ref: 8837ac26d00f5a433ec9fd8bc08446b6df4c5bd5
dir: /src/base/ftstroke.c/
/****************************************************************************
*
* ftstroke.c
*
* FreeType path stroker (body).
*
* Copyright (C) 2002-2019 by
* David Turner, Robert Wilhelm, and Werner Lemberg.
*
* This file is part of the FreeType project, and may only be used,
* modified, and distributed under the terms of the FreeType project
* license, LICENSE.TXT. By continuing to use, modify, or distribute
* this file you indicate that you have read the license and
* understand and accept it fully.
*
*/
#include <ft2build.h>
#include FT_STROKER_H
#include FT_TRIGONOMETRY_H
#include FT_OUTLINE_H
#include FT_INTERNAL_MEMORY_H
#include FT_INTERNAL_DEBUG_H
#include FT_INTERNAL_OBJECTS_H
/* declare an extern to access `ft_outline_glyph_class' globally */
/* allocated in `ftglyph.c' */
FT_CALLBACK_TABLE const FT_Glyph_Class ft_outline_glyph_class;
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_StrokerBorder )
FT_Outline_GetInsideBorder( FT_Outline* outline )
{
FT_Orientation o = FT_Outline_Get_Orientation( outline );
return o == FT_ORIENTATION_TRUETYPE ? FT_STROKER_BORDER_RIGHT
: FT_STROKER_BORDER_LEFT;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_StrokerBorder )
FT_Outline_GetOutsideBorder( FT_Outline* outline )
{
FT_Orientation o = FT_Outline_Get_Orientation( outline );
return o == FT_ORIENTATION_TRUETYPE ? FT_STROKER_BORDER_LEFT
: FT_STROKER_BORDER_RIGHT;
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** BEZIER COMPUTATIONS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
#define FT_SMALL_CONIC_THRESHOLD ( FT_ANGLE_PI / 6 )
#define FT_SMALL_CUBIC_THRESHOLD ( FT_ANGLE_PI / 8 )
#define FT_EPSILON 2
#define FT_IS_SMALL( x ) ( (x) > -FT_EPSILON && (x) < FT_EPSILON )
static FT_Pos
ft_pos_abs( FT_Pos x )
{
return x >= 0 ? x : -x;
}
static void
ft_conic_split( FT_Vector* base )
{
FT_Pos a, b;
base[4].x = base[2].x;
b = base[1].x;
a = base[3].x = ( base[2].x + b ) / 2;
b = base[1].x = ( base[0].x + b ) / 2;
base[2].x = ( a + b ) / 2;
base[4].y = base[2].y;
b = base[1].y;
a = base[3].y = ( base[2].y + b ) / 2;
b = base[1].y = ( base[0].y + b ) / 2;
base[2].y = ( a + b ) / 2;
}
static FT_Bool
ft_conic_is_small_enough( FT_Vector* base,
FT_Angle *angle_in,
FT_Angle *angle_out )
{
FT_Vector d1, d2;
FT_Angle theta;
FT_Int close1, close2;
d1.x = base[1].x - base[2].x;
d1.y = base[1].y - base[2].y;
d2.x = base[0].x - base[1].x;
d2.y = base[0].y - base[1].y;
close1 = FT_IS_SMALL( d1.x ) && FT_IS_SMALL( d1.y );
close2 = FT_IS_SMALL( d2.x ) && FT_IS_SMALL( d2.y );
if ( close1 )
{
if ( close2 )
{
/* basically a point; */
/* do nothing to retain original direction */
}
else
{
*angle_in =
*angle_out = FT_Atan2( d2.x, d2.y );
}
}
else /* !close1 */
{
if ( close2 )
{
*angle_in =
*angle_out = FT_Atan2( d1.x, d1.y );
}
else
{
*angle_in = FT_Atan2( d1.x, d1.y );
*angle_out = FT_Atan2( d2.x, d2.y );
}
}
theta = ft_pos_abs( FT_Angle_Diff( *angle_in, *angle_out ) );
return FT_BOOL( theta < FT_SMALL_CONIC_THRESHOLD );
}
static void
ft_cubic_split( FT_Vector* base )
{
FT_Pos a, b, c, d;
base[6].x = base[3].x;
c = base[1].x;
d = base[2].x;
base[1].x = a = ( base[0].x + c ) / 2;
base[5].x = b = ( base[3].x + d ) / 2;
c = ( c + d ) / 2;
base[2].x = a = ( a + c ) / 2;
base[4].x = b = ( b + c ) / 2;
base[3].x = ( a + b ) / 2;
base[6].y = base[3].y;
c = base[1].y;
d = base[2].y;
base[1].y = a = ( base[0].y + c ) / 2;
base[5].y = b = ( base[3].y + d ) / 2;
c = ( c + d ) / 2;
base[2].y = a = ( a + c ) / 2;
base[4].y = b = ( b + c ) / 2;
base[3].y = ( a + b ) / 2;
}
/* Return the average of `angle1' and `angle2'. */
/* This gives correct result even if `angle1' and `angle2' */
/* have opposite signs. */
static FT_Angle
ft_angle_mean( FT_Angle angle1,
FT_Angle angle2 )
{
return angle1 + FT_Angle_Diff( angle1, angle2 ) / 2;
}
static FT_Bool
ft_cubic_is_small_enough( FT_Vector* base,
FT_Angle *angle_in,
FT_Angle *angle_mid,
FT_Angle *angle_out )
{
FT_Vector d1, d2, d3;
FT_Angle theta1, theta2;
FT_Int close1, close2, close3;
d1.x = base[2].x - base[3].x;
d1.y = base[2].y - base[3].y;
d2.x = base[1].x - base[2].x;
d2.y = base[1].y - base[2].y;
d3.x = base[0].x - base[1].x;
d3.y = base[0].y - base[1].y;
close1 = FT_IS_SMALL( d1.x ) && FT_IS_SMALL( d1.y );
close2 = FT_IS_SMALL( d2.x ) && FT_IS_SMALL( d2.y );
close3 = FT_IS_SMALL( d3.x ) && FT_IS_SMALL( d3.y );
if ( close1 )
{
if ( close2 )
{
if ( close3 )
{
/* basically a point; */
/* do nothing to retain original direction */
}
else /* !close3 */
{
*angle_in =
*angle_mid =
*angle_out = FT_Atan2( d3.x, d3.y );
}
}
else /* !close2 */
{
if ( close3 )
{
*angle_in =
*angle_mid =
*angle_out = FT_Atan2( d2.x, d2.y );
}
else /* !close3 */
{
*angle_in =
*angle_mid = FT_Atan2( d2.x, d2.y );
*angle_out = FT_Atan2( d3.x, d3.y );
}
}
}
else /* !close1 */
{
if ( close2 )
{
if ( close3 )
{
*angle_in =
*angle_mid =
*angle_out = FT_Atan2( d1.x, d1.y );
}
else /* !close3 */
{
*angle_in = FT_Atan2( d1.x, d1.y );
*angle_out = FT_Atan2( d3.x, d3.y );
*angle_mid = ft_angle_mean( *angle_in, *angle_out );
}
}
else /* !close2 */
{
if ( close3 )
{
*angle_in = FT_Atan2( d1.x, d1.y );
*angle_mid =
*angle_out = FT_Atan2( d2.x, d2.y );
}
else /* !close3 */
{
*angle_in = FT_Atan2( d1.x, d1.y );
*angle_mid = FT_Atan2( d2.x, d2.y );
*angle_out = FT_Atan2( d3.x, d3.y );
}
}
}
theta1 = ft_pos_abs( FT_Angle_Diff( *angle_in, *angle_mid ) );
theta2 = ft_pos_abs( FT_Angle_Diff( *angle_mid, *angle_out ) );
return FT_BOOL( theta1 < FT_SMALL_CUBIC_THRESHOLD &&
theta2 < FT_SMALL_CUBIC_THRESHOLD );
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** STROKE BORDERS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
typedef enum FT_StrokeTags_
{
FT_STROKE_TAG_ON = 1, /* on-curve point */
FT_STROKE_TAG_CUBIC = 2, /* cubic off-point */
FT_STROKE_TAG_BEGIN = 4, /* sub-path start */
