ref: b46a2d8a7448955dae9b1ec5d853a2d3c9be3481
dir: /demos/src/ftgrays2.c/
/*****************************************************************************/
/* */
/* ftgrays2.c - a new version of the standard FreeType anti-aliaser */
/* */
/* (c) 2000 David Turner - <[email protected]> */
/* */
/* Beware, this code is still in heavy beta.. */
/* */
/* After writing a "perfect" anti-aliaser (see ftgrays.c), it is clear */
/* that the standard FreeType renderer is better at generating glyph images */
/* because it uses an approximation that simply produced more contrasted */
/* edges, making its output more legible.. */
/* */
/* This code is an attempt to rewrite the standard renderer in order to */
/* support the following: */
/* */
/* - get rid of al rendering artifacts produced by the original algorithm */
/* - allow direct composition, by generating the output image as a "list" */
/* of span in successive scan-lines (the standard code is forced to use */
/* an intermediate buffer, and this is just _bad_ :-) */
/* */
#include <ftimage.h>
#define _STANDALONE_
#define xxxDEBUG_GRAYS
#define SPECIAL
#define HORZ
#define ErrRaster_Invalid_Outline -1
#define ErrRaster_Overflow -2
#include "ftgrays2.h"
/* include the FreeType main header if necessary */
#ifndef _STANDALONE_
#include "freetype.h" /* for FT_MulDiv & FT_Outline_Decompose */
#endif
#ifdef DEBUG_GRAYS
#include <stdio.h>
#endif
#ifndef FT_STATIC_RASTER
#define RAS_ARG PRaster raster
#define RAS_ARG_ PRaster raster,
#define RAS_VAR raster
#define RAS_VAR_ raster,
#define ras (*raster)
#else
#define RAS_ARG
#define RAS_ARG_
#define RAS_VAR
#define RAS_VAR_
static TRaster ras;
#endif
#define FMulDiv(a,b,c) ((long)(a)*(b)/(c))
#ifdef _STANDALONE_
#define SMulDiv(a,b,c) FMulDiv(a,b,c) /* XXXX - TO BE CHANGED LATER */
#else
#define SMulDiv(a,b,c) FT_MulDiv(a,b,c)
#endif
/* note: PIXEL_BITS must not be less than 6 !! */
#define PIXEL_BITS 6
#define ONE_PIXEL (1L << PIXEL_BITS)
#define ONE_HALF (ONE_PIXEL/2)
#define PIXEL_MASK (-1L << PIXEL_BITS)
#define TRUNC(x) ((x) >> PIXEL_BITS)
#define FRAC(x) ((x) & (ONE_PIXEL-1))
#define SUBPIXELS(x) ((x) << PIXEL_BITS)
#define FLOOR(x) ((x) & -ONE_PIXEL)
#define CEILING(x) (((x)+ONE_PIXEL-1) & -ONE_PIXEL)
#define ROUND(x) (((x)+ONE_HALF) & -ONE_PIXEL)
#define UPSCALE(x) ((x) << (PIXEL_BITS-6))
#define DOWNSCALE(x) ((x) >> (PIXEL_BITS-6))
#define WRITE_CELL(top,u,v,dir) write_cell( RAS_VAR_ top, u, v, dir )
/****************************************************************************/
/* */
/* INITIALIZE THE CELLS TABLE */
/* */
static
void init_cells( RAS_ARG_ void* buffer, long byte_size )
{
ras.cells = (PCell)buffer;
ras.max_cells = byte_size / sizeof(TCell);
ras.cell_limit = ras.cells + ras.max_cells;
ras.num_cells = 0;
}
/****************************************************************************/
/* */
/* WRITE ONE CELL IN THE RENDER POOL */
/* */
static
int write_cell( RAS_ARG_ PCell cell, TPos u, TPos v, TDir dir )
{
#ifdef DEBUG_GRAYS
static const char dirs[5] = "udrl?";
#endif
if (dir & dir_horizontal)
{
/* only keep horizontal cells within our clipping box */
if ( u < ras.min_y || u >= ras.max_y ||
v < ras.min_x || v >= ras.max_x ) goto Nope;
/* get rid of horizontal cells with pos == 0, they're irrelevant */
if ( FRAC(u) == 0 ) goto Nope;
cell->y = TRUNC( u - ras.min_y );
cell->x = TRUNC( v - ras.min_x );
}
else
{
/* get rid of vertical cells that are below or above our clipping */
/* box. Also discard all cells that are on the right of the clipping */
/* box.. */
