Commit 1c19b549997fc5adb59644b81d4156c1e36db4e3
2017-01-28T11:39:51
freetype.h: Improve Unicode Variation Sequence documentation.
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diff --git a/include/freetype/freetype.h b/include/freetype/freetype.h
index 2230d3c..1e623ec 100644
--- a/include/freetype/freetype.h
+++ b/include/freetype/freetype.h
@@ -3804,40 +3804,51 @@ FT_BEGIN_HEADER
/* glyph_variants */
/* */
/* <Title> */
- /* Glyph Variants */
+ /* Unicode Variation Sequences */
/* */
/* <Abstract> */
- /* The FreeType~2 interface to Unicode Ideographic Variation */
- /* Sequences (IVS), using the SFNT cmap format~14. */
+ /* The FreeType~2 interface to Unicode Variation Sequences (UVS), */
+ /* using the SFNT cmap format~14. */
/* */
/* <Description> */
- /* Many CJK characters have variant forms. They are a sort of grey */
- /* area somewhere between being totally irrelevant and semantically */
- /* distinct; for this reason, the Unicode consortium decided to */
- /* introduce Ideographic Variation Sequences (IVS), consisting of a */
- /* Unicode base character and one of 240 variant selectors */
- /* (U+E0100-U+E01EF), instead of further extending the already huge */
- /* code range for CJK characters. */
- /* */
- /* An IVS is registered and unique; for further details please refer */
- /* to Unicode Technical Standard #37, the Ideographic Variation */
- /* Database: */
- /* */
- /* http://www.unicode.org/reports/tr37/ */
- /* http://www.unicode.org/ivd/ */
- /* */
- /* To date (January 2017), the character with the most variants is */
- /* U+9089, having 32 such IVS. */
- /* */
- /* Adobe and MS decided to support IVS with a new cmap subtable */
- /* (format~14). It is an odd subtable because it is not a mapping of */
- /* input code points to glyphs, but contains lists of all variants */
- /* supported by the font. */
- /* */
- /* A variant may be either `default' or `non-default'. A default */
- /* variant is the one you will get for that code point if you look it */
- /* up in the standard Unicode cmap. A non-default variant is a */
- /* different glyph. */
+ /* Many characters, especially for CJK scripts, have variant forms. */
+ /* They are a sort of grey area somewhere between being totally */
+ /* irrelevant and semantically distinct; for this reason, the Unicode */
+ /* consortium decided to introduce Variation Sequences (VS), */
+ /* consisting of a Unicode base character and a variation selector */
+ /* instead of further extending the already huge number of */
+ /* characters. */
+ /* */
+ /* Unicode maintains two different sets, namely `Standardized */
+ /* Variation Sequences' and registered `Ideographic Variation */
+ /* Sequences' (IVS), collected in the `Ideographic Variation */
+ /* Database' (IVD). */
+ /* */
+ /* http://unicode.org/Public/UCD/latest/ucd/StandardizedVariants.txt */
+ /* http://unicode.org/reports/tr37/ */
+ /* http://unicode.org/ivd/ */
+ /* */
+ /* To date (January 2017), the character with the most ideographic */
+ /* variations is U+9089, having 32 such IVS. */
+ /* */
+ /* Three Mongolian Variation Selectors have the values U+180B-U+180D; */
+ /* 256 generic Variation Selectors are encoded in the ranges */
+ /* U+FE00-U+FE0F and U+E0100-U+E01EF. IVS currently use Variation */
+ /* Selectors from the range U+E0100-U+E01EF only. */
+ /* */
+ /* A VS consists of the base character value followed by a single */
+ /* Variation Selector. For example, to get the first variation of */
+ /* U+9089, you have to write the character sequence `U+9089 U+E0100'. */
+ /* */
+ /* Adobe and MS decided to support both standardized and ideographic */
+ /* VS with a new cmap subtable (format~14). It is an odd subtable */
+ /* because it is not a mapping of input code points to glyphs, but */
+ /* contains lists of all variations supported by the font. */
+ /* */
+ /* A variation may be either `default' or `non-default' for a given */
+ /* font. A default variation is the one you will get for that code */
+ /* point if you look it up in the standard Unicode cmap. A */
+ /* non-default variation is a different glyph. */
/* */
/*************************************************************************/
@@ -3893,8 +3904,8 @@ FT_BEGIN_HEADER
/* FT_Face_GetCharVariantIsDefault */
/* */
/* <Description> */
- /* Check whether this variant of this Unicode character is the one to */
- /* be found in the `cmap'. */
+ /* Check whether this variation of this Unicode character is the one */
+ /* to be found in the `cmap'. */
/* */
/* <Input> */
/* face :: */
@@ -3908,7 +3919,7 @@ FT_BEGIN_HEADER
/* */
/* <Return> */
/* 1~if found in the standard (Unicode) cmap, 0~if found in the */
- /* variation selector cmap, or -1 if it is not a variant. */
+ /* variation selector cmap, or -1 if it is not a variation. */
/* */
/* <Note> */
/* This function is only meaningful if the font has a variation */
@@ -3929,7 +3940,7 @@ FT_BEGIN_HEADER
/* FT_Face_GetVariantSelectors */
/* */
/* <Description> */
- /* Return a zero-terminated list of Unicode variant selectors found */
+ /* Return a zero-terminated list of Unicode variation selectors found */
/* in the font. */
/* */
/* <Input> */
@@ -3938,7 +3949,7 @@ FT_BEGIN_HEADER
/* */
/* <Return> */
/* A pointer to an array of selector code points, or NULL if there is */
- /* no valid variant selector cmap subtable. */
+ /* no valid variation selector cmap subtable. */
/* */
/* <Note> */
/* The last item in the array is~0; the array is owned by the */
@@ -3958,7 +3969,7 @@ FT_BEGIN_HEADER
/* FT_Face_GetVariantsOfChar */
/* */
/* <Description> */
- /* Return a zero-terminated list of Unicode variant selectors found */
+ /* Return a zero-terminated list of Unicode variation selectors found */
/* for the specified character code. */
/* */
/* <Input> */
@@ -3969,7 +3980,7 @@ FT_BEGIN_HEADER
/* The character codepoint in Unicode. */
/* */
/* <Return> */
- /* A pointer to an array of variant selector code points that are */
+ /* A pointer to an array of variation selector code points that are */
/* active for the given character, or NULL if the corresponding list */
/* is empty. */
/* */
@@ -3993,19 +4004,19 @@ FT_BEGIN_HEADER
/* */
/* <Description> */
/* Return a zero-terminated list of Unicode character codes found for */
- /* the specified variant selector. */
+ /* the specified variation selector. */
/* */
/* <Input> */
/* face :: */
/* A handle to the source face object. */
/* */
/* variantSelector :: */
- /* The variant selector code point in Unicode. */
+ /* The variation selector code point in Unicode. */
/* */
/* <Return> */
/* A list of all the code points that are specified by this selector */
/* (both default and non-default codes are returned) or NULL if there */
- /* is no valid cmap or the variant selector is invalid. */
+ /* is no valid cmap or the variation selector is invalid. */
/* */
/* <Note> */
/* The last item in the array is~0; the array is owned by the */