FT_STROKE_TAG_END = 8 /* sub-path end */
} FT_StrokeTags;
#define FT_STROKE_TAG_BEGIN_END ( FT_STROKE_TAG_BEGIN | FT_STROKE_TAG_END )
typedef struct FT_StrokeBorderRec_
{
FT_UInt num_points;
FT_UInt max_points;
FT_Vector* points;
FT_Byte* tags;
FT_Bool movable; /* TRUE for ends of lineto borders */
FT_Int start; /* index of current sub-path start point */
FT_Memory memory;
FT_Bool valid;
} FT_StrokeBorderRec, *FT_StrokeBorder;
static FT_Error
ft_stroke_border_grow( FT_StrokeBorder border,
FT_UInt new_points )
{
FT_UInt old_max = border->max_points;
FT_UInt new_max = border->num_points + new_points;
FT_Error error = FT_Err_Ok;
if ( new_max > old_max )
{
FT_UInt cur_max = old_max;
FT_Memory memory = border->memory;
while ( cur_max < new_max )
cur_max += ( cur_max >> 1 ) + 16;
if ( FT_RENEW_ARRAY( border->points, old_max, cur_max ) ||
FT_RENEW_ARRAY( border->tags, old_max, cur_max ) )
goto Exit;
border->max_points = cur_max;
}
Exit:
return error;
}
static void
ft_stroke_border_close( FT_StrokeBorder border,
FT_Bool reverse )
{
FT_UInt start = (FT_UInt)border->start;
FT_UInt count = border->num_points;
FT_ASSERT( border->start >= 0 );
/* don't record empty paths! */
if ( count <= start + 1U )
border->num_points = start;
else
{
/* copy the last point to the start of this sub-path, since */
/* it contains the `adjusted' starting coordinates */
border->num_points = --count;
border->points[start] = border->points[count];
border->tags[start] = border->tags[count];
if ( reverse )
{
/* reverse the points */
{
FT_Vector* vec1 = border->points + start + 1;
FT_Vector* vec2 = border->points + count - 1;
for ( ; vec1 < vec2; vec1++, vec2-- )
{
FT_Vector tmp;
tmp = *vec1;
*vec1 = *vec2;
*vec2 = tmp;
}
}
/* then the tags */
{
FT_Byte* tag1 = border->tags + start + 1;
FT_Byte* tag2 = border->tags + count - 1;
for ( ; tag1 < tag2; tag1++, tag2-- )
{
FT_Byte tmp;
tmp = *tag1;
*tag1 = *tag2;
*tag2 = tmp;
}
}
}
border->tags[start ] |= FT_STROKE_TAG_BEGIN;
border->tags[count - 1] |= FT_STROKE_TAG_END;
}
border->start = -1;
border->movable = FALSE;
}
static FT_Error
ft_stroke_border_lineto( FT_StrokeBorder border,
FT_Vector* to,
FT_Bool movable )
{
FT_Error error = FT_Err_Ok;
FT_ASSERT( border->start >= 0 );
if ( border->movable )
{
/* move last point */
border->points[border->num_points - 1] = *to;
}
else
{
/* don't add zero-length lineto, but always add moveto */
if ( border->num_points > (FT_UInt)border->start &&
FT_IS_SMALL( border->points[border->num_points - 1].x - to->x ) &&
FT_IS_SMALL( border->points[border->num_points - 1].y - to->y ) )
return error;
/* add one point */
error = ft_stroke_border_grow( border, 1 );
if ( !error )
{
FT_Vector* vec = border->points + border->num_points;
FT_Byte* tag = border->tags + border->num_points;
vec[0] = *to;
tag[0] = FT_STROKE_TAG_ON;
border->num_points += 1;
}
}
border->movable = movable;
return error;
}
static FT_Error
ft_stroke_border_conicto( FT_StrokeBorder border,
FT_Vector* control,
FT_Vector* to )
{
FT_Error error;
FT_ASSERT( border->start >= 0 );
error = ft_stroke_border_grow( border, 2 );
if ( !error )
{
FT_Vector* vec = border->points + border->num_points;
FT_Byte* tag = border->tags + border->num_points;
vec[0] = *control;
vec[1] = *to;
tag[0] = 0;
tag[1] = FT_STROKE_TAG_ON;
border->num_points += 2;
}
border->movable = FALSE;
return error;
}
static FT_Error
ft_stroke_border_cubicto( FT_StrokeBorder border,
FT_Vector* control1,
FT_Vector* control2,
FT_Vector* to )
{
FT_Error error;
FT_ASSERT( border->start >= 0 );
error = ft_stroke_border_grow( border, 3 );
if ( !error )
{
FT_Vector* vec = border->points + border->num_points;
FT_Byte* tag = border->tags + border->num_points;
vec[0] = *control1;
vec[1] = *control2;
vec[2] = *to;
tag[0] = FT_STROKE_TAG_CUBIC;
tag[1] = FT_STROKE_TAG_CUBIC;
tag[2] = FT_STROKE_TAG_ON;
border->num_points += 3;
}
border->movable = FALSE;
return error;
}
#define FT_ARC_CUBIC_ANGLE ( FT_ANGLE_PI / 2 )
static FT_Error
ft_stroke_border_arcto( FT_StrokeBorder border,
FT_Vector* center,
FT_Fixed radius,
FT_Angle angle_start,
FT_Angle angle_diff )
{
FT_Angle total, angle, step, rotate, next, theta;
FT_Vector a, b, a2, b2;
FT_Fixed length;
FT_Error error = FT_Err_Ok;
/* compute start point */
FT_Vector_From_Polar( &a, radius, angle_start );
a.x += center->x;
a.y += center->y;
total = angle_diff;
angle = angle_start;
rotate = ( angle_diff >= 0 ) ? FT_ANGLE_PI2 : -FT_ANGLE_PI2;
while ( total != 0 )
{
step = total;
if ( step > FT_ARC_CUBIC_ANGLE )
step = FT_ARC_CUBIC_ANGLE;
else if ( step < -FT_ARC_CUBIC_ANGLE )
step = -FT_ARC_CUBIC_ANGLE;
next = angle + step;
theta = step;
if ( theta < 0 )
theta = -theta;
theta >>= 1;
/* compute end point */
FT_Vector_From_Polar( &b, radius, next );
b.x += center->x;
b.y += center->y;
/* compute first and second control points */
length = FT_MulDiv( radius, FT_Sin( theta ) * 4,
( 0x10000L + FT_Cos( theta ) ) * 3 );
FT_Vector_From_Polar( &a2, length, angle + rotate );
a2.x += a.x;
a2.y += a.y;
FT_Vector_From_Polar( &b2, length, next - rotate );
b2.x += b.x;
b2.y += b.y;
/* add cubic arc */
error = ft_stroke_border_cubicto( border, &a2, &b2, &b );
if ( error )
break;
/* process the rest of the arc ?? */
a = b;
total -= step;
angle = next;
}
return error;
}
static FT_Error
ft_stroke_border_moveto( FT_StrokeBorder border,
FT_Vector* to )
{
/* close current open path if any ? */
if ( border->start >= 0 )
ft_stroke_border_close( border, FALSE );
border->start = (FT_Int)border->num_points;
border->movable = FALSE;
return ft_stroke_border_lineto( border, to, FALSE );
}
static void
ft_stroke_border_init( FT_StrokeBorder border,
FT_Memory memory )
{
border->memory = memory;
border->points = NULL;
border->tags = NULL;
border->num_points = 0;
border->max_points = 0;
border->start = -1;
border->valid = FALSE;
}
static void
ft_stroke_border_reset( FT_StrokeBorder border )
