| java.lang.Object
 com.ibm.icu.text.ArabicShaping
| ArabicShaping | | final public class ArabicShaping (Code) | | Shape Arabic text on a character basis.
ArabicShaping performs basic operations for "shaping" Arabic text. It is most
useful for use with legacy data formats and legacy display technology
(simple terminals). All operations are performed on Unicode characters.
Text-based shaping means that some character code points in the text are
replaced by others depending on the context. It transforms one kind of text
into another. In comparison, modern displays for Arabic text select
appropriate, context-dependent font glyphs for each text element, which means
that they transform text into a glyph vector.
Text transformations are necessary when modern display technology is not
available or when text needs to be transformed to or from legacy formats that
use "shaped" characters. Since the Arabic script is cursive, connecting
adjacent letters to each other, computers select images for each letter based
on the surrounding letters. This usually results in four images per Arabic
letter: initial, middle, final, and isolated forms. In Unicode, on the other
hand, letters are normally stored abstract, and a display system is expected
to select the necessary glyphs. (This makes searching and other text
processing easier because the same letter has only one code.) It is possible
to mimic this with text transformations because there are characters in
Unicode that are rendered as letters with a specific shape
(or cursive connectivity). They were included for interoperability with
legacy systems and codepages, and for unsophisticated display systems.
A second kind of text transformations is supported for Arabic digits:
For compatibility with legacy codepages that only include European digits,
it is possible to replace one set of digits by another, changing the
character code points. These operations can be performed for either
Arabic-Indic Digits (U+0660...U+0669) or Eastern (Extended) Arabic-Indic
digits (U+06f0...U+06f9).
Some replacements may result in more or fewer characters (code points).
By default, this means that the destination buffer may receive text with a
length different from the source length. Some legacy systems rely on the
length of the text to be constant. They expect extra spaces to be added
or consumed either next to the affected character or at the end of the
text.
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| Field Summary | |
| final public static int | DIGITS_AN2EN
Digit shaping option: Replace Arabic-Indic digits by European digits (U+0030...U+0039). | | final public static int | DIGITS_EN2AN
Digit shaping option: Replace European digits (U+0030...U+0039) by Arabic-Indic digits. | | final public static int | DIGITS_EN2AN_INIT_AL
Digit shaping option:
Replace European digits (U+0030...U+0039) by Arabic-Indic digits
if the most recent strongly directional character
is an Arabic letter (its Bidi direction value is RIGHT_TO_LEFT_ARABIC). | | final public static int | DIGITS_EN2AN_INIT_LR
Digit shaping option:
Replace European digits (U+0030...U+0039) by Arabic-Indic digits
if the most recent strongly directional character
is an Arabic letter (its Bidi direction value is RIGHT_TO_LEFT_ARABIC). | | final public static int | DIGITS_MASK
Bit mask for digit shaping options. | | final public static int | DIGITS_NOOP
Digit shaping option: do not perform digit shaping. | | final public static int | DIGIT_TYPE_AN
Digit type option: Use Arabic-Indic digits (U+0660...U+0669). | | final public static int | DIGIT_TYPE_AN_EXTENDED
Digit type option: Use Eastern (Extended) Arabic-Indic digits (U+06f0...U+06f9). | | final public static int | DIGIT_TYPE_MASK
Bit mask for digit type options. | | final public static int | LENGTH_FIXED_SPACES_AT_BEGINNING
Memory option: the result must have the same length as the source. | | final public static int | LENGTH_FIXED_SPACES_AT_END
Memory option: the result must have the same length as the source. | | final public static int | LENGTH_FIXED_SPACES_NEAR
Memory option: the result must have the same length as the source. | | final public static int | LENGTH_GROW_SHRINK
Memory option: allow the result to have a different length than the source. | | final public static int | LENGTH_MASK
Bit mask for memory options. | | final public static int | LETTERS_MASK
Bit mask for letter shaping options. | | final public static int | LETTERS_NOOP
Letter shaping option: do not perform letter shaping. | | final public static int | LETTERS_SHAPE
Letter shaping option: replace normative letter characters in the U+0600 (Arabic) block,
by shaped ones in the U+FE70 (Presentation Forms B) block. | | final public static int | LETTERS_SHAPE_TASHKEEL_ISOLATED
Letter shaping option: replace normative letter characters in the U+0600 (Arabic) block,
except for the TASHKEEL characters at U+064B...U+0652, by shaped ones in the U+Fe70
(Presentation Forms B) block. | | final public static int | LETTERS_UNSHAPE
Letter shaping option: replace shaped letter characters in the U+FE70 (Presentation Forms B) block
by normative ones in the U+0600 (Arabic) block. | | final public static int | TEXT_DIRECTION_LOGICAL
Direction indicator: the source is in logical (keyboard) order. | | final public static int | TEXT_DIRECTION_MASK
Bit mask for direction indicators. | | final public static int | TEXT_DIRECTION_VISUAL_LTR
Direction indicator: the source is in visual (display) order, that is,
the leftmost displayed character is stored first. |
| Constructor Summary | |
| public | ArabicShaping(int options)
Construct ArabicShaping using the options flags. |
| Method Summary | |
| public boolean | equals(Object rhs)
| | public int | hashCode()
| | public int | shape(char[] source, int sourceStart, int sourceLength, char[] dest, int destStart, int destSize)
Convert a range of text in the source array, putting the result
into a range of text in the destination array, and return the number
of characters written.
