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mpv/libass/ass_drawing.c

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/*
* Copyright (C) 2009 Grigori Goronzy <greg@geekmind.org>
*
* This file is part of libass.
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <ft2build.h>
#include FT_GLYPH_H
#include FT_OUTLINE_H
#include FT_BBOX_H
#include <math.h>
#include "ass_utils.h"
#include "ass_font.h"
#include "ass_drawing.h"
#define CURVE_ACCURACY 64.0
#define GLYPH_INITIAL_POINTS 100
#define GLYPH_INITIAL_CONTOURS 5
/*
* \brief Get and prepare a FreeType glyph
*/
static void drawing_make_glyph(ASS_Drawing *drawing, void *fontconfig_priv,
ASS_Font *font, ASS_Hinting hint)
{
FT_OutlineGlyph glyph;
// This is hacky...
glyph = (FT_OutlineGlyph) ass_font_get_glyph(fontconfig_priv, font,
(uint32_t) ' ', hint, 0);
if (glyph) {
FT_Outline_Done(drawing->ftlibrary, &glyph->outline);
FT_Outline_New(drawing->ftlibrary, GLYPH_INITIAL_POINTS,
GLYPH_INITIAL_CONTOURS, &glyph->outline);
glyph->outline.n_contours = 0;
glyph->outline.n_points = 0;
glyph->root.advance.x = glyph->root.advance.y = 0;
}
drawing->glyph = glyph;
}
/*
* \brief Add a single point to a contour.
*/
static inline void drawing_add_point(ASS_Drawing *drawing,
FT_Vector *point)
{
FT_Outline *ol = &drawing->glyph->outline;
if (ol->n_points >= drawing->max_points) {
drawing->max_points *= 2;
ol->points = realloc(ol->points, sizeof(FT_Vector) *
drawing->max_points);
ol->tags = realloc(ol->tags, drawing->max_points);
}
ol->points[ol->n_points].x = point->x;
ol->points[ol->n_points].y = point->y;
ol->tags[ol->n_points] = 1;
ol->n_points++;
}
/*
* \brief Close a contour and check glyph size overflow.
*/
static inline void drawing_close_shape(ASS_Drawing *drawing)
{
FT_Outline *ol = &drawing->glyph->outline;
if (ol->n_contours >= drawing->max_contours) {
drawing->max_contours *= 2;
ol->contours = realloc(ol->contours, sizeof(short) *
drawing->max_contours);
}
if (ol->n_points) {
ol->contours[ol->n_contours] = ol->n_points - 1;
ol->n_contours++;
}
}
/*
* \brief Prepare drawing for parsing. This just sets a few parameters.
*/
static void drawing_prepare(ASS_Drawing *drawing)
{
// Scaling parameters
drawing->point_scale_x = drawing->scale_x *
64.0 / (1 << (drawing->scale - 1));
drawing->point_scale_y = drawing->scale_y *
64.0 / (1 << (drawing->scale - 1));
}
/*
* \brief Finish a drawing. This only sets the horizontal advance according
* to the glyph's bbox at the moment.
*/
static void drawing_finish(ASS_Drawing *drawing, int raw_mode)
{
int i, offset;
FT_BBox bbox;
FT_Outline *ol = &drawing->glyph->outline;
// Close the last contour
drawing_close_shape(drawing);
#if 0
// Dump points
for (i = 0; i < ol->n_points; i++) {
printf("point (%d, %d)\n", (int) ol->points[i].x,
(int) ol->points[i].y);
}
// Dump contours
for (i = 0; i < ol->n_contours; i++)
printf("contour %d\n", ol->contours[i]);
#endif
ass_msg(drawing->library, MSGL_V,
"Parsed drawing with %d points and %d contours", ol->n_points,
ol->n_contours);
if (raw_mode)
return;
FT_Outline_Get_CBox(&drawing->glyph->outline, &bbox);
drawing->glyph->root.advance.x = d6_to_d16(bbox.xMax - bbox.xMin);
drawing->desc = double_to_d6(-drawing->pbo * drawing->scale_y);
drawing->asc = bbox.yMax - bbox.yMin + drawing->desc;
// Place it onto the baseline
offset = (bbox.yMax - bbox.yMin) + double_to_d6(-drawing->pbo *
drawing->scale_y);
for (i = 0; i < ol->n_points; i++)
ol->points[i].y += offset;
}
/*
* \brief Check whether a number of items on the list is available
*/
static int token_check_values(ASS_DrawingToken *token, int i, int type)
{
int j;
