarkStyleFromUnsigned(
    unsigned int centermark_as_unsigned
  );
   

  static ON_DimStyle::LengthDisplay LengthDisplayFromUnitsAndFormat(
    ON::LengthUnitSystem units, 
    ON_DimStyle::OBSOLETE_length_format lengthformat
  );

  /// <summary>
  /// Dimension length units and format
  ///</summary>
  ON_DimStyle::LengthDisplay DimensionLengthDisplay() const;

  /// <summary>
  /// Set dimension length units and format
  ///</summary>
  ON_DimStyle::LengthDisplay AlternateDimensionLengthDisplay() const;

  /// <summary>
  /// Alternate dimension length units and format
  ///</summary>
  void SetDimensionLengthDisplay(ON_DimStyle::LengthDisplay length_display);

  /// <summary>
  /// Set alternate dimension length units and format
  ///</summary>
  void SetAlternateDimensionLengthDisplay(ON_DimStyle::LengthDisplay length_display);

  /// <summary>
  /// Parameters:
  ///   model_sn - 0, a model serial number, or ON_UNSET_UINT_INDEX to
  ///   use the dimstyle's ModelSerialNumber() value.
  /// Returns
  ///   Unit system for dimension length display.
  ///   If DimensionLengthDisplay() == ON_DimStyle::LengthDisplay::ModelUnits
  ///   and model_sn > 0, then the value of ON::LengthUnitSystemFromModelSerialNumber(model_sn)
  ///   is returned.
  ///   If DimensionLengthDisplay() == ON_DimStyle::LengthDisplay::ModelUnits
  ///   and model_sn == 0, then ON::LengthUnitSystem::None is returned.
  ///</summary>
  ON::LengthUnitSystem DimensionLengthDisplayUnit(
    unsigned int model_sn
    ) const;

  /// <summary>
  /// Parameters:
  ///   model_sn - 0, a model serial number, or ON_UNSET_UINT_INDEX to
  ///   use the dimstyle's ModelSerialNumber() value.
  /// Returns
  ///   Unit system for dimension length display.
  ///   If DimensionLengthDisplay() == ON_DimStyle::LengthDisplay::ModelUnits
  ///   and model_sn > 0, then the value of ON::LengthUnitSystemFromModelSerialNumber(model_sn)
  ///   is returned.
  ///   If DimensionLengthDisplay() == ON_DimStyle::LengthDisplay::ModelUnits
  ///   and model_sn == 0, then ON::LengthUnitSystem::None is returned.
  ///</summary>
  ON::LengthUnitSystem AlternateDimensionLengthDisplayUnit(
    unsigned int model_sn
    ) const;

private:
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetBoolMember(
    ON_DimStyle::field field_id,
    bool value,
    bool& class_member
  );
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetUnsignedCharMember(
    ON_DimStyle::field field_id,
    unsigned char value,
    unsigned char& class_member
  );
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetIntMember(
    ON_DimStyle::field field_id,
    int value,
    int& class_member
  );
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetColorMember(
    ON_DimStyle::field field_id,
    ON_Color value,
    ON_Color& class_member
  );
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetDoubleMember(
    ON_DimStyle::field field_id,
    double value,
    double& class_member
  );
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetIdMember(
    ON_DimStyle::field field_id,
    ON_UUID value,
    ON_UUID& class_member
  );
  /*
  Returns:
    true if value was changed.
  */
  bool Internal_SetStringMember(
    ON_DimStyle::field field_id,
    const wchar_t* value,
    ON_wString& class_member
  );

  void Internal_SetOverrideDimStyleCandidateFieldOverride(ON_DimStyle::field field_id);

public:  
  // Extension line extension
  double ExtExtension() const;
  void SetExtExtension(const double);

  // Extension line offset
  double ExtOffset() const;
  void SetExtOffset(const double);

  // Arrow size
  double ArrowSize() const;
  void SetArrowSize(const double);

  // Arrow size
  double LeaderArrowSize() const;
  void SetLeaderArrowSize(const double);

  // Centermark size
  double CenterMark() const;
  void SetCenterMark(const double);

  // Centermark style
  ON_DimStyle::centermark_style CenterMarkStyle() const;
  void SetCenterMarkStyle(ON_DimStyle::centermark_style style);

  // The location of text relative to the dimension line in linear, angular, and ordinate dimensions.
  ON_DimStyle::TextLocation DimTextLocation() const;
  void SetDimTextLocation(ON_DimStyle::TextLocation);

  // The location of text relative to the dimension line in radial dimensions.
  ON_DimStyle::TextLocation DimRadialTextLocation() const;
  void SetDimRadialTextLocation(ON_DimStyle::TextLocation);

  angle_format AngleFormat() const;
  void SetAngleFormat(angle_format format);

  // Display resolution for distance measurements
  int LengthResolution() const;
  void SetLengthResolution(int);

  // Display resolution for angle measurements
  int AngleResolution() const;
  void SetAngleResolution(int);

public:
  /*
  Description:
    Set the font used to render text.
  Parameters:
    font_characteristics - [in]
      This parameter does not have to be a managed font.
  Remarks:
    If the parameter is a managed font (font_characteristics.IsManagedFont() is true),
    then the identical value is returned by ON_DimStyle.Font(). 
    If the parameter is not a managed font (font_characteristics.IsManagedFont() is false),
    then the ON_Font::GetManagedFont(font_characteristics) will be returned by
    ON_DimStyle.Font().
  */
  void SetFont(
    const class ON_Font& font_characteristics
  );

  /*
  Returns:
    The managed font used to render text.
  */
  const class ON_Font& Font() const;

  /*
  Returns:
    A copy of the font_characteristics information.
  Remarks:
    You probably want to use Font(). This function is only useful
    in isolated situations and is typically used to study font
    substitutions when a model moves between computers or platforms.
  */
  const class ON_Font& FontCharacteristics() const;

  /*
  Returns:
   True if the font returned by Font() is a substitute 
   for the font passed to SetFont(). 
  Remarks:
    Font substitution can occur when a model is moved between
    computers that have different fonts installed.
  */
  const bool FontSubstituted() const;

public:
  /*
  Description:
    Two dimension styles have identical text orientation, glyph content, 
    and size parameters if and only if the have identical values of 
    TextPositionPropertiesHash().
  Returns:
    A SHA-1 hash of the information that controls text position and size.
  Remarks:
    Independent of id, parent id, name, and index.
  */
  const class ON_SHA1_Hash TextPositionPropertiesHash() const;