{
border->num_points = 0;
border->start = -1;
border->valid = FALSE;
}
static void
ft_stroke_border_done( FT_StrokeBorder border )
{
FT_Memory memory = border->memory;
FT_FREE( border->points );
FT_FREE( border->tags );
border->num_points = 0;
border->max_points = 0;
border->start = -1;
border->valid = FALSE;
}
static FT_Error
ft_stroke_border_get_counts( FT_StrokeBorder border,
FT_UInt *anum_points,
FT_UInt *anum_contours )
{
FT_Error error = FT_Err_Ok;
FT_UInt num_points = 0;
FT_UInt num_contours = 0;
FT_UInt count = border->num_points;
FT_Vector* point = border->points;
FT_Byte* tags = border->tags;
FT_Int in_contour = 0;
for ( ; count > 0; count--, num_points++, point++, tags++ )
{
if ( tags[0] & FT_STROKE_TAG_BEGIN )
{
if ( in_contour != 0 )
goto Fail;
in_contour = 1;
}
else if ( in_contour == 0 )
goto Fail;
if ( tags[0] & FT_STROKE_TAG_END )
{
in_contour = 0;
num_contours++;
}
}
if ( in_contour != 0 )
goto Fail;
border->valid = TRUE;
Exit:
*anum_points = num_points;
*anum_contours = num_contours;
return error;
Fail:
num_points = 0;
num_contours = 0;
goto Exit;
}
static void
ft_stroke_border_export( FT_StrokeBorder border,
FT_Outline* outline )
{
/* copy point locations */
if ( border->num_points )
FT_ARRAY_COPY( outline->points + outline->n_points,
border->points,
border->num_points );
/* copy tags */
{
FT_UInt count = border->num_points;
FT_Byte* read = border->tags;
FT_Byte* write = (FT_Byte*)outline->tags + outline->n_points;
for ( ; count > 0; count--, read++, write++ )
{
if ( *read & FT_STROKE_TAG_ON )
*write = FT_CURVE_TAG_ON;
else if ( *read & FT_STROKE_TAG_CUBIC )
*write = FT_CURVE_TAG_CUBIC;
else
*write = FT_CURVE_TAG_CONIC;
}
}
/* copy contours */
{
FT_UInt count = border->num_points;
FT_Byte* tags = border->tags;
FT_Short* write = outline->contours + outline->n_contours;
FT_Short idx = (FT_Short)outline->n_points;
for ( ; count > 0; count--, tags++, idx++ )
{
if ( *tags & FT_STROKE_TAG_END )
{
*write++ = idx;
outline->n_contours++;
}
}
}
outline->n_points += (short)border->num_points;
FT_ASSERT( FT_Outline_Check( outline ) == 0 );
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** STROKER *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
#define FT_SIDE_TO_ROTATE( s ) ( FT_ANGLE_PI2 - (s) * FT_ANGLE_PI )
typedef struct FT_StrokerRec_
{
FT_Angle angle_in; /* direction into curr join */
FT_Angle angle_out; /* direction out of join */
FT_Vector center; /* current position */
FT_Fixed line_length; /* length of last lineto */
FT_Bool first_point; /* is this the start? */
FT_Bool subpath_open; /* is the subpath open? */
FT_Angle subpath_angle; /* subpath start direction */
FT_Vector subpath_start; /* subpath start position */
FT_Fixed subpath_line_length; /* subpath start lineto len */
FT_Bool handle_wide_strokes; /* use wide strokes logic? */
FT_Stroker_LineCap line_cap;
FT_Stroker_LineJoin line_join;
FT_Stroker_LineJoin line_join_saved;
FT_Fixed miter_limit;
FT_Fixed radius;
FT_StrokeBorderRec borders[2];
FT_Library library;
} FT_StrokerRec;
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_New( FT_Library library,
FT_Stroker *astroker )
{
FT_Error error; /* assigned in FT_NEW */
FT_Memory memory;
FT_Stroker stroker = NULL;
if ( !library )
return FT_THROW( Invalid_Library_Handle );
if ( !astroker )
return FT_THROW( Invalid_Argument );
memory = library->memory;
if ( !FT_NEW( stroker ) )
{
stroker->library = library;
ft_stroke_border_init( &stroker->borders[0], memory );
ft_stroke_border_init( &stroker->borders[1], memory );
}
*astroker = stroker;
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( void )
FT_Stroker_Set( FT_Stroker stroker,
FT_Fixed radius,
FT_Stroker_LineCap line_cap,
FT_Stroker_LineJoin line_join,
FT_Fixed miter_limit )
{
if ( !stroker )
return;
stroker->radius = radius;
stroker->line_cap = line_cap;
stroker->line_join = line_join;
stroker->miter_limit = miter_limit;
/* ensure miter limit has sensible value */
if ( stroker->miter_limit < 0x10000L )
stroker->miter_limit = 0x10000L;
/* save line join style: */
/* line join style can be temporarily changed when stroking curves */
stroker->line_join_saved = line_join;
FT_Stroker_Rewind( stroker );
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( void )
FT_Stroker_Rewind( FT_Stroker stroker )
{
if ( stroker )
{
ft_stroke_border_reset( &stroker->borders[0] );
ft_stroke_border_reset( &stroker->borders[1] );
}
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( void )
FT_Stroker_Done( FT_Stroker stroker )
{
if ( stroker )
{
FT_Memory memory = stroker->library->memory;
ft_stroke_border_done( &stroker->borders[0] );
ft_stroke_border_done( &stroker->borders[1] );
stroker->library = NULL;
FT_FREE( stroker );
}
}
/* create a circular arc at a corner or cap */
static FT_Error
ft_stroker_arcto( FT_Stroker stroker,
FT_Int side )
{
FT_Angle total, rotate;
FT_Fixed radius = stroker->radius;
FT_Error error = FT_Err_Ok;
FT_StrokeBorder border = stroker->borders + side;
rotate = FT_SIDE_TO_ROTATE( side );
total = FT_Angle_Diff( stroker->angle_in, stroker->angle_out );
if ( total == FT_ANGLE_PI )
total = -rotate * 2;
error = ft_stroke_border_arcto( border,
&stroker->center,
radius,
stroker->angle_in + rotate,
total );
border->movable = FALSE;
return error;
}
/* add a cap at the end of an opened path */
static FT_Error
ft_stroker_cap( FT_Stroker stroker,
FT_Angle angle,
FT_Int side )
{
FT_Error error = FT_Err_Ok;
if ( stroker->line_cap == FT_STROKER_LINECAP_ROUND )
{
/* add a round cap */
stroker->angle_in = angle;
stroker->angle_out = angle + FT_ANGLE_PI;
error = ft_stroker_arcto( stroker, side );
}
else if ( stroker->line_cap == FT_STROKER_LINECAP_SQUARE )
{
/* add a square cap */
FT_Vector delta, delta2;
FT_Angle rotate = FT_SIDE_TO_ROTATE( side );
FT_Fixed radius = stroker->radius;
FT_StrokeBorder border = stroker->borders + side;
