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ES-DE/3rdparty/software/sw_ft_raster.c

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Squashed 'external/lunasvg/' content from commit 7417baa0a git-subtree-dir: external/lunasvg git-subtree-split: 7417baa0aff477f361e44e2aa793fdb0c7aae352
2022-10-03 16:25:42 +00:00
/***************************************************************************/
/* */
/* ftgrays.c */
/* */
/* A new `perfect' anti-aliasing renderer (body). */
/* */
/* Copyright 2000-2003, 2005-2014 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. */
/* */
/***************************************************************************/
/*************************************************************************/
/* */
/* This is a new anti-aliasing scan-converter for FreeType 2. The */
/* algorithm used here is _very_ different from the one in the standard */
/* `ftraster' module. Actually, `ftgrays' computes the _exact_ */
/* coverage of the outline on each pixel cell. */
/* */
/* It is based on ideas that I initially found in Raph Levien's */
/* excellent LibArt graphics library (see http://www.levien.com/libart */
/* for more information, though the web pages do not tell anything */
/* about the renderer; you'll have to dive into the source code to */
/* understand how it works). */
/* */
/* Note, however, that this is a _very_ different implementation */
/* compared to Raph's. Coverage information is stored in a very */
/* different way, and I don't use sorted vector paths. Also, it doesn't */
/* use floating point values. */
/* */
/* This renderer has the following advantages: */
/* */
/* - It doesn't need an intermediate bitmap. Instead, one can supply a */
/* callback function that will be called by the renderer to draw gray */
/* spans on any target surface. You can thus do direct composition on */
/* any kind of bitmap, provided that you give the renderer the right */
/* callback. */
/* */
/* - A perfect anti-aliaser, i.e., it computes the _exact_ coverage on */
/* each pixel cell. */
/* */
/* - It performs a single pass on the outline (the `standard' FT2 */
/* renderer makes two passes). */
/* */
/* - It can easily be modified to render to _any_ number of gray levels */
/* cheaply. */
/* */
/* - For small (< 20) pixel sizes, it is faster than the standard */
/* renderer. */
/* */
/*************************************************************************/
#include "sw_ft_raster.h"
#include "sw_ft_math.h"
/* Auxiliary macros for token concatenation. */
#define SW_FT_ERR_XCAT(x, y) x##y
#define SW_FT_ERR_CAT(x, y) SW_FT_ERR_XCAT(x, y)
#define SW_FT_BEGIN_STMNT do {
#define SW_FT_END_STMNT \
} \
while (0)
#include <limits.h>
#include <setjmp.h>
#include <stddef.h>
#include <string.h>
#define SW_FT_UINT_MAX UINT_MAX
#define SW_FT_INT_MAX INT_MAX
#define SW_FT_ULONG_MAX ULONG_MAX
#define SW_FT_CHAR_BIT CHAR_BIT
#define ft_memset memset
#define ft_setjmp setjmp
#define ft_longjmp longjmp
#define ft_jmp_buf jmp_buf
typedef ptrdiff_t SW_FT_PtrDist;
#define ErrRaster_Invalid_Mode -2
#define ErrRaster_Invalid_Outline -1
#define ErrRaster_Invalid_Argument -3
#define ErrRaster_Memory_Overflow -4
#define SW_FT_BEGIN_HEADER
#define SW_FT_END_HEADER
/* This macro is used to indicate that a function parameter is unused. */
/* Its purpose is simply to reduce compiler warnings. Note also that */
/* simply defining it as `(void)x' doesn't avoid warnings with certain */
/* ANSI compilers (e.g. LCC). */
#define SW_FT_UNUSED(x) (x) = (x)
#define SW_FT_THROW(e) SW_FT_ERR_CAT(ErrRaster_, e)
/* The size in bytes of the render pool used by the scan-line converter */
/* to do all of its work. */
#define SW_FT_RENDER_POOL_SIZE 16384L
typedef int (*SW_FT_Outline_MoveToFunc)(const SW_FT_Vector* to, void* user);
#define SW_FT_Outline_MoveTo_Func SW_FT_Outline_MoveToFunc
typedef int (*SW_FT_Outline_LineToFunc)(const SW_FT_Vector* to, void* user);
#define SW_FT_Outline_LineTo_Func SW_FT_Outline_LineToFunc
typedef int (*SW_FT_Outline_ConicToFunc)(const SW_FT_Vector* control,
const SW_FT_Vector* to, void* user);
#define SW_FT_Outline_ConicTo_Func SW_FT_Outline_ConicToFunc
