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ES-DE/external/lunasvg/3rdparty/plutovg/plutovg-ft-stroker.c

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/***************************************************************************/
/* */
/* ftstroke.c */
/* */
/* FreeType path stroker (body). */
/* */
/* Copyright 2002-2006, 2008-2011, 2013 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 "plutovg-ft-stroker.h"
#include "plutovg-ft-math.h"
#include <assert.h>
#include <stdlib.h>
#include <string.h>
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** BEZIER COMPUTATIONS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
#define PVG_FT_SMALL_CONIC_THRESHOLD (PVG_FT_ANGLE_PI / 6)
#define PVG_FT_SMALL_CUBIC_THRESHOLD (PVG_FT_ANGLE_PI / 8)
#define PVG_FT_EPSILON 2
#define PVG_FT_IS_SMALL(x) ((x) > -PVG_FT_EPSILON && (x) < PVG_FT_EPSILON)
static PVG_FT_Pos ft_pos_abs(PVG_FT_Pos x)
{
return x >= 0 ? x : -x;
}
static void ft_conic_split(PVG_FT_Vector* base)
{
PVG_FT_Pos a, b;
base[4].x = base[2].x;
a = base[0].x + base[1].x;
b = base[1].x + base[2].x;
base[3].x = b >> 1;
base[2].x = ( a + b ) >> 2;
base[1].x = a >> 1;
base[4].y = base[2].y;
a = base[0].y + base[1].y;
b = base[1].y + base[2].y;
base[3].y = b >> 1;
base[2].y = ( a + b ) >> 2;
base[1].y = a >> 1;
}
static PVG_FT_Bool ft_conic_is_small_enough(PVG_FT_Vector* base,
PVG_FT_Angle* angle_in,
PVG_FT_Angle* angle_out)
{
PVG_FT_Vector d1, d2;
PVG_FT_Angle theta;
PVG_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 = PVG_FT_IS_SMALL(d1.x) && PVG_FT_IS_SMALL(d1.y);
close2 = PVG_FT_IS_SMALL(d2.x) && PVG_FT_IS_SMALL(d2.y);
if (close1) {
if (close2) {
/* basically a point; */
/* do nothing to retain original direction */
} else {
*angle_in = *angle_out = PVG_FT_Atan2(d2.x, d2.y);
}
} else /* !close1 */
{
if (close2) {
*angle_in = *angle_out = PVG_FT_Atan2(d1.x, d1.y);
} else {
*angle_in = PVG_FT_Atan2(d1.x, d1.y);
*angle_out = PVG_FT_Atan2(d2.x, d2.y);
}
}
theta = ft_pos_abs(PVG_FT_Angle_Diff(*angle_in, *angle_out));
return PVG_FT_BOOL(theta < PVG_FT_SMALL_CONIC_THRESHOLD);
}
static void ft_cubic_split(PVG_FT_Vector* base)
{
PVG_FT_Pos a, b, c;
base[6].x = base[3].x;
a = base[0].x + base[1].x;
b = base[1].x + base[2].x;
c = base[2].x + base[3].x;
base[5].x = c >> 1;
c += b;
base[4].x = c >> 2;
base[1].x = a >> 1;
a += b;
base[2].x = a >> 2;
base[3].x = ( a + c ) >> 3;
base[6].y = base[3].y;
a = base[0].y + base[1].y;
b = base[1].y + base[2].y;
c = base[2].y + base[3].y;
base[5].y = c >> 1;
c += b;
base[4].y = c >> 2;
base[1].y = a >> 1;
a += b;
base[2].y = a >> 2;
base[3].y = ( a + c ) >> 3;
}
/* Return the average of `angle1' and `angle2'. */
/* This gives correct result even if `angle1' and `angle2' */
/* have opposite signs. */
static PVG_FT_Angle ft_angle_mean(PVG_FT_Angle angle1, PVG_FT_Angle angle2)
{
return angle1 + PVG_FT_Angle_Diff(angle1, angle2) / 2;
}
static PVG_FT_Bool ft_cubic_is_small_enough(PVG_FT_Vector* base,
PVG_FT_Angle* angle_in,
PVG_FT_Angle* angle_mid,
PVG_FT_Angle* angle_out)
{
PVG_FT_Vector d1, d2, d3;
PVG_FT_Angle theta1, theta2;
PVG_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 = PVG_FT_IS_SMALL(d1.x) && PVG_FT_IS_SMALL(d1.y);
close2 = PVG_FT_IS_SMALL(d2.x) && PVG_FT_IS_SMALL(d2.y);
close3 = PVG_FT_IS_SMALL(d3.x) && PVG_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 = PVG_FT_Atan2(d3.x, d3.y);
}
} else /* !close2 */
{
if (close3) {
*angle_in = *angle_mid = *angle_out = PVG_FT_Atan2(d2.x, d2.y);
} else /* !close3 */
{
*angle_in = *angle_mid = PVG_FT_Atan2(d2.x, d2.y);
*angle_out = PVG_FT_Atan2(d3.x, d3.y);
}
}
} else /* !close1 */
{
if (close2) {
if (close3) {
*angle_in = *angle_mid = *angle_out = PVG_FT_Atan2(d1.x, d1.y);
} else /* !close3 */
{
*angle_in = PVG_FT_Atan2(d1.x, d1.y);
*angle_out = PVG_FT_Atan2(d3.x, d3.y);
*angle_mid = ft_angle_mean(*angle_in, *angle_out);
}
} else /* !close2 */
{
if (close3) {
*angle_in = PVG_FT_Atan2(d1.x, d1.y);
*angle_mid = *angle_out = PVG_FT_Atan2(d2.x, d2.y);
} else /* !close3 */
{
*angle_in = PVG_FT_Atan2(d1.x, d1.y);
*angle_mid = PVG_FT_Atan2(d2.x, d2.y);
*angle_out = PVG_FT_Atan2(d3.x, d3.y);
}
}
}
theta1 = ft_pos_abs(PVG_FT_Angle_Diff(*angle_in, *angle_mid));
theta2 = ft_pos_abs(PVG_FT_Angle_Diff(*angle_mid, *angle_out));
return PVG_FT_BOOL(theta1 < PVG_FT_SMALL_CUBIC_THRESHOLD &&
theta2 < PVG_FT_SMALL_CUBIC_THRESHOLD);