FT_Vector_From_Polar( &delta2, radius, angle + rotate );
FT_Vector_From_Polar( &delta, radius, angle );
delta.x += stroker->center.x + delta2.x;
delta.y += stroker->center.y + delta2.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
FT_Vector_From_Polar( &delta2, radius, angle - rotate );
FT_Vector_From_Polar( &delta, radius, angle );
delta.x += delta2.x + stroker->center.x;
delta.y += delta2.y + stroker->center.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
}
else if ( stroker->line_cap == FT_STROKER_LINECAP_BUTT )
{
/* add a butt ending */
FT_Vector delta;
FT_Angle rotate = FT_SIDE_TO_ROTATE( side );
FT_Fixed radius = stroker->radius;
FT_StrokeBorder border = stroker->borders + side;
FT_Vector_From_Polar( &delta, radius, angle + rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
FT_Vector_From_Polar( &delta, radius, angle - rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
}
Exit:
return error;
}
/* process an inside corner, i.e. compute intersection */
static FT_Error
ft_stroker_inside( FT_Stroker stroker,
FT_Int side,
FT_Fixed line_length )
{
FT_StrokeBorder border = stroker->borders + side;
FT_Angle phi, theta, rotate;
FT_Fixed length, thcos;
FT_Vector delta;
FT_Error error = FT_Err_Ok;
FT_Bool intersect; /* use intersection of lines? */
rotate = FT_SIDE_TO_ROTATE( side );
theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out ) / 2;
/* Only intersect borders if between two lineto's and both */
/* lines are long enough (line_length is zero for curves). */
/* Also avoid U-turns of nearly 180 degree. */
if ( !border->movable || line_length == 0 ||
theta > 0x59C000 || theta < -0x59C000 )
intersect = FALSE;
else
{
/* compute minimum required length of lines */
FT_Fixed min_length = ft_pos_abs( FT_MulFix( stroker->radius,
FT_Tan( theta ) ) );
intersect = FT_BOOL( min_length &&
stroker->line_length >= min_length &&
line_length >= min_length );
}
if ( !intersect )
{
FT_Vector_From_Polar( &delta, stroker->radius,
stroker->angle_out + rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
border->movable = FALSE;
}
else
{
/* compute median angle */
phi = stroker->angle_in + theta;
thcos = FT_Cos( theta );
length = FT_DivFix( stroker->radius, thcos );
FT_Vector_From_Polar( &delta, length, phi + rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
}
error = ft_stroke_border_lineto( border, &delta, FALSE );
return error;
}
/* process an outside corner, i.e. compute bevel/miter/round */
static FT_Error
ft_stroker_outside( FT_Stroker stroker,
FT_Int side,
FT_Fixed line_length )
{
FT_StrokeBorder border = stroker->borders + side;
FT_Error error;
FT_Angle rotate;
if ( stroker->line_join == FT_STROKER_LINEJOIN_ROUND )
error = ft_stroker_arcto( stroker, side );
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;
rotate = FT_SIDE_TO_ROTATE( side );
bevel =
FT_BOOL( stroker->line_join == FT_STROKER_LINEJOIN_BEVEL );
fixed_bevel =
FT_BOOL( stroker->line_join != FT_STROKER_LINEJOIN_MITER_VARIABLE );
if ( !bevel )
{
theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out );
if ( theta == FT_ANGLE_PI )
{
theta = rotate;
phi = stroker->angle_in;
}
else
{
theta /= 2;
phi = stroker->angle_in + theta + rotate;
}
thcos = FT_Cos( theta );
sigma = FT_MulFix( stroker->miter_limit, thcos );
/* is miter limit exceeded? */
if ( sigma < 0x10000L )
{
/* don't create variable bevels for very small deviations; */
/* FT_Sin(x) = 0 for x <= 57 */
if ( fixed_bevel || ft_pos_abs( theta ) > 57 )
bevel = TRUE;
}
}
if ( bevel ) /* this is a bevel (broken angle) */
{
if ( fixed_bevel )
{
/* the outer corners are simply joined together */
FT_Vector delta;
/* add bevel */
FT_Vector_From_Polar( &delta,
radius,
stroker->angle_out + rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
border->movable = FALSE;
error = ft_stroke_border_lineto( border, &delta, FALSE );
}
else /* variable bevel */
{
/* the miter is truncated */
FT_Vector middle, delta;
FT_Fixed length;
/* compute middle point */
FT_Vector_From_Polar( &middle,
FT_MulFix( radius, stroker->miter_limit ),
phi );
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;
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;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
/* finally, add an end point; only needed if not lineto */
/* (line_length is zero for curves) */
if ( line_length == 0 )
{
FT_Vector_From_Polar( &delta,
radius,
stroker->angle_out + rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
}
}
}
else /* this is a miter (intersection) */
{
FT_Fixed length;
FT_Vector delta;
length = FT_DivFix( stroker->radius, thcos );
FT_Vector_From_Polar( &delta, length, phi );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
/* now add an end point; only needed if not lineto */
/* (line_length is zero for curves) */
if ( line_length == 0 )
{
FT_Vector_From_Polar( &delta,
stroker->radius,
stroker->angle_out + rotate );
delta.x += stroker->center.x;
delta.y += stroker->center.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
}
}
}
Exit:
return error;
}
static FT_Error
ft_stroker_process_corner( FT_Stroker stroker,
FT_Fixed line_length )
{
FT_Error error = FT_Err_Ok;
FT_Angle turn;
FT_Int inside_side;
turn = FT_Angle_Diff( stroker->angle_in, stroker->angle_out );
/* no specific corner processing is required if the turn is 0 */
if ( turn == 0 )
goto Exit;
/* when we turn to the right, the inside side is 0 */
/* otherwise, the inside side is 1 */
inside_side = ( turn < 0 );
/* process the inside side */
error = ft_stroker_inside( stroker, inside_side, line_length );
if ( error )
goto Exit;
/* process the outside side */
error = ft_stroker_outside( stroker, !inside_side, line_length );
Exit:
return error;
}
/* add two points to the left and right borders corresponding to the */
/* start of the subpath */
static FT_Error
ft_stroker_subpath_start( FT_Stroker stroker,
FT_Angle start_angle,
FT_Fixed line_length )
