diff --git a/ChangeLog b/ChangeLog index c9f93b207..ddc68cee2 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,23 @@ +2014-04-28 Werner Lemberg + + [autofit] Introduce neutral blue zones to the latin module. + + Such blue zones match either the top or the bottom of a contour. We + need them for scripts where accent-like elements directly touch the + base character (for example, some vowel signs in Devanagari, cf. + U+0913 or U+0914). + + * src/autofit/afblue.hin (AF_BLUE_PROPERTY_LATIN_NEUTRAL): New + property. + + * src/autofit/afblue.h: Regenerated. + + * src/autofit/aflatin.h (AF_LATIN_IS_NEUTRAL_BLUE): New macro. + (AF_LATIN_BLUE_NEUTRAL): New enumeration value. + + * src/autofit/aflatin.c (af_latin_metrics_init_blues, + af_latin_hints_compute_blue_edges): Handle neutral blue zones. + 2014-04-25 Werner Lemberg * src/autofit/hbshim.c: Partially revert commit from 2014-04-17. @@ -47,7 +67,7 @@ * src/autofit/afblue.hin (AF_BLUE_PROPERTY_CJK_FILL): Removed, no longer used. - (AF_BLUE_PROPERTY_CJK_TOP, AF_BLUE_PROPERTY_CJK_HORIZ): Fix values. + (AF_BLUE_PROPERTY_CJK_TOP, AF_BLUE_PROPERTY_CJK_HORIZ): Fix values. This is error #3. * src/autofit/afblue.c, src/autofit/afblue.h: Regenerated. @@ -57,7 +77,7 @@ values. Improve tracing messages, synchronizing them with the latin auto-hinter. - (af_cjk_hints_compute_blue_edges): Fix value of `is_top_right_blue'. + (af_cjk_hints_compute_blue_edges): Fix value of `is_top_right_blue'. This is error #2. (af_cjk_align_linked_edge): Add tracing message. diff --git a/src/autofit/afblue.dat b/src/autofit/afblue.dat index ad3aeff76..4923f9ce5 100644 --- a/src/autofit/afblue.dat +++ b/src/autofit/afblue.dat @@ -34,11 +34,11 @@ // using C syntax. There can be only one string per line, thus the // starting and ending double quote must be the first and last character // in the line, respectively, ignoring whitespace before and after the -// string. If there are multiple strings (in multiple lines), they are -// concatenated to a single string. In the output, a string gets -// represented as a series of singles bytes, followed by a zero byte. The -// enumeration values simply hold byte offsets to the start of the -// corresponding strings. +// string. Space characters within the string are ignored too. If there +// are multiple strings (in multiple lines), they are concatenated to a +// single string. In the output, a string gets represented as a series of +// singles bytes, followed by a zero byte. The enumeration values simply +// hold byte offsets to the start of the corresponding strings. // // - Data blocks enclosed in balanced braces, which get copied verbatim and // which can span multiple lines. The opening brace of a block must be @@ -163,6 +163,10 @@ AF_BLUE_STRING_ENUM AF_BLUE_STRINGS_ARRAY AF_BLUE_STRING_MAX_LEN: // wider than 0.75 pixels (otherwise the blue zone gets ignored). All // entries must have `AF_BLUE_STRING_MAX' as the final line. // +// During the glyph analysis, edges are sorted from bottom to top, and then +// sequentially checked, edge by edge, against the blue zones in the order +// given below. +// // // latin auto-hinter // ----------------- @@ -178,7 +182,22 @@ AF_BLUE_STRING_ENUM AF_BLUE_STRINGS_ARRAY AF_BLUE_STRING_MAX_LEN: // // LATIN_TOP // Take the maximum flat and round coordinate values of the blue string -// characters. If not set, take the minimum values. +// characters for computing the blue zone's reference and overshoot +// values. +// +// If not set, take the minimum values. +// +// LATIN_NEUTRAL +// Ignore round extrema and define the blue zone with flat values only. +// Both top and bottom of contours can match. This is useful for +// scripts like Devanagari where vowel signs attach to the base +// character and are implemented as components of composite glyphs. +// +// If not set, both round and flat extrema are taken into account. +// Additionally, only the top or the bottom of a contour can match, +// depending on the LATIN_TOP flag. +// +// Neutral blue zones should always follow non-neutral blue zones. // // LATIN_X_HEIGHT // Scale all glyphs vertically from the corresponding script to make the diff --git a/src/autofit/afblue.h b/src/autofit/afblue.h index a16849fed..a656c28db 100644 --- a/src/autofit/afblue.h +++ b/src/autofit/afblue.h @@ -132,12 +132,13 @@ FT_BEGIN_HEADER /* Properties are specific to a writing system. We assume that a given */ /* blue string can't be used in more than a single writing system, which */ /* is a safe bet. */ -#define AF_BLUE_PROPERTY_LATIN_TOP ( 1 << 0 ) -#define AF_BLUE_PROPERTY_LATIN_X_HEIGHT ( 1 << 1 ) -#define AF_BLUE_PROPERTY_LATIN_LONG ( 1 << 2 ) +#define AF_BLUE_PROPERTY_LATIN_TOP ( 1 << 0 ) /* must have value 1 */ +#define AF_BLUE_PROPERTY_LATIN_NEUTRAL ( 1 << 1 ) +#define AF_BLUE_PROPERTY_LATIN_X_HEIGHT ( 1 << 2 ) +#define AF_BLUE_PROPERTY_LATIN_LONG ( 1 << 3 ) -#define AF_BLUE_PROPERTY_CJK_TOP ( 1 << 0 ) -#define AF_BLUE_PROPERTY_CJK_HORIZ ( 1 << 1 ) +#define AF_BLUE_PROPERTY_CJK_TOP ( 1 << 0 ) /* must have value 1 */ +#define AF_BLUE_PROPERTY_CJK_HORIZ ( 1 << 1 ) /* must have value 2 */ #define AF_BLUE_PROPERTY_CJK_RIGHT AF_BLUE_PROPERTY_CJK_TOP diff --git a/src/autofit/afblue.hin b/src/autofit/afblue.hin index c4f2526b1..0b4b48d7f 100644 --- a/src/autofit/afblue.hin +++ b/src/autofit/afblue.hin @@ -96,12 +96,13 @@ FT_BEGIN_HEADER /* Properties are specific to a writing system. We assume that a given */ /* blue string can't be used in more than a single writing system, which */ /* is a safe bet. */ -#define AF_BLUE_PROPERTY_LATIN_TOP ( 1 << 0 ) -#define AF_BLUE_PROPERTY_LATIN_X_HEIGHT ( 1 << 1 ) -#define AF_BLUE_PROPERTY_LATIN_LONG ( 1 << 2 ) +#define AF_BLUE_PROPERTY_LATIN_TOP ( 1 << 0 ) /* must have value 1 */ +#define AF_BLUE_PROPERTY_LATIN_NEUTRAL ( 1 << 1 ) +#define AF_BLUE_PROPERTY_LATIN_X_HEIGHT ( 1 << 2 ) +#define AF_BLUE_PROPERTY_LATIN_LONG ( 1 << 3 ) -#define AF_BLUE_PROPERTY_CJK_TOP ( 1 << 0 ) -#define AF_BLUE_PROPERTY_CJK_HORIZ ( 1 << 1 ) +#define AF_BLUE_PROPERTY_CJK_TOP ( 1 << 0 ) /* must have value 1 */ +#define AF_BLUE_PROPERTY_CJK_HORIZ ( 1 << 1 ) /* must have value 2 */ #define AF_BLUE_PROPERTY_CJK_RIGHT AF_BLUE_PROPERTY_CJK_TOP diff --git a/src/autofit/aflatin.c b/src/autofit/aflatin.c index 32dd577ce..825c3612e 100644 --- a/src/autofit/aflatin.c +++ b/src/autofit/aflatin.c @@ -306,6 +306,14 @@ have_flag = 1; } + if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) + { + if ( have_flag ) + FT_TRACE5(( ", " )); + FT_TRACE5(( "neutral" )); + have_flag = 1; + } + if ( AF_LATIN_IS_X_HEIGHT_BLUE( bs ) ) { if ( have_flag ) @@ -697,6 +705,13 @@ FT_CURVE_TAG( outline.tags[best_segment_last] ) != FT_CURVE_TAG_ON ); + if ( round && AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) + { + /* only use flat segments for a neutral blue zone */ + FT_TRACE5(( " (round, skipped)\n" )); + continue; + } + FT_TRACE5(( " (%s)\n", round ? "round" : "flat" )); } @@ -767,6 +782,8 @@ blue->flags = 0; if ( AF_LATIN_IS_TOP_BLUE( bs ) ) blue->flags |= AF_LATIN_BLUE_TOP; + if ( AF_LATIN_IS_NEUTRAL_BLUE( bs ) ) + blue->flags |= AF_LATIN_BLUE_NEUTRAL; /* * The following flag is used later to adjust the y and x scales @@ -1846,17 +1863,16 @@ if ( !( blue->flags & AF_LATIN_BLUE_ACTIVE ) ) continue; - /* if it is a top zone, check for right edges -- if it is a bottom */ - /* zone, check for left edges */ - /* */ - /* of course, that's for TrueType */ + /* if it is a top zone, check for right edges (against the major */ + /* direction); if it is a bottom zone, check for left edges (in */ + /* the major direction) -- this assumes the TrueType convention */ + /* for the orientation of contours */ is_top_blue = (FT_Byte)( ( blue->flags & AF_LATIN_BLUE_TOP ) != 0 ); is_major_dir = FT_BOOL( edge->dir == axis->major_dir ); - /* if it is a top zone, the edge must be against the major */ - /* direction; if it is a bottom zone, it must be in the major */ - /* direction */ - if ( is_top_blue ^ is_major_dir ) + /* neutral blue zones are handled for both directions */ + if ( is_top_blue ^ is_major_dir || + blue->flags & AF_LATIN_BLUE_NEUTRAL ) { FT_Pos dist; @@ -1876,8 +1892,11 @@ /* now compare it to the overshoot position and check whether */ /* the edge is rounded, and whether the edge is over the */ /* reference position of a top zone, or under the reference */ - /* position of a bottom zone */ - if ( edge->flags & AF_EDGE_ROUND && dist != 0 ) + /* position of a bottom zone (provided we don't have a */ + /* neutral blue zone) */ + if ( edge->flags & AF_EDGE_ROUND && + dist != 0 && + !( blue->flags & AF_LATIN_BLUE_NEUTRAL ) ) { FT_Bool is_under_ref = FT_BOOL( edge->fpos < blue->ref.org ); diff --git a/src/autofit/aflatin.h b/src/autofit/aflatin.h index 0f62186ce..2c0bfca18 100644 --- a/src/autofit/aflatin.h +++ b/src/autofit/aflatin.h @@ -53,6 +53,8 @@ FT_BEGIN_HEADER #define AF_LATIN_IS_TOP_BLUE( b ) \ ( (b)->properties & AF_BLUE_PROPERTY_LATIN_TOP ) +#define AF_LATIN_IS_NEUTRAL_BLUE( b ) \ + ( (b)->properties & AF_BLUE_PROPERTY_LATIN_NEUTRAL ) #define AF_LATIN_IS_X_HEIGHT_BLUE( b ) \ ( (b)->properties & AF_BLUE_PROPERTY_LATIN_X_HEIGHT ) #define AF_LATIN_IS_LONG_BLUE( b ) \ @@ -63,10 +65,11 @@ FT_BEGIN_HEADER enum { - AF_LATIN_BLUE_ACTIVE = 1 << 0, /* set if zone height is <= 3/4px */ - AF_LATIN_BLUE_TOP = 1 << 1, /* result of AF_LATIN_IS_TOP_BLUE */ - AF_LATIN_BLUE_ADJUSTMENT = 1 << 2, /* used for scale adjustment */ - /* optimization */ + AF_LATIN_BLUE_ACTIVE = 1 << 0, /* set if zone height is <= 3/4px */ + AF_LATIN_BLUE_TOP = 1 << 1, /* set if we have a top blue zone */ + AF_LATIN_BLUE_NEUTRAL = 1 << 2, /* set if we have neutral blue zone */ + AF_LATIN_BLUE_ADJUSTMENT = 1 << 3, /* used for scale adjustment */ + /* optimization */ AF_LATIN_BLUE_FLAG_MAX };