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** STROKE BORDERS *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
typedef enum PVG_FT_StrokeTags_ {
PVG_FT_STROKE_TAG_ON = 1, /* on-curve point */
PVG_FT_STROKE_TAG_CUBIC = 2, /* cubic off-point */
PVG_FT_STROKE_TAG_BEGIN = 4, /* sub-path start */
PVG_FT_STROKE_TAG_END = 8 /* sub-path end */
} PVG_FT_StrokeTags;
#define PVG_FT_STROKE_TAG_BEGIN_END \
(PVG_FT_STROKE_TAG_BEGIN | PVG_FT_STROKE_TAG_END)
typedef struct PVG_FT_StrokeBorderRec_ {
PVG_FT_UInt num_points;
PVG_FT_UInt max_points;
PVG_FT_Vector* points;
PVG_FT_Byte* tags;
PVG_FT_Bool movable; /* TRUE for ends of lineto borders */
PVG_FT_Int start; /* index of current sub-path start point */
PVG_FT_Bool valid;
} PVG_FT_StrokeBorderRec, *PVG_FT_StrokeBorder;
PVG_FT_Error PVG_FT_Outline_Check(PVG_FT_Outline* outline)
{
if (outline) {
PVG_FT_Int n_points = outline->n_points;
PVG_FT_Int n_contours = outline->n_contours;
PVG_FT_Int end0, end;
PVG_FT_Int n;
/* empty glyph? */
if (n_points == 0 && n_contours == 0) return 0;
/* check point and contour counts */
if (n_points <= 0 || n_contours <= 0) goto Bad;
end0 = end = -1;
for (n = 0; n < n_contours; n++) {
end = outline->contours[n];
/* note that we don't accept empty contours */
if (end <= end0 || end >= n_points) goto Bad;
end0 = end;
}
if (end != n_points - 1) goto Bad;
/* XXX: check the tags array */
return 0;
}
Bad:
return -1; // PVG_FT_THROW( Invalid_Argument );
}
void PVG_FT_Outline_Get_CBox(const PVG_FT_Outline* outline, PVG_FT_BBox* acbox)
{
PVG_FT_Pos xMin, yMin, xMax, yMax;
if (outline && acbox) {
if (outline->n_points == 0) {
xMin = 0;
yMin = 0;
xMax = 0;
yMax = 0;
} else {
PVG_FT_Vector* vec = outline->points;
PVG_FT_Vector* limit = vec + outline->n_points;
xMin = xMax = vec->x;
yMin = yMax = vec->y;
vec++;
for (; vec < limit; vec++) {
PVG_FT_Pos x, y;
x = vec->x;
if (x < xMin) xMin = x;
if (x > xMax) xMax = x;
y = vec->y;
if (y < yMin) yMin = y;
if (y > yMax) yMax = y;
}
}
acbox->xMin = xMin;
acbox->xMax = xMax;
acbox->yMin = yMin;
acbox->yMax = yMax;
}
}
static PVG_FT_Error ft_stroke_border_grow(PVG_FT_StrokeBorder border,
PVG_FT_UInt new_points)
{
PVG_FT_UInt old_max = border->max_points;
PVG_FT_UInt new_max = border->num_points + new_points;
PVG_FT_Error error = 0;
if (new_max > old_max) {
PVG_FT_UInt cur_max = old_max;
while (cur_max < new_max) cur_max += (cur_max >> 1) + 16;
border->points = (PVG_FT_Vector*)realloc(border->points,
cur_max * sizeof(PVG_FT_Vector));
border->tags =
(PVG_FT_Byte*)realloc(border->tags, cur_max * sizeof(PVG_FT_Byte));
if (!border->points || !border->tags) goto Exit;
border->max_points = cur_max;
}
Exit:
return error;
}
static void ft_stroke_border_close(PVG_FT_StrokeBorder border,
PVG_FT_Bool reverse)
{
PVG_FT_UInt start = border->start;
PVG_FT_UInt count = border->num_points;
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 */
{
PVG_FT_Vector* vec1 = border->points + start + 1;
PVG_FT_Vector* vec2 = border->points + count - 1;
for (; vec1 < vec2; vec1++, vec2--) {
PVG_FT_Vector tmp;
tmp = *vec1;
*vec1 = *vec2;
*vec2 = tmp;
}
}
/* then the tags */
{
PVG_FT_Byte* tag1 = border->tags + start + 1;
PVG_FT_Byte* tag2 = border->tags + count - 1;
for (; tag1 < tag2; tag1++, tag2--) {
PVG_FT_Byte tmp;
tmp = *tag1;
*tag1 = *tag2;
*tag2 = tmp;
}
}
}
border->tags[start] |= PVG_FT_STROKE_TAG_BEGIN;
border->tags[count - 1] |= PVG_FT_STROKE_TAG_END;
}
border->start = -1;
border->movable = FALSE;
}
static PVG_FT_Error ft_stroke_border_lineto(PVG_FT_StrokeBorder border,
PVG_FT_Vector* to, PVG_FT_Bool movable)
{
PVG_FT_Error error = 0;
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 &&
PVG_FT_IS_SMALL(border->points[border->num_points - 1].x - to->x) &&
PVG_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) {
PVG_FT_Vector* vec = border->points + border->num_points;
PVG_FT_Byte* tag = border->tags + border->num_points;
vec[0] = *to;
tag[0] = PVG_FT_STROKE_TAG_ON;
border->num_points += 1;
}
}
border->movable = movable;
return error;
}
static PVG_FT_Error ft_stroke_border_conicto(PVG_FT_StrokeBorder border,
PVG_FT_Vector* control,
PVG_FT_Vector* to)
{
PVG_FT_Error error;
assert(border->start >= 0);
error = ft_stroke_border_grow(border, 2);
if (!error) {
PVG_FT_Vector* vec = border->points + border->num_points;
PVG_FT_Byte* tag = border->tags + border->num_points;
vec[0] = *control;
vec[1] = *to;
tag[0] = 0;
tag[1] = PVG_FT_STROKE_TAG_ON;
border->num_points += 2;
}