Parameters:
source - An array containing the input text
Parameters:
sourceStart - The start of the range of text to convert
Parameters:
sourceLength - The length of the range of text to convert
Parameters:
dest - The destination array that will receive the result.It may be NULL only if destSize is 0. | | public void | shape(char[] source, int start, int length)
Convert a range of text in place. | | public String | shape(String text)
Convert a string, returning the new string. | | public String | toString()
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| DIGITS_AN2EN | | final public static int DIGITS_AN2EN(Code) | | Digit shaping option: Replace Arabic-Indic digits by European digits (U+0030...U+0039).
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| DIGITS_EN2AN | | final public static int DIGITS_EN2AN(Code) | | Digit shaping option: Replace European digits (U+0030...U+0039) by Arabic-Indic digits.
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| DIGITS_EN2AN_INIT_AL | | final public static int DIGITS_EN2AN_INIT_AL(Code) | | Digit shaping option:
Replace European digits (U+0030...U+0039) by Arabic-Indic digits
if the most recent strongly directional character
is an Arabic letter (its Bidi direction value is RIGHT_TO_LEFT_ARABIC).
The initial state at the start of the text is assumed to be an Arabic,
letter, so European digits at the start of the text will change.
Compare to DIGITS_ALEN2AN_INT_LR.
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| DIGITS_EN2AN_INIT_LR | | final public static int DIGITS_EN2AN_INIT_LR(Code) | | Digit shaping option:
Replace European digits (U+0030...U+0039) by Arabic-Indic digits
if the most recent strongly directional character
is an Arabic letter (its Bidi direction value is RIGHT_TO_LEFT_ARABIC).
The initial state at the start of the text is assumed to be not an Arabic,
letter, so European digits at the start of the text will not change.
Compare to DIGITS_ALEN2AN_INIT_AL.
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| DIGITS_MASK | | final public static int DIGITS_MASK(Code) | | Bit mask for digit shaping options.
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| DIGITS_NOOP | | final public static int DIGITS_NOOP(Code) | | Digit shaping option: do not perform digit shaping.
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| DIGIT_TYPE_AN | | final public static int DIGIT_TYPE_AN(Code) | | Digit type option: Use Arabic-Indic digits (U+0660...U+0669).
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| DIGIT_TYPE_AN_EXTENDED | | final public static int DIGIT_TYPE_AN_EXTENDED(Code) | | Digit type option: Use Eastern (Extended) Arabic-Indic digits (U+06f0...U+06f9).
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| DIGIT_TYPE_MASK | | final public static int DIGIT_TYPE_MASK(Code) | | Bit mask for digit type options.
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| LENGTH_FIXED_SPACES_AT_BEGINNING | | final public static int LENGTH_FIXED_SPACES_AT_BEGINNING(Code) | | Memory option: the result must have the same length as the source.
If more room is necessary, then try to consume spaces at the beginning of the text.
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| LENGTH_FIXED_SPACES_AT_END | | final public static int LENGTH_FIXED_SPACES_AT_END(Code) | | Memory option: the result must have the same length as the source.
If more room is necessary, then try to consume spaces at the end of the text.
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| LENGTH_FIXED_SPACES_NEAR | | final public static int LENGTH_FIXED_SPACES_NEAR(Code) | | Memory option: the result must have the same length as the source.
If more room is necessary, then try to consume spaces next to modified characters.