  /*
  Description:
    Two dimension styles have identical content if and only 
    if they have identical values of ContentHash().
  Returns:
    A SHA-1 hash of the information that controls annotation appearance.
  Remarks:
    Independent of id, parent id, name, and index.
  */
  const class ON_SHA1_Hash& ContentHash() const;

private:
  void Internal_TextPositionPropertiesChange();

public:

  // Distance from dimension lines to text
  double TextGap() const;
  void SetTextGap(double gap);

  // Height of dimension text
  double TextHeight() const;
  void SetTextHeight(double height);

  /// <summary>
  /// LengthFactor is a rarely used. It applies when a model is being
  /// drawn to a scale and the dimension length values should be
  /// reverse scaled. For example, if a model is drawn at 1/4 scale,
  /// a line 5 units long indicates the real world line is 20 units
  /// long. In this case setting LengthFactor to 4 would cause
  /// a linear dimension applied to that line to display a value of 20.
  ///</summary>
  double LengthFactor() const;
    
  /// <summary>
  /// LengthFactor is a rarely used. It applies when a model is being
  /// drawn to a scale and the dimension length values should be
  /// reverse scaled. For example, if a model is drawn at 1/4 scale,
  /// a line 5 units long indicates the real world line is 20 units
  /// long. In this case setting LengthFactor to 4 would cause
  /// a linear dimension applied to that line to display a value of 20.
  ///</summary>
  void SetLengthFactor(double);

  // Additional measurement display toggle
  bool Alternate() const;
  void SetAlternate(bool);

  // Distance scale factor for alternate display
  /// <summary>
  /// AlternateLengthFactor is a rarely used. See Length factor for
  /// a discription of this property.
  ///</summary>
  double AlternateLengthFactor() const;

  /// <summary>
  /// AlternateLengthFactor is a rarely used. See Length factor for
  /// a discription of this property.
  ///</summary>
  void SetAlternateLengthFactor(double);

  // Display resolution for alternate length measurements
  int AlternateLengthResolution() const;
  void SetAlternateLengthResolution(int);

  // Dimension prefix text
  const ON_wString& Prefix() const;
  void SetPrefix(const wchar_t*);

  // Dimension suffix text
  const ON_wString& Suffix() const;
  void SetSuffix(const wchar_t*);

  // Dimension alternate prefix text
  const ON_wString& AlternatePrefix() const;
  void SetAlternatePrefix(const wchar_t*);

  // Dimension alternate suffix text
  const ON_wString& AlternateSuffix() const;
  void SetAlternateSuffix(const wchar_t*);

  // Suppress first dimension extension line
  bool SuppressExtension1() const;
  void SetSuppressExtension1(bool);

  // Suppress second dimension extension line
  bool SuppressExtension2() const;
  void SetSuppressExtension2(bool);

  // Extension of dimension line past extension lines
  double DimExtension() const;
  void SetDimExtension(const double e);


  //// Colors of Text
  //ON_Color TextColor() const;
  //void SetTextColor(ON_Color color);
  //
  // Combines a field id and a field value
  // Dimensions will have an array of DimstyleField's to record 
  // dimension style overrides for individual dimensions
  class DimstyleField
  {
  public:
    DimstyleField()
      : m_next(nullptr)
      , m_field_id(ON_DimStyle::field::Unset)
    {
      m_val.s_val = nullptr;
    }
    ~DimstyleField()
    {
      if (nullptr != m_next)
      {
        delete m_next;
        m_next = nullptr;
      }
      if (nullptr != m_val.s_val)
      {
        delete m_val.s_val;
        m_val.s_val = nullptr;
      }
    }

    DimstyleField* m_next;
    ON_DimStyle::field m_field_id;
    union
    {
      bool b_val;
      int  i_val;
      unsigned char uc_val;
      double d_val;
      unsigned int c_val;
      const ON_wString* s_val;
    }  m_val;
  };

  /*
  Parameters:
    field_id - [in]
  Returns:
    false: (default)
      The setting identified by field_id is inherited from the parent dimension style identified by ParentId().
    true:
      The setting identified by field_id is independet of any parent dimension style.
  */
  bool IsFieldOverride(ON_DimStyle::field field_id) const;

  /*
  Parameters:
    field_id - [in]
    bOverrideParent - [in]
      false:
        The setting identified by field_id is inherited from the parent dimension style identified by ParentId().
      true:
        The setting identified by field_id is independent of any parent dimension style.
  */
  void SetFieldOverride(ON_DimStyle::field field_id, bool bOverrideParent);

  /*
  Parameters:
    bOverrideParent - [in]
      true - if a field permits overriding, set it to true.
      false - set all field override values to false.
  */
  void SetFieldOverrideAll(bool bOverrideParent);

  /*
  Description:
    All dimension style settings identified the ON_DimStyle::field enum, 
    except Name and Id, are inherited from the parent dimension style.
  */
  void ClearAllFieldOverrides();

  /*
  Returns:
    false: (default)
      Every setting identified by a ON_DimStyle::field enum value, except name and id, 
      is inherited from the parent dimension style identified by ParentId().
    true:
      At least one setting identified by a ON_DimStyle::field enum value is
      is independent of any parent dimension style.
  */
  bool HasOverrides() const;

  /*
  Returns:
    The content hash of the parent dimstyle. If there is no parent dimstyle, then
    ON_SHA1_Hash::EmptyContent is returned.
  */
  const ON_SHA1_Hash& ParentContentHash() const;

  /*
  Description:
    Create a dimstyle from this that is configured to be customized for use
    in creating a new annotation object.
  Example:
        ON_DimStyleContext = dim_style_context = ...;
        ON_DimStyle my_dim_style = dim_style_context.CurrentDimStyle().CreateOverrideCandidate().
        // Customize my_dim_style
        my_dim_style.Set...(...);
  Returns:
    An ON_DimStyle configured to be modified and used as an override dimstyle for annotation objects.
  */
  const ON_DimStyle CreateOverrideCandidate() const;