border->movable = FALSE;
return error;
}
static PVG_FT_Error ft_stroke_border_cubicto(PVG_FT_StrokeBorder border,
PVG_FT_Vector* control1,
PVG_FT_Vector* control2,
PVG_FT_Vector* to)
{
PVG_FT_Error error;
assert(border->start >= 0);
error = ft_stroke_border_grow(border, 3);
if (!error) {
PVG_FT_Vector* vec = border->points + border->num_points;
PVG_FT_Byte* tag = border->tags + border->num_points;
vec[0] = *control1;
vec[1] = *control2;
vec[2] = *to;
tag[0] = PVG_FT_STROKE_TAG_CUBIC;
tag[1] = PVG_FT_STROKE_TAG_CUBIC;
tag[2] = PVG_FT_STROKE_TAG_ON;
border->num_points += 3;
}
border->movable = FALSE;
return error;
}
#define PVG_FT_ARC_CUBIC_ANGLE (PVG_FT_ANGLE_PI / 2)
static PVG_FT_Error
ft_stroke_border_arcto( PVG_FT_StrokeBorder border,
PVG_FT_Vector* center,
PVG_FT_Fixed radius,
PVG_FT_Angle angle_start,
PVG_FT_Angle angle_diff )
{
PVG_FT_Fixed coef;
PVG_FT_Vector a0, a1, a2, a3;
PVG_FT_Int i, arcs = 1;
PVG_FT_Error error = 0;
/* number of cubic arcs to draw */
while ( angle_diff > PVG_FT_ARC_CUBIC_ANGLE * arcs ||
-angle_diff > PVG_FT_ARC_CUBIC_ANGLE * arcs )
arcs++;
/* control tangents */
coef = PVG_FT_Tan( angle_diff / ( 4 * arcs ) );
coef += coef / 3;
/* compute start and first control point */
PVG_FT_Vector_From_Polar( &a0, radius, angle_start );
a1.x = PVG_FT_MulFix( -a0.y, coef );
a1.y = PVG_FT_MulFix( a0.x, coef );
a0.x += center->x;
a0.y += center->y;
a1.x += a0.x;
a1.y += a0.y;
for ( i = 1; i <= arcs; i++ )
{
/* compute end and second control point */
PVG_FT_Vector_From_Polar( &a3, radius,
angle_start + i * angle_diff / arcs );
a2.x = PVG_FT_MulFix( a3.y, coef );
a2.y = PVG_FT_MulFix( -a3.x, coef );
a3.x += center->x;
a3.y += center->y;
a2.x += a3.x;
a2.y += a3.y;
/* add cubic arc */
error = ft_stroke_border_cubicto( border, &a1, &a2, &a3 );
if ( error )
break;
/* a0 = a3; */
a1.x = a3.x - a2.x + a3.x;
a1.y = a3.y - a2.y + a3.y;
}
return error;
}
static PVG_FT_Error ft_stroke_border_moveto(PVG_FT_StrokeBorder border,
PVG_FT_Vector* to)
{
/* close current open path if any ? */
if (border->start >= 0) ft_stroke_border_close(border, FALSE);
border->start = border->num_points;
border->movable = FALSE;
return ft_stroke_border_lineto(border, to, FALSE);
}
static void ft_stroke_border_init(PVG_FT_StrokeBorder border)
{
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(PVG_FT_StrokeBorder border)
{
border->num_points = 0;
border->start = -1;
border->valid = FALSE;
}
static void ft_stroke_border_done(PVG_FT_StrokeBorder border)
{
free(border->points);
free(border->tags);
border->num_points = 0;
border->max_points = 0;
border->start = -1;
border->valid = FALSE;
}
static PVG_FT_Error ft_stroke_border_get_counts(PVG_FT_StrokeBorder border,
PVG_FT_UInt* anum_points,
PVG_FT_UInt* anum_contours)
{
PVG_FT_Error error = 0;
PVG_FT_UInt num_points = 0;
PVG_FT_UInt num_contours = 0;
PVG_FT_UInt count = border->num_points;
PVG_FT_Vector* point = border->points;
PVG_FT_Byte* tags = border->tags;
PVG_FT_Int in_contour = 0;
for (; count > 0; count--, num_points++, point++, tags++) {
if (tags[0] & PVG_FT_STROKE_TAG_BEGIN) {
if (in_contour != 0) goto Fail;
in_contour = 1;
} else if (in_contour == 0)
goto Fail;
if (tags[0] & PVG_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(PVG_FT_StrokeBorder border,
PVG_FT_Outline* outline)
{
/* copy point locations */
memcpy(outline->points + outline->n_points, border->points,
border->num_points * sizeof(PVG_FT_Vector));
/* copy tags */
{
PVG_FT_UInt count = border->num_points;
PVG_FT_Byte* read = border->tags;
PVG_FT_Byte* write = (PVG_FT_Byte*)outline->tags + outline->n_points;
for (; count > 0; count--, read++, write++) {
if (*read & PVG_FT_STROKE_TAG_ON)
*write = PVG_FT_CURVE_TAG_ON;
else if (*read & PVG_FT_STROKE_TAG_CUBIC)
*write = PVG_FT_CURVE_TAG_CUBIC;
else
*write = PVG_FT_CURVE_TAG_CONIC;
}
}
/* copy contours */
{
PVG_FT_UInt count = border->num_points;
PVG_FT_Byte* tags = border->tags;
PVG_FT_Int* write = outline->contours + outline->n_contours;
PVG_FT_Int idx = (PVG_FT_Int)outline->n_points;
for (; count > 0; count--, tags++, idx++) {
if (*tags & PVG_FT_STROKE_TAG_END) {
*write++ = idx;
outline->n_contours++;
}
}
}
outline->n_points = (int)(outline->n_points + border->num_points);
assert(PVG_FT_Outline_Check(outline) == 0);
}
/*************************************************************************/
/*************************************************************************/
/***** *****/