typedef int (*SW_FT_Outline_CubicToFunc)(const SW_FT_Vector* control1,
const SW_FT_Vector* control2,
const SW_FT_Vector* to, void* user);
#define SW_FT_Outline_CubicTo_Func SW_FT_Outline_CubicToFunc
typedef struct SW_FT_Outline_Funcs_ {
SW_FT_Outline_MoveToFunc move_to;
SW_FT_Outline_LineToFunc line_to;
SW_FT_Outline_ConicToFunc conic_to;
SW_FT_Outline_CubicToFunc cubic_to;
int shift;
SW_FT_Pos delta;
} SW_FT_Outline_Funcs;
#define SW_FT_DEFINE_OUTLINE_FUNCS(class_, move_to_, line_to_, conic_to_, \
cubic_to_, shift_, delta_) \
static const SW_FT_Outline_Funcs class_ = {move_to_, line_to_, conic_to_, \
cubic_to_, shift_, delta_};
#define SW_FT_DEFINE_RASTER_FUNCS(class_, raster_new_, raster_reset_, \
raster_render_, raster_done_) \
const SW_FT_Raster_Funcs class_ = {raster_new_, raster_reset_, \
raster_render_, raster_done_};
#ifndef SW_FT_MEM_SET
#define SW_FT_MEM_SET(d, s, c) ft_memset(d, s, c)
#endif
#ifndef SW_FT_MEM_ZERO
#define SW_FT_MEM_ZERO(dest, count) SW_FT_MEM_SET(dest, 0, count)
#endif
/* as usual, for the speed hungry :-) */
#undef RAS_ARG
#undef RAS_ARG_
#undef RAS_VAR
#undef RAS_VAR_
#ifndef SW_FT_STATIC_RASTER
#define RAS_ARG gray_PWorker worker
#define RAS_ARG_ gray_PWorker worker,
#define RAS_VAR worker
#define RAS_VAR_ worker,
#else /* SW_FT_STATIC_RASTER */
#define RAS_ARG /* empty */
#define RAS_ARG_ /* empty */
#define RAS_VAR /* empty */
#define RAS_VAR_ /* empty */
#endif /* SW_FT_STATIC_RASTER */
/* must be at least 6 bits! */
#define PIXEL_BITS 8
#undef FLOOR
#undef CEILING
#undef TRUNC
#undef SCALED
#define ONE_PIXEL (1L << PIXEL_BITS)
#define PIXEL_MASK (-1L << PIXEL_BITS)
#define TRUNC(x) ((TCoord)((x) >> PIXEL_BITS))
#define SUBPIXELS(x) ((TPos)(x) << PIXEL_BITS)
#define FLOOR(x) ((x) & -ONE_PIXEL)
#define CEILING(x) (((x) + ONE_PIXEL - 1) & -ONE_PIXEL)
#define ROUND(x) (((x) + ONE_PIXEL / 2) & -ONE_PIXEL)
#if PIXEL_BITS >= 6
#define UPSCALE(x) ((x) << (PIXEL_BITS - 6))
#define DOWNSCALE(x) ((x) >> (PIXEL_BITS - 6))
#else
#define UPSCALE(x) ((x) >> (6 - PIXEL_BITS))
#define DOWNSCALE(x) ((x) << (6 - PIXEL_BITS))
#endif
/* Compute `dividend / divisor' and return both its quotient and */
/* remainder, cast to a specific type. This macro also ensures that */
/* the remainder is always positive. */
#define SW_FT_DIV_MOD(type, dividend, divisor, quotient, remainder) \
SW_FT_BEGIN_STMNT(quotient) = (type)((dividend) / (divisor)); \
(remainder) = (type)((dividend) % (divisor)); \
if ((remainder) < 0) { \
(quotient)--; \
(remainder) += (type)(divisor); \
} \
SW_FT_END_STMNT
#ifdef __arm__
/* Work around a bug specific to GCC which make the compiler fail to */
/* optimize a division and modulo operation on the same parameters */
/* into a single call to `__aeabi_idivmod'. See */
/* */
/* http://gcc.gnu.org/bugzilla/show_bug.cgi?id=43721 */
#undef SW_FT_DIV_MOD
#define SW_FT_DIV_MOD(type, dividend, divisor, quotient, remainder) \
SW_FT_BEGIN_STMNT(quotient) = (type)((dividend) / (divisor)); \
(remainder) = (type)((dividend) - (quotient) * (divisor)); \
if ((remainder) < 0) { \
(quotient)--; \
(remainder) += (type)(divisor); \
} \
SW_FT_END_STMNT
#endif /* __arm__ */
/* These macros speed up repetitive divisions by replacing them */
/* with multiplications and right shifts. */
#define SW_FT_UDIVPREP(b) \
long b##_r = (long)(SW_FT_ULONG_MAX >> PIXEL_BITS) / (b)
#define SW_FT_UDIV(a, b) \
(((unsigned long)(a) * (unsigned long)(b##_r)) >> \
(sizeof(long) * SW_FT_CHAR_BIT - PIXEL_BITS))
/*************************************************************************/
/* */
/* TYPE DEFINITIONS */
/* */
/* don't change the following types to SW_FT_Int or SW_FT_Pos, since we might */
/* need to define them to "float" or "double" when experimenting with */
/* new algorithms */
typedef long TCoord; /* integer scanline/pixel coordinate */
typedef long TPos; /* sub-pixel coordinate */
/* determine the type used to store cell areas. This normally takes at */
/* least PIXEL_BITS*2 + 1 bits. On 16-bit systems, we need to use */
/* `long' instead of `int', otherwise bad things happen */
#if PIXEL_BITS <= 7
typedef int TArea;
#else /* PIXEL_BITS >= 8 */
/* approximately determine the size of integers using an ANSI-C header */
