ref: b97daa286191ae31e7d7259fa4844c38b0e0623a
dir: /src/base/ftstroke.c/
/***************************************************************************/ /* */ /* ftstroke.c */ /* */ /* FreeType path stroker (body). */ /* */ /* Copyright 2002, 2003, 2004, 2005, 2006 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 /* 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 / 6 ) #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 ) *angle_in = *angle_out = 0; else *angle_in = *angle_out = FT_Atan2( d2.x, d2.y ); } else 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; } 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 || close3 ) { if ( close2 ) { /* basically a point */ *angle_in = *angle_out = *angle_mid = 0; } else if ( close1 ) { *angle_in = *angle_mid = FT_Atan2( d2.x, d2.y ); *angle_out = FT_Atan2( d3.x, d3.y ); } else /* close2 */ { *angle_in = FT_Atan2( d1.x, d1.y ); *angle_mid = *angle_out = FT_Atan2( d2.x, d2.y ); } } else if ( close2 ) { *angle_in = *angle_mid = FT_Atan2( d1.x, d1.y ); *angle_out = FT_Atan2( d3.x, d3.y ); } else { *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_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; 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 = 0; 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 = 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 = 0; } static FT_Error ft_stroke_border_lineto( FT_StrokeBorder border, FT_Vector* to, FT_Bool movable ) { FT_Error error = 0; FT_ASSERT( border->start >= 0 ); if ( border->movable ) { /* move last point */ border->points[border->num_points - 1] = *to; } else { /* 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 = 0; 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 = 0; 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 = 0; /* 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, 0 ); border->start = border->num_points; border->movable = 0; return ft_stroke_border_lineto( border, to, 0 ); } 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 = 0; } static void ft_stroke_border_reset( FT_StrokeBorder border ) { border->num_points = 0; border->start = -1; border->valid = 0; } 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 = 0; } static FT_Error ft_stroke_border_get_counts( FT_StrokeBorder border, FT_UInt *anum_points, FT_UInt *anum_contours ) { FT_Error error = 0; 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 ) { if ( in_contour == 0 ) goto Fail; in_contour = 0; num_contours++; } } if ( in_contour != 0 ) goto Fail; border->valid = 1; 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)( outline->n_points + 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; FT_Angle angle_out; FT_Vector center; FT_Bool first_point; FT_Bool subpath_open; FT_Angle subpath_angle; FT_Vector subpath_start; FT_Stroker_LineCap line_cap; FT_Stroker_LineJoin line_join; FT_Fixed miter_limit; FT_Fixed radius; FT_Bool valid; FT_StrokeBorderRec borders[2]; FT_Memory memory; } FT_StrokerRec; /* documentation is in ftstroke.h */ FT_EXPORT_DEF( FT_Error ) FT_Stroker_New( FT_Library library, FT_Stroker *astroker ) { FT_Error error; FT_Memory memory; FT_Stroker stroker; if ( !library ) return FT_Err_Invalid_Argument; memory = library->memory; if ( !FT_NEW( stroker ) ) { stroker->memory = memory; 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 ) { stroker->radius = radius; stroker->line_cap = line_cap; stroker->line_join = line_join; stroker->miter_limit = miter_limit; 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->memory; ft_stroke_border_done( &stroker->borders[0] ); ft_stroke_border_done( &stroker->borders[1] ); stroker->memory = NULL; FT_FREE( stroker ); } } /* creates 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 = 0; 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 = 0; return error; } /* adds 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 = 0; 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, 0 ); 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, 0 ); } Exit: return error; } /* process an inside corner, i.e. compute intersection */ static FT_Error ft_stroker_inside( FT_Stroker stroker, FT_Int side) { FT_StrokeBorder border = stroker->borders + side; FT_Angle phi, theta, rotate; FT_Fixed length, thcos, sigma; FT_Vector delta; FT_Error error = 0; rotate = FT_SIDE_TO_ROTATE( side ); /* compute median angle */ theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out ); if ( theta == FT_ANGLE_PI ) theta = rotate; else theta = theta / 2; phi = stroker->angle_in + theta; thcos = FT_Cos( theta ); sigma = FT_MulFix( stroker->miter_limit, thcos ); /* TODO: find better criterion to switch off the optimization */ if ( sigma < 0x10000L ) { FT_Vector_From_Polar( &delta, stroker->radius, stroker->angle_out + rotate ); delta.x += stroker->center.x; delta.y += stroker->center.y; border->movable = 0; } else { 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, 0 ); 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_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 or beveled corner */ FT_Fixed sigma, radius = stroker->radius; FT_Angle theta, phi; FT_Fixed thcos; FT_Bool miter; rotate = FT_SIDE_TO_ROTATE( side ); miter = FT_BOOL( stroker->line_join == FT_STROKER_LINEJOIN_MITER ); theta = FT_Angle_Diff( stroker->angle_in, stroker->angle_out ); if ( theta == FT_ANGLE_PI ) { theta = rotate; phi = stroker->angle_in; } else { theta = theta / 2; phi = stroker->angle_in + theta + rotate; } thcos = FT_Cos( theta ); sigma = FT_MulFix( stroker->miter_limit, thcos ); if ( sigma >= 0x10000L ) miter = 0; if ( miter ) /* this is a miter (broken angle) */ { 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_MulFix( radius, FT_DivFix( 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, 0 ); 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, 0 ); if ( error ) goto Exit; /* finally, add a movable end point */ 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, 1 ); } else /* this is a bevel (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, 0 ); if (error) goto Exit; /* now add end point */ 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, 1 ); } } Exit: return error; } static FT_Error ft_stroker_process_corner( FT_Stroker stroker ) { FT_Error error = 0; 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 */ 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 ); if ( error ) goto Exit; /* process the outside side */ error = ft_stroker_outside( stroker, 1 - inside_side ); 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_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 for last cap */ stroker->subpath_angle = start_angle; stroker->first_point = 0; 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 = 0; FT_StrokeBorder border; FT_Vector delta; FT_Angle angle; FT_Int side; delta.x = to->x - stroker->center.x; delta.y = to->y - stroker->center.y; 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 ); if ( error ) goto Exit; } else { /* process the current corner */ stroker->angle_out = angle; error = ft_stroker_process_corner( stroker ); 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; error = ft_stroke_border_lineto( border, &point, 1 ); if ( error ) goto Exit; delta.x = -delta.x; delta.y = -delta.y; } stroker->angle_in = angle; stroker->center = *to; 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 = 0; FT_Vector bez_stack[34]; FT_Vector* arc; FT_Vector* limit = bez_stack + 30; FT_Angle start_angle; FT_Bool first_arc = 1; arc = bez_stack; arc[0] = *to; arc[1] = *control; arc[2] = stroker->center; while ( arc >= bez_stack ) { FT_Angle angle_in, angle_out; angle_in = angle_out = 0; /* remove compiler warnings */ if ( arc < limit && !ft_conic_is_small_enough( arc, &angle_in, &angle_out ) ) { ft_conic_split( arc ); arc += 2; continue; } if ( first_arc ) { first_arc = 0; start_angle = angle_in; /* process corner if necessary */ if ( stroker->first_point ) error = ft_stroker_subpath_start( stroker, start_angle ); else { stroker->angle_out = start_angle; error = ft_stroker_process_corner( stroker ); } } /* the arc's angle is small enough; we can add it directly to each */ /* border */ { FT_Vector ctrl, end; FT_Angle theta, phi, rotate; FT_Fixed length; FT_Int side; theta = FT_Angle_Diff( angle_in, angle_out ) / 2; phi = angle_in + theta; length = FT_DivFix( stroker->radius, FT_Cos( theta ) ); for ( side = 0; side <= 1; side++ ) { 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; error = ft_stroke_border_conicto( stroker->borders + side, &ctrl, &end ); if ( error ) goto Exit; } } arc -= 2; if ( arc < bez_stack ) 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 = 0; FT_Vector bez_stack[37]; FT_Vector* arc; FT_Vector* limit = bez_stack + 32; FT_Angle start_angle; FT_Bool first_arc = 1; 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; /* remove compiler warnings */ angle_in = angle_out = angle_mid = 0; if ( arc < limit && !ft_cubic_is_small_enough( arc, &angle_in, &angle_mid, &angle_out ) ) { ft_cubic_split( arc ); arc += 3; continue; } if ( first_arc ) { first_arc = 0; /* process corner if necessary */ start_angle = angle_in; if ( stroker->first_point ) error = ft_stroker_subpath_start( stroker, start_angle ); else { stroker->angle_out = start_angle; error = ft_stroker_process_corner( stroker ); } 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; FT_Fixed length1, length2; FT_Int side; theta1 = ft_pos_abs( angle_mid - angle_in ) / 2; theta2 = ft_pos_abs( angle_out - angle_mid ) / 2; phi1 = (angle_mid + angle_in ) / 2; phi2 = (angle_mid + angle_out ) / 2; length1 = FT_DivFix( stroker->radius, FT_Cos( theta1 ) ); length2 = FT_DivFix( stroker->radius, FT_Cos(theta2) ); for ( side = 0; side <= 1; side++ ) { 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; error = ft_stroke_border_cubicto( stroker->borders + side, &ctrl1, &ctrl2, &end ); if ( error ) goto Exit; } } arc -= 3; if ( arc < bez_stack ) 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 ) { /* We cannot process the first point, because there is not enough */ /* information regarding its corner/cap. The latter will be processed */ /* in the "end_subpath" routine. */ /* */ stroker->first_point = 1; stroker->center = *to; stroker->subpath_open = open; /* record the subpath start point index for each border */ stroker->subpath_start = *to; return 0; } 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 = 0; FT_ASSERT( left->start >= 0 ); new_points = 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 = left->start; right->num_points += new_points; right->movable = 0; left->movable = 0; } 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 = 0; 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, 1 ); 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, 0 ); } 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 */ inside_side = 0; /* otherwise, the inside side is 1 */ if ( turn < 0 ) inside_side = 1; error = ft_stroker_inside( stroker, inside_side ); if ( error ) goto Exit; /* process the outside side */ error = ft_stroker_outside( stroker, 1 - inside_side ); if ( error ) goto Exit; } /* then end our two subpaths */ ft_stroke_border_close( stroker->borders + 0, 1 ); ft_stroke_border_close( stroker->borders + 1, 0 ); } 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_Err_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; 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 */ FT_EXPORT_DEF( void ) FT_Stroker_ExportBorder( FT_Stroker stroker, FT_StrokerBorder border, FT_Outline* outline ) { 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 || !stroker ) return FT_Err_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 = 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 and record its position */ /* for closure */ v_start.x = ( v_start.x + v_last.x ) / 2; v_start.y = ( v_start.y + v_last.y ) / 2; v_last = v_start; } 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; error = FT_Stroker_EndSubPath( stroker ); if ( error ) goto Exit; first = last + 1; } return 0; Exit: return error; Invalid_Outline: return FT_Err_Invalid_Outline; } extern const FT_Glyph_Class ft_outline_glyph_class; /* documentation is in ftstroke.h */ FT_EXPORT_DEF( FT_Error ) FT_Glyph_Stroke( FT_Glyph *pglyph, FT_Stroker stroker, FT_Bool destroy ) { FT_Error error = FT_Err_Invalid_Argument; FT_Glyph glyph = NULL; if ( pglyph == NULL ) goto Exit; glyph = *pglyph; if ( glyph == NULL || glyph->clazz != &ft_outline_glyph_class ) goto Exit; { FT_Glyph copy; error = FT_Glyph_Copy( glyph, © ); if ( error ) goto Exit; glyph = copy; } { FT_OutlineGlyph oglyph = (FT_OutlineGlyph) glyph; FT_Outline* outline = &oglyph->outline; FT_UInt num_points, num_contours; error = FT_Stroker_ParseOutline( stroker, outline, 0 ); if ( error ) goto Fail; (void)FT_Stroker_GetCounts( stroker, &num_points, &num_contours ); FT_Outline_Done( glyph->library, outline ); error = FT_Outline_New( glyph->library, num_points, num_contours, outline ); if ( error ) goto Fail; outline->n_points = 0; outline->n_contours = 0; FT_Stroker_Export( stroker, outline ); } if ( destroy ) FT_Done_Glyph( *pglyph ); *pglyph = glyph; goto Exit; Fail: FT_Done_Glyph( glyph ); glyph = NULL; if ( !destroy ) *pglyph = NULL; Exit: return error; } /* documentation is in ftstroke.h */ FT_EXPORT_DEF( FT_Error ) FT_Glyph_StrokeBorder( FT_Glyph *pglyph, FT_Stroker stroker, FT_Bool inside, FT_Bool destroy ) { FT_Error error = FT_Err_Invalid_Argument; FT_Glyph glyph = NULL; if ( pglyph == NULL ) goto Exit; glyph = *pglyph; if ( glyph == NULL || glyph->clazz != &ft_outline_glyph_class ) goto Exit; { FT_Glyph copy; error = FT_Glyph_Copy( glyph, © ); if ( error ) goto Exit; glyph = copy; } { FT_OutlineGlyph oglyph = (FT_OutlineGlyph) glyph; FT_StrokerBorder border; FT_Outline* outline = &oglyph->outline; FT_UInt num_points, num_contours; border = FT_Outline_GetOutsideBorder( outline ); if ( inside ) { if ( border == FT_STROKER_BORDER_LEFT ) border = FT_STROKER_BORDER_RIGHT; else border = FT_STROKER_BORDER_LEFT; } error = FT_Stroker_ParseOutline( stroker, outline, 0 ); if ( error ) goto Fail; (void)FT_Stroker_GetBorderCounts( stroker, border, &num_points, &num_contours ); FT_Outline_Done( glyph->library, outline ); error = FT_Outline_New( glyph->library, num_points, 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 */