com.itextpdf.text.pdf
Class BidiOrder

java.lang.Object
  extended by com.itextpdf.text.pdf.BidiOrder

public final class BidiOrder
extends Object


Field Summary
static byte AL
          Right-to-Left Arabic
static byte AN
          Arabic Number
static byte B
          Paragraph Separator
private static char[] baseTypes
           
static byte BN
          Boundary Neutral
static byte CS
          Common Number Separator
private  byte[] embeddings
           
static byte EN
          European Number
static byte ES
          European Number Separator
static byte ET
          European Number Terminator
private  byte[] initialTypes
           
static byte L
          Left-to-right
static byte LRE
          Left-to-Right Embedding
static byte LRO
          Left-to-Right Override
static byte NSM
          Non-Spacing Mark
static byte ON
          Other Neutrals
private  byte paragraphEmbeddingLevel
           
static byte PDF
          Pop Directional Format
static byte R
          Right-to-Left
private  byte[] resultLevels
           
private  byte[] resultTypes
           
static byte RLE
          Right-to-Left Embedding
static byte RLO
          Right-to-Left Override
private static byte[] rtypes
           
static byte S
          Segment Separator
private  int textLength
           
static byte TYPE_MAX
          Maximum bidi type value.
static byte TYPE_MIN
          Minimum bidi type value.
static byte WS
          Whitespace
 
Constructor Summary
BidiOrder(byte[] types)
          Initialize using an array of direction types.
BidiOrder(byte[] types, byte paragraphEmbeddingLevel)
          Initialize using an array of direction types and an externally supplied paragraph embedding level.
BidiOrder(char[] text, int offset, int length, byte paragraphEmbeddingLevel)
           
 
Method Summary
private static int[] computeMultilineReordering(byte[] levels, int[] linebreaks)
          Return multiline reordering array for a given level array.
private static int[] computeReordering(byte[] levels)
          Return reordering array for a given level array.
private  void determineExplicitEmbeddingLevels()
          Process embedding format codes.
private  void determineParagraphEmbeddingLevel()
          1) determining the paragraph level.
private  int findRunLimit(int index, int limit, byte[] validSet)
          Return the limit of the run starting at index that includes only resultTypes in validSet.
private  int findRunStart(int index, byte[] validSet)
          Return the start of the run including index that includes only resultTypes in validSet.
 byte getBaseLevel()
          Return the base level of the paragraph.
static byte getDirection(char c)
           
 byte[] getLevels()
           
 byte[] getLevels(int[] linebreaks)
          Return levels array breaking lines at offsets in linebreaks.
 int[] getReordering(int[] linebreaks)
          Return reordering array breaking lines at offsets in linebreaks.
private static boolean isWhitespace(byte biditype)
          Return true if the type is considered a whitespace type for the line break rules.
private static byte[] processEmbeddings(byte[] resultTypes, byte paragraphEmbeddingLevel)
          2) determining explicit levels Rules X1 - X8 The interaction of these rules makes handling them a bit complex.
private  int reinsertExplicitCodes(int textLength)
          Reinsert levels information for explicit codes.
private  int removeExplicitCodes()
          Rules X9.
private  void resolveImplicitLevels(int start, int limit, byte level, byte sor, byte eor)
          7) resolving implicit embedding levels Rules I1, I2.
private  void resolveNeutralTypes(int start, int limit, byte level, byte sor, byte eor)
          6) resolving neutral types Rules N1-N2.
private  void resolveWeakTypes(int start, int limit, byte level, byte sor, byte eor)
          3) resolving weak types Rules W1-W7.
private  void runAlgorithm()
          The algorithm.
private  void setLevels(int start, int limit, byte newLevel)
          Set resultLevels from start up to (but not including) limit to newLevel.
private  void setTypes(int start, int limit, byte newType)
          Set resultTypes from start up to (but not including) limit to newType.
private static byte typeForLevel(int level)
          Return the strong type (L or R) corresponding to the level.
private static void validateLineBreaks(int[] linebreaks, int textLength)
          Throw exception if line breaks array is invalid.
private static void validateParagraphEmbeddingLevel(byte paragraphEmbeddingLevel)
          Throw exception if paragraph embedding level is invalid.
private static void validateTypes(byte[] types)
          Throw exception if type array is invalid.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