#if SW_FT_UINT_MAX == 0xFFFFU
typedef long TArea;
#else
typedef int TArea;
#endif
#endif /* PIXEL_BITS >= 8 */
/* maximum number of gray spans in a call to the span callback */
#define SW_FT_MAX_GRAY_SPANS 256
typedef struct TCell_* PCell;
typedef struct TCell_ {
TPos x; /* same with gray_TWorker.ex */
TCoord cover; /* same with gray_TWorker.cover */
TArea area;
PCell next;
} TCell;
#if defined(_MSC_VER) /* Visual C++ (and Intel C++) */
/* We disable the warning `structure was padded due to */
/* __declspec(align())' in order to compile cleanly with */
/* the maximum level of warnings. */
#pragma warning(push)
#pragma warning(disable : 4324)
#endif /* _MSC_VER */
typedef struct gray_TWorker_ {
TCoord ex, ey;
TPos min_ex, max_ex;
TPos min_ey, max_ey;
TPos count_ex, count_ey;
TArea area;
TCoord cover;
int invalid;
PCell cells;
SW_FT_PtrDist max_cells;
SW_FT_PtrDist num_cells;
TPos x, y;
SW_FT_Vector bez_stack[32 * 3 + 1];
int lev_stack[32];
SW_FT_Outline outline;
SW_FT_BBox clip_box;
int bound_left;
int bound_top;
int bound_right;
int bound_bottom;
SW_FT_Span gray_spans[SW_FT_MAX_GRAY_SPANS];
int num_gray_spans;
SW_FT_Raster_Span_Func render_span;
void* render_span_data;
int band_size;
int band_shoot;
ft_jmp_buf jump_buffer;
void* buffer;
long buffer_size;
PCell* ycells;
TPos ycount;
} gray_TWorker, *gray_PWorker;
#if defined(_MSC_VER)
#pragma warning(pop)
#endif
#ifndef SW_FT_STATIC_RASTER
#define ras (*worker)
#else
static gray_TWorker ras;
#endif
typedef struct gray_TRaster_ {
void* memory;
} gray_TRaster, *gray_PRaster;
/*************************************************************************/
/* */
/* Initialize the cells table. */
/* */
static void gray_init_cells(RAS_ARG_ void* buffer, long byte_size)
{
ras.buffer = buffer;
ras.buffer_size = byte_size;
ras.ycells = (PCell*)buffer;
ras.cells = NULL;
ras.max_cells = 0;
ras.num_cells = 0;
ras.area = 0;
ras.cover = 0;
ras.invalid = 1;
ras.bound_left = INT_MAX;
ras.bound_top = INT_MAX;
ras.bound_right = INT_MIN;
ras.bound_bottom = INT_MIN;
}
/*************************************************************************/
/* */
/* Compute the outline bounding box. */
/* */
static void gray_compute_cbox(RAS_ARG)
{
SW_FT_Outline* outline = &ras.outline;
SW_FT_Vector* vec = outline->points;
SW_FT_Vector* limit = vec + outline->n_points;
if (outline->n_points <= 0) {
ras.min_ex = ras.max_ex = 0;
ras.min_ey = ras.max_ey = 0;
return;
}
ras.min_ex = ras.max_ex = vec->x;
ras.min_ey = ras.max_ey = vec->y;
vec++;
for (; vec < limit; vec++) {
TPos x = vec->x;
TPos y = vec->y;
if (x < ras.min_ex) ras.min_ex = x;
if (x > ras.max_ex) ras.max_ex = x;
if (y < ras.min_ey) ras.min_ey = y;
if (y > ras.max_ey) ras.max_ey = y;
}
/* truncate the bounding box to integer pixels */
ras.min_ex = ras.min_ex >> 6;
ras.min_ey = ras.min_ey >> 6;
ras.max_ex = (ras.max_ex + 63) >> 6;
ras.max_ey = (ras.max_ey + 63) >> 6;
}
/*************************************************************************/
/* */
/* Record the current cell in the table. */
/* */
static PCell gray_find_cell(RAS_ARG)
{
PCell *pcell, cell;
TPos x = ras.ex;
if (x > ras.count_ex) x = ras.count_ex;
pcell = &ras.ycells[ras.ey];
for (;;) {
cell = *pcell;
if (cell == NULL || cell->x > x) break;
if (cell->x == x) goto Exit;
pcell = &cell->next;
}
if (ras.num_cells >= ras.max_cells) ft_longjmp(ras.jump_buffer, 1);
cell = ras.cells + ras.num_cells++;
cell->x = x;
cell->area = 0;
cell->cover = 0;
cell->next = *pcell;
*pcell = cell;
Exit:
return cell;
}
static void gray_record_cell(RAS_ARG)
{
if (ras.area | ras.cover) {
PCell cell = gray_find_cell(RAS_VAR);
cell->area += ras.area;
cell->cover += ras.cover;
}
}
/*************************************************************************/
/* */
/* Set the current cell to a new position. */
/* */
static void gray_set_cell(RAS_ARG_ TCoord ex, TCoord ey)
{
/* Move the cell pointer to a new position. We set the `invalid' */
/* flag to indicate that the cell isn't part of those we're interested */
/* in during the render phase. This means that: */
/* */
/* . the new vertical position must be within min_ey..max_ey-1. */