  /*
  Description:
    Get an ON_DimStyle with the specified properties.
  Parameters:
    parent_dim_style - [in]
      If you are getting ready to modify and existing annotation object,
      a good options for this paramter is the dimstyle returned by ON_Annotation.DimStyle();
      If you are getting ready to create a new annotation object, then get
      an ON_DimStyleContext class and pass ON_DimStyleContext.CurrentDimStyle().
      In Rhino, use CRhinoDoc.DimStyleContext() to get an ON_DimStyleContext.
      In an ONX_Model, use ONX_Model.DimStyleContext() to get an ON_DimStyleContext.
      In other situations, you can pass on of the system dimstyles like
      ON_DimStyle::DefaultMillimeterSmall or ON_DimStyle::DefaultMillimeterArchitecture.
      The worst possible choices are ON_DimStyle::Default or ON_DimStyle::Unset.
    annotation_type - [in]
      ON::AnnotationType::Unset if style will be used for multiple types of annotation
      or a specific type. For example, if you are making a text object, pass ON::AnnotationType::Text; 
      if you are making a leader, pass ON::AnnotationType::Leader, and so on.
    font - [in]
      nullptr for current default or specify the font you want.
      When in doubt, pass nullptr
    model_space_text_scale - [in]
      If > 0, then ON_DimStyle.DimScale() is set, otherwise current default is used.
      When in doubt, pass ON_UNSET_VALUE.
    text_height - [in]
    text_height_unit_system - [in]
      If text_height > 0, then ON_DimStyle.TextHeight() is set, otherwise current default is used.
      When in doubt, pass ON_UNSET_VALUE.
    valign - [in]
    halign - [in]
      valign and halign control placement  of text in text objects and leaders. 
      The value of the annotation_type parameter determines which objects use the
      valign and halign settings.
    text_orientation - [in]
    dim_text_location - [in]
      Controls placement of text in linear, angular, radial and ordinate dimensions.
      When in doubt, pass parent_dim_style.DimTextLocation().
  Returns:
    A dimstyle with the specified text properties. 
  Remarks:
    This is a useful tool for creating the dimension style parameters to
    CRhinoDoc.AddTextObject() and CRhinoDoc.AddLeaderObject().
  */
  static const ON_DimStyle CreateFromProperties(
    const ON_DimStyle& parent_dim_style,
    ON::AnnotationType annotation_type,
    const ON_Font* font,
    double model_space_text_scale,
    double text_height,
    ON::LengthUnitSystem text_height_unit_system,
    ON::TextVerticalAlignment valign,
    ON::TextHorizontalAlignment halign
  );

  static const ON_DimStyle CreateFromProperties(
    const ON_DimStyle& parent_dim_style,
    ON::AnnotationType annotation_type,
    const ON_Font* font,
    double model_space_text_scale,
    double text_height,
    ON::LengthUnitSystem text_height_unit_system,
    ON::TextVerticalAlignment valign,
    ON::TextHorizontalAlignment halign,
    ON::TextOrientation orientation,
    ON_DimStyle::TextLocation dim_text_location
  );

  static const ON_DimStyle CreateFromProperties(
    const ON_DimStyle& parent_dim_style,
    ON::AnnotationType annotation_type,
    const ON_Font* font,
    double model_space_text_scale,
    double text_height,
    ON::LengthUnitSystem text_height_unit_system
  );

private:
  static void Internal_CreateFromProperties(
    const ON_DimStyle& parent_dim_style,
    ON::AnnotationType annotation_type,
    const ON_Font* font,
    double model_space_text_scale,
    double text_height,
    ON::LengthUnitSystem text_height_unit_system,
    bool bSetAlignment,
    ON::TextVerticalAlignment valign,
    ON::TextHorizontalAlignment halign,
    bool bSetOrientation,
    ON::TextOrientation orientation,
    bool bSetLocation,
    ON_DimStyle::TextLocation dim_text_location,
    ON_DimStyle& destination
  );
public:

  /*

  */
  bool IsOverrideDimStyleCandidate(
    ON_UUID parent_id,
    bool bRequireSetOverrides,
    ON_wString* error_description = nullptr
  ) const;


  /*
  Description:
    For every dimension style property identified by a field_id ON_DimStyle::field enum,
    except Name and Index, do the following:

    if ( source.IsFieldOverride(field_id) )
      copy corresponding value from source to this
    else
      copy corresponding value from parent to this

    Set this->ParentId() = parent.Id().
  Parameters:
    src - [in]
      It is permitted for src to be this.
    parent - [in]
      It is permitted for parent to be this.
  */
  void OverrideFields(
    const ON_DimStyle& source, 
    const ON_DimStyle& parent
    );

  /*
  Description:
    For every dimension style property identified by a field_id ON_DimStyle::field enum,
    except Name and Index, if source and parent have different values, then
    set the field overide for that property to true.
  Parameters:
    src - [in]
      It is permitted for src to be this.
    parent - [in]
      It is permitted for parent to be this.
  */
  void OverrideFieldsWithDifferentValues(
    const ON_DimStyle& source, 
    const ON_DimStyle& parent
    );

  /*
  Descripton:
    Set the parent dimension style id to parent.Id() and copies
    all inherited appearance properties from parent.
  Parameters:
    parent - [in]
      If this->IsFieldOverride(field_id) is false, then the dimension style
      property value corresponding to field_id is copied from parent to "this".      
  Remarks:
    Identical to calling this->OverrideFields(*this,parent).
  */
  void InheritFields(const ON_DimStyle& parent);

  // Test if this dimstyle is the child of any other dimstyle
  bool IsChildDimstyle() const;

  /*
  Returns:
    True if parent_id is not nil and parent_id == this->ParentId().
  */
  bool IsChildOf(const ON_UUID& parent_id) const;

  tolerance_format ToleranceFormat() const;
  int  ToleranceResolution() const;
  double ToleranceUpperValue() const;
  double ToleranceLowerValue() const;
  double ToleranceHeightScale() const;

  void SetToleranceFormat(ON_DimStyle::tolerance_format format);
  void SetToleranceResolution(int resolution);
  void SetToleranceUpperValue(double upper_value);
  void SetToleranceLowerValue(double lower_value);
  void SetToleranceHeightScale(double scale);

  double BaselineSpacing() const;
  void SetBaselineSpacing(double spacing);