initialTypes

private byte[] initialTypes

embeddings

private byte[] embeddings

paragraphEmbeddingLevel

private byte paragraphEmbeddingLevel

textLength

private int textLength

resultTypes

private byte[] resultTypes

resultLevels

private byte[] resultLevels

L

public static final byte L
Left-to-right

See Also:
Constant Field Values

LRE

public static final byte LRE
Left-to-Right Embedding

See Also:
Constant Field Values

LRO

public static final byte LRO
Left-to-Right Override

See Also:
Constant Field Values

R

public static final byte R
Right-to-Left

See Also:
Constant Field Values

AL

public static final byte AL
Right-to-Left Arabic

See Also:
Constant Field Values

RLE

public static final byte RLE
Right-to-Left Embedding

See Also:
Constant Field Values

RLO

public static final byte RLO
Right-to-Left Override

See Also:
Constant Field Values

PDF

public static final byte PDF
Pop Directional Format

See Also:
Constant Field Values

EN

public static final byte EN
European Number

See Also:
Constant Field Values

ES

public static final byte ES
European Number Separator

See Also:
Constant Field Values

ET

public static final byte ET
European Number Terminator

See Also:
Constant Field Values

AN

public static final byte AN
Arabic Number

See Also:
Constant Field Values

CS

public static final byte CS
Common Number Separator

See Also:
Constant Field Values

NSM

public static final byte NSM
Non-Spacing Mark

See Also:
Constant Field Values

BN

public static final byte BN
Boundary Neutral

See Also:
Constant Field Values

B

public static final byte B
Paragraph Separator

See Also:
Constant Field Values

S

public static final byte S
Segment Separator

See Also:
Constant Field Values

WS

public static final byte WS
Whitespace

See Also:
Constant Field Values

ON

public static final byte ON
Other Neutrals

See Also:
Constant Field Values

TYPE_MIN

public static final byte TYPE_MIN
Minimum bidi type value.

See Also:
Constant Field Values

TYPE_MAX

public static final byte TYPE_MAX
Maximum bidi type value.

See Also:
Constant Field Values

rtypes

private static final byte[] rtypes

baseTypes

private static char[] baseTypes
Constructor Detail

BidiOrder

public BidiOrder(byte[] types)
Initialize using an array of direction types. Types range from TYPE_MIN to TYPE_MAX inclusive and represent the direction codes of the characters in the text.

Parameters:
types - the types array

BidiOrder

public BidiOrder(byte[] types,
                 byte paragraphEmbeddingLevel)
Initialize using an array of direction types and an externally supplied paragraph embedding level. The embedding level may be -1, 0, or 1. -1 means to apply the default algorithm (rules P2 and P3), 0 is for LTR paragraphs, and 1 is for RTL paragraphs.

Parameters:
types - the types array
paragraphEmbeddingLevel - the externally supplied paragraph embedding level.

BidiOrder

public BidiOrder(char[] text,
                 int offset,
                 int length,
                 byte paragraphEmbeddingLevel)
Method Detail

getDirection

public static final byte getDirection(char c)

runAlgorithm

private void runAlgorithm()
The algorithm. Does not include line-based processing (Rules L1, L2). These are applied later in the line-based phase of the algorithm.


determineParagraphEmbeddingLevel

private void determineParagraphEmbeddingLevel()
1) determining the paragraph level.

Rules P2, P3.

At the end of this function, the member variable paragraphEmbeddingLevel is set to either 0 or 1.


determineExplicitEmbeddingLevels

private void determineExplicitEmbeddingLevels()
Process embedding format codes.

Calls processEmbeddings to generate an embedding array from the explicit format codes. The embedding overrides in the array are then applied to the result types, and the result levels are initialized.

See Also:
processEmbeddings(byte[], byte)

removeExplicitCodes

private int removeExplicitCodes()
Rules X9. Remove explicit codes so that they may be ignored during the remainder of the main portion of the algorithm. The length of the resulting text is returned.

Returns:
the length of the data excluding explicit codes and BN.

reinsertExplicitCodes

private int reinsertExplicitCodes(int textLength)
Reinsert levels information for explicit codes. This is for ease of relating the level information to the original input data. Note that the levels assigned to these codes are arbitrary, they're chosen so as to avoid breaking level runs.