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| LENGTH_GROW_SHRINK | | final public static int LENGTH_GROW_SHRINK(Code) | | Memory option: allow the result to have a different length than the source.
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| LENGTH_MASK | | final public static int LENGTH_MASK(Code) | | Bit mask for memory options.
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| LETTERS_MASK | | final public static int LETTERS_MASK(Code) | | Bit mask for letter shaping options.
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| LETTERS_NOOP | | final public static int LETTERS_NOOP(Code) | | Letter shaping option: do not perform letter shaping.
|
| LETTERS_SHAPE | | final public static int LETTERS_SHAPE(Code) | | Letter shaping option: replace normative letter characters in the U+0600 (Arabic) block,
by shaped ones in the U+FE70 (Presentation Forms B) block. Performs Lam-Alef ligature
substitution.
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| LETTERS_SHAPE_TASHKEEL_ISOLATED | | final public static int LETTERS_SHAPE_TASHKEEL_ISOLATED(Code) | | Letter shaping option: replace normative letter characters in the U+0600 (Arabic) block,
except for the TASHKEEL characters at U+064B...U+0652, by shaped ones in the U+Fe70
(Presentation Forms B) block. The TASHKEEL characters will always be converted to
the isolated forms rather than to their correct shape.
|
| LETTERS_UNSHAPE | | final public static int LETTERS_UNSHAPE(Code) | | Letter shaping option: replace shaped letter characters in the U+FE70 (Presentation Forms B) block
by normative ones in the U+0600 (Arabic) block. Converts Lam-Alef ligatures to pairs of Lam and
Alef characters, consuming spaces if required.
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| TEXT_DIRECTION_LOGICAL | | final public static int TEXT_DIRECTION_LOGICAL(Code) | | Direction indicator: the source is in logical (keyboard) order.
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| TEXT_DIRECTION_MASK | | final public static int TEXT_DIRECTION_MASK(Code) | | Bit mask for direction indicators.
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| TEXT_DIRECTION_VISUAL_LTR | | final public static int TEXT_DIRECTION_VISUAL_LTR(Code) | | Direction indicator: the source is in visual (display) order, that is,
the leftmost displayed character is stored first.
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| ArabicShaping | | public ArabicShaping(int options)(Code) | | Construct ArabicShaping using the options flags.
The flags are as follows:
'LENGTH' flags control whether the text can change size, and if not,
how to maintain the size of the text when LamAlef ligatures are
formed or broken.
'TEXT_DIRECTION' flags control whether the text is read and written
in visual order or in logical order.
'LETTERS_SHAPE' flags control whether conversion is to or from
presentation forms.
'DIGITS' flags control whether digits are shaped, and whether from
European to Arabic-Indic or vice-versa.
'DIGIT_TYPE' flags control whether standard or extended Arabic-Indic
digits are used when performing digit conversion.
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| hashCode | | public int hashCode()(Code) | | |
| shape | | public int shape(char[] source, int sourceStart, int sourceLength, char[] dest, int destStart, int destSize) throws ArabicShapingException(Code) | | Convert a range of text in the source array, putting the result
into a range of text in the destination array, and return the number
of characters written.
Parameters:
source - An array containing the input text
Parameters:
sourceStart - The start of the range of text to convert
Parameters:
sourceLength - The length of the range of text to convert
Parameters:
dest - The destination array that will receive the result.It may be NULL only if destSize is 0.
Parameters:
destStart - The start of the range of the destination buffer to use.
Parameters:
destSize - The size (capacity) of the destination buffer.If destSize is 0, then no output is produced,but the necessary buffer size is returned ("preflighting"). Thisdoes not validate the text against the options, for example, if letters are being unshaped, and spaces are being consumedfollowing lamalef, this will not detect a lamalef without a corresponding space. An error will be thrown when the actualconversion is attempted. The number of chars written to the destination buffer.If an error occurs, then no output was written, or it may beincomplete.
throws:
ArabicShapingException - if the text cannot be converted according to the options. |
| shape | | public void shape(char[] source, int start, int length) throws ArabicShapingException(Code) | | Convert a range of text in place. This may only be used if the Length option
does not grow or shrink the text.
Parameters:
source - An array containing the input text
Parameters:
start - The start of the range of text to convert
Parameters:
length - The length of the range of text to convert
throws:
ArabicShapingException - if the text cannot be converted according to the options. |
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