  // Determines whether or not to draw a Text Mask
  bool DrawTextMask() const;
  void SetDrawTextMask(bool bDraw);

  // Determines where to get the color to draw a Text Mask
  ON_TextMask::MaskType  MaskFillType() const;
  void SetMaskFillType(ON_TextMask::MaskType  source);

  ON_Color MaskColor() const;  // Only works right if MaskColorSource returns 1.
  // Does not return viewport background color
  void SetMaskColor(ON_Color color);

  // Offset for the border around text to the rectangle used to draw the mask
  // This number is the offset on each side of the tight rectangle around the
  // text characters to the mask rectangle.
  double MaskBorder() const;
  void SetMaskBorder(double offset);

  // The ON_TextMask class contains the property values for
  //   DrawTextMask()
  //   MaskColor()
  //   MaskFillType()
  //   MaskBorder()
  // Use the 
  //   SetDrawTextMask()
  //   SetMaskColor()
  //   SetMaskFillType()
  //   SetMaskBorder()
  //   functions to modify text mask properties.
  const ON_TextMask& TextMask() const;
  void SetTextMask(const ON_TextMask& text_mask);

private:
  void Internal_SetTextMask(
    const ON_TextMask& text_mask
  );
public:

  void Scale(double scale);

  // UUID of the dimstyle this was originally copied from
  // so Restore Defaults has some place to look
  void SetSourceDimstyle(ON_UUID source_uuid);
  ON_UUID SourceDimstyle() const;

  void SetExtensionLineColorSource(const ON::object_color_source src);
  ON::object_color_source ExtensionLineColorSource() const;
  void SetDimensionLineColorSource(const ON::object_color_source src);
  ON::object_color_source DimensionLineColorSource() const;
  void SetArrowColorSource(const ON::object_color_source src);
  ON::object_color_source ArrowColorSource() const;
  void SetTextColorSource(const ON::object_color_source src);
  ON::object_color_source TextColorSource() const;
  void SetExtensionLineColor(ON_Color c);
  ON_Color ExtensionLineColor() const;
  void SetDimensionLineColor(ON_Color c);
  ON_Color DimensionLineColor() const;
  void SetArrowColor(ON_Color c);
  ON_Color ArrowColor() const;
  void SetTextColor(ON_Color c);
  ON_Color TextColor() const;

  void SetExtensionLinePlotColorSource(const ON::plot_color_source src);
  ON::plot_color_source ExtensionLinePlotColorSource() const;
  void SetDimensionLinePlotColorSource(const ON::plot_color_source src);
  ON::plot_color_source DimensionLinePlotColorSource() const;
  void SetArrowPlotColorSource(const ON::plot_color_source src);
  ON::plot_color_source ArrowPlotColorSource() const;
  void SetTextPlotColorSource(const ON::object_color_source src);
  ON::object_color_source TextPlotColorSource() const;
  void SetExtensionLinePlotColor(ON_Color c);
  ON_Color ExtensionLinePlotColor() const;
  void SetDimensionLinePlotColor(ON_Color c);
  ON_Color DimensionLinePlotColor() const;
  void SetArrowPlotColor(ON_Color c);
  ON_Color ArrowPlotColor() const;
  void SetTextPlotColor(ON_Color c);
  ON_Color TextPlotColor() const;

  void SetExtensionLinePlotWeightSource(const ON::plot_weight_source src);
  ON::plot_weight_source ExtensionLinePlotWeightSource() const;
  void SetDimensionLinePlotWeightSource(const ON::plot_weight_source src);
  ON::plot_weight_source DimensionLinePlotWeightSource() const;
  void SetExtensionLinePlotWeight(double w);
  double ExtensionLinePlotWeight() const;
  void SetDimensionLinePlotWeight(double w);
  double DimensionLinePlotWeight() const;

  void SetFixedExtensionLen(double l);
  double FixedExtensionLen() const;
  void SetFixedExtensionLenOn(bool on);
  bool FixedExtensionLenOn() const;

  void SetTextRotation(double r);
  double TextRotation() const;

  void SetAlternateToleranceResolution(int r);
  int AlternateToleranceResolution() const;

  void SetSuppressArrow1(bool s);
  bool SuppressArrow1() const;
  void SetSuppressArrow2(bool s);
  bool SuppressArrow2() const;
  void SetTextMoveLeader(int m);

  int TextMoveLeader() const;
  void SetArcLengthSymbol(int m);
  int ArcLengthSymbol() const;

  void SetStackFractionFormat(ON_DimStyle::stack_format f);
  ON_DimStyle::stack_format StackFractionFormat() const;
  void SetStackHeightScale(double f);
  double StackHeightScale() const;

  void SetRoundOff(double r);
  double RoundOff() const;
  void SetAlternateRoundOff(double r);
  double AlternateRoundOff() const;
  void SetAngleRoundOff(double r);
  double AngleRoundOff() const;
  void SetZeroSuppress(ON_DimStyle::suppress_zero s);
  ON_DimStyle::suppress_zero ZeroSuppress() const;
  void SetAlternateZeroSuppress(ON_DimStyle::suppress_zero s);
  ON_DimStyle::suppress_zero AlternateZeroSuppress() const;

  // OBSOLETE - The ZeroSuppress() or  AlternateZeroSuppress() property
  // is used to format tolerance display.  ToleranceZeroSuppress() is ignored.
  void SetToleranceZeroSuppress(ON_DimStyle::suppress_zero s);

  // OBSOLETE - The ZeroSuppress() or  AlternateZeroSuppress() property
  // is used to format tolerance display.  ToleranceZeroSuppress() is ignored.
  ON_DimStyle::suppress_zero ToleranceZeroSuppress() const;

  void SetAngleZeroSuppress(ON_DimStyle::suppress_zero s);
  ON_DimStyle::suppress_zero AngleZeroSuppress() const;
  void SetAlternateBelow(bool below);