Parameters:
textLength - the length of the data after compression
Returns:
the length of the data (original length of types array supplied to constructor)

processEmbeddings

private static byte[] processEmbeddings(byte[] resultTypes,
                                        byte paragraphEmbeddingLevel)
2) determining explicit levels Rules X1 - X8 The interaction of these rules makes handling them a bit complex. This examines resultTypes but does not modify it. It returns embedding and override information in the result array. The low 7 bits are the level, the high bit is set if the level is an override, and clear if it is an embedding.


resolveWeakTypes

private void resolveWeakTypes(int start,
                              int limit,
                              byte level,
                              byte sor,
                              byte eor)
3) resolving weak types Rules W1-W7. Note that some weak types (EN, AN) remain after this processing is complete.


resolveNeutralTypes

private void resolveNeutralTypes(int start,
                                 int limit,
                                 byte level,
                                 byte sor,
                                 byte eor)
6) resolving neutral types Rules N1-N2.


resolveImplicitLevels

private void resolveImplicitLevels(int start,
                                   int limit,
                                   byte level,
                                   byte sor,
                                   byte eor)
7) resolving implicit embedding levels Rules I1, I2.


getLevels

public byte[] getLevels()

getLevels

public byte[] getLevels(int[] linebreaks)
Return levels array breaking lines at offsets in linebreaks.
Rule L1.

The returned levels array contains the resolved level for each bidi code passed to the constructor.

The linebreaks array must include at least one value. The values must be in strictly increasing order (no duplicates) between 1 and the length of the text, inclusive. The last value must be the length of the text.

Parameters:
linebreaks - the offsets at which to break the paragraph
Returns:
the resolved levels of the text

getReordering

public int[] getReordering(int[] linebreaks)
Return reordering array breaking lines at offsets in linebreaks.

The reordering array maps from a visual index to a logical index. Lines are concatenated from left to right. So for example, the fifth character from the left on the third line is

 getReordering(linebreaks)[linebreaks[1] + 4]
(linebreaks[1] is the position after the last character of the second line, which is also the index of the first character on the third line, and adding four gets the fifth character from the left).

The linebreaks array must include at least one value. The values must be in strictly increasing order (no duplicates) between 1 and the length of the text, inclusive. The last value must be the length of the text.

Parameters:
linebreaks - the offsets at which to break the paragraph.

computeMultilineReordering

private static int[] computeMultilineReordering(byte[] levels,
                                                int[] linebreaks)
Return multiline reordering array for a given level array. Reordering does not occur across a line break.


computeReordering

private static int[] computeReordering(byte[] levels)
Return reordering array for a given level array. This reorders a single line. The reordering is a visual to logical map. For example, the leftmost char is string.charAt(order[0]). Rule L2.


getBaseLevel

public byte getBaseLevel()
Return the base level of the paragraph.


isWhitespace

private static boolean isWhitespace(byte biditype)
Return true if the type is considered a whitespace type for the line break rules.


typeForLevel

private static byte typeForLevel(int level)
Return the strong type (L or R) corresponding to the level.


findRunLimit

private int findRunLimit(int index,
                         int limit,
                         byte[] validSet)
Return the limit of the run starting at index that includes only resultTypes in validSet. This checks the value at index, and will return index if that value is not in validSet.


findRunStart

private int findRunStart(int index,
                         byte[] validSet)
Return the start of the run including index that includes only resultTypes in validSet. This assumes the value at index is valid, and does not check it.


setTypes

private void setTypes(int start,
                      int limit,
                      byte newType)
Set resultTypes from start up to (but not including) limit to newType.


setLevels

private void setLevels(int start,
                       int limit,
                       byte newLevel)
Set resultLevels from start up to (but not including) limit to newLevel.


validateTypes

private static void validateTypes(byte[] types)
Throw exception if type array is invalid.


validateParagraphEmbeddingLevel

private static void validateParagraphEmbeddingLevel(byte paragraphEmbeddingLevel)
Throw exception if paragraph embedding level is invalid. Special allowance for -1 so that default processing can still be performed when using this API.


validateLineBreaks

private static void validateLineBreaks(int[] linebreaks,
                                       int textLength)
Throw exception if line breaks array is invalid.


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