/***** STROKER *****/
/***** *****/
/*************************************************************************/
/*************************************************************************/
#define PVG_FT_SIDE_TO_ROTATE(s) (PVG_FT_ANGLE_PI2 - (s)*PVG_FT_ANGLE_PI)
typedef struct PVG_FT_StrokerRec_ {
PVG_FT_Angle angle_in; /* direction into curr join */
PVG_FT_Angle angle_out; /* direction out of join */
PVG_FT_Vector center; /* current position */
PVG_FT_Fixed line_length; /* length of last lineto */
PVG_FT_Bool first_point; /* is this the start? */
PVG_FT_Bool subpath_open; /* is the subpath open? */
PVG_FT_Angle subpath_angle; /* subpath start direction */
PVG_FT_Vector subpath_start; /* subpath start position */
PVG_FT_Fixed subpath_line_length; /* subpath start lineto len */
PVG_FT_Bool handle_wide_strokes; /* use wide strokes logic? */
PVG_FT_Stroker_LineCap line_cap;
PVG_FT_Stroker_LineJoin line_join;
PVG_FT_Stroker_LineJoin line_join_saved;
PVG_FT_Fixed miter_limit;
PVG_FT_Fixed radius;
PVG_FT_StrokeBorderRec borders[2];
} PVG_FT_StrokerRec;
/* documentation is in ftstroke.h */
PVG_FT_Error PVG_FT_Stroker_New(PVG_FT_Stroker* astroker)
{
PVG_FT_Error error = 0; /* assigned in PVG_FT_NEW */
PVG_FT_Stroker stroker = NULL;
stroker = (PVG_FT_StrokerRec*)calloc(1, sizeof(PVG_FT_StrokerRec));
if (stroker) {
ft_stroke_border_init(&stroker->borders[0]);
ft_stroke_border_init(&stroker->borders[1]);
}
*astroker = stroker;
return error;
}
void PVG_FT_Stroker_Rewind(PVG_FT_Stroker stroker)
{
if (stroker) {
ft_stroke_border_reset(&stroker->borders[0]);
ft_stroke_border_reset(&stroker->borders[1]);
}
}
/* documentation is in ftstroke.h */
void PVG_FT_Stroker_Set(PVG_FT_Stroker stroker, PVG_FT_Fixed radius,
PVG_FT_Stroker_LineCap line_cap,
PVG_FT_Stroker_LineJoin line_join,
PVG_FT_Fixed miter_limit)
{
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 < 0x10000) stroker->miter_limit = 0x10000;
/* save line join style: */
/* line join style can be temporarily changed when stroking curves */
stroker->line_join_saved = line_join;
PVG_FT_Stroker_Rewind(stroker);
}
/* documentation is in ftstroke.h */
void PVG_FT_Stroker_Done(PVG_FT_Stroker stroker)
{
if (stroker) {
ft_stroke_border_done(&stroker->borders[0]);
ft_stroke_border_done(&stroker->borders[1]);
free(stroker);
}
}
/* create a circular arc at a corner or cap */
static PVG_FT_Error ft_stroker_arcto(PVG_FT_Stroker stroker, PVG_FT_Int side)
{
PVG_FT_Angle total, rotate;
PVG_FT_Fixed radius = stroker->radius;
PVG_FT_Error error = 0;
PVG_FT_StrokeBorder border = stroker->borders + side;
rotate = PVG_FT_SIDE_TO_ROTATE(side);
total = PVG_FT_Angle_Diff(stroker->angle_in, stroker->angle_out);
if (total == PVG_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 PVG_FT_Error
ft_stroker_cap(PVG_FT_Stroker stroker,
PVG_FT_Angle angle,
PVG_FT_Int side)
{
PVG_FT_Error error = 0;
if (stroker->line_cap == PVG_FT_STROKER_LINECAP_ROUND)
{
/* add a round cap */
stroker->angle_in = angle;
stroker->angle_out = angle + PVG_FT_ANGLE_PI;
error = ft_stroker_arcto(stroker, side);
}
else
{
/* add a square or butt cap */
PVG_FT_Vector middle, delta;
PVG_FT_Fixed radius = stroker->radius;
PVG_FT_StrokeBorder border = stroker->borders + side;
/* compute middle point and first angle point */
PVG_FT_Vector_From_Polar( &middle, radius, angle );
delta.x = side ? middle.y : -middle.y;
delta.y = side ? -middle.x : middle.x;
if ( stroker->line_cap == PVG_FT_STROKER_LINECAP_SQUARE )
{
middle.x += stroker->center.x;
middle.y += stroker->center.y;
}
else /* PVG_FT_STROKER_LINECAP_BUTT */
{
middle.x = stroker->center.x;
middle.y = stroker->center.y;
}
delta.x += middle.x;
delta.y += middle.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
/* compute second angle point */
delta.x = middle.x - delta.x + middle.x;
delta.y = middle.y - delta.y + middle.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
}
Exit:
return error;
}
/* process an inside corner, i.e. compute intersection */
static PVG_FT_Error ft_stroker_inside(PVG_FT_Stroker stroker, PVG_FT_Int side,
PVG_FT_Fixed line_length)
{
PVG_FT_StrokeBorder border = stroker->borders + side;
PVG_FT_Angle phi, theta, rotate;
PVG_FT_Fixed length;
PVG_FT_Vector sigma = {0, 0};
PVG_FT_Vector delta;
PVG_FT_Error error = 0;
PVG_FT_Bool intersect; /* use intersection of lines? */
rotate = PVG_FT_SIDE_TO_ROTATE(side);
theta = PVG_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). */