for (j = 0; j < i; j++) {
if (!token || token->type != type) return 0;
token = token->next;
}
return 1;
}
/*
* \brief Tokenize a drawing string into a list of ASS_DrawingToken
* This also expands points for closing b-splines
*/
static ASS_DrawingToken *drawing_tokenize(char *str)
{
char *p = str;
int i, val, type = -1, is_set = 0;
FT_Vector point = {0, 0};
ASS_DrawingToken *root = NULL, *tail = NULL, *spline_start = NULL;
while (*p) {
if (*p == 'c' && spline_start) {
// Close b-splines: add the first three points of the b-spline
// back to the end
if (token_check_values(spline_start->next, 2, TOKEN_B_SPLINE)) {
for (i = 0; i < 3; i++) {
tail->next = calloc(1, sizeof(ASS_DrawingToken));
tail->next->prev = tail;
tail = tail->next;
tail->type = TOKEN_B_SPLINE;
tail->point = spline_start->point;
spline_start = spline_start->next;
}
spline_start = NULL;
}
} else if (!is_set && mystrtoi(&p, &val)) {
point.x = val;
is_set = 1;
p--;
} else if (is_set == 1 && mystrtoi(&p, &val)) {
point.y = val;
is_set = 2;
p--;
} else if (*p == 'm')
type = TOKEN_MOVE;
else if (*p == 'n')
type = TOKEN_MOVE_NC;
else if (*p == 'l')
type = TOKEN_LINE;
else if (*p == 'b')
type = TOKEN_CUBIC_BEZIER;
else if (*p == 'q')
type = TOKEN_CONIC_BEZIER;
else if (*p == 's')
type = TOKEN_B_SPLINE;
// We're simply ignoring TOKEN_EXTEND_B_SPLINE here.
// This is not harmful at all, since it can be ommitted with
// similar result (the spline is extended anyway).
if (type != -1 && is_set == 2) {
if (root) {
tail->next = calloc(1, sizeof(ASS_DrawingToken));
tail->next->prev = tail;
tail = tail->next;
} else
root = tail = calloc(1, sizeof(ASS_DrawingToken));
tail->type = type;
tail->point = point;
is_set = 0;
if (type == TOKEN_B_SPLINE && !spline_start)
spline_start = tail->prev;
}
p++;
}
#if 0
// Check tokens
ASS_DrawingToken *t = root;
while(t) {
printf("token %d point (%d, %d)\n", t->type, t->point.x, t->point.y);
t = t->next;
}
#endif
return root;
}
/*
* \brief Free a list of tokens
*/
static void drawing_free_tokens(ASS_DrawingToken *token)
{
while (token) {
ASS_DrawingToken *at = token;
token = token->next;
free(at);
}
}
/*
* \brief Translate and scale a point coordinate according to baseline
* offset and scale.
*/
static inline void translate_point(ASS_Drawing *drawing, FT_Vector *point)
{
point->x = drawing->point_scale_x * point->x;
point->y = drawing->point_scale_y * -point->y;
}
/*
* \brief Evaluate a curve into lines
* This curve evaluator is also used in VSFilter (RTS.cpp); it's a simple
* implementation of the De Casteljau algorithm.
*/
static void drawing_evaluate_curve(ASS_Drawing *drawing,
ASS_DrawingToken *token, char spline,
int started)
{
double cx3, cx2, cx1, cx0, cy3, cy2, cy1, cy0;
double t, h, max_accel, max_accel1, max_accel2;
FT_Vector cur = {0, 0};
cur = token->point;
translate_point(drawing, &cur);
int x0 = cur.x;
int y0 = cur.y;
token = token->next;
cur = token->point;
translate_point(drawing, &cur);
int x1 = cur.x;
int y1 = cur.y;
token = token->next;
cur = token->point;
translate_point(drawing, &cur);
int x2 = cur.x;
int y2 = cur.y;
token = token->next;
cur = token->point;
translate_point(drawing, &cur);
int x3 = cur.x;
int y3 = cur.y;
if (spline) {
// 1 [-1 +3 -3 +1]
// - * [+3 -6 +3 0]
// 6 [-3 0 +3 0]
// [+1 +4 +1 0]
double div6 = 1.0/6.0;
cx3 = div6*(- x0+3*x1-3*x2+x3);
cx2 = div6*( 3*x0-6*x1+3*x2);
cx1 = div6*(-3*x0 +3*x2);
cx0 = div6*( x0+4*x1+1*x2);
cy3 = div6*(- y0+3*y1-3*y2+y3);
cy2 = div6*( 3*y0-6*y1+3*y2);
cy1 = div6*(-3*y0 +3*y2);
cy0 = div6*( y0+4*y1+1*y2);
} else {
// [-1 +3 -3 +1]
// [+3 -6 +3 0]
// [-3 +3 0 0]
// [+1 0 0 0]
cx3 = - x0+3*x1-3*x2+x3;