/* . the new horizontal position must be strictly less than max_ex */
/* */
/* Note that if a cell is to the left of the clipping region, it is */
/* actually set to the (min_ex-1) horizontal position. */
/* All cells that are on the left of the clipping region go to the */
/* min_ex - 1 horizontal position. */
ey -= ras.min_ey;
if (ex > ras.max_ex) ex = ras.max_ex;
ex -= ras.min_ex;
if (ex < 0) ex = -1;
/* are we moving to a different cell ? */
if (ex != ras.ex || ey != ras.ey) {
/* record the current one if it is valid */
if (!ras.invalid) gray_record_cell(RAS_VAR);
ras.area = 0;
ras.cover = 0;
ras.ex = ex;
ras.ey = ey;
}
ras.invalid =
((unsigned)ey >= (unsigned)ras.count_ey || ex >= ras.count_ex);
}
/*************************************************************************/
/* */
/* Start a new contour at a given cell. */
/* */
static void gray_start_cell(RAS_ARG_ TCoord ex, TCoord ey)
{
if (ex > ras.max_ex) ex = (TCoord)(ras.max_ex);
if (ex < ras.min_ex) ex = (TCoord)(ras.min_ex - 1);
ras.area = 0;
ras.cover = 0;
ras.ex = ex - ras.min_ex;
ras.ey = ey - ras.min_ey;
ras.invalid = 0;
gray_set_cell(RAS_VAR_ ex, ey);
}
/*************************************************************************/
/* */
/* Render a straight line across multiple cells in any direction. */
/* */
static void gray_render_line(RAS_ARG_ TPos to_x, TPos to_y)
{
TPos dx, dy, fx1, fy1, fx2, fy2;
TCoord ex1, ex2, ey1, ey2;
ex1 = TRUNC(ras.x);
ex2 = TRUNC(to_x);
ey1 = TRUNC(ras.y);
ey2 = TRUNC(to_y);
/* perform vertical clipping */
if ((ey1 >= ras.max_ey && ey2 >= ras.max_ey) ||
(ey1 < ras.min_ey && ey2 < ras.min_ey))
goto End;
dx = to_x - ras.x;
dy = to_y - ras.y;
fx1 = ras.x - SUBPIXELS(ex1);
fy1 = ras.y - SUBPIXELS(ey1);
if (ex1 == ex2 && ey1 == ey2) /* inside one cell */
;
else if (dy == 0) /* ex1 != ex2 */ /* any horizontal line */
{
ex1 = ex2;
gray_set_cell(RAS_VAR_ ex1, ey1);
} else if (dx == 0) {
if (dy > 0) /* vertical line up */
do {
fy2 = ONE_PIXEL;
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * fx1 * 2;
fy1 = 0;
ey1++;
gray_set_cell(RAS_VAR_ ex1, ey1);
} while (ey1 != ey2);
else /* vertical line down */
do {
fy2 = 0;
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * fx1 * 2;
fy1 = ONE_PIXEL;
ey1--;
gray_set_cell(RAS_VAR_ ex1, ey1);
} while (ey1 != ey2);
} else /* any other line */
{
TArea prod = dx * fy1 - dy * fx1;
SW_FT_UDIVPREP(dx);
SW_FT_UDIVPREP(dy);
/* The fundamental value `prod' determines which side and the */
/* exact coordinate where the line exits current cell. It is */
/* also easily updated when moving from one cell to the next. */
do {
if (prod <= 0 && prod - dx * ONE_PIXEL > 0) /* left */
{
fx2 = 0;
fy2 = (TPos)SW_FT_UDIV(-prod, -dx);
prod -= dy * ONE_PIXEL;
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * (fx1 + fx2);
fx1 = ONE_PIXEL;
fy1 = fy2;
ex1--;
} else if (prod - dx * ONE_PIXEL <= 0 &&
prod - dx * ONE_PIXEL + dy * ONE_PIXEL > 0) /* up */
{
prod -= dx * ONE_PIXEL;
fx2 = (TPos)SW_FT_UDIV(-prod, dy);
fy2 = ONE_PIXEL;
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * (fx1 + fx2);
fx1 = fx2;
fy1 = 0;
ey1++;
} else if (prod - dx * ONE_PIXEL + dy * ONE_PIXEL <= 0 &&
prod + dy * ONE_PIXEL >= 0) /* right */
{
prod += dy * ONE_PIXEL;
fx2 = ONE_PIXEL;
fy2 = (TPos)SW_FT_UDIV(prod, dx);
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * (fx1 + fx2);
fx1 = 0;
fy1 = fy2;
ex1++;
} else /* ( prod + dy * ONE_PIXEL < 0 &&
prod > 0 ) down */
{
fx2 = (TPos)SW_FT_UDIV(prod, -dy);
fy2 = 0;
prod += dx * ONE_PIXEL;
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * (fx1 + fx2);
fx1 = fx2;
fy1 = ONE_PIXEL;
ey1--;
}
gray_set_cell(RAS_VAR_ ex1, ey1);
} while (ex1 != ex2 || ey1 != ey2);
}
fx2 = to_x - SUBPIXELS(ex2);
fy2 = to_y - SUBPIXELS(ey2);
ras.cover += (fy2 - fy1);
ras.area += (fy2 - fy1) * (fx1 + fx2);
End:
ras.x = to_x;
ras.y = to_y;
}
static void gray_split_conic(SW_FT_Vector* base)
{
TPos 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 void gray_render_conic(RAS_ARG_ const SW_FT_Vector* control,
const SW_FT_Vector* to)
{
TPos dx, dy;
TPos min, max, y;
int top, level;
int* levels;
SW_FT_Vector* arc;
levels = ras.lev_stack;
arc = ras.bez_stack;
arc[0].x = UPSCALE(to->x);
arc[0].y = UPSCALE(to->y);
