public final Class FontUtilities

Referenced by code in the JDK which wants to test for the maximum char code for which layout may be required. Note this does not account for supplementary characters where the caller interprets 'layout' to mean any case where one 'char' (ie the java type char) does not map to one glyph

Referenced by code in the JDK which wants to test for the minimum char code for which layout may be required. Note that even basic latin text can benefit from ligatures, eg "ffi" but we presently apply those only if explicitly requested with TextAttribute.LIGATURES_ON. The value here indicates the lowest char code for which failing to invoke layout would prevent acceptable rendering.

Calls the private getFont2D() method in java.awt.Font objects.

Parameters

font:Font

the font object to call

Returns:Font2D

the Font2D object returned by Font.getFont2D()

Return true if there any characters which would trigger layout. This method considers supplementary characters to be simple, since we do not presently invoke layout on any code points in outside the BMP.

If there is anything in the text which triggers a case where char->glyph does not map 1:1 in straightforward left->right ordering, then this method returns true. Scripts which might require it but are not treated as such due to JDK implementations will not return true. ie a 'true' return is an indication of the treatment by the implementation. Whether supplementary characters should be considered is dependent on the needs of the caller. Since this method accepts the 'char' type then such chars are always represented by a pair. From a rendering perspective these will all (in the cases I know of) still be one unicode character -> one glyph. But if a caller is using this to discover any case where it cannot make naive assumptions about the number of chars, and how to index through them, then it may need the option to have a 'true' return in such a case.

Checks whether or not the specified codepoint is ignorable by default, per the Unicode standard (with exceptions for HarfBuzz and Uniscribe compatibility). The codepoints categorized as ignorable should remain in sync with HarfBuzz's is_default_ignorable() in hb-unicode.hh.

See the original Unicode list of default-ignorable codepoints here:

00AD         # Cf       SOFT HYPHEN
034F         # Mn       COMBINING GRAPHEME JOINER
061C         # Cf       ARABIC LETTER MARK
115F..1160   # Lo   [2] HANGUL CHOSEONG FILLER..HANGUL JUNGSEONG FILLER
17B4..17B5   # Mn   [2] KHMER VOWEL INHERENT AQ..KHMER VOWEL INHERENT AA
180B..180D   # Mn   [3] MONGOLIAN FREE VARIATION SELECTOR ONE..MONGOLIAN FREE VARIATION SELECTOR THREE
180E         # Cf       MONGOLIAN VOWEL SEPARATOR
180F         # Mn       MONGOLIAN FREE VARIATION SELECTOR FOUR
200B..200F   # Cf   [5] ZERO WIDTH SPACE..RIGHT-TO-LEFT MARK
202A..202E   # Cf   [5] LEFT-TO-RIGHT EMBEDDING..RIGHT-TO-LEFT OVERRIDE
2060..2064   # Cf   [5] WORD JOINER..INVISIBLE PLUS
2065         # Cn       
2066..206F   # Cf  [10] LEFT-TO-RIGHT ISOLATE..NOMINAL DIGIT SHAPES
3164         # Lo       HANGUL FILLER
FE00..FE0F   # Mn  [16] VARIATION SELECTOR-1..VARIATION SELECTOR-16
FEFF         # Cf       ZERO WIDTH NO-BREAK SPACE
FFA0         # Lo       HALFWIDTH HANGUL FILLER
FFF0..FFF8   # Cn   [9] ..
1BCA0..1BCA3 # Cf   [4] SHORTHAND FORMAT LETTER OVERLAP..SHORTHAND FORMAT UP STEP
1D173..1D17A # Cf   [8] MUSICAL SYMBOL BEGIN BEAM..MUSICAL SYMBOL END PHRASE
E0000        # Cn       
E0001        # Cf       LANGUAGE TAG
E0002..E001F # Cn  [30] ..
E0020..E007F # Cf  [96] TAG SPACE..CANCEL TAG
E0080..E00FF # Cn [128] ..
E0100..E01EF # Mn [240] VARIATION SELECTOR-17..VARIATION SELECTOR-256
E01F0..E0FFF # Cn [3600] ..

Checks whether or not the specified codepoint is whitespace which is ignorable at the shaping stage of text rendering. These ignorable whitespace characters should be used prior to text shaping and rendering to determine the position of the text, but are not themselves rendered.

Includes 0x0009 (horizontal tab / TAB), 0x000A (line feed / LF), 0x000B (vertical tab / VT), 0x000C (form feed / FF), 0x000D (carriage return / CR), 0x0085 (next line / NEL), 0x2028 (line separator / LS), 0x2029 (paragraph separator / PS).

Parameters

ch:int

the codepoint to check

Returns:boolean

whether the specified codepoint is ignorable whitespace

Used by windows printing to assess if a font is likely to be layout compatible with JDK TrueType fonts should be, but if they have no GPOS table, but do have a GSUB table, then they are probably older fonts GDI handles differently.