{
FT_Vector delta;
FT_Vector point;
FT_Error error;
FT_StrokeBorder border;
FT_Vector_From_Polar( &delta, stroker->radius,
start_angle + FT_ANGLE_PI2 );
point.x = stroker->center.x + delta.x;
point.y = stroker->center.y + delta.y;
border = stroker->borders;
error = ft_stroke_border_moveto( border, &point );
if ( error )
goto Exit;
point.x = stroker->center.x - delta.x;
point.y = stroker->center.y - delta.y;
border++;
error = ft_stroke_border_moveto( border, &point );
/* save angle, position, and line length for last join */
/* (line_length is zero for curves) */
stroker->subpath_angle = start_angle;
stroker->first_point = FALSE;
stroker->subpath_line_length = line_length;
Exit:
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_LineTo( FT_Stroker stroker,
FT_Vector* to )
{
FT_Error error = FT_Err_Ok;
FT_StrokeBorder border;
FT_Vector delta;
FT_Angle angle;
FT_Int side;
FT_Fixed line_length;
if ( !stroker || !to )
return FT_THROW( Invalid_Argument );
delta.x = to->x - stroker->center.x;
delta.y = to->y - stroker->center.y;
/* a zero-length lineto is a no-op; avoid creating a spurious corner */
if ( delta.x == 0 && delta.y == 0 )
goto Exit;
/* compute length of line */
line_length = FT_Vector_Length( &delta );
angle = FT_Atan2( delta.x, delta.y );
FT_Vector_From_Polar( &delta, stroker->radius, angle + FT_ANGLE_PI2 );
/* process corner if necessary */
if ( stroker->first_point )
{
/* This is the first segment of a subpath. We need to */
/* add a point to each border at their respective starting */
/* point locations. */
error = ft_stroker_subpath_start( stroker, angle, line_length );
if ( error )
goto Exit;
}
else
{
/* process the current corner */
stroker->angle_out = angle;
error = ft_stroker_process_corner( stroker, line_length );
if ( error )
goto Exit;
}
/* now add a line segment to both the `inside' and `outside' paths */
for ( border = stroker->borders, side = 1; side >= 0; side--, border++ )
{
FT_Vector point;
point.x = to->x + delta.x;
point.y = to->y + delta.y;
/* the ends of lineto borders are movable */
error = ft_stroke_border_lineto( border, &point, TRUE );
if ( error )
goto Exit;
delta.x = -delta.x;
delta.y = -delta.y;
}
stroker->angle_in = angle;
stroker->center = *to;
stroker->line_length = line_length;
Exit:
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_ConicTo( FT_Stroker stroker,
FT_Vector* control,
FT_Vector* to )
{
FT_Error error = FT_Err_Ok;
FT_Vector bez_stack[34];
FT_Vector* arc;
FT_Vector* limit = bez_stack + 30;
FT_Bool first_arc = TRUE;
if ( !stroker || !control || !to )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* if all control points are coincident, this is a no-op; */
/* avoid creating a spurious corner */
if ( FT_IS_SMALL( stroker->center.x - control->x ) &&
FT_IS_SMALL( stroker->center.y - control->y ) &&
FT_IS_SMALL( control->x - to->x ) &&
FT_IS_SMALL( control->y - to->y ) )
{
stroker->center = *to;
goto Exit;
}
arc = bez_stack;
arc[0] = *to;
arc[1] = *control;
arc[2] = stroker->center;
while ( arc >= bez_stack )
{
FT_Angle angle_in, angle_out;
/* initialize with current direction */
angle_in = angle_out = stroker->angle_in;
if ( arc < limit &&
!ft_conic_is_small_enough( arc, &angle_in, &angle_out ) )
{
if ( stroker->first_point )
stroker->angle_in = angle_in;
ft_conic_split( arc );
arc += 2;
continue;
}
if ( first_arc )
{
first_arc = FALSE;
/* process corner if necessary */
if ( stroker->first_point )
error = ft_stroker_subpath_start( stroker, angle_in, 0 );
else
{
stroker->angle_out = angle_in;
error = ft_stroker_process_corner( stroker, 0 );
}
}
else if ( ft_pos_abs( FT_Angle_Diff( stroker->angle_in, angle_in ) ) >
FT_SMALL_CONIC_THRESHOLD / 4 )
{
/* if the deviation from one arc to the next is too great, */
/* add a round corner */
stroker->center = arc[2];
stroker->angle_out = angle_in;
stroker->line_join = FT_STROKER_LINEJOIN_ROUND;
error = ft_stroker_process_corner( stroker, 0 );
/* reinstate line join style */
stroker->line_join = stroker->line_join_saved;
}
if ( error )
goto Exit;
/* the arc's angle is small enough; we can add it directly to each */
/* border */
{
FT_Vector ctrl, end;
FT_Angle theta, phi, rotate, alpha0 = 0;
FT_Fixed length;
FT_StrokeBorder border;
FT_Int side;
theta = FT_Angle_Diff( angle_in, angle_out ) / 2;
phi = angle_in + theta;
length = FT_DivFix( stroker->radius, FT_Cos( theta ) );
/* compute direction of original arc */
if ( stroker->handle_wide_strokes )
alpha0 = FT_Atan2( arc[0].x - arc[2].x, arc[0].y - arc[2].y );
for ( border = stroker->borders, side = 0;
side <= 1;
side++, border++ )
{
rotate = FT_SIDE_TO_ROTATE( side );
/* compute control point */
FT_Vector_From_Polar( &ctrl, length, phi + rotate );
ctrl.x += arc[1].x;
ctrl.y += arc[1].y;
/* compute end point */
FT_Vector_From_Polar( &end, stroker->radius, angle_out + rotate );
end.x += arc[0].x;
end.y += arc[0].y;
if ( stroker->handle_wide_strokes )
{
FT_Vector start;
FT_Angle alpha1;
/* determine whether the border radius is greater than the */
/* radius of curvature of the original arc */
start = border->points[border->num_points - 1];
alpha1 = FT_Atan2( end.x - start.x, end.y - start.y );
/* is the direction of the border arc opposite to */
/* that of the original arc? */
if ( ft_pos_abs( FT_Angle_Diff( alpha0, alpha1 ) ) >
FT_ANGLE_PI / 2 )
{
FT_Angle beta, gamma;
FT_Vector bvec, delta;
FT_Fixed blen, sinA, sinB, alen;
/* use the sine rule to find the intersection point */
beta = FT_Atan2( arc[2].x - start.x, arc[2].y - start.y );
gamma = FT_Atan2( arc[0].x - end.x, arc[0].y - end.y );
bvec.x = end.x - start.x;
bvec.y = end.y - start.y;
blen = FT_Vector_Length( &bvec );
sinA = ft_pos_abs( FT_Sin( alpha1 - gamma ) );
sinB = ft_pos_abs( FT_Sin( beta - gamma ) );
alen = FT_MulDiv( blen, sinA, sinB );
FT_Vector_From_Polar( &delta, alen, beta );
delta.x += start.x;
delta.y += start.y;