arc[1].x = UPSCALE(control->x);
arc[1].y = UPSCALE(control->y);
arc[2].x = ras.x;
arc[2].y = ras.y;
top = 0;
dx = SW_FT_ABS(arc[2].x + arc[0].x - 2 * arc[1].x);
dy = SW_FT_ABS(arc[2].y + arc[0].y - 2 * arc[1].y);
if (dx < dy) dx = dy;
if (dx < ONE_PIXEL / 4) goto Draw;
/* short-cut the arc that crosses the current band */
min = max = arc[0].y;
y = arc[1].y;
if (y < min) min = y;
if (y > max) max = y;
y = arc[2].y;
if (y < min) min = y;
if (y > max) max = y;
if (TRUNC(min) >= ras.max_ey || TRUNC(max) < ras.min_ey) goto Draw;
level = 0;
do {
dx >>= 2;
level++;
} while (dx > ONE_PIXEL / 4);
levels[0] = level;
do {
level = levels[top];
if (level > 0) {
gray_split_conic(arc);
arc += 2;
top++;
levels[top] = levels[top - 1] = level - 1;
continue;
}
Draw:
gray_render_line(RAS_VAR_ arc[0].x, arc[0].y);
top--;
arc -= 2;
} while (top >= 0);
}
static void gray_split_cubic(SW_FT_Vector* base)
{
TPos 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;
}
static void
gray_render_cubic(RAS_ARG_ const SW_FT_Vector* control1,
const SW_FT_Vector* control2,
const SW_FT_Vector* to)
{
SW_FT_Vector* arc = ras.bez_stack;
arc[0].x = UPSCALE( to->x );
arc[0].y = UPSCALE( to->y );
arc[1].x = UPSCALE( control2->x );
arc[1].y = UPSCALE( control2->y );
arc[2].x = UPSCALE( control1->x );
arc[2].y = UPSCALE( control1->y );
arc[3].x = ras.x;
arc[3].y = ras.y;
/* short-cut the arc that crosses the current band */
if ( ( TRUNC( arc[0].y ) >= ras.max_ey &&
TRUNC( arc[1].y ) >= ras.max_ey &&
TRUNC( arc[2].y ) >= ras.max_ey &&
TRUNC( arc[3].y ) >= ras.max_ey ) ||
( TRUNC( arc[0].y ) < ras.min_ey &&
TRUNC( arc[1].y ) < ras.min_ey &&
TRUNC( arc[2].y ) < ras.min_ey &&
TRUNC( arc[3].y ) < ras.min_ey ) )
{
ras.x = arc[0].x;
ras.y = arc[0].y;
return;
}
for (;;)
{
/* with each split, control points quickly converge towards */
/* chord trisection points and the vanishing distances below */
/* indicate when the segment is flat enough to draw */
if ( SW_FT_ABS( 2 * arc[0].x - 3 * arc[1].x + arc[3].x ) > ONE_PIXEL / 2 ||
SW_FT_ABS( 2 * arc[0].y - 3 * arc[1].y + arc[3].y ) > ONE_PIXEL / 2 ||
SW_FT_ABS( arc[0].x - 3 * arc[2].x + 2 * arc[3].x ) > ONE_PIXEL / 2 ||
SW_FT_ABS( arc[0].y - 3 * arc[2].y + 2 * arc[3].y ) > ONE_PIXEL / 2 )
goto Split;
gray_render_line( RAS_VAR_ arc[0].x, arc[0].y );
if ( arc == ras.bez_stack )
return;
arc -= 3;
continue;
Split:
gray_split_cubic( arc );
arc += 3;
}
}
static int gray_move_to(const SW_FT_Vector* to, gray_PWorker worker)
{
TPos x, y;
/* record current cell, if any */
if (!ras.invalid) gray_record_cell(RAS_VAR);
/* start to a new position */
x = UPSCALE(to->x);
y = UPSCALE(to->y);
gray_start_cell(RAS_VAR_ TRUNC(x), TRUNC(y));
worker->x = x;
worker->y = y;
return 0;
}
static int gray_line_to(const SW_FT_Vector* to, gray_PWorker worker)
{
gray_render_line(RAS_VAR_ UPSCALE(to->x), UPSCALE(to->y));
return 0;
}
static int gray_conic_to(const SW_FT_Vector* control, const SW_FT_Vector* to,
gray_PWorker worker)
{
gray_render_conic(RAS_VAR_ control, to);
return 0;
}
static int gray_cubic_to(const SW_FT_Vector* control1,
const SW_FT_Vector* control2, const SW_FT_Vector* to,
gray_PWorker worker)
{
gray_render_cubic(RAS_VAR_ control1, control2, to);
return 0;
}
static void gray_hline(RAS_ARG_ TCoord x, TCoord y, TPos area, TCoord acount)
{
int coverage;
/* compute the coverage line's coverage, depending on the */
/* outline fill rule */
/* */
/* the coverage percentage is area/(PIXEL_BITS*PIXEL_BITS*2) */
/* */
coverage = (int)(area >> (PIXEL_BITS * 2 + 1 - 8));
/* use range 0..256 */
if (coverage < 0) coverage = -coverage;
if (ras.outline.flags & SW_FT_OUTLINE_EVEN_ODD_FILL) {
coverage &= 511;
if (coverage > 256)
coverage = 512 - coverage;
else if (coverage == 256)
coverage = 255;
} else {
/* normal non-zero winding rule */
if (coverage >= 256) coverage = 255;
}
y += (TCoord)ras.min_ey;
x += (TCoord)ras.min_ex;
/* SW_FT_Span.x is a 16-bit short, so limit our coordinates appropriately */
if (x >= 32767) x = 32767;
/* SW_FT_Span.y is an integer, so limit our coordinates appropriately */
if (y >= SW_FT_INT_MAX) y = SW_FT_INT_MAX;
if (coverage) {
SW_FT_Span* span;
int count;
// update bounding box.