  /*
  Description:
    The valid choices for ON_DimStyle::suppress_zero depend on
    the dimension length display.
  Parameters:
    zero_suppress - [in]
    length_display - [in]
  Returns:
    True if zero_suppression is a valid setting when
    DimensionLengthDiplay = dimension_length_display
  Remarks:
   LengthDisplay: Inch fractional – No zero suppression matches
   LengthDisplay : FeetAndInches – Zero suppress can be
                                              None, 
                                              Suppress zero feet,
                                              Suppress zero inches or
                                              Suppress zero feet and zero inches.
   LengthDisplay : ModelUnits or any Decimal mode – Zero suppress can be
                                              None,
                                              Suppress leading,
                                              Suppress trailing or
                                              Suppress leading and trailing.
  */
  static bool ZeroSuppressMatchesLengthDisplay(
    ON_DimStyle::suppress_zero zero_suppress,
    ON_DimStyle::LengthDisplay length_display);

  bool AlternateBelow() const;

  ON_Arrowhead::arrow_type ArrowType1() const;
  void SetArrowType1(ON_Arrowhead::arrow_type);
  ON_Arrowhead::arrow_type ArrowType2() const;
  void SetArrowType2(ON_Arrowhead::arrow_type);
  void SetArrowType1And2(ON_Arrowhead::arrow_type);
  ON_Arrowhead::arrow_type LeaderArrowType() const;
  void SetLeaderArrowType(ON_Arrowhead::arrow_type);

  void SetArrowBlockId1(ON_UUID id);
  ON_UUID ArrowBlockId1() const;
  void SetArrowBlockId2(ON_UUID id);
  ON_UUID ArrowBlockId2() const;
  void SetLeaderArrowBlockId(ON_UUID id);
  ON_UUID LeaderArrowBlockId() const;

  ON::TextVerticalAlignment TextVerticalAlignment() const;
  void SetTextVerticalAlignment(ON::TextVerticalAlignment style);
  ON::TextVerticalAlignment LeaderTextVerticalAlignment() const; // was attachstyle
  void SetLeaderTextVerticalAlignment(ON::TextVerticalAlignment style);
  ON_DimStyle::ContentAngleStyle LeaderContentAngleStyle() const; // was contentalignment
  void SetLeaderContentAngleStyle(ON_DimStyle::ContentAngleStyle style);
  ON_DimStyle::leader_curve_type LeaderCurveType() const;
  void SetLeaderCurveType(ON_DimStyle::leader_curve_type type);
  bool LeaderHasLanding() const;
  void SetLeaderHasLanding(bool landing);
  double LeaderLandingLength() const;
  void SetLeaderLandingLength(double length);
  double LeaderContentAngleRadians() const;
  void SetLeaderContentAngleRadians(double angle_radians);
  double LeaderContentAngleDegrees() const;
  void SetLeaderContentAngleDegrees(double angle_degrees);
  ON::TextHorizontalAlignment TextHorizontalAlignment() const;
  void SetTextHorizontalAlignment(ON::TextHorizontalAlignment halign);
  ON::TextHorizontalAlignment LeaderTextHorizontalAlignment() const;
  void SetLeaderTextHorizontalAlignment(ON::TextHorizontalAlignment halign);
  bool DrawForward() const;
  void SetDrawForward(bool drawforward);
  bool SignedOrdinate() const;
  void SetSignedOrdinate(bool allowsigned);

  /// <summary>
  /// Unit system for dimension rendering sizes like  TextHeight, TextGap, ArrowSize, ExtOffset,
  /// and dozens of other properties that control the appearance and placement of the components
  /// used to render a dimension.
  ///</summary>
  ON::LengthUnitSystem UnitSystem() const;

  /// <summary>
  /// Unit system for dimension rendering sizes like  TextHeight, TextGap, ArrowSize, ExtOffset,
  /// and dozens of other properties that control the appearance and placement of the components
  /// used to render a dimension.
  ///</summary>
  void SetUnitSystem(ON::LengthUnitSystem us);

  /*
  Description:
    When a dimension style unit system is not set,
    this function examines the context the dimension style is
    being used in and sets the unit system.
  Parameters:
    bUseName - [in]
      Consider the name when assinging a unit system.
      For example, a dimension style name "Millimters Small" would 
      be assinged a unit system of millimeters.
    source_unit_system - [in]
      unit system in the model or file where the dimension
      style originated.
    destination_unit_system - [in]
      unit system in the model or file where the dimension
      style will be used.
  */
  void SetUnitSystemFromContext(
    bool bUseName,
    ON::LengthUnitSystem source_unit_system,
    ON::LengthUnitSystem destination_unit_system
  );

  /*
  Returns:
    true if the unit system is set to an explicit valid length unit.
  */
  bool UnitSystemIsSet() const;

  const ON_ScaleValue& ScaleValue() const;
  void SetDimScale(ON_ScaleValue sv);
  void SetDimScale(double left_val, ON::LengthUnitSystem left_us, double right_val, ON::LengthUnitSystem right_us);
  
  double ScaleLeftLength_mm() const;
  double ScaleRightLength_mm() const;

  void SetDimScale(double scale);
  double DimScale() const;

  void SetDimScaleSource(int source);
  int DimScaleSource() const;          // 0: Global DimScale, 1: DimStyle DimScale

  void SetTextOrientation(ON::TextOrientation);
  ON::TextOrientation TextOrientation() const;

  void SetLeaderTextOrientation(ON::TextOrientation);
  ON::TextOrientation LeaderTextOrientation() const;

  void SetDimTextOrientation(ON::TextOrientation);
  ON::TextOrientation DimTextOrientation() const;

  void SetDimRadialTextOrientation(ON::TextOrientation);
  ON::TextOrientation DimRadialTextOrientation() const;

  ON_DimStyle::ContentAngleStyle DimTextAngleStyle() const;
  void SetDimTextAngleStyle(ON_DimStyle::ContentAngleStyle style);

  ON_DimStyle::ContentAngleStyle DimRadialTextAngleStyle() const;
  void SetDimRadialTextAngleStyle(ON_DimStyle::ContentAngleStyle style);

  bool TextUnderlined() const;
  void SetTextUnderlined(bool underlined);

  //double ModelSize() const;
  //void SetModelSize(double size);
  //double PaperSize() const;
  //void SetPaperSize(double size);