/* circumnavigate the negative sector backwards */
border->movable = FALSE;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
error = ft_stroke_border_lineto( border, &end, FALSE );
if ( error )
goto Exit;
error = ft_stroke_border_conicto( border, &ctrl, &start );
if ( error )
goto Exit;
/* and then move to the endpoint */
error = ft_stroke_border_lineto( border, &end, FALSE );
if ( error )
goto Exit;
continue;
}
/* else fall through */
}
/* simply add an arc */
error = ft_stroke_border_conicto( border, &ctrl, &end );
if ( error )
goto Exit;
}
}
arc -= 2;
stroker->angle_in = angle_out;
}
stroker->center = *to;
Exit:
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_CubicTo( FT_Stroker stroker,
FT_Vector* control1,
FT_Vector* control2,
FT_Vector* to )
{
FT_Error error = FT_Err_Ok;
FT_Vector bez_stack[37];
FT_Vector* arc;
FT_Vector* limit = bez_stack + 32;
FT_Bool first_arc = TRUE;
if ( !stroker || !control1 || !control2 || !to )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
/* if all control points are coincident, this is a no-op; */
/* avoid creating a spurious corner */
if ( FT_IS_SMALL( stroker->center.x - control1->x ) &&
FT_IS_SMALL( stroker->center.y - control1->y ) &&
FT_IS_SMALL( control1->x - control2->x ) &&
FT_IS_SMALL( control1->y - control2->y ) &&
FT_IS_SMALL( control2->x - to->x ) &&
FT_IS_SMALL( control2->y - to->y ) )
{
stroker->center = *to;
goto Exit;
}
arc = bez_stack;
arc[0] = *to;
arc[1] = *control2;
arc[2] = *control1;
arc[3] = stroker->center;
while ( arc >= bez_stack )
{
FT_Angle angle_in, angle_mid, angle_out;
/* initialize with current direction */
angle_in = angle_out = angle_mid = stroker->angle_in;
if ( arc < limit &&
!ft_cubic_is_small_enough( arc, &angle_in,
&angle_mid, &angle_out ) )
{
if ( stroker->first_point )
stroker->angle_in = angle_in;
ft_cubic_split( arc );
arc += 3;
continue;
}
if ( first_arc )
{
first_arc = FALSE;
/* process corner if necessary */
if ( stroker->first_point )
error = ft_stroker_subpath_start( stroker, angle_in, 0 );
else
{
stroker->angle_out = angle_in;
error = ft_stroker_process_corner( stroker, 0 );
}
}
else if ( ft_pos_abs( FT_Angle_Diff( stroker->angle_in, angle_in ) ) >
FT_SMALL_CUBIC_THRESHOLD / 4 )
{
/* if the deviation from one arc to the next is too great, */
/* add a round corner */
stroker->center = arc[3];
stroker->angle_out = angle_in;
stroker->line_join = FT_STROKER_LINEJOIN_ROUND;
error = ft_stroker_process_corner( stroker, 0 );
/* reinstate line join style */
stroker->line_join = stroker->line_join_saved;
}
if ( error )
goto Exit;
/* the arc's angle is small enough; we can add it directly to each */
/* border */
{
FT_Vector ctrl1, ctrl2, end;
FT_Angle theta1, phi1, theta2, phi2, rotate, alpha0 = 0;
FT_Fixed length1, length2;
FT_StrokeBorder border;
FT_Int side;
theta1 = FT_Angle_Diff( angle_in, angle_mid ) / 2;
theta2 = FT_Angle_Diff( angle_mid, angle_out ) / 2;
phi1 = ft_angle_mean( angle_in, angle_mid );
phi2 = ft_angle_mean( angle_mid, angle_out );
length1 = FT_DivFix( stroker->radius, FT_Cos( theta1 ) );
length2 = FT_DivFix( stroker->radius, FT_Cos( theta2 ) );
/* compute direction of original arc */
if ( stroker->handle_wide_strokes )
alpha0 = FT_Atan2( arc[0].x - arc[3].x, arc[0].y - arc[3].y );
for ( border = stroker->borders, side = 0;
side <= 1;
side++, border++ )
{
rotate = FT_SIDE_TO_ROTATE( side );
/* compute control points */
FT_Vector_From_Polar( &ctrl1, length1, phi1 + rotate );
ctrl1.x += arc[2].x;
ctrl1.y += arc[2].y;
FT_Vector_From_Polar( &ctrl2, length2, phi2 + rotate );
ctrl2.x += arc[1].x;
ctrl2.y += arc[1].y;
/* compute end point */
FT_Vector_From_Polar( &end, stroker->radius, angle_out + rotate );
end.x += arc[0].x;
end.y += arc[0].y;
if ( stroker->handle_wide_strokes )
{
FT_Vector start;
FT_Angle alpha1;
/* determine whether the border radius is greater than the */
/* radius of curvature of the original arc */
start = border->points[border->num_points - 1];
alpha1 = FT_Atan2( end.x - start.x, end.y - start.y );
/* is the direction of the border arc opposite to */
/* that of the original arc? */
if ( ft_pos_abs( FT_Angle_Diff( alpha0, alpha1 ) ) >
FT_ANGLE_PI / 2 )
{
FT_Angle beta, gamma;
FT_Vector bvec, delta;
FT_Fixed blen, sinA, sinB, alen;
/* use the sine rule to find the intersection point */
beta = FT_Atan2( arc[3].x - start.x, arc[3].y - start.y );
gamma = FT_Atan2( arc[0].x - end.x, arc[0].y - end.y );
bvec.x = end.x - start.x;
bvec.y = end.y - start.y;
blen = FT_Vector_Length( &bvec );
sinA = ft_pos_abs( FT_Sin( alpha1 - gamma ) );
sinB = ft_pos_abs( FT_Sin( beta - gamma ) );
alen = FT_MulDiv( blen, sinA, sinB );
FT_Vector_From_Polar( &delta, alen, beta );
delta.x += start.x;
delta.y += start.y;
/* circumnavigate the negative sector backwards */
border->movable = FALSE;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
error = ft_stroke_border_lineto( border, &end, FALSE );
if ( error )
goto Exit;
error = ft_stroke_border_cubicto( border,
&ctrl2,
&ctrl1,
&start );
if ( error )
goto Exit;
/* and then move to the endpoint */
error = ft_stroke_border_lineto( border, &end, FALSE );
if ( error )
goto Exit;
continue;
}
/* else fall through */
}
/* simply add an arc */
error = ft_stroke_border_cubicto( border, &ctrl1, &ctrl2, &end );
if ( error )
goto Exit;
}
}
arc -= 3;
stroker->angle_in = angle_out;
}
stroker->center = *to;
Exit:
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_BeginSubPath( FT_Stroker stroker,
FT_Vector* to,
FT_Bool open )
{
if ( !stroker || !to )
return FT_THROW( Invalid_Argument );
/* We cannot process the first point, because there is not enough */
/* information regarding its corner/cap. The latter will be processed */
/* in the `FT_Stroker_EndSubPath' routine. */
/* */
stroker->first_point = TRUE;
stroker->center = *to;
stroker->subpath_open = open;
/* Determine if we need to check whether the border radius is greater */