if (x < ras.bound_left) ras.bound_left = x;
if (y < ras.bound_top) ras.bound_top = y;
if (y > ras.bound_bottom) ras.bound_bottom = y;
if (x + acount > ras.bound_right) ras.bound_right = x + acount;
/* see whether we can add this span to the current list */
count = ras.num_gray_spans;
span = ras.gray_spans + count - 1;
if (count > 0 && span->y == y && (int)span->x + span->len == (int)x &&
span->coverage == coverage) {
span->len = (unsigned short)(span->len + acount);
return;
}
if (count >= SW_FT_MAX_GRAY_SPANS) {
if (ras.render_span && count > 0)
ras.render_span(count, ras.gray_spans, ras.render_span_data);
#ifdef DEBUG_GRAYS
if (1) {
int n;
fprintf(stderr, "count = %3d ", count);
span = ras.gray_spans;
for (n = 0; n < count; n++, span++)
fprintf(stderr, "[%d , %d..%d] : %d ", span->y, span->x,
span->x + span->len - 1, span->coverage);
fprintf(stderr, "\n");
}
#endif /* DEBUG_GRAYS */
ras.num_gray_spans = 0;
span = ras.gray_spans;
} else
span++;
/* add a gray span to the current list */
span->x = (short)x;
span->y = (short)y;
span->len = (unsigned short)acount;
span->coverage = (unsigned char)coverage;
ras.num_gray_spans++;
}
}
static void gray_sweep(RAS_ARG)
{
int yindex;
if (ras.num_cells == 0) return;
ras.num_gray_spans = 0;
for (yindex = 0; yindex < ras.ycount; yindex++) {
PCell cell = ras.ycells[yindex];
TCoord cover = 0;
TCoord x = 0;
for (; cell != NULL; cell = cell->next) {
TPos area;
if (cell->x > x && cover != 0)
gray_hline(RAS_VAR_ x, yindex, cover * (ONE_PIXEL * 2),
cell->x - x);
cover += cell->cover;
area = cover * (ONE_PIXEL * 2) - cell->area;
if (area != 0 && cell->x >= 0)
gray_hline(RAS_VAR_ cell->x, yindex, area, 1);
x = cell->x + 1;
}
if (cover != 0)
gray_hline(RAS_VAR_ x, yindex, cover * (ONE_PIXEL * 2),
ras.count_ex - x);
}
if (ras.render_span && ras.num_gray_spans > 0)
ras.render_span(ras.num_gray_spans, ras.gray_spans,
ras.render_span_data);
}
/*************************************************************************/
/* */
/* The following function should only compile in stand-alone mode, */
/* i.e., when building this component without the rest of FreeType. */
/* */
/*************************************************************************/
/*************************************************************************/
/* */
/* <Function> */
/* SW_FT_Outline_Decompose */
/* */
/* <Description> */
/* Walk over an outline's structure to decompose it into individual */
/* segments and Bézier arcs. This function is also able to emit */
/* `move to' and `close to' operations to indicate the start and end */
/* of new contours in the outline. */
/* */
/* <Input> */
/* outline :: A pointer to the source target. */
/* */
/* func_interface :: A table of `emitters', i.e., function pointers */
/* called during decomposition to indicate path */
/* operations. */
/* */
/* <InOut> */
/* user :: A typeless pointer which is passed to each */
/* emitter during the decomposition. It can be */
/* used to store the state during the */
/* decomposition. */
/* */
/* <Return> */
/* Error code. 0 means success. */
/* */
static int SW_FT_Outline_Decompose(const SW_FT_Outline* outline,
const SW_FT_Outline_Funcs* func_interface,
void* user)
{
#undef SCALED
#define SCALED(x) (((x) << shift) - delta)
SW_FT_Vector v_last;
SW_FT_Vector v_control;
SW_FT_Vector v_start;
SW_FT_Vector* point;
SW_FT_Vector* limit;
char* tags;
int error;
int n; /* index of contour in outline */
int first; /* index of first point in contour */
char tag; /* current point's state */
int shift;
TPos delta;
if (!outline || !func_interface) return SW_FT_THROW(Invalid_Argument);
shift = func_interface->shift;
delta = func_interface->delta;
first = 0;
for (n = 0; n < outline->n_contours; n++) {
int last; /* index of last point in contour */
last = outline->contours[n];
if (last < 0) goto Invalid_Outline;
limit = outline->points + last;
v_start = outline->points[first];
v_start.x = SCALED(v_start.x);
v_start.y = SCALED(v_start.y);