if (!border->movable || line_length == 0 ||
theta > 0x59C000 || theta < -0x59C000 )
intersect = FALSE;
else {
/* compute minimum required length of lines */
PVG_FT_Fixed min_length;
PVG_FT_Vector_Unit( &sigma, theta );
min_length =
ft_pos_abs( PVG_FT_MulDiv( stroker->radius, sigma.y, sigma.x ) );
intersect = PVG_FT_BOOL( min_length &&
stroker->line_length >= min_length &&
line_length >= min_length );
}
if (!intersect) {
PVG_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 + rotate;
length = PVG_FT_DivFix( stroker->radius, sigma.x );
PVG_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);
return error;
}
/* process an outside corner, i.e. compute bevel/miter/round */
static PVG_FT_Error
ft_stroker_outside( PVG_FT_Stroker stroker,
PVG_FT_Int side,
PVG_FT_Fixed line_length )
{
PVG_FT_StrokeBorder border = stroker->borders + side;
PVG_FT_Error error;
PVG_FT_Angle rotate;
if ( stroker->line_join == PVG_FT_STROKER_LINEJOIN_ROUND )
error = ft_stroker_arcto( stroker, side );
else
{
/* this is a mitered (pointed) or beveled (truncated) corner */
PVG_FT_Fixed radius = stroker->radius;
PVG_FT_Vector sigma = {0, 0};
PVG_FT_Angle theta = 0, phi = 0;
PVG_FT_Bool bevel, fixed_bevel;
rotate = PVG_FT_SIDE_TO_ROTATE( side );
bevel =
PVG_FT_BOOL( stroker->line_join == PVG_FT_STROKER_LINEJOIN_BEVEL );
fixed_bevel =
PVG_FT_BOOL( stroker->line_join != PVG_FT_STROKER_LINEJOIN_MITER_VARIABLE );
/* check miter limit first */
if ( !bevel )
{
theta = PVG_FT_Angle_Diff( stroker->angle_in, stroker->angle_out ) / 2;
if ( theta == PVG_FT_ANGLE_PI2 )
theta = -rotate;
phi = stroker->angle_in + theta + rotate;
PVG_FT_Vector_From_Polar( &sigma, stroker->miter_limit, theta );
/* is miter limit exceeded? */
if ( sigma.x < 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 */
PVG_FT_Vector delta;
/* add bevel */
PVG_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 or clipped miter */
{
/* the miter is truncated */
PVG_FT_Vector middle, delta;
PVG_FT_Fixed coef;
/* compute middle point and first angle point */
PVG_FT_Vector_From_Polar( &middle,
PVG_FT_MulFix( radius, stroker->miter_limit ),
phi );
coef = PVG_FT_DivFix( 0x10000L - sigma.x, sigma.y );
delta.x = PVG_FT_MulFix( middle.y, coef );
delta.y = PVG_FT_MulFix( -middle.x, coef );
middle.x += stroker->center.x;
middle.y += stroker->center.y;
delta.x += middle.x;
delta.y += middle.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
/* compute second angle point */
delta.x = middle.x - delta.x + middle.x;
delta.y = middle.y - delta.y + middle.y;
error = ft_stroke_border_lineto( border, &delta, FALSE );
if ( error )
goto Exit;
/* finally, add an end point; only needed if not lineto */
/* (line_length is zero for curves) */
if ( line_length == 0 )
{
PVG_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) */
{
PVG_FT_Fixed length;
PVG_FT_Vector delta;
length = PVG_FT_MulDiv( stroker->radius, stroker->miter_limit, sigma.x );
PVG_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 )
{
PVG_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 PVG_FT_Error ft_stroker_process_corner(PVG_FT_Stroker stroker,
PVG_FT_Fixed line_length)
{
PVG_FT_Error error = 0;
PVG_FT_Angle turn;
PVG_FT_Int inside_side;
turn = PVG_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 */
inside_side = 0;
/* otherwise, the inside side is 1 */
if (turn < 0) inside_side = 1;
/* 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, 1 - inside_side, line_length);
Exit:
return error;
}
/* add two points to the left and right borders corresponding to the */
/* start of the subpath */
static PVG_FT_Error ft_stroker_subpath_start(PVG_FT_Stroker stroker,
PVG_FT_Angle start_angle,
PVG_FT_Fixed line_length)
{
PVG_FT_Vector delta;
PVG_FT_Vector point;
PVG_FT_Error error;
PVG_FT_StrokeBorder border;
PVG_FT_Vector_From_Polar(&delta, stroker->radius,
start_angle + PVG_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 */
PVG_FT_Error PVG_FT_Stroker_LineTo(PVG_FT_Stroker stroker, PVG_FT_Vector* to)
{
PVG_FT_Error error = 0;
PVG_FT_StrokeBorder border;
PVG_FT_Vector delta;
PVG_FT_Angle angle;
PVG_FT_Int side;
PVG_FT_Fixed line_length;
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 = PVG_FT_Vector_Length(&delta);
angle = PVG_FT_Atan2(delta.x, delta.y);
PVG_FT_Vector_From_Polar(&delta, stroker->radius, angle + PVG_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++) {
PVG_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 */