  // For converting to and from V5 Dimstyles
  static int V5ArrowType(ON_Arrowhead::arrow_type v6type);
  static int V5LengthFormat(ON_DimStyle::OBSOLETE_length_format v6format);
  static int V5AngleFormat(ON_DimStyle::angle_format v6format);
  static int V5ToleranceFormat(ON_DimStyle::tolerance_format v6format);
  static int V5MaskColorSourceFromV6MaskType(ON_TextMask::MaskType mask_type);
  static ON_Arrowhead::arrow_type V6ArrowType(int v5type);
  static ON_DimStyle::OBSOLETE_length_format V6LengthFormat(int v5format);
  static ON_DimStyle::angle_format V6AngleFormat(int v5format);
  static ON_DimStyle::tolerance_format V6ToleranceFormat(int v5format);
  static ON_TextMask::MaskType V6MaskTypeFromV5MaskColorSource(int v5_mask_color_source);

private:
  double m_extextension                            = 0.5; // extension line extension
  double m_extoffset                               = 0.5;    // extension line offset
  double m_arrowsize                               = 1.0;  // length of an arrow - may mean different things to different arrows
  double m_leaderarrowsize                         = 1.0;  // length of an arrow for leader style dimensions
  double m_centermark                              = 0.5; // size of the + at circle centers
  ON_DimStyle::centermark_style m_centermark_style = ON_DimStyle::centermark_style::Mark; // Display style for centermarks
  double m_textgap                                 = 0.25;    // gap around the text for clipping dim line
  double m_textheight                              = 1.0; // model unit height of dimension text before applying dimscale

  //ON::OBSOLETE_V5_TextDisplayMode m_REMOVE_ME_dimstyle_textalign  = ON::OBSOLETE_V5_TextDisplayMode::kAboveLine;
  ON_DimStyle::TextLocation m_dim_text_location    = ON_DimStyle::TextLocation::AboveDimLine;
  ON_DimStyle::TextLocation m_dimradial_text_location = ON_DimStyle::TextLocation::InDimLine;

  ON_DimStyle::angle_format m_angleformat          = ON_DimStyle::angle_format::DecimalDegrees;
  int m_angleresolution = 2;    // for decimal degrees, digits past decimal

  /// <summary>
  /// The DimensionLengthDisplay is property controls the unit system and format
  /// of for display of lengths in dimensions. For more information, see the 
  /// descriptions of the ON_DimStyle::LengthDisplay enum values.
  ///</summary>
  ON_DimStyle::LengthDisplay m_dimension_length_display = ON_DimStyle::LengthDisplay::ModelUnits;

  /// <summary>
  /// Alternate DimensionLengthDisplay property. 
  /// See the description of m_dimension_length_display for more information about this property.
  ///</summary>
  ON_DimStyle::LengthDisplay m_alternate_dimension_length_display = ON_DimStyle::LengthDisplay::ModelUnits;

  /// <summary>
  /// The LengthResolution property controls the precision of dimension length display.
  ///
  /// DECIMAL LENGHT DISPLAY: 
  ///   If m_dimension_length_display is any of the ON_DimStyle::LengthDisplay decimal formats,
  ///   then m_lengthresolution is the number of digits after the decimal point.
  ///   For example, if m_lengthresolution is 2, then dimension length display will be n.ff
  ///   If m_lengthresolution=7,  then dimension length display will be n.fffffff.
  ///
  /// FRACTONAL LENGHT DISPLAY: 
  ///   If m_dimension_length_display is ON_DimStyle::LengthDisplay::InchesFractional or
  ///   ON_DimStyle::LengthDisplay::FeetAndInches, then fractional length display is used.
  ///   In this case any fractional part will be rouded to the closest multiple 
  ///   of 1/(2^m_alternate_lengthresolution). 
  ///   Examples: If fractional length display is used and m_lengthresolution=2, 
  //    then the possible fractions are 1/4, 1/2(=2/4), 3/4. 
  ///   If fractional length display is used and m_lengthresolution=7, 
  //    then any fractional part is rounded to the closest multipl of 1/128 (128=2^7).
  /// </summary>
  int m_lengthresolution = 2;

  /// <summary>
  /// Alternate LengthResolution property. 
  /// See the description of m_lengthresolution for more information about this property.
  ///</summary>
  int m_alternate_lengthresolution = 2;

  /// <summary>
  /// The LengthFactor is property a rarely used. It applies when a model is being
  /// drawn to a scale and the dimension length values should be
  /// reverse scaled. For example, if a model is drawn at 1/4 scale,
  /// a line 5 units long indicates the real world line is 20 units
  /// long. In this case setting LengthFactor to 4 would cause
  /// a linear dimension applied to that line to display a value of 20.
  /// Use the DimensionLengthDisplay property to control length unit system scaling.
  ///</summary>
  double m_lengthfactor = 1.0;  // (dimlfac) model units multiplier for length display

  /// <summary>
  /// Alternate LengthFactor property. 
  /// See the description of m_lengthfactor for more information about this property.
  ///</summary>
  double m_alternate_lengthfactor = 1.0; // (dimaltf) model units multiplier for alternate length display

  
private:
  // A copy of the font_characteristics passed to SetFont. 
  // This information is saved in 3dm archives.
  ON_Font m_font_characteristics = ON_Font::Default;

  // The managed font returned by ON_Font::GetManagedFont(m_font).
  // This is the value returned by ON_DimStyle.Font().
  const ON_Font* m_managed_font = &ON_Font::Default;

private:
  // all dim style content
  mutable ON_SHA1_Hash m_content_hash = ON_SHA1_Hash::EmptyContentHash;

  // text position properties content
  mutable ON_SHA1_Hash m_text_position_properties_hash = ON_SHA1_Hash::EmptyContentHash;

  mutable ON_SHA1_Hash m_reserved_hash2 = ON_SHA1_Hash::EmptyContentHash;

  // parent dim style content
  // All code should use ParentContentHash() to inspect this value.
  // Is is set by OverrideFields(). It may be cleared by a call to ParentContentHash().
  mutable ON_SHA1_Hash m_parent_dim_style_content_hash = ON_SHA1_Hash::EmptyContentHash;
  
private:
    

  bool m_bAlternate                                = false;      // (dimalt) display alternate dimension string (or not)