v_last = outline->points[last];
v_last.x = SCALED(v_last.x);
v_last.y = SCALED(v_last.y);
v_control = v_start;
point = outline->points + first;
tags = outline->tags + first;
tag = SW_FT_CURVE_TAG(tags[0]);
/* A contour cannot start with a cubic control point! */
if (tag == SW_FT_CURVE_TAG_CUBIC) goto Invalid_Outline;
/* check first point to determine origin */
if (tag == SW_FT_CURVE_TAG_CONIC) {
/* first point is conic control. Yes, this happens. */
if (SW_FT_CURVE_TAG(outline->tags[last]) == SW_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;
}
point--;
tags--;
}
error = func_interface->move_to(&v_start, user);
if (error) goto Exit;
while (point < limit) {
point++;
tags++;
tag = SW_FT_CURVE_TAG(tags[0]);
switch (tag) {
case SW_FT_CURVE_TAG_ON: /* emit a single line_to */
{
SW_FT_Vector vec;
vec.x = SCALED(point->x);
vec.y = SCALED(point->y);
error = func_interface->line_to(&vec, user);
if (error) goto Exit;
continue;
}
case SW_FT_CURVE_TAG_CONIC: /* consume conic arcs */
v_control.x = SCALED(point->x);
v_control.y = SCALED(point->y);
Do_Conic:
if (point < limit) {
SW_FT_Vector vec;
SW_FT_Vector v_middle;
point++;
tags++;
tag = SW_FT_CURVE_TAG(tags[0]);
vec.x = SCALED(point->x);
vec.y = SCALED(point->y);
if (tag == SW_FT_CURVE_TAG_ON) {
error =
func_interface->conic_to(&v_control, &vec, user);
if (error) goto Exit;
continue;
}
if (tag != SW_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 =
func_interface->conic_to(&v_control, &v_middle, user);
if (error) goto Exit;
v_control = vec;
goto Do_Conic;
}
error = func_interface->conic_to(&v_control, &v_start, user);
goto Close;
default: /* SW_FT_CURVE_TAG_CUBIC */
{
SW_FT_Vector vec1, vec2;
if (point + 1 > limit ||
SW_FT_CURVE_TAG(tags[1]) != SW_FT_CURVE_TAG_CUBIC)
goto Invalid_Outline;
point += 2;
tags += 2;
vec1.x = SCALED(point[-2].x);
vec1.y = SCALED(point[-2].y);
vec2.x = SCALED(point[-1].x);
vec2.y = SCALED(point[-1].y);
if (point <= limit) {
SW_FT_Vector vec;
vec.x = SCALED(point->x);
vec.y = SCALED(point->y);
error = func_interface->cubic_to(&vec1, &vec2, &vec, user);
if (error) goto Exit;
continue;
}
error = func_interface->cubic_to(&vec1, &vec2, &v_start, user);
goto Close;
}
}
}
/* close the contour with a line segment */
error = func_interface->line_to(&v_start, user);
Close:
if (error) goto Exit;
first = last + 1;
}
return 0;
Exit:
return error;
Invalid_Outline:
return SW_FT_THROW(Invalid_Outline);
}
typedef struct gray_TBand_ {
TPos min, max;
} gray_TBand;
SW_FT_DEFINE_OUTLINE_FUNCS(func_interface,
(SW_FT_Outline_MoveTo_Func)gray_move_to,
(SW_FT_Outline_LineTo_Func)gray_line_to,
(SW_FT_Outline_ConicTo_Func)gray_conic_to,
(SW_FT_Outline_CubicTo_Func)gray_cubic_to, 0, 0)
static int gray_convert_glyph_inner(RAS_ARG)
{
volatile int error = 0;
if (ft_setjmp(ras.jump_buffer) == 0) {
error = SW_FT_Outline_Decompose(&ras.outline, &func_interface, &ras);
if (!ras.invalid) gray_record_cell(RAS_VAR);
} else
error = SW_FT_THROW(Memory_Overflow);
return error;
}
static int gray_convert_glyph(RAS_ARG)
{
gray_TBand bands[40];
gray_TBand* volatile band;
int volatile n, num_bands;
TPos volatile min, max, max_y;
SW_FT_BBox* clip;
/* Set up state in the raster object */
gray_compute_cbox(RAS_VAR);
/* clip to target bitmap, exit if nothing to do */
clip = &ras.clip_box;
if (ras.max_ex <= clip->xMin || ras.min_ex >= clip->xMax ||
ras.max_ey <= clip->yMin || ras.min_ey >= clip->yMax)
return 0;
if (ras.min_ex < clip->xMin) ras.min_ex = clip->xMin;
if (ras.min_ey < clip->yMin) ras.min_ey = clip->yMin;
if (ras.max_ex > clip->xMax) ras.max_ex = clip->xMax;
if (ras.max_ey > clip->yMax) ras.max_ey = clip->yMax;
ras.count_ex = ras.max_ex - ras.min_ex;
ras.count_ey = ras.max_ey - ras.min_ey;
/* set up vertical bands */
num_bands = (int)((ras.max_ey - ras.min_ey) / ras.band_size);
if (num_bands == 0) num_bands = 1;
if (num_bands >= 39) num_bands = 39;
ras.band_shoot = 0;
min = ras.min_ey;
max_y = ras.max_ey;
for (n = 0; n < num_bands; n++, min = max) {