if (u >= ras.max_x || v < ras.min_y || v >= ras.max_y) goto Nope;
u -= ras.min_x;
v -= ras.min_y;
/* all cells that are on the left of the clipping box are located */
/* on the same virtual "border" cell.. */
if (u < 0) u = -1;
cell->x = TRUNC( u );
cell->y = TRUNC( v );
}
cell->dir = dir;
cell->pos = FRAC(u);
#ifdef DEBUG_GRAYS
fprintf( stderr, "[%d,%d,%c,%d]\n",
(int)cell->y,
(int)cell->x,
dirs[dir],
cell->pos );
#endif
return 1;
Nope:
return 0;
}
/****************************************************************************/
/* */
/* COMPUTE THE OUTLINE BOUNDING BOX */
/* */
static
void compute_cbox( RAS_ARG_ FT_Outline* outline )
{
FT_Vector* vec = outline->points;
FT_Vector* limit = vec + outline->n_points;
if ( outline->n_points <= 0 )
{
ras.min_x = ras.max_x = 0;
ras.min_y = ras.max_y = 0;
goto Exit;
}
ras.min_x = ras.max_x = vec->x;
ras.min_y = ras.max_y = vec->y;
vec++;
for ( ; vec < limit; vec++ )
{
TPos x = vec->x;
TPos y = vec->y;
if ( x < ras.min_x ) ras.min_x = x;
if ( x > ras.max_x ) ras.max_x = x;
if ( y < ras.min_y ) ras.min_y = y;
if ( y > ras.max_y ) ras.max_y = y;
}
/* grid-fit the bounding box to integer pixels */
ras.min_x &= -64;
ras.min_y &= -64;
ras.max_x = (ras.max_x+63) & -64;
ras.max_y = (ras.max_y+63) & -64;
Exit:
ras.min_ex = ras.min_x >> 6;
ras.max_ex = ras.max_x >> 6;
ras.min_ey = ras.min_y >> 6;
ras.max_ey = ras.max_y >> 6;
}
/*************************************************************************/
/* */
/* <Function> */
/* compute_intersects */
/* */
/* <Description> */
/* Computes the scan-line intersections of a given line and store */
/* the corresonding cells in the render pool.. */
/* */
/* <Input> */
/* u1 :: The start u coordinate. */
/* v1 :: The start v coordinate. */
/* u2 :: The end u coordinate. */
/* v2 :: The end v coordinate. */
/* minv :: The minimum vertical grid coordinate. */
/* maxv :: The maximum vertical grid coordinate. */
/* dir :: The line direction.. */
/* */
/* <Return> */
/* error code. 0 means success.. */
/* */
static
int compute_intersects( RAS_ARG_ TPos u1, TPos v1,
TPos u2, TPos v2,
TPos minv, TPos maxv,
TDir dir )
{
TPos du, dv, u, v, iu, iv, ru, nu;
TScan e1, e2, size;
PCell top;
int reverse;
/* exit if dv == 0 */
if ( v1 == v2 ) goto Exit;
/* adjust to scanline center */
v1 -= ONE_HALF;
v2 -= ONE_HALF;
maxv -= ONE_PIXEL;
/* reverse direction in order to get dv > 0 */
reverse = 0;
if ( v2 < v1 )
{
TPos tmp;
v1 = -v1; v2 = -v2;
tmp = minv; minv = -maxv; maxv = -tmp;
reverse = 1;
}
/* check that we have an intersection */
if ( v2 < minv || v1 > maxv )
goto Exit;
du = u2 - u1;
dv = v2 - v1;
/* compute the first scanline in "e1" */
e1 = CEILING(v1);
if (e1 == v1 && ras.joint)
e1 += ONE_PIXEL;
/* compute the last scanline in "e2" */
if (v2 <= maxv)
{
e2 = FLOOR(v2);
ras.joint = (v2 == e2);
}
else
{
e2 = maxv;
ras.joint = 0;
}
size = TRUNC(e2-e1) + 1;
if (size <= 0) goto Exit;
/* check that there is enough space in the render pool */
if ( ras.cursor + size > ras.cell_limit )
{
ras.error = ErrRaster_Overflow;
goto Fail;
}
if (e1-v1 > 0)
u1 += SMulDiv( e1-v1, du, dv );
u = u1;
v = e1; if (reverse) v = -e1;
v += ONE_HALF;
iv = (1-2*reverse)*ONE_PIXEL;
/* compute decision variables */
if (du)
{
du <<= PIXEL_BITS;
iu = du / dv;
ru = du % dv;
if (ru < 0)
{
iu --;
ru += dv;
}
nu = -dv;
ru <<= 1;
dv <<= 1;
}
else
{
iu = 0;
ru = 0;
nu = -dv;
}
top = ras.cursor;
for ( ; size > 0; size-- )
{
if (WRITE_CELL( top, u, v, dir ))
top++;
u += iu;
nu += ru;
if (nu >= 0)
{
nu -= dv;
u++;
}
v += iv;
}
ras.cursor = top;
Exit:
return 0;
Fail:
return 1;
}