  ON_wString m_prefix;              // string preceding dimension value string
  ON_wString m_suffix;              // string following dimension value string
  ON_wString m_alternate_prefix;    // string preceding alternate value string (Default = " [")
  ON_wString m_alternate_suffix;    // string following alternate value string (Default = "]")

  double m_dimextension                            = 0.0;  // (dimdle) dimension line extension past the "tip" location

  bool   m_bSuppressExtension1                     = false;   // flag to not draw extension lines
  bool   m_bSuppressExtension2                     = false;   // flag to not draw extension lines
  bool   m_bReserved1 = false;
  bool   m_bReserved2 = false; 
  
  // m_field_override_count
  //   number of ON_DimStyle::field settings that are independent of the parent dimension style.
  //   (not inherited from)
  //   A value of 0 indicates every possible setting is inherited from the parent dimension style.
  //   A value > 0 indicates at least one setting is independent of the parent dimension style.
  ON__UINT32 m_field_override_parent_count              = 0;

  // m_field_override_bitsN (Up to 128 true/false) values.
  //   Each ON_DimStyle::field enum value > ON_DimStyle::field::Unset and < ON_DimStyle::field::Count
  //   has a corresponding bit in on of the m_field_override_bitsN values. 
  //   When the bit is clear (0), the corresponding override parent setting value = false and 
  //   that setting is inheritied from the parent dimension style. 0 is the default setting.
  //   When the bit is set (1), the corresponding override parent setting value = true and 
  //   that setting is independent of the parent dimension style.
  ON__UINT32 m_field_override_parent_bits0 = 0;
  ON__UINT32 m_field_override_parent_bits1 = 0;
  ON__UINT32 m_field_override_parent_bits2 = 0;
  ON__UINT32 m_field_override_parent_bits3 = 0;
  // Please do not replace this bitfield with an array of bools.
  // Using bools approach will change the size of this class when additional dimension style
  // settings are added and makes construction code more complicated.


  /*
  Parameters:
    mask - [out]
      0: field_id is not valid 
        (Unset, Name, Index, >= Count) 
        Name and Index settings cannot be inherited from the parent dimension style
      not 0:
        mask identifies the bit in the 
    mask - [out]
      0: field_id is not valid 
        (Unset, Name, Index, >= Count) 
        Name and Index settings cannot be inherited from the parent dimension style
      not 0:
        mask identifies the bit in the 
  Returns:
    nullptr:
      field_id is not valid 
        (Unset, Name, Index, >= Count) 
        Name and Index settings cannot be inherited from the parent dimension style.
    not nullptr:
      Address of the m_field_override_bitsN member that mask applies to.
  */
  ON__UINT32* Internal_GetOverrideParentBit(ON_DimStyle::field field_id, ON__UINT32* mask) const;

  ON_DimStyle::tolerance_format m_tolerance_format = ON_DimStyle::tolerance_format::None;
  int    m_tolerance_resolution                    = 4;
  double m_tolerance_upper_value                   = 0.0;   // or both upper and lower in symmetrical style
  double m_tolerance_lower_value                   = 0.0;
  double m_tolerance_height_scale                  = 0.7;  // relative to the main dimension text

  double m_baseline_spacing                        = 3.0;

  ON_TextMask m_text_mask                          = ON_TextMask::None;

  // m_dimscale replaced by m_scale_value.RightToLeftScale()
  //double   m_dimscale                              = 1.0;
  int      m_dimscale_source                       = 0;

  // Uuid of source dimstyle to restore defaults
  ON_UUID  m_source_dimstyle                       = ON_nil_uuid;

  // Sub-object draw colors
  unsigned char   m_ext_line_color_source          = 0;
  unsigned char   m_dim_line_color_source          = 0;
  unsigned char   m_arrow_color_source             = 0;
  unsigned char   m_text_color_source              = 0;
  ON_Color        m_ext_line_color                 = ON_Color::Black;
  ON_Color        m_dim_line_color                 = ON_Color::Black;
  ON_Color        m_arrow_color                    = ON_Color::Black;
  ON_Color        m_text_color                     = ON_Color::Black;
  unsigned char   m_ext_line_plot_color_source     = 0;
  unsigned char   m_dim_line_plot_color_source     = 0;
  unsigned char   m_arrow_plot_color_source        = 0;
  unsigned char   m_text_plot_color_source         = 0;
  ON_Color        m_ext_line_plot_color            = ON_Color::Black;
  ON_Color        m_dim_line_plot_color            = ON_Color::Black;
  ON_Color        m_arrow_plot_color               = ON_Color::Black;
  ON_Color        m_text_plot_color                = ON_Color::Black;
  unsigned char   m_ext_line_plot_weight_source    = 0;
  unsigned char   m_dim_line_plot_weight_source    = 0;
  double          m_ext_line_plot_weight_mm        = 0.0;
  double          m_dim_line_plot_weight_mm        = 0.0;

  double          m_fixed_extension_len            = 1.0;        // Fixed extension line length if m_fixed_extension_len_on is true
  bool            m_fixed_extension_len_on         = false;     // true: use fixed_extension_len, false: don't use m_fixed_extension_len

  double          m_text_rotation                  = 0.0;              // Dimension text rotation around text point (radians)
  int             m_alternate_tolerance_resolution = 4; // for decimal, digits past the decimal point, fractions: 1/2^n
  double          m_tol_textheight_fraction        = 0.6;    // fraction of main text height

  bool            m_suppress_arrow1                = false;            // false: dont suppress, true: suppress
  bool            m_suppress_arrow2                = false;            // false: dont suppress, true: suppress
  int             m_textmove_leader                = 0;                // 0: move text anywhere, 1: add leader when moving text
  int             m_arclength_sym                  = 0;                // 0: symbol before dim text, 1: symbol above dim text, no symbol
  double          m_stack_textheight_fraction      = 0.7;              // fraction of main text height
  ON_DimStyle::stack_format    m_stack_format      = ON_DimStyle::stack_format::StackHorizontal;
  double          m_alt_round                      = 0.0;              // rounds to nearest specified value
  double          m_round                          = 0.0;
  double          m_angular_round                  = 0.0;

  ON_DimStyle::suppress_zero   m_zero_suppress     = ON_DimStyle::suppress_zero::None;
  ON_DimStyle::suppress_zero   m_alt_zero_suppress = ON_DimStyle::suppress_zero::None;