PVG_FT_Error PVG_FT_Stroker_ConicTo(PVG_FT_Stroker stroker, PVG_FT_Vector* control,
PVG_FT_Vector* to)
{
PVG_FT_Error error = 0;
PVG_FT_Vector bez_stack[34];
PVG_FT_Vector* arc;
PVG_FT_Vector* limit = bez_stack + 30;
PVG_FT_Bool first_arc = TRUE;
/* if all control points are coincident, this is a no-op; */
/* avoid creating a spurious corner */
if (PVG_FT_IS_SMALL(stroker->center.x - control->x) &&
PVG_FT_IS_SMALL(stroker->center.y - control->y) &&
PVG_FT_IS_SMALL(control->x - to->x) &&
PVG_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) {
PVG_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(PVG_FT_Angle_Diff(stroker->angle_in, angle_in)) >
PVG_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 = PVG_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 */
{
PVG_FT_Vector ctrl, end;
PVG_FT_Angle theta, phi, rotate, alpha0 = 0;
PVG_FT_Fixed length;
PVG_FT_StrokeBorder border;
PVG_FT_Int side;
theta = PVG_FT_Angle_Diff(angle_in, angle_out) / 2;
phi = angle_in + theta;
length = PVG_FT_DivFix(stroker->radius, PVG_FT_Cos(theta));
/* compute direction of original arc */
if (stroker->handle_wide_strokes)
alpha0 = PVG_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 = PVG_FT_SIDE_TO_ROTATE(side);
/* compute control point */
PVG_FT_Vector_From_Polar(&ctrl, length, phi + rotate);
ctrl.x += arc[1].x;
ctrl.y += arc[1].y;
/* compute end point */
PVG_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) {
PVG_FT_Vector start;
PVG_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 = PVG_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(PVG_FT_Angle_Diff(alpha0, alpha1)) >
PVG_FT_ANGLE_PI / 2) {
PVG_FT_Angle beta, gamma;
PVG_FT_Vector bvec, delta;
PVG_FT_Fixed blen, sinA, sinB, alen;
/* use the sine rule to find the intersection point */
beta =
PVG_FT_Atan2(arc[2].x - start.x, arc[2].y - start.y);
gamma = PVG_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 = PVG_FT_Vector_Length(&bvec);
sinA = ft_pos_abs(PVG_FT_Sin(alpha1 - gamma));
sinB = ft_pos_abs(PVG_FT_Sin(beta - gamma));
alen = PVG_FT_MulDiv(blen, sinA, sinB);
PVG_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;
stroker->line_length = 0;
Exit:
return error;
}
/* documentation is in ftstroke.h */
PVG_FT_Error PVG_FT_Stroker_CubicTo(PVG_FT_Stroker stroker, PVG_FT_Vector* control1,
PVG_FT_Vector* control2, PVG_FT_Vector* to)
{
PVG_FT_Error error = 0;
PVG_FT_Vector bez_stack[37];
PVG_FT_Vector* arc;
PVG_FT_Vector* limit = bez_stack + 32;
PVG_FT_Bool first_arc = TRUE;
/* if all control points are coincident, this is a no-op; */
/* avoid creating a spurious corner */
if (PVG_FT_IS_SMALL(stroker->center.x - control1->x) &&
PVG_FT_IS_SMALL(stroker->center.y - control1->y) &&
PVG_FT_IS_SMALL(control1->x - control2->x) &&
PVG_FT_IS_SMALL(control1->y - control2->y) &&
PVG_FT_IS_SMALL(control2->x - to->x) &&
PVG_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) {
PVG_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(PVG_FT_Angle_Diff(stroker->angle_in, angle_in)) >
PVG_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 = PVG_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 */
{
PVG_FT_Vector ctrl1, ctrl2, end;
PVG_FT_Angle theta1, phi1, theta2, phi2, rotate, alpha0 = 0;
PVG_FT_Fixed length1, length2;
PVG_FT_StrokeBorder border;
PVG_FT_Int side;
theta1 = PVG_FT_Angle_Diff(angle_in, angle_mid) / 2;
theta2 = PVG_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 = PVG_FT_DivFix(stroker->radius, PVG_FT_Cos(theta1));
length2 = PVG_FT_DivFix(stroker->radius, PVG_FT_Cos(theta2));
/* compute direction of original arc */
if (stroker->handle_wide_strokes)
alpha0 = PVG_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 = PVG_FT_SIDE_TO_ROTATE(side);
/* compute control points */
PVG_FT_Vector_From_Polar(&ctrl1, length1, phi1 + rotate);
ctrl1.x += arc[2].x;
ctrl1.y += arc[2].y;
PVG_FT_Vector_From_Polar(&ctrl2, length2, phi2 + rotate);
ctrl2.x += arc[1].x;
ctrl2.y += arc[1].y;
/* compute end point */
PVG_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) {
PVG_FT_Vector start;
PVG_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 = PVG_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(PVG_FT_Angle_Diff(alpha0, alpha1)) >
PVG_FT_ANGLE_PI / 2) {
PVG_FT_Angle beta, gamma;
PVG_FT_Vector bvec, delta;
PVG_FT_Fixed blen, sinA, sinB, alen;
/* use the sine rule to find the intersection point */
beta =
PVG_FT_Atan2(arc[3].x - start.x, arc[3].y - start.y);