/*************************************************************************/
/* */
/* <Function> */
/* render_line */
/* */
/* <Description> */
/* This function injects a new line segment in the render pool. */
/* */
/* <Input> */
/* x :: target x coordinate (scaled subpixels) */
/* y :: target y coordinate (scaled subpixels) */
/* raster :: A pointer to the current raster object. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
static
int render_line( RAS_ARG_ TPos x, TPos y )
{
TPos minv, maxv;
TDir new_dir;
minv = ras.min_y;
maxv = ras.max_y;
if (ras.horizontal)
{
minv = ras.min_x;
maxv = ras.max_x;
}
new_dir = ras.dir;
/* first of all, detect a change of direction */
if ( y != ras.y )
{
new_dir = ( y > ras.y ) ? dir_up : dir_down;
if (ras.horizontal) new_dir |= dir_horizontal;
if ( new_dir != ras.dir )
{
ras.joint = 0;
ras.dir = new_dir;
}
}
/* then compute line intersections */
if ( compute_intersects( RAS_VAR_ ras.x, ras.y, x, y,
minv, maxv, new_dir ) )
goto Fail;
ras.x = x;
ras.y = y;
return 0;
Fail:
return 1;
}
static
void split_conic( FT_Vector* base )
{
TPos 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
int render_conic( RAS_ARG_ TPos x1, TPos y1, TPos x2, TPos y2 )
{
TPos x0, y0;
TPos dx, dy;
int top, level;
int* levels;
FT_Vector* arc;
x0 = ras.x;
y0 = ras.y;
dx = x0 + x2 - 2*x1; if (dx < 0) dx = -dx;
dy = y0 + y2 - 2*y1; if (dy < 0) dy = -dy;
if (dx < dy) dx = dy;
level = 1;
dx = DOWNSCALE(dx)/32;
while ( dx > 0 )
{
dx >>= 1;
level++;
}
if (level <= 1)
return render_line( RAS_VAR_ x2, y2 );
arc = ras.bez_stack;
arc[0].x = x2;
arc[0].y = y2;
arc[1].x = x1;
arc[1].y = y1;
arc[2].x = x0;
arc[2].y = y0;
levels = ras.lev_stack;
top = 0;
levels[0] = level;
for (;;)
{
level = levels[top];
if (level > 1)
{
split_conic(arc);
arc += 2;
top ++;
levels[top] = levels[top-1] = level-1;
}
else
{
if (render_line( RAS_VAR_ arc[0].x, arc[0].y )) return 1;
top--;
arc-=2;
if (top < 0)
return 0;
}
}
}
static
void split_cubic( FT_Vector* base )
{
TPos 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
int render_cubic( RAS_ARG_ TPos x1, TPos y1,
TPos x2, TPos y2,
TPos x3, TPos y3 )
{
TPos x0, y0;
TPos dx, dy, da, db;
int top, level;
int* levels;
FT_Vector* arc;
x0 = ras.x;
y0 = ras.y;
dx = x0 + x3 - 2*x1; if (dx < 0) dx = -dx;
dy = y0 + y3 - 2*y1; if (dy < 0) dy = -dy;
da = dy; if (da < dx) da = dx;
dx = x0 + x3 - 3*(x1+x2); if (dx < 0) dx = -dx;
dy = y0 + y3 - 3*(y1+y2); if (dy < 0) dy = -dy;
db = dy; if (db < dx) db = dx;
da = DOWNSCALE(da);
db = DOWNSCALE(db);
level = 1;
da = da/64;
db = db/128;
while ( da > 0 || db > 0 )
{
da >>= 1;
db >>= 2;
level++;
}
if (level <= 1)
return render_line( RAS_VAR_ x3, y3 );
arc = ras.bez_stack;
arc[0].x = x3;
arc[0].y = y3;
arc[1].x = x2;
arc[1].y = y2;
arc[2].x = x1;
arc[2].y = y1;
arc[3].x = x0;
arc[3].y = y0;
levels = ras.lev_stack;
top = 0;
levels[0] = level;
for (;;)
{
level = levels[top];
if (level > 1)
{
split_cubic(arc);
arc += 3;
top ++;
levels[top] = levels[top-1] = level-1;
}
else
{
if (render_line( RAS_VAR_ arc[0].x, arc[0].y )) return 1;
top --;
arc -= 3;
if (top < 0)
return 0;
}
}
}
static
int is_less_than( PCell a, PCell b )
{
if (a->y < b->y) goto Yes;
if (a->y == b->y)
{
if (a->x < b->x) goto Yes;
if (a->x == b->x)
{
TDir ad = a->dir & dir_horizontal;
TDir bd = b->dir & dir_horizontal;
if ( ad < bd ) goto Yes;
if ( ad == bd && a->pos < b->pos) goto Yes;
}
}
return 0;
Yes:
return 1;
}
/* a macro comparing two cell pointers. returns true if a <= b */
#define LESS_THAN(a,b) is_less_than( (PCell)(a), (PCell)(b) )
