XdkWrl: Text Class Reference

6.66 Text

6.66.1 Introduction

The Text node specifies a two-sided, flat text string object positioned in the Z=0 plane of the local coordinate system based on values defined in the fontStyle field (see 6.20, FontStyle). Text nodes may contain multiple text strings specified using the UTF-8 encoding as specified by ISO 10646-1:1993 (see 2.[UTF8]). The text strings are stored in the order in which the text mode characters are to be produced as defined by the parameters in the FontStyle node.

The text strings are contained in the string field. The fontStyle field contains one FontStyle node that specifies the font size, font family and style, direction of the text strings, and any specific language rendering techniques used for the text.

The maxExtent field limits and compresses all of the text strings if the length of the maximum string is longer than the maximum extent, as measured in the local coordinate system. If the text string with the maximum length is shorter than the maxExtent, then there is no compressing. The maximum extent is measured horizontally for horizontal text (FontStyle node: horizontal=TRUE) and vertically for vertical text (FontStyle node: horizontal=FALSE). The maxExtent field shall be greater than or equal to zero.

The length field contains an MFFloat value that specifies the length of each text string in the local coordinate system. If the string is too short, it is stretched (either by scaling the text or by adding space between the characters). If the string is too long, it is compressed (either by scaling the text or by subtracting space between the characters). If a length value is missing (for example, if there are four strings but only three length values), the missing values are considered to be 0. The length field shall be greater than or equal to zero.

Specifying a value of 0 for both the maxExtent and length fields indicates that the string may be any length.

6.66.2 ISO 10646-1:1993 Character Encodings

Characters in ISO 10646 (see 2.[UTF8]) are encoded in multiple octets. Code space is divided into four units, as follows:

+-------------+-------------+-----------+------------+
| Group-octet | Plane-octet | Row-octet | Cell-octet |
+-------------+-------------+-----------+------------+

ISO 10646-1:1993 allows two basic forms for characters:

UCS-2 (Universal Coded Character Set-2). This form is also known as the Basic Multilingual Plane (BMP). Characters are encoded in the lower two octets (row and cell).
UCS-4 (Universal Coded Character Set-4). Characters are encoded in the full four octets.

In addition, three transformation formats (UCS Transformation Format or UTF) are accepted: UTF-7, UTF-8, and UTF-16. Each represents the nature of the transformation: 7-bit, 8-bit, or 16-bit. UTF-7 and UTF-16 are referenced in 2.[UTF8].

UTF-8 maintains transparency for all ASCII code values (0...127). It allows ASCII text (0x0..0x7F) to appear without any changes and encodes all characters from 0x80.. 0x7FFFFFFF into a series of six or fewer bytes.

If the most significant bit of the first character is 0, the remaining seven bits are interpreted as an ASCII character. Otherwise, the number of leading 1 bits indicates the number of bytes following. There is always a zero bit between the count bits and any data.

The first byte is one of the following. The X indicates bits available to encode the character:

 0XXXXXXX only one byte   0..0x7F (ASCII)
 110XXXXX two bytes       Maximum character value is 0x7FF
 1110XXXX three bytes     Maximum character value is 0xFFFF
 11110XXX four bytes      Maximum character value is 0x1FFFFF
 111110XX five bytes      Maximum character value is 0x3FFFFFF
 1111110X six bytes       Maximum character value is 0x7FFFFFFF

All following bytes have the format 10XXXXXX.

As a two byte example, the symbol for a register trade mark is ® or 174 in ISO Latin-1 (see 2.[I8859]). It is encoded as 0x00AE in UCS-2 of ISO 10646. In UTF-8, it has the following two byte encoding: 0xC2, 0xAE.

6.66.3 Appearance

Textures are applied to text as follows. The texture origin is at the origin of the first string, as determined by the justification. The texture is scaled equally in both S and T dimensions, with the font height representing 1 unit. S increases to the right, and T increases up.

4.14, Lighting model, has details on VRML lighting equations and how Appearance, Material and textures interact with lighting.

The Text node does not participate in collision detection.

Constructor & Destructor Documentation

Text ( const char * name = "" )

Construct a node with all its fields set to default value, which is equivalent to the code below:

  maxExtent = 0;

Member Function Documentation

wrl::Node * duplicate ( std::map< const Node *, Node * > & ) const [virtual]

Implements Node.

wrl::Node * duplicate ( ) const [virtual]

Returns a deep copy of this node, that is a fully independant node with all children (if any) also copied. This is mainly useful for instanciating protos.