gamma = PVG_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 = PVG_FT_Vector_Length(&bvec);
sinA = ft_pos_abs(PVG_FT_Sin(alpha1 - gamma));
sinB = ft_pos_abs(PVG_FT_Sin(beta - gamma));
alen = PVG_FT_MulDiv(blen, sinA, sinB);
PVG_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;
stroker->line_length = 0;
Exit:
return error;
}
/* documentation is in ftstroke.h */
PVG_FT_Error PVG_FT_Stroker_BeginSubPath(PVG_FT_Stroker stroker, PVG_FT_Vector* to,
PVG_FT_Bool open)
{
/* We cannot process the first point, because there is not enough */
/* information regarding its corner/cap. The latter will be processed */
/* in the `PVG_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 =
PVG_FT_BOOL(stroker->line_join != PVG_FT_STROKER_LINEJOIN_ROUND ||
(stroker->subpath_open &&
stroker->line_cap == PVG_FT_STROKER_LINECAP_BUTT));
/* record the subpath start point for each border */
stroker->subpath_start = *to;
stroker->angle_in = 0;
return 0;
}
static PVG_FT_Error ft_stroker_add_reverse_left(PVG_FT_Stroker stroker,
PVG_FT_Bool open)
{
PVG_FT_StrokeBorder right = stroker->borders + 0;
PVG_FT_StrokeBorder left = stroker->borders + 1;
PVG_FT_Int new_points;
PVG_FT_Error error = 0;
assert(left->start >= 0);
new_points = left->num_points - left->start;
if (new_points > 0) {
error = ft_stroke_border_grow(right, (PVG_FT_UInt)new_points);
if (error) goto Exit;
{
PVG_FT_Vector* dst_point = right->points + right->num_points;
PVG_FT_Byte* dst_tag = right->tags + right->num_points;
PVG_FT_Vector* src_point = left->points + left->num_points - 1;
PVG_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] &= ~PVG_FT_STROKE_TAG_BEGIN_END;
else {
PVG_FT_Byte ttag =
(PVG_FT_Byte)(dst_tag[0] & PVG_FT_STROKE_TAG_BEGIN_END);
/* switch begin/end tags if necessary */
if (ttag == PVG_FT_STROKE_TAG_BEGIN ||
ttag == PVG_FT_STROKE_TAG_END)
dst_tag[0] ^= PVG_FT_STROKE_TAG_BEGIN_END;
}
src_point--;
src_tag--;
dst_point++;
dst_tag++;
}
}
left->num_points = left->start;
right->num_points += 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! */
PVG_FT_Error PVG_FT_Stroker_EndSubPath(PVG_FT_Stroker stroker)
{
PVG_FT_Error error = 0;
if (stroker->subpath_open) {
PVG_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 + PVG_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 {
PVG_FT_Angle turn;
PVG_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 = PVG_FT_Stroker_LineTo(stroker, &stroker->subpath_start);
if (error) goto Exit;
}
/* process the corner */
stroker->angle_out = stroker->subpath_angle;
turn = PVG_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 */
inside_side = 0;
/* otherwise, the inside side is 1 */
if (turn < 0) inside_side = 1;
error = ft_stroker_inside(stroker, inside_side,
stroker->subpath_line_length);
if (error) goto Exit;
/* process the outside side */
error = ft_stroker_outside(stroker, 1 - 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 */
PVG_FT_Error PVG_FT_Stroker_GetBorderCounts(PVG_FT_Stroker stroker,
PVG_FT_StrokerBorder border,
PVG_FT_UInt* anum_points,
PVG_FT_UInt* anum_contours)
{
PVG_FT_UInt num_points = 0, num_contours = 0;
PVG_FT_Error error;
if (!stroker || border > 1) {
error = -1; // PVG_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 */
PVG_FT_Error PVG_FT_Stroker_GetCounts(PVG_FT_Stroker stroker,
PVG_FT_UInt* anum_points,
PVG_FT_UInt* anum_contours)
{
PVG_FT_UInt count1, count2, num_points = 0;
PVG_FT_UInt count3, count4, num_contours = 0;
PVG_FT_Error error;
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:
*anum_points = num_points;
*anum_contours = num_contours;
return error;
}
/* documentation is in ftstroke.h */
void PVG_FT_Stroker_ExportBorder(PVG_FT_Stroker stroker,
PVG_FT_StrokerBorder border,
PVG_FT_Outline* outline)
{
if (border == PVG_FT_STROKER_BORDER_LEFT ||
border == PVG_FT_STROKER_BORDER_RIGHT) {
PVG_FT_StrokeBorder sborder = &stroker->borders[border];
if (sborder->valid) ft_stroke_border_export(sborder, outline);
}
}
/* documentation is in ftstroke.h */
void PVG_FT_Stroker_Export(PVG_FT_Stroker stroker, PVG_FT_Outline* outline)
{
PVG_FT_Stroker_ExportBorder(stroker, PVG_FT_STROKER_BORDER_LEFT, outline);
PVG_FT_Stroker_ExportBorder(stroker, PVG_FT_STROKER_BORDER_RIGHT, outline);
}
/* documentation is in ftstroke.h */
/*
* The following is very similar to PVG_FT_Outline_Decompose, except
* that we do support opened paths, and do not scale the outline.