  ON_DimStyle::suppress_zero   m_ang_zero_suppress = ON_DimStyle::suppress_zero::None;

  bool            m_alt_below = false;                  // true: display alternate text below main text
                                                        // false: display alternate text after main text
  ON_Arrowhead::arrow_type m_arrow_type_1          = ON_Arrowhead::arrow_type::SolidTriangle;      // Arrow types for ON_Dimension derived dimensions
  ON_Arrowhead::arrow_type m_arrow_type_2          = ON_Arrowhead::arrow_type::SolidTriangle;
  ON_Arrowhead::arrow_type m_leader_arrow_type     = ON_Arrowhead::arrow_type::SolidTriangle;
  ON_UUID         m_arrow_block_id_1               = ON_nil_uuid;
  ON_UUID         m_arrow_block_id_2               = ON_nil_uuid;
  ON_UUID         m_leader_arrow_block_id          = ON_nil_uuid;

  // Text 
  ON::TextVerticalAlignment  m_text_vertical_alignment    = ON::TextVerticalAlignment::Top;
  ON::TextHorizontalAlignment m_text_horizontal_alignment    = ON::TextHorizontalAlignment::Left;

  // Leader
  ON::TextVerticalAlignment  m_leader_text_vertical_alignment  = ON::TextVerticalAlignment::Middle;
  ON::TextHorizontalAlignment m_leader_text_horizontal_alignment  = ON::TextHorizontalAlignment::Left;

  ON_DimStyle::ContentAngleStyle   m_leader_content_angle_style = ON_DimStyle::ContentAngleStyle::Horizontal;
  ON_DimStyle::leader_curve_type   m_leader_curve_type          = ON_DimStyle::leader_curve_type::Polyline;
  double              m_leader_content_angle       = 0.0;
  bool                m_leader_has_landing         = true;
  double              m_leader_landing_length      = 1.0;

  bool                m_draw_forward               = true;
  bool                m_signed_ordinate            = true;
  ON_ScaleValue       m_scale_value                = ON_ScaleValue::OneToOne;

  // Unit system for dimension rendering sizes like text height, and arrow head length.
  // m_textheight, m_textgap, m_arrowsize, m_extoffset, and dozens of other properties
  // that control the appearance and placement of the components used to render
  // a dimension.
  ON::LengthUnitSystem m_unitsystem                = ON::LengthUnitSystem::None;

  ON::TextOrientation m_text_orientation                        = ON::TextOrientation::InPlane;
  ON::TextOrientation m_leader_text_orientation                 = ON::TextOrientation::InPlane;
  ON::TextOrientation m_dim_text_orientation                    = ON::TextOrientation::InPlane;
  ON::TextOrientation m_dimradial_text_orientation              = ON::TextOrientation::InPlane;

  ON_DimStyle::ContentAngleStyle       m_dim_text_angle_style       = ON_DimStyle::ContentAngleStyle::Aligned;
  ON_DimStyle::ContentAngleStyle       m_dimradial_text_angle_style = ON_DimStyle::ContentAngleStyle::Horizontal;

  bool m_text_underlined = false; // extra/extended line under text block in leaders and radial dimensions

private:
  ON__UINT_PTR m_reserved = 0;

private:
  void Internal_ContentChange() const;
};


/*
Description:
  A general and portable interface to access a model's available dimension styles.
Remarks:
  The Rhino C++ SDK function CRhinoDoc.DimStyleContext() will return an ON_DimStyleContext for the Rhino model.
  The ONX_Model function ONX_Model.DimStyleContext() will return an ON_DimStyleContext for ONX_Model model.
*/
class ON_CLASS ON_DimStyleContext
{
public:
  ON_DimStyleContext() = default;
  virtual ~ON_DimStyleContext();
  ON_DimStyleContext(const ON_DimStyleContext&) = default;
  ON_DimStyleContext& operator=(const ON_DimStyleContext&) = default;

public:
  virtual const ON_DimStyle& CurrentDimStyle() const;

  virtual const ON_DimStyle* DimStyleFromId(
    ON_UUID id,
    const ON_DimStyle* not_found_result = nullptr
  ) const;

  virtual const ON_DimStyle* DimStyleFromName(
    const ON_NameHash& name_hash,
    const ON_DimStyle* not_found_result = nullptr
  ) const;

  virtual const ON_DimStyle* DimStyleFromContentHash(
    const ON_SHA1_Hash& content_hash,
    const ON_DimStyle* not_found_result = nullptr
  ) const;

  virtual const ON_DimStyle* DimStyleFromFont(
    const ON_Font& font,
    double model_space_text_scale,
    double text_height,
    ON::LengthUnitSystem text_height_unit_system,
    bool bReturnClosestMatch = true,
    const ON_DimStyle* not_found_result = nullptr
  ) const;

  virtual bool AddDimStyle(
    const ON_DimStyle& dim_style,
    bool bResolveNameAndIdConflicts
  );

  virtual bool ModifyDimStyle(
    ON_UUID model_dim_style_id,
    const ON_DimStyle& dim_style
  );

  virtual const ON_DimStyle* FirstDimStyle(
    bool bIncludeSystemDimStyles = false,
    bool bIncludeDeletedDimStyles = false
  ) const;

  virtual const ON_DimStyle* NextDimStyle(
    ON_UUID id,
    bool bIncludeSystemDimStyles = false,
    bool bIncludeDeletedDimStyles = false
  ) const;

  virtual const ON_DimStyle* PrevDimStyle(
    ON_UUID id,
    bool bIncludeSystemDimStyles = false,
    bool bIncludeDeletedDimStyles = false
  ) const;

  virtual ON::LengthUnitSystem ModelUnitSystem() const;
  
  virtual ON__UINT64 ModelSerialNumber() const;

protected:
  mutable ON::LengthUnitSystem m_unit_system = ON::LengthUnitSystem::Millimeters;
  mutable ON__UINT64 m_model_serial_number = 0;
};


#if defined(ON_DLL_TEMPLATE)
ON_DLL_TEMPLATE template class ON_CLASS ON_SimpleArray<ON_DimStyle*>;
ON_DLL_TEMPLATE template class ON_CLASS ON_ObjectArray<ON_DimStyle>;
#endif

#endif