#define SWAP_CELLS(a,b,temp) { temp = *(a); *(a) = *(b); *(b) = temp; }
#define DEBUG_SORT
#define QUICK_SORT
#ifdef SHELL_SORT
/* A simple shell sort algorithm that works directly on our */
/* cells table.. */
static
void shell_sort ( PCell cells,
int count )
{
PCell i, j, limit = cells + count;
TCell temp;
int gap;
/* compute initial gap */
for (gap = 0; ++gap < count; gap *=3 );
while ( gap /= 3 )
{
for ( i = cells+gap; i < limit; i++ )
{
for ( j = i-gap; ; j -= gap )
{
PCell k = j+gap;
if ( LESS_THAN(j,k) )
break;
SWAP_CELLS(j,k,temp);
if ( j < cells+gap )
break;
}
}
}
}
#endif
#ifdef QUICK_SORT
/* this is a non-recursive quicksort that directly process our cells array */
/* it should be faster than calling the stdlib qsort(), and we can even */
/* tailor our insertion threshold... */
#define QSORT_THRESHOLD 4 /* below this size, a sub-array will be sorted */
/* through a normal insertion sort.. */
static
void quick_sort( PCell cells,
int count )
{
PCell stack[40]; /* should be enough ;-) */
PCell* top; /* top of stack */
PCell base, limit;
TCell temp;
limit = cells + count;
base = cells;
top = stack;
for (;;)
{
int len = limit-base;
PCell i, j;
if ( len > QSORT_THRESHOLD)
{
/* we use base+len/2 as the pivot */
SWAP_CELLS( base, base+len/2, temp );
i = base+1;
j = limit-1;
/* now ensure that *i <= *base <= *j */
if (LESS_THAN(j,i))
SWAP_CELLS( i, j, temp );
if (LESS_THAN(base,i))
SWAP_CELLS( base, i, temp );
if (LESS_THAN(j,base))
SWAP_CELLS( base, j, temp );
for (;;)
{
do i++; while (LESS_THAN(i,base));
do j--; while (LESS_THAN(base,j));
if (i > j)
break;
SWAP_CELLS( i,j, temp );
}
/* move pivot to correct place */
SWAP_CELLS( base, j, temp );
/* now, push the largest sub-array */
if ( j - base > limit -i )
{
top[0] = base;
top[1] = j;
base = i;
}
else
{
top[0] = i;
top[1] = limit;
limit = j;
}
top += 2;
}
else
{
/* the sub-array is small, perform insertion sort */
j = base;
i = j+1;
for ( ; i < limit; j = i, i++ )
{
for ( ; LESS_THAN(j+1,j); j-- )
{
SWAP_CELLS( j+1, j, temp );
if (j == base)
break;
}
}
if (top > stack)
{
top -= 2;
base = top[0];
limit = top[1];
} else
break;
}
}
}
#endif
#ifdef DEBUG_GRAYS
#ifdef DEBUG_SORT
static
int check_sort( PCell cells, int count )
{
PCell p, q;
for ( p = cells + count-2; p >= cells; p-- )
{
q = p+1;
if (!LESS_THAN(p,q))
return 0;
}
return 1;
}
#endif
#endif
#ifdef _STANDALONE_
#if 1
static
int FT_Outline_Decompose( FT_Outline* outline,
FT_Outline_Funcs* interface,
void* user )
{
typedef enum _phases
{
phase_point,
phase_conic,
phase_cubic,
phase_cubic2
} TPhase;
FT_Vector v_first;
FT_Vector v_last;
FT_Vector v_control;
FT_Vector v_start;
FT_Vector* point;
FT_Vector* limit;
char* tags;
int n; /* index of contour in outline */
int first; /* index of first point in contour */
int error;
char tag; /* current point's state */
first = 0;
for ( n = 0; n < outline->n_contours; n++ )
{
int last; /* index of last point in contour */
last = outline->contours[n];
limit = outline->points + last;
v_first = outline->points[first];
v_last = outline->points[last];
v_start = v_control = v_first;
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 = interface->move_to( &v_start, user );
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 */
{
error = interface->line_to( point, user );
if (error) goto Exit;
continue;
}
case FT_Curve_Tag_Conic: /* consume conic arcs */
{
v_control = point[0];
Do_Conic:
if (point < limit)
{
FT_Vector v_middle;
point++;
tags++;
tag = FT_CURVE_TAG( tags[0] );
if (tag == FT_Curve_Tag_On)
{
error = interface->conic_to( &v_control, point, user );