*/
PVG_FT_Error PVG_FT_Stroker_ParseOutline(PVG_FT_Stroker stroker,
const PVG_FT_Outline* outline)
{
PVG_FT_Vector v_last;
PVG_FT_Vector v_control;
PVG_FT_Vector v_start;
PVG_FT_Vector* point;
PVG_FT_Vector* limit;
char* tags;
PVG_FT_Error error;
PVG_FT_Int n; /* index of contour in outline */
PVG_FT_UInt first; /* index of first point in contour */
PVG_FT_Int tag; /* current point's state */
if (!outline || !stroker) return -1; // PVG_FT_THROW( Invalid_Argument );
PVG_FT_Stroker_Rewind(stroker);
first = 0;
for (n = 0; n < outline->n_contours; n++) {
PVG_FT_UInt last; /* index of last point in contour */
last = 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 = PVG_FT_CURVE_TAG(tags[0]);
/* A contour cannot start with a cubic control point! */
if (tag == PVG_FT_CURVE_TAG_CUBIC) goto Invalid_Outline;
/* check first point to determine origin */
if (tag == PVG_FT_CURVE_TAG_CONIC) {
/* First point is conic control. Yes, this happens. */
if (PVG_FT_CURVE_TAG(outline->tags[last]) == PVG_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 = PVG_FT_Stroker_BeginSubPath(stroker, &v_start, outline->contours_flag[n]);
if (error) goto Exit;
while (point < limit) {
point++;
tags++;
tag = PVG_FT_CURVE_TAG(tags[0]);
switch (tag) {
case PVG_FT_CURVE_TAG_ON: /* emit a single line_to */
{
PVG_FT_Vector vec;
vec.x = point->x;
vec.y = point->y;
error = PVG_FT_Stroker_LineTo(stroker, &vec);
if (error) goto Exit;
continue;
}
case PVG_FT_CURVE_TAG_CONIC: /* consume conic arcs */
v_control.x = point->x;
v_control.y = point->y;
Do_Conic:
if (point < limit) {
PVG_FT_Vector vec;
PVG_FT_Vector v_middle;
point++;
tags++;
tag = PVG_FT_CURVE_TAG(tags[0]);
vec = point[0];
if (tag == PVG_FT_CURVE_TAG_ON) {
error =
PVG_FT_Stroker_ConicTo(stroker, &v_control, &vec);
if (error) goto Exit;
continue;
}
if (tag != PVG_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 =
PVG_FT_Stroker_ConicTo(stroker, &v_control, &v_middle);
if (error) goto Exit;
v_control = vec;
goto Do_Conic;
}
error = PVG_FT_Stroker_ConicTo(stroker, &v_control, &v_start);
goto Close;
default: /* PVG_FT_CURVE_TAG_CUBIC */
{
PVG_FT_Vector vec1, vec2;
if (point + 1 > limit ||
PVG_FT_CURVE_TAG(tags[1]) != PVG_FT_CURVE_TAG_CUBIC)
goto Invalid_Outline;
point += 2;
tags += 2;
vec1 = point[-2];
vec2 = point[-1];
if (point <= limit) {
PVG_FT_Vector vec;
vec = point[0];
error = PVG_FT_Stroker_CubicTo(stroker, &vec1, &vec2, &vec);
if (error) goto Exit;
continue;
}
error = PVG_FT_Stroker_CubicTo(stroker, &vec1, &vec2, &v_start);
goto Close;
}
}
}
Close:
if (error) goto Exit;
if (stroker->first_point) {
stroker->subpath_open = TRUE;
error = ft_stroker_subpath_start(stroker, 0, 0);
if (error) goto Exit;
}
error = PVG_FT_Stroker_EndSubPath(stroker);
if (error) goto Exit;
first = last + 1;
}
return 0;
Exit:
return error;
Invalid_Outline:
return -2; // PVG_FT_THROW( Invalid_Outline );
}
/* END */
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