/* than the radius of curvature of a curve, to handle this case */
/* specially. This is only required if bevel joins or butt caps may */
/* be created, because round & miter joins and round & square caps */
/* cover the negative sector created with wide strokes. */
stroker->handle_wide_strokes =
FT_BOOL( stroker->line_join != FT_STROKER_LINEJOIN_ROUND ||
( stroker->subpath_open &&
stroker->line_cap == FT_STROKER_LINECAP_BUTT ) );
/* record the subpath start point for each border */
stroker->subpath_start = *to;
stroker->angle_in = 0;
return FT_Err_Ok;
}
static FT_Error
ft_stroker_add_reverse_left( FT_Stroker stroker,
FT_Bool open )
{
FT_StrokeBorder right = stroker->borders + 0;
FT_StrokeBorder left = stroker->borders + 1;
FT_Int new_points;
FT_Error error = FT_Err_Ok;
FT_ASSERT( left->start >= 0 );
new_points = (FT_Int)left->num_points - left->start;
if ( new_points > 0 )
{
error = ft_stroke_border_grow( right, (FT_UInt)new_points );
if ( error )
goto Exit;
{
FT_Vector* dst_point = right->points + right->num_points;
FT_Byte* dst_tag = right->tags + right->num_points;
FT_Vector* src_point = left->points + left->num_points - 1;
FT_Byte* src_tag = left->tags + left->num_points - 1;
while ( src_point >= left->points + left->start )
{
*dst_point = *src_point;
*dst_tag = *src_tag;
if ( open )
dst_tag[0] &= ~FT_STROKE_TAG_BEGIN_END;
else
{
FT_Byte ttag =
(FT_Byte)( dst_tag[0] & FT_STROKE_TAG_BEGIN_END );
/* switch begin/end tags if necessary */
if ( ttag == FT_STROKE_TAG_BEGIN ||
ttag == FT_STROKE_TAG_END )
dst_tag[0] ^= FT_STROKE_TAG_BEGIN_END;
}
src_point--;
src_tag--;
dst_point++;
dst_tag++;
}
}
left->num_points = (FT_UInt)left->start;
right->num_points += (FT_UInt)new_points;
right->movable = FALSE;
left->movable = FALSE;
}
Exit:
return error;
}
/* documentation is in ftstroke.h */
/* there's a lot of magic in this function! */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_EndSubPath( FT_Stroker stroker )
{
FT_Error error = FT_Err_Ok;
if ( !stroker )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
if ( stroker->subpath_open )
{
FT_StrokeBorder right = stroker->borders;
/* All right, this is an opened path, we need to add a cap between */
/* right & left, add the reverse of left, then add a final cap */
/* between left & right. */
error = ft_stroker_cap( stroker, stroker->angle_in, 0 );
if ( error )
goto Exit;
/* add reversed points from `left' to `right' */
error = ft_stroker_add_reverse_left( stroker, TRUE );
if ( error )
goto Exit;
/* now add the final cap */
stroker->center = stroker->subpath_start;
error = ft_stroker_cap( stroker,
stroker->subpath_angle + FT_ANGLE_PI, 0 );
if ( error )
goto Exit;
/* Now end the right subpath accordingly. The left one is */
/* rewind and doesn't need further processing. */
ft_stroke_border_close( right, FALSE );
}
else
{
FT_Angle turn;
FT_Int inside_side;
/* close the path if needed */
if ( stroker->center.x != stroker->subpath_start.x ||
stroker->center.y != stroker->subpath_start.y )
{
error = FT_Stroker_LineTo( stroker, &stroker->subpath_start );
if ( error )
goto Exit;
}
/* process the corner */
stroker->angle_out = stroker->subpath_angle;
turn = FT_Angle_Diff( stroker->angle_in,
stroker->angle_out );
/* no specific corner processing is required if the turn is 0 */
if ( turn != 0 )
{
/* when we turn to the right, the inside side is 0 */
/* otherwise, the inside side is 1 */
inside_side = ( turn < 0 );
error = ft_stroker_inside( stroker,
inside_side,
stroker->subpath_line_length );
if ( error )
goto Exit;
/* process the outside side */
error = ft_stroker_outside( stroker,
!inside_side,
stroker->subpath_line_length );
if ( error )
goto Exit;
}
/* then end our two subpaths */
ft_stroke_border_close( stroker->borders + 0, FALSE );
ft_stroke_border_close( stroker->borders + 1, TRUE );
}
Exit:
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_GetBorderCounts( FT_Stroker stroker,
FT_StrokerBorder border,
FT_UInt *anum_points,
FT_UInt *anum_contours )
{
FT_UInt num_points = 0, num_contours = 0;
FT_Error error;
if ( !stroker || border > 1 )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
error = ft_stroke_border_get_counts( stroker->borders + border,
&num_points, &num_contours );
Exit:
if ( anum_points )
*anum_points = num_points;
if ( anum_contours )
*anum_contours = num_contours;
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Stroker_GetCounts( FT_Stroker stroker,
FT_UInt *anum_points,
FT_UInt *anum_contours )
{
FT_UInt count1, count2, num_points = 0;
FT_UInt count3, count4, num_contours = 0;
FT_Error error;
if ( !stroker )
{
error = FT_THROW( Invalid_Argument );
goto Exit;
}
error = ft_stroke_border_get_counts( stroker->borders + 0,
&count1, &count2 );
if ( error )
goto Exit;
error = ft_stroke_border_get_counts( stroker->borders + 1,
&count3, &count4 );
if ( error )
goto Exit;
num_points = count1 + count3;
num_contours = count2 + count4;
Exit:
if ( anum_points )
*anum_points = num_points;
if ( anum_contours )
*anum_contours = num_contours;
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( void )
FT_Stroker_ExportBorder( FT_Stroker stroker,
FT_StrokerBorder border,
FT_Outline* outline )
{
if ( !stroker || !outline )
return;
if ( border == FT_STROKER_BORDER_LEFT ||
border == FT_STROKER_BORDER_RIGHT )
{
FT_StrokeBorder sborder = & stroker->borders[border];
if ( sborder->valid )
ft_stroke_border_export( sborder, outline );
}
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( void )
FT_Stroker_Export( FT_Stroker stroker,
FT_Outline* outline )
{
FT_Stroker_ExportBorder( stroker, FT_STROKER_BORDER_LEFT, outline );
FT_Stroker_ExportBorder( stroker, FT_STROKER_BORDER_RIGHT, outline );
}
/* documentation is in ftstroke.h */
/*
* The following is very similar to FT_Outline_Decompose, except
* that we do support opened paths, and do not scale the outline.