if (error) goto Exit;
continue;
}
if (tag != FT_Curve_Tag_Conic)
goto Invalid_Outline;
v_middle.x = (v_control.x + point->x)/2;
v_middle.y = (v_control.y + point->y)/2;
error = interface->conic_to( &v_control, &v_middle, user );
if (error) goto Exit;
v_control = point[0];
goto Do_Conic;
}
error = interface->conic_to( &v_control, &v_start, user );
goto Close;
}
default: /* FT_Curve_Tag_Cubic */
{
if ( point+1 > limit ||
FT_CURVE_TAG( tags[1] ) != FT_Curve_Tag_Cubic )
goto Invalid_Outline;
point += 2;
tags += 2;
if (point <= limit)
{
error = interface->cubic_to( point-2, point-1, point, user );
if (error) goto Exit;
continue;
}
error = interface->cubic_to( point-2, point-1, &v_start, user );
goto Close;
}
}
}
/* close the contour with a line segment */
error = interface->line_to( &v_start, user );
Close:
if (error) goto Exit;
first = last+1;
}
return 0;
Exit:
return error;
Invalid_Outline:
return -1;
}
#else
static
int FT_Outline_Decompose( FT_Outline* outline,
FT_Outline_Funcs* interface,
void* user )
{
typedef enum _phases
{
phase_point,
phase_conic,
phase_cubic,
phase_cubic2
} TPhase;
FT_Vector v_last;
FT_Vector v_control;
FT_Vector v_control2;
FT_Vector v_start;
FT_Vector* point;
char* tags;
int n; /* index of contour in outline */
int first; /* index of first point in contour */
int index; /* current point's index */
int error;
char tag; /* current point's state */
TPhase phase;
first = 0;
for ( n = 0; n < outline->n_contours; n++ )
{
int last; /* index of last point in contour */
last = outline->contours[n];
v_start = outline->points[first];
v_last = outline->points[last];
v_control = v_start;
tag = FT_CURVE_TAG( outline->tags[first] );
index = first;
/* A contour cannot start with a cubic control point! */
if ( tag == FT_Curve_Tag_Cubic )
return ErrRaster_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;
}
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;
}
phase = phase_conic;
}
else
phase = phase_point;
/* Begin a new contour with MOVE_TO */
error = interface->move_to( &v_start, user );
if ( error )
return error;
point = outline->points + first;
tags = outline->tags + first;
/* now process each contour point individually */
while ( index < last )
{
index++;
point++;
tags++;
tag = FT_CURVE_TAG( tags[0] );
switch ( phase )
{
case phase_point: /* the previous point was on the curve */
switch ( tag )
{
/* two succesive on points -> emit segment */
case FT_Curve_Tag_On:
error = interface->line_to( point, user );
break;
/* on point + conic control -> remember control point */
case FT_Curve_Tag_Conic:
v_control = point[0];
phase = phase_conic;
break;
/* on point + cubic control -> remember first control */
default:
v_control = point[0];
phase = phase_cubic;
break;
}
break;
case phase_conic: /* the previous point was a conic control */
switch ( tag )
{
/* conic control + on point -> emit conic arc */
case FT_Curve_Tag_On:
error = interface->conic_to( &v_control, point, user );
phase = phase_point;
break;
/* two successive conics -> emit conic arc `in between' */
case FT_Curve_Tag_Conic:
{
FT_Vector v_middle;
v_middle.x = (v_control.x + point->x)/2;
v_middle.y = (v_control.y + point->y)/2;
error = interface->conic_to( &v_control,
&v_middle, user );
v_control = point[0];
}
break;
default:
error = ErrRaster_Invalid_Outline;
}
break;
case phase_cubic: /* the previous point was a cubic control */
/* this point _must_ be a cubic control too */
if ( tag != FT_Curve_Tag_Cubic )
return ErrRaster_Invalid_Outline;
v_control2 = point[0];
phase = phase_cubic2;
break;
