From 432efa25b3476a6884426c0a30f6d6a624310e5d Mon Sep 17 00:00:00 2001 From: Alexei Podtelezhnikov Date: Wed, 25 Sep 2019 21:50:16 -0400 Subject: [PATCH] * src/base/ftstroke.c (ft_stroker_outside): Speed up clipped miter. * include/freetype/ftstroke.h: Wordsmith miter docs. --- ChangeLog | 5 ++++ include/freetype/ftstroke.h | 31 ++++++++++---------- src/base/ftstroke.c | 58 ++++++++++++++++--------------------- 3 files changed, 46 insertions(+), 48 deletions(-) diff --git a/ChangeLog b/ChangeLog index 16a556818..fe91986aa 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2019-09-25 Alexei Podtelezhnikov + + * src/base/ftstroke.c (ft_stroker_outside): Speed up clipped miter. + * include/freetype/ftstroke.h: Wordsmith miter docs. + 2019-09-25 Werner Lemberg * src/sfnt/sfwoff2.c (woff2_open_font): Check (sum of) table sizes. diff --git a/include/freetype/ftstroke.h b/include/freetype/ftstroke.h index 01a9c1811..282f6f6d2 100644 --- a/include/freetype/ftstroke.h +++ b/include/freetype/ftstroke.h @@ -114,22 +114,19 @@ FT_BEGIN_HEADER * FT_STROKER_LINEJOIN_MITER_FIXED :: * Used to render mitered line joins, with fixed bevels if the miter * limit is exceeded. The outer edges of the strokes for the two - * segments are extended until they meet at an angle. If the segments - * meet at too sharp an angle (such that the miter would extend from - * the intersection of the segments a distance greater than the product - * of the miter limit value and the border radius), then a bevel join - * (see above) is used instead. This prevents long spikes being - * created. `FT_STROKER_LINEJOIN_MITER_FIXED` generates a miter line - * join as used in PostScript and PDF. + * segments are extended until they meet at an angle. A bevel join + * (see above) is used if the segments meet at too sharp an angle and + * the outer edges meet beyond a distance corresponding to the meter + * limit. This prevents long spikes being created. + * `FT_STROKER_LINEJOIN_MITER_FIXED` generates a miter line join as + * used in PostScript and PDF. * * FT_STROKER_LINEJOIN_MITER_VARIABLE :: * FT_STROKER_LINEJOIN_MITER :: * Used to render mitered line joins, with variable bevels if the miter - * limit is exceeded. The intersection of the strokes is clipped at a - * line perpendicular to the bisector of the angle between the strokes, - * at the distance from the intersection of the segments equal to the - * product of the miter limit value and the border radius. This - * prevents long spikes being created. + * limit is exceeded. The intersection of the strokes is clipped + * perpendicularly to the bisector, at a distance corresponding to + * the miter limit. This prevents long spikes being created. * `FT_STROKER_LINEJOIN_MITER_VARIABLE` generates a mitered line join * as used in XPS. `FT_STROKER_LINEJOIN_MITER` is an alias for * `FT_STROKER_LINEJOIN_MITER_VARIABLE`, retained for backward @@ -296,13 +293,17 @@ FT_BEGIN_HEADER * The line join style. * * miter_limit :: - * The miter limit for the `FT_STROKER_LINEJOIN_MITER_FIXED` and - * `FT_STROKER_LINEJOIN_MITER_VARIABLE` line join styles, expressed as - * 16.16 fixed-point value. + * The maximum reciprocal sine of half-angle at the miter join, + * expressed as 16.16 fixed point value. * * @note: * The radius is expressed in the same units as the outline coordinates. * + * The miter limit multiplied by the radius gives the maximum size + * of a miter spike, at which it is clipped for + * `FT_STROKER_LINEJOIN_MITER_VARIABLE` or replaced with a bevel join for + * `FT_STROKER_LINEJOIN_MITER_FIXED`. + * * This function calls @FT_Stroker_Rewind automatically. */ FT_EXPORT( void ) diff --git a/src/base/ftstroke.c b/src/base/ftstroke.c index 18c746f2c..b02658f0c 100644 --- a/src/base/ftstroke.c +++ b/src/base/ftstroke.c @@ -1062,10 +1062,10 @@ else { /* this is a mitered (pointed) or beveled (truncated) corner */ - FT_Fixed sigma = 0, radius = stroker->radius; - FT_Angle theta = 0, phi = 0; - FT_Fixed thcos = 0; - FT_Bool bevel, fixed_bevel; + FT_Fixed radius = stroker->radius; + FT_Vector sigma; + FT_Angle theta = 0, phi = 0; + FT_Bool bevel, fixed_bevel; rotate = FT_SIDE_TO_ROTATE( side ); @@ -1076,26 +1076,20 @@ fixed_bevel = FT_BOOL( stroker->line_join != FT_STROKER_LINEJOIN_MITER_VARIABLE ); + /* check miter limit first */ if ( !bevel ) { - theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out ); + theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out ) / 2; - if ( theta == FT_ANGLE_PI ) - { - theta = rotate; - phi = stroker->angle_in; - } - else - { - theta /= 2; - phi = stroker->angle_in + theta + rotate; - } + if ( theta == FT_ANGLE_PI2 ) + theta = -rotate; - thcos = FT_Cos( theta ); - sigma = FT_MulFix( stroker->miter_limit, thcos ); + phi = stroker->angle_in + theta + rotate; + + FT_Vector_From_Polar( &sigma, stroker->miter_limit, theta ); /* is miter limit exceeded? */ - if ( sigma < 0x10000L ) + if ( sigma.x < 0x10000L ) { /* don't create variable bevels for very small deviations; */ /* FT_Sin(x) = 0 for x <= 57 */ @@ -1122,36 +1116,34 @@ border->movable = FALSE; error = ft_stroke_border_lineto( border, &delta, FALSE ); } - else /* variable bevel */ + else /* variable bevel or clipped miter */ { /* the miter is truncated */ FT_Vector middle, delta; - FT_Fixed length; + FT_Fixed coef; - /* compute middle point */ + /* compute middle point and first angle point */ FT_Vector_From_Polar( &middle, FT_MulFix( radius, stroker->miter_limit ), phi ); + + coef = FT_DivFix( 0x10000L - sigma.x, sigma.y ); + delta.x = FT_MulFix( middle.y, coef ); + delta.y = FT_MulFix( -middle.x, coef ); + middle.x += stroker->center.x; middle.y += stroker->center.y; - - /* compute first angle point */ - length = FT_MulDiv( radius, 0x10000L - sigma, - ft_pos_abs( FT_Sin( theta ) ) ); - - FT_Vector_From_Polar( &delta, length, phi + rotate ); - delta.x += middle.x; - delta.y += middle.y; + delta.x += middle.x; + delta.y += middle.y; error = ft_stroke_border_lineto( border, &delta, FALSE ); if ( error ) goto Exit; /* compute second angle point */ - FT_Vector_From_Polar( &delta, length, phi - rotate ); - delta.x += middle.x; - delta.y += middle.y; + delta.x = middle.x - delta.x + middle.x; + delta.y = middle.y - delta.y + middle.y; error = ft_stroke_border_lineto( border, &delta, FALSE ); if ( error ) @@ -1178,7 +1170,7 @@ FT_Vector delta; - length = FT_DivFix( stroker->radius, thcos ); + length = FT_MulDiv( stroker->radius, stroker->miter_limit, sigma.x ); FT_Vector_From_Polar( &delta, length, phi ); delta.x += stroker->center.x;