max = min + ras.band_size;
if (n == num_bands - 1 || max > max_y) max = max_y;
bands[0].min = min;
bands[0].max = max;
band = bands;
while (band >= bands) {
TPos bottom, top, middle;
int error;
{
PCell cells_max;
int yindex;
long cell_start, cell_end, cell_mod;
ras.ycells = (PCell*)ras.buffer;
ras.ycount = band->max - band->min;
cell_start = sizeof(PCell) * ras.ycount;
cell_mod = cell_start % sizeof(TCell);
if (cell_mod > 0) cell_start += sizeof(TCell) - cell_mod;
cell_end = ras.buffer_size;
cell_end -= cell_end % sizeof(TCell);
cells_max = (PCell)((char*)ras.buffer + cell_end);
ras.cells = (PCell)((char*)ras.buffer + cell_start);
if (ras.cells >= cells_max) goto ReduceBands;
ras.max_cells = cells_max - ras.cells;
if (ras.max_cells < 2) goto ReduceBands;
for (yindex = 0; yindex < ras.ycount; yindex++)
ras.ycells[yindex] = NULL;
}
ras.num_cells = 0;
ras.invalid = 1;
ras.min_ey = band->min;
ras.max_ey = band->max;
ras.count_ey = band->max - band->min;
error = gray_convert_glyph_inner(RAS_VAR);
if (!error) {
gray_sweep(RAS_VAR);
band--;
continue;
} else if (error != ErrRaster_Memory_Overflow)
return 1;
ReduceBands:
/* render pool overflow; we will reduce the render band by half */
bottom = band->min;
top = band->max;
middle = bottom + ((top - bottom) >> 1);
/* This is too complex for a single scanline; there must */
/* be some problems. */
if (middle == bottom) {
return 1;
}
if (bottom - top >= ras.band_size) ras.band_shoot++;
band[1].min = bottom;
band[1].max = middle;
band[0].min = middle;
band[0].max = top;
band++;
}
}
if (ras.band_shoot > 8 && ras.band_size > 16)
ras.band_size = ras.band_size / 2;
return 0;
}
static int gray_raster_render(gray_PRaster raster,
const SW_FT_Raster_Params* params)
{
SW_FT_UNUSED(raster);
const SW_FT_Outline* outline = (const SW_FT_Outline*)params->source;
gray_TWorker worker[1];
TCell buffer[SW_FT_RENDER_POOL_SIZE / sizeof(TCell)];
long buffer_size = sizeof(buffer);
int band_size = (int)(buffer_size / (long)(sizeof(TCell) * 8));
if (!outline) return SW_FT_THROW(Invalid_Outline);
/* return immediately if the outline is empty */
if (outline->n_points == 0 || outline->n_contours <= 0) return 0;
if (!outline->contours || !outline->points)
return SW_FT_THROW(Invalid_Outline);
if (outline->n_points != outline->contours[outline->n_contours - 1] + 1)
return SW_FT_THROW(Invalid_Outline);
/* this version does not support monochrome rendering */
if (!(params->flags & SW_FT_RASTER_FLAG_AA))
return SW_FT_THROW(Invalid_Mode);
if (params->flags & SW_FT_RASTER_FLAG_CLIP)
ras.clip_box = params->clip_box;
else {
ras.clip_box.xMin = -32768L;
ras.clip_box.yMin = -32768L;
ras.clip_box.xMax = 32767L;
ras.clip_box.yMax = 32767L;
}
gray_init_cells(RAS_VAR_ buffer, buffer_size);
ras.outline = *outline;
ras.num_cells = 0;
ras.invalid = 1;
ras.band_size = band_size;
ras.num_gray_spans = 0;
ras.render_span = (SW_FT_Raster_Span_Func)params->gray_spans;
ras.render_span_data = params->user;
gray_convert_glyph(RAS_VAR);
params->bbox_cb(ras.bound_left, ras.bound_top,
ras.bound_right - ras.bound_left,
ras.bound_bottom - ras.bound_top + 1, params->user);
return 1;
}
/**** RASTER OBJECT CREATION: In stand-alone mode, we simply use *****/
/**** a static object. *****/
static int gray_raster_new(SW_FT_Raster* araster)
{
static gray_TRaster the_raster;
*araster = (SW_FT_Raster)&the_raster;
SW_FT_MEM_ZERO(&the_raster, sizeof(the_raster));
return 0;
}
static void gray_raster_done(SW_FT_Raster raster)
{
/* nothing */
SW_FT_UNUSED(raster);
}
static void gray_raster_reset(SW_FT_Raster raster, char* pool_base,
long pool_size)
{
SW_FT_UNUSED(raster);
SW_FT_UNUSED(pool_base);
SW_FT_UNUSED(pool_size);
}
SW_FT_DEFINE_RASTER_FUNCS(sw_ft_grays_raster,
(SW_FT_Raster_New_Func)gray_raster_new,
(SW_FT_Raster_Reset_Func)gray_raster_reset,
(SW_FT_Raster_Render_Func)gray_raster_render,
(SW_FT_Raster_Done_Func)gray_raster_done)
/* END */
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