/***************************************************************************/ | |
/* */ | |
/* ftstroke.c */ | |
/* */ | |
/* FreeType path stroker (body). */ | |
/* */ | |
/* Copyright 2002-2015 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 | |
#include "basepic.h" | |
/* declare an extern to access `ft_outline_glyph_class' globally */ | |
/* allocated in `ftglyph.c', and use the FT_OUTLINE_GLYPH_CLASS_GET */ | |
/* macro to access it when FT_CONFIG_OPTION_PIC is defined */ | |
#ifndef FT_CONFIG_OPTION_PIC | |
FT_CALLBACK_TABLE const FT_Glyph_Class ft_outline_glyph_class; | |
#endif | |
/* 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]; | |
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 */ | |
if ( border->num_points > 0 && | |
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 */ | |
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; | |
/* for FT_OUTLINE_GLYPH_CLASS_GET (in PIC mode) */ | |
FT_Library library = stroker->library; | |
FT_UNUSED( library ); | |
if ( !pglyph ) | |
goto Exit; | |
glyph = *pglyph; | |
if ( !glyph || glyph->clazz != FT_OUTLINE_GLYPH_CLASS_GET ) | |
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; | |
/* for FT_OUTLINE_GLYPH_CLASS_GET (in PIC mode) */ | |
FT_Library library = stroker->library; | |
FT_UNUSED( library ); | |
if ( !pglyph ) | |
goto Exit; | |
glyph = *pglyph; | |
if ( !glyph || glyph->clazz != FT_OUTLINE_GLYPH_CLASS_GET ) | |
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 */ |