case phase_cubic2: /* the two previous points were cubics */
/* this point _must_ be an on point */
if ( tag != FT_Curve_Tag_On )
error = ErrRaster_Invalid_Outline;
else
error = interface->cubic_to( &v_control, &v_control2,
point, user );
phase = phase_point;
break;
}
/* lazy error testing */
if ( error )
return error;
}
/* end of contour, close curve cleanly */
error = 0;
tag = FT_CURVE_TAG( outline->tags[first] );
switch ( phase )
{
case phase_point:
if ( tag == FT_Curve_Tag_On )
error = interface->line_to( &v_start, user );
break;
case phase_conic:
error = interface->conic_to( &v_control, &v_start, user );
break;
case phase_cubic2:
if ( tag == FT_Curve_Tag_On )
error = interface->cubic_to( &v_control, &v_control2,
&v_start, user );
else
error = ErrRaster_Invalid_Outline;
break;
default:
error = ErrRaster_Invalid_Outline;
break;
}
if ( error )
return error;
first = last + 1;
}
return 0;
}
#endif
#endif /* _STANDALONE_ */
static
int Move_To2( FT_Vector* to,
FT_Raster raster )
{
PRaster rast = (PRaster)raster;
FT_Pos* to_x;
FT_Pos* to_y;
to_x = &to->x;
to_y = &to->y;
if (rast->horizontal)
{
to_x = &to->y;
to_y = &to->x;
}
rast->starter.x = UPSCALE(*to_x);
rast->starter.y = UPSCALE(*to_y);
rast->joint = 0;
rast->dir = dir_unknown;
rast->last = 0;
rast->start = 0;
if ((*to_x & 63) == 32)
{
rast->starter.x |= 1;
rast->start = to;
}
if ((*to_y & 63) == 32)
{
rast->starter.y |= 1;
rast->start = to;
}
rast->x = rast->starter.x;
rast->y = rast->starter.y;
return 0;
}
static
int Line_To2( FT_Vector* to,
FT_Raster raster )
{
TPos x, y;
PRaster rast = (PRaster)raster;
if ( to == rast->start )
{
x = rast->starter.x;
y = rast->starter.y;
}
else
{
if ( rast->horizontal )
{
x = to->y;
y = to->x;
}
else
{
x = to->x;
y = to->y;
}
x = UPSCALE(x);
y = UPSCALE(y);
}
return render_line( rast, x, y );
}
static
int Conic_To2( FT_Vector* control,
FT_Vector* to,
FT_Raster raster )
{
PRaster rast = (PRaster)raster;
FT_Vector ctr, to2;
ctr = *control;
to2 = *to;
if (rast->horizontal)
{
ctr.x = control->y;
ctr.y = control->x;
to2.x = to->y;
to2.y = to->x;
}
if ( to == rast->start )
to2 = rast->starter;
else
{
to2.x = UPSCALE(to2.x);
to2.y = UPSCALE(to2.y);
}
return render_conic( rast, UPSCALE(ctr.x), UPSCALE(ctr.y), to2.x, to2.y );
}
static
int Cubic_To2( FT_Vector* control1,
FT_Vector* control2,
FT_Vector* to,
FT_Raster raster )
{
PRaster rast = (PRaster)raster;
FT_Vector ctr1, ctr2, to2;
ctr1 = *control1;
ctr2 = *control2;
to2 = *to;
if (rast->horizontal)
{
ctr1.x = control1->y; ctr1.y = control1->x;
ctr2.x = control2->y; ctr2.y = control2->x;
to2.x = to->y; to2.y = to->x;
}
if ( to == rast->start )
to2 = rast->starter;
else
{
to2.x = UPSCALE(to2.x);
to2.y = UPSCALE(to2.y);
}
return render_cubic( rast, UPSCALE(ctr1.x), UPSCALE(ctr1.y),
UPSCALE(ctr2.x), UPSCALE(ctr2.y),
to2.x, to2.y );
}
static
void grays_render_span( int y, int count, FT_GraySpan* spans, PRaster raster )
{
unsigned char *p, *q, *limit;
FT_Bitmap* map = &raster->target;
/* first of all, compute the scanline offset */
p = (unsigned char*)map->buffer - y*map->pitch;
if (map->pitch >= 0)
p += (map->rows-1)*map->pitch;
for ( ; count > 0; count--, spans++ )
{
if (spans->coverage)
{
q = p + spans->x;
limit = q + spans->len;
for ( ; q < limit; q++ )
q[0] = (spans->coverage+1) >> 1;
}
}
}
#ifdef DEBUG_GRAYS
#include <stdio.h>
static
void dump_cells( RAS_ARG )
{
static const char dirs[5] = "udrl?";
PCell cell, limit;
int y = -1;
cell = ras.cells;
limit = cell + ras.num_cells;
for ( ; cell < limit; cell++ )
{
if ( cell->y != y )
{
fprintf( stderr, "\n%2d: ", (int)cell->y );