Implements Node.

wrl::Node::EventInHandle eventIn ( const unsigned int n ) [virtual]

Return a handle on the i th event in of the node or a "unknown" typed handle if there is no such node. emarks This class has no eventIn. This function is useful, with nbEventsIn() if you want to traverse all events in of a Node.

Implements Node.

wrl::Node::EventInHandle eventIn ( const std::string & n ) [virtual]

Return a handle on the event in named n of the node or a "unknown" typed handle if there is no such event. Valid names are:

set_string
set_fontStyle
set_length
set_maxExtent

Implements Node.

wrl::Node::EventOutHandle eventOut ( const unsigned int n ) [virtual]

Return a handle on the i th event out of the node or a "unknown" typed handle if there is no such node. Here is how i is related to fields:

0 : string_changed
1 : fontStyle_changed
2 : length_changed
3 : maxExtent_changed This function is useful, with nbEventsOut() if you want to traverse all events in of a Node.

Implements Node.

wrl::Node::EventOutHandle eventOut ( const std::string & n ) [virtual]

Return a handle on the event out named n of the node or a "unknown" typed handle if there is no such event. Valid names are:

string_changed
fontStyle_changed
length_changed
maxExtent_changed

Implements Node.

wrl::Node::FieldHandle field ( const unsigned int n ) [virtual]

Return a handle on the i th field of the node or a "unknown" typed handle if there is no such node. Here is how i is related to fields:

0 : string
1 : fontStyle
2 : length
3 : maxExtent This function is useful, with nbFields() if you want to traverse all fields of a Node.

Implements Node.

wrl::Node::FieldHandle field ( const std::string & n ) [virtual]

Return a handle on the field named n of the node or a "unknown" typed handle if there is no such field. Valid names are:

string
fontStyle
length
maxExtent

Implements Node.

bool isSetToDefaultValue ( const unsigned int i ) const [virtual]

Implements Node.

unsigned int nbEventsIn ( ) const [inline, virtual]

Returns the number of events in for this node type.

Implements Node.

unsigned int nbEventsOut ( ) const [inline, virtual]

Returns the number of events out for this node type.

Implements Node.

unsigned int nbFields ( ) const [inline, virtual]

Returns the number of fields (exposed or not) for this node type.

Implements Node.

const char * typeName ( ) const [inline, virtual]

Returns "Text". Useful for printing.

Implements Node.


Public Member Functions
	Text (const char *name="")
virtual	~Text ()
virtual unsigned int	nbFields () const
virtual FieldHandle	field (const std::string &n)
virtual FieldHandle	field (const unsigned int i)
virtual bool	isSetToDefaultValue (const unsigned int i) const
virtual unsigned int	nbEventsIn () const
virtual EventInHandle	eventIn (const std::string &n)
virtual EventInHandle	eventIn (const unsigned int i)
virtual unsigned int	nbEventsOut () const
virtual EventOutHandle	eventOut (const std::string &n)
virtual EventOutHandle	eventOut (const unsigned int i)
const char *	typeName () const
virtual Node *	duplicate () const
virtual Node *	duplicate (std::map< const Node , Node > &) const
Public Attributes
Exposed Fields
A field that is capable of receiving events via an eventIn to change its value(s), and generating events via an eventOut when its value(s) change.
MFString	string
SFNode	fontStyle
MFFloat	length
SFFloat	maxExtent
Events In
EventIn< MFString >	set_string
EventIn< SFNode >	set_fontStyle
EventIn< MFFloat >	set_length
EventIn< SFFloat >	set_maxExtent
Events Out
EventOut< MFString >	string_changed
EventOut< SFNode >	fontStyle_changed
EventOut< MFFloat >	length_changed
EventOut< SFFloat >	maxExtent_changed

Text Class Reference
[Standard Node Types]

Public Member Functions

Public Attributes

Detailed Description

6.66 Text

6.66.1 Introduction

6.66.2 ISO 10646-1:1993 Character Encodings

6.66.3 Appearance

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Text Class Reference [Standard Node Types]

Public Member Functions

Public Attributes

Detailed Description

6.66 Text

6.66.1 Introduction

6.66.2 ISO 10646-1:1993 Character Encodings

6.66.3 Appearance

Constructor & Destructor Documentation

Member Function Documentation

Member Data Documentation

Text Class Reference
[Standard Node Types]