*/
FT_EXPORT_DEF( FT_Error )
FT_Stroker_ParseOutline( FT_Stroker stroker,
FT_Outline* outline,
FT_Bool opened )
{
FT_Vector v_last;
FT_Vector v_control;
FT_Vector v_start;
FT_Vector* point;
FT_Vector* limit;
char* tags;
FT_Error error;
FT_Int n; /* index of contour in outline */
FT_UInt first; /* index of first point in contour */
FT_Int tag; /* current point's state */
if ( !outline )
return FT_THROW( Invalid_Outline );
if ( !stroker )
return FT_THROW( Invalid_Argument );
FT_Stroker_Rewind( stroker );
first = 0;
for ( n = 0; n < outline->n_contours; n++ )
{
FT_UInt last; /* index of last point in contour */
last = (FT_UInt)outline->contours[n];
limit = outline->points + last;
/* skip empty points; we don't stroke these */
if ( last <= first )
{
first = last + 1;
continue;
}
v_start = outline->points[first];
v_last = outline->points[last];
v_control = v_start;
point = outline->points + first;
tags = outline->tags + first;
tag = FT_CURVE_TAG( tags[0] );
/* A contour cannot start with a cubic control point! */
if ( tag == FT_CURVE_TAG_CUBIC )
goto Invalid_Outline;
/* check first point to determine origin */
if ( tag == FT_CURVE_TAG_CONIC )
{
/* First point is conic control. Yes, this happens. */
if ( FT_CURVE_TAG( outline->tags[last] ) == FT_CURVE_TAG_ON )
{
/* start at last point if it is on the curve */
v_start = v_last;
limit--;
}
else
{
/* if both first and last points are conic, */
/* start at their middle */
v_start.x = ( v_start.x + v_last.x ) / 2;
v_start.y = ( v_start.y + v_last.y ) / 2;
}
point--;
tags--;
}
error = FT_Stroker_BeginSubPath( stroker, &v_start, opened );
if ( error )
goto Exit;
while ( point < limit )
{
point++;
tags++;
tag = FT_CURVE_TAG( tags[0] );
switch ( tag )
{
case FT_CURVE_TAG_ON: /* emit a single line_to */
{
FT_Vector vec;
vec.x = point->x;
vec.y = point->y;
error = FT_Stroker_LineTo( stroker, &vec );
if ( error )
goto Exit;
continue;
}
case FT_CURVE_TAG_CONIC: /* consume conic arcs */
v_control.x = point->x;
v_control.y = point->y;
Do_Conic:
if ( point < limit )
{
FT_Vector vec;
FT_Vector v_middle;
point++;
tags++;
tag = FT_CURVE_TAG( tags[0] );
vec = point[0];
if ( tag == FT_CURVE_TAG_ON )
{
error = FT_Stroker_ConicTo( stroker, &v_control, &vec );
if ( error )
goto Exit;
continue;
}
if ( tag != FT_CURVE_TAG_CONIC )
goto Invalid_Outline;
v_middle.x = ( v_control.x + vec.x ) / 2;
v_middle.y = ( v_control.y + vec.y ) / 2;
error = FT_Stroker_ConicTo( stroker, &v_control, &v_middle );
if ( error )
goto Exit;
v_control = vec;
goto Do_Conic;
}
error = FT_Stroker_ConicTo( stroker, &v_control, &v_start );
goto Close;
default: /* FT_CURVE_TAG_CUBIC */
{
FT_Vector vec1, vec2;
if ( point + 1 > limit ||
FT_CURVE_TAG( tags[1] ) != FT_CURVE_TAG_CUBIC )
goto Invalid_Outline;
point += 2;
tags += 2;
vec1 = point[-2];
vec2 = point[-1];
if ( point <= limit )
{
FT_Vector vec;
vec = point[0];
error = FT_Stroker_CubicTo( stroker, &vec1, &vec2, &vec );
if ( error )
goto Exit;
continue;
}
error = FT_Stroker_CubicTo( stroker, &vec1, &vec2, &v_start );
goto Close;
}
}
}
Close:
if ( error )
goto Exit;
/* don't try to end the path if no segments have been generated */
if ( !stroker->first_point )
{
error = FT_Stroker_EndSubPath( stroker );
if ( error )
goto Exit;
}
first = last + 1;
}
return FT_Err_Ok;
Exit:
return error;
Invalid_Outline:
return FT_THROW( Invalid_Outline );
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Glyph_Stroke( FT_Glyph *pglyph,
FT_Stroker stroker,
FT_Bool destroy )
{
FT_Error error = FT_ERR( Invalid_Argument );
FT_Glyph glyph = NULL;
if ( !pglyph )
goto Exit;
glyph = *pglyph;
if ( !glyph || glyph->clazz != &ft_outline_glyph_class )
goto Exit;
{
FT_Glyph copy;
error = FT_Glyph_Copy( glyph, © );
if ( error )
goto Exit;
glyph = copy;
}
{
FT_OutlineGlyph oglyph = (FT_OutlineGlyph)glyph;
FT_Outline* outline = &oglyph->outline;
FT_UInt num_points, num_contours;
error = FT_Stroker_ParseOutline( stroker, outline, FALSE );
if ( error )
goto Fail;
FT_Stroker_GetCounts( stroker, &num_points, &num_contours );
FT_Outline_Done( glyph->library, outline );
error = FT_Outline_New( glyph->library,
num_points,
(FT_Int)num_contours,
outline );
if ( error )
goto Fail;
outline->n_points = 0;
outline->n_contours = 0;
FT_Stroker_Export( stroker, outline );
}
if ( destroy )
FT_Done_Glyph( *pglyph );
*pglyph = glyph;
goto Exit;
Fail:
FT_Done_Glyph( glyph );
glyph = NULL;
if ( !destroy )
*pglyph = NULL;
Exit:
return error;
}
/* documentation is in ftstroke.h */
FT_EXPORT_DEF( FT_Error )
FT_Glyph_StrokeBorder( FT_Glyph *pglyph,
FT_Stroker stroker,
FT_Bool inside,
FT_Bool destroy )
{
FT_Error error = FT_ERR( Invalid_Argument );
FT_Glyph glyph = NULL;
if ( !pglyph )
goto Exit;
glyph = *pglyph;
if ( !glyph || glyph->clazz != &ft_outline_glyph_class )
goto Exit;
{
FT_Glyph copy;
error = FT_Glyph_Copy( glyph, © );
if ( error )
goto Exit;
glyph = copy;
}
{
FT_OutlineGlyph oglyph = (FT_OutlineGlyph)glyph;
FT_StrokerBorder border;
FT_Outline* outline = &oglyph->outline;
FT_UInt num_points, num_contours;
border = FT_Outline_GetOutsideBorder( outline );
if ( inside )
{
if ( border == FT_STROKER_BORDER_LEFT )
border = FT_STROKER_BORDER_RIGHT;
else
border = FT_STROKER_BORDER_LEFT;
}
error = FT_Stroker_ParseOutline( stroker, outline, FALSE );
if ( error )
goto Fail;
FT_Stroker_GetBorderCounts( stroker, border,
&num_points, &num_contours );
FT_Outline_Done( glyph->library, outline );
error = FT_Outline_New( glyph->library,
num_points,
(FT_Int)num_contours,
outline );
if ( error )
goto Fail;
outline->n_points = 0;
outline->n_contours = 0;
FT_Stroker_ExportBorder( stroker, border, outline );
}
if ( destroy )
FT_Done_Glyph( *pglyph );
*pglyph = glyph;
goto Exit;
Fail:
FT_Done_Glyph( glyph );
glyph = NULL;
if ( !destroy )
*pglyph = NULL;
Exit:
return error;
}
/* END */