y = cell->y;
}
fprintf( stderr, "[%d %c %d]",
(int)cell->x,
dirs[cell->dir & 3],
cell->pos );
}
fprintf(stderr, "\n" );
}
#endif
static
void grays_hline( RAS_ARG_ TScan y, TScan x, int coverage, int acount )
{
FT_GraySpan* span;
int count;
/* compute the coverage line's coverage, depending on the */
/* outline fill rule.. */
/* */
/* The coverage percentage is area/ONE_PIXEL */
/* */
coverage <<= 1;
coverage >>= (PIXEL_BITS-6);
if (coverage < 0)
coverage = -coverage;
if (coverage >= 256)
coverage = 255;
if (coverage)
{
/* see if we can add this span to the current list */
count = ras.num_gray_spans;
span = ras.gray_spans + count-1;
if (count > 0 && ras.span_y == y && (int)span->x + span->len == (int)x &&
span->coverage == coverage)
{
span->len += acount;
return;
}
if ( ras.span_y != y || count >= FT_MAX_GRAY_SPANS)
{
if (ras.render_span)
ras.render_span( ras.span_y, count, ras.gray_spans, ras.render_span_closure );
/* ras.render_span( span->y, ras.gray_spans, count ); */
#ifdef DEBUG_GRAYS
if (ras.span_y >= 0)
{
int n;
fprintf( stderr, "y=%3d ", ras.span_y );
span = ras.gray_spans;
for (n = 0; n < count; n++, span++)
{
if (span->len > 1)
fprintf( stderr, "[%d..%d]:%02x ", span->x, span->x + span->len-1, span->coverage );
else
fprintf( stderr, "[%d]:%02x ", span->x, span->coverage );
}
fprintf( stderr, "\n" );
}
#endif
ras.num_gray_spans = 0;
ras.span_y = y;
count = 0;
span = ras.gray_spans;
}
else
span++;
/* add a gray span to the current list */
span->x = (short)x;
span->len = (unsigned char)acount;
span->coverage = (unsigned char)coverage;
ras.num_gray_spans++;
}
}
static
void grays_sweep( RAS_ARG_ FT_Bitmap* target )
{
TScan x, y, cover, x_black;
int varea, harea, hpos;
PCell start, cur, limit;
cur = ras.cells;
limit = cur + ras.num_cells;
cover = 0;
ras.span_y = -1;
ras.num_gray_spans = 0;
cover = 0;
x_black = 32000;
/* fprintf( stderr, "%2d:", cur->y ); */
for (;;)
{
int is_black, icover;
int area, numv;
start = cur;
y = start->y;
x = start->x;
icover = cover;
varea = cover << PIXEL_BITS;
harea = 0;
hpos = varea;
numv = 0;
/* accumulate all start cells */
for (;;)
{
/* XXX : for now, only deal with vertical intersections */
switch ((cur->dir)&3)
{
case dir_up:
varea += ONE_PIXEL - cur->pos;
if (cur->pos <= 32)
hpos = ONE_PIXEL;
cover++;
numv++;
break;
case dir_down:
varea -= ONE_PIXEL - cur->pos;
if (cur->pos <= 32)
hpos = 0;
cover--;
numv++;
break;
case dir_left:
harea += ONE_PIXEL - cur->pos;
break;
default:
harea -= ONE_PIXEL - cur->pos;
break;
}
++cur;
if (cur >= limit || cur->y != start->y || cur->x != start->x)
break;
}
/* nom compute the "real" area in the pixel */
if (varea < 0) varea += ONE_PIXEL;
if (harea < 0) harea += ONE_PIXEL;
if (harea)
area = varea + harea;
else
area = 2*varea;
#if 1
if ( varea < ONE_PIXEL && harea == 0 && (icover|cover) == 0 && area < ONE_PIXEL)
area += ONE_HALF;
#endif
is_black = ( area >= 2*ONE_PIXEL );
/* if the start cell isn't black, we may need to draw a black */
/* segment from a previous cell.. */
if ( !is_black && start->x > x_black )
{
/* printf( stderr, " b[%d..%d]", x_black, start->x-1 ); */
grays_hline( RAS_VAR_ y, x_black, 2*ONE_PIXEL, start->x - x_black );
}
/* if the cell is black, then record its position in "x_black" */
if ( is_black )
{
if ( x_black > start->x )
x_black = start->x;
}
/* if the cell is gray, draw a single gray pixel, then record */
/* the next cell's position in "x_black" if "cover" is black */
else
{
x_black = 32000;
if ( area )
{
/* fprintf( stderr, " [%d:%d]", start->x, varea ); */