cx2 = 3*x0-6*x1+3*x2;
cx1 = -3*x0+3*x1;
cx0 = x0;
cy3 = - y0+3*y1-3*y2+y3;
cy2 = 3*y0-6*y1+3*y2;
cy1 = -3*y0+3*y1;
cy0 = y0;
}
max_accel1 = fabs(2 * cy2) + fabs(6 * cy3);
max_accel2 = fabs(2 * cx2) + fabs(6 * cx3);
max_accel = FFMAX(max_accel1, max_accel2);
h = 1.0;
if (max_accel > CURVE_ACCURACY)
h = sqrt(CURVE_ACCURACY / max_accel);
if (!started) {
cur.x = cx0;
cur.y = cy0;
drawing_add_point(drawing, &cur);
}
for (t = 0; t < 1.0; t += h) {
cur.x = cx0 + t * (cx1 + t * (cx2 + t * cx3));
cur.y = cy0 + t * (cy1 + t * (cy2 + t * cy3));
drawing_add_point(drawing, &cur);
}
cur.x = cx0 + cx1 + cx2 + cx3;
cur.y = cy0 + cy1 + cy2 + cy3;
drawing_add_point(drawing, &cur);
}
/*
* \brief Create and initialize a new drawing and return it
*/
ASS_Drawing *ass_drawing_new(void *fontconfig_priv, ASS_Font *font,
ASS_Hinting hint, FT_Library lib)
{
ASS_Drawing *drawing;
drawing = calloc(1, sizeof(*drawing));
drawing->text = calloc(1, DRAWING_INITIAL_SIZE);
drawing->size = DRAWING_INITIAL_SIZE;
drawing->ftlibrary = lib;
if (font) {
drawing->library = font->library;
drawing_make_glyph(drawing, fontconfig_priv, font, hint);
}
drawing->scale_x = 1.;
drawing->scale_y = 1.;
drawing->max_contours = GLYPH_INITIAL_CONTOURS;
drawing->max_points = GLYPH_INITIAL_POINTS;
return drawing;
}
/*
* \brief Free a drawing
*/
void ass_drawing_free(ASS_Drawing* drawing)
{
if (drawing) {
if (drawing->glyph)
FT_Done_Glyph((FT_Glyph) drawing->glyph);
free(drawing->text);
}
free(drawing);
}
/*
* \brief Add one ASCII character to the drawing text buffer
*/
void ass_drawing_add_char(ASS_Drawing* drawing, char symbol)
{
drawing->text[drawing->i++] = symbol;
drawing->text[drawing->i] = 0;
if (drawing->i + 1 >= drawing->size) {
drawing->size *= 2;
drawing->text = realloc(drawing->text, drawing->size);
}
}
/*
* \brief Create a hashcode for the drawing
* XXX: To avoid collisions a better hash algorithm might be useful.
*/
void ass_drawing_hash(ASS_Drawing* drawing)
{
drawing->hash = fnv_32a_str(drawing->text, FNV1_32A_INIT);
}
/*
* \brief Convert token list to outline. Calls the line and curve evaluators.
*/
FT_OutlineGlyph *ass_drawing_parse(ASS_Drawing *drawing, int raw_mode)
{
int started = 0;
ASS_DrawingToken *token;
FT_Vector pen = {0, 0};
if (!drawing->glyph)
return NULL;
drawing->tokens = drawing_tokenize(drawing->text);
drawing_prepare(drawing);
token = drawing->tokens;
while (token) {
// Draw something according to current command
switch (token->type) {
case TOKEN_MOVE_NC:
pen = token->point;
translate_point(drawing, &pen);
token = token->next;
break;
case TOKEN_MOVE:
pen = token->point;
translate_point(drawing, &pen);
if (started) {
drawing_close_shape(drawing);
started = 0;
}
token = token->next;
break;
case TOKEN_LINE: {
FT_Vector to;
to = token->point;
translate_point(drawing, &to);
if (!started) drawing_add_point(drawing, &pen);
drawing_add_point(drawing, &to);
started = 1;
token = token->next;
break;
}
case TOKEN_CUBIC_BEZIER:
if (token_check_values(token, 3, TOKEN_CUBIC_BEZIER) &&
token->prev) {
drawing_evaluate_curve(drawing, token->prev, 0, started);
token = token->next;
token = token->next;
token = token->next;
started = 1;
} else
token = token->next;
break;
case TOKEN_B_SPLINE:
if (token_check_values(token, 3, TOKEN_B_SPLINE) &&
token->prev) {
drawing_evaluate_curve(drawing, token->prev, 1, started);
token = token->next;
started = 1;
} else
token = token->next;
break;
default:
token = token->next;
break;
}
}
drawing_finish(drawing, raw_mode);
drawing_free_tokens(drawing->tokens);
return &drawing->glyph;
}
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