grays_hline( RAS_VAR_ y, start->x, area, 1 );
if (cover)
x_black = start->x+1;
}
}
/* now process scanline changes/end */
if (cur >= limit || cur->y != start->y)
{
if (cover && x_black < ras.max_ex)
{
/* fprintf( stderr, " f[%d..%d]", x_black, ras.max_ex-1 ); */
grays_hline( RAS_VAR_ y, x_black, 2*ONE_PIXEL, ras.max_ex-x_black );
}
if (cur >= limit)
break;
/* fprintf( stderr, "\n%2d:", cur->y ); */
cover = 0;
x_black = 32000;
}
}
if (ras.render_span && ras.num_gray_spans > 0)
ras.render_span( ras.span_y, ras.num_gray_spans,
ras.gray_spans, ras.render_span_closure );
#ifdef DEBUG_GRAYS
{
int n;
FT_GraySpan* span;
fprintf( stderr, "y=%3d ", ras.span_y );
span = ras.gray_spans;
for (n = 0; n < ras.num_gray_spans; n++, span++)
{
if (span->len > 1)
fprintf( stderr, "[%d..%d]:%02x ", span->x, span->x + span->len-1, span->coverage );
else
fprintf( stderr, "[%d]:%02x ", span->x, span->coverage );
}
fprintf( stderr, "\n" );
}
#endif
}
static
int Convert_Glyph( RAS_ARG_ FT_Outline* outline )
{
static
FT_Outline_Funcs interface =
{
(FT_Outline_MoveTo_Func)Move_To2,
(FT_Outline_LineTo_Func)Line_To2,
(FT_Outline_ConicTo_Func)Conic_To2,
(FT_Outline_CubicTo_Func)Cubic_To2
};
/* Set up state in the raster object */
compute_cbox( RAS_VAR_ outline );
if (ras.min_ex < 0) ras.min_ex = 0;
if (ras.min_ey < 0) ras.min_ey = 0;
if (ras.max_ex > ras.target.width) ras.max_ex = ras.target.width;
if (ras.max_ey > ras.target.rows) ras.max_ey = ras.target.rows;
ras.min_x = UPSCALE(ras.min_ex << 6);
ras.min_y = UPSCALE(ras.min_ey << 6);
ras.max_x = UPSCALE(ras.max_ex << 6);
ras.max_y = UPSCALE(ras.max_ey << 6);
ras.num_cells = 0;
ras.contour_cell = 0;
ras.horizontal = 0;
/* compute vertical intersections */
if (FT_Outline_Decompose( outline, &interface, &ras ))
return 1;
#if 1
/* compute horizontal intersections */
ras.horizontal = 1;
return FT_Outline_Decompose( outline, &interface, &ras );
#endif
}
extern
int grays2_raster_render( TRaster* raster,
FT_Outline* outline,
FT_Bitmap* target_map )
{
if ( !raster || !raster->cells || !raster->max_cells )
return -1;
/* return immediately if the outline is empty */
if ( outline->n_points == 0 || outline->n_contours <= 0 )
return 0;
if ( !outline || !outline->contours || !outline->points )
return -1;
if ( outline->n_points != outline->contours[outline->n_contours - 1] + 1 )
return -1;
if ( !target_map || !target_map->buffer )
return -1;
ras.outline = *outline;
ras.target = *target_map;
ras.num_cells = 0;
ras.cursor = ras.cells;
if (Convert_Glyph( (PRaster)raster, outline ))
return 1;
ras.num_cells = ras.cursor - ras.cells;
#ifdef SHELL_SORT
shell_sort( ras.cells, ras.num_cells );
#else
quick_sort( ras.cells, ras.num_cells );
#endif
#ifdef DEBUG_GRAYS
check_sort( ras.cells, ras.num_cells );
dump_cells( RAS_VAR );
#endif
#if 1
ras.render_span = (FT_GraySpan_Func)grays_render_span;
ras.render_span_closure = &ras;
grays_sweep( (PRaster)raster, target_map );
return 0;
#else
return 0;
#endif
}
extern
int grays2_raster_init( FT_Raster raster,
const char* pool_base,
long pool_size )
{
/* static const char default_palette[5] = { 0, 1, 2, 3, 4 }; */
/* check the object address */
if ( !raster )
return -1;
/* check the render pool - we won't go under 4 Kb */
if ( !pool_base || pool_size < 4096 )
return -1;
/* save the pool */
init_cells( (PRaster)raster, (char*)pool_base, pool_size );
return 0;
}
FT_Raster_Interface ft_grays2_raster =
{
sizeof( TRaster ),
ft_glyph_format_outline,
(FT_Raster_Init_Proc) grays2_raster_init,
(FT_Raster_Set_Mode_Proc) 0,
(FT_Raster_Render_Proc) grays2_raster_render
};