ass_render.c

来自「君正早期ucos系统(只有早期的才不没有打包成库),MPLAYER,文件系统,图」· C语言 代码 · 共 2,195 行 · 第 1/5 页

 * This function goes through text_info and calculates text parameters.
 * The following text_info fields are filled:
 *   height
 *   lines[].height
 *   lines[].asc
 *   lines[].desc
 */
static void measure_text(void)
{
	int cur_line = 0, max_asc = 0, max_desc = 0;
	int i;
	text_info.height = 0;
	for (i = 0; i < text_info.length + 1; ++i) {
		if ((i == text_info.length) || text_info.glyphs[i].linebreak) {
			text_info.lines[cur_line].asc = max_asc;
			text_info.lines[cur_line].desc = max_desc;
			text_info.height += max_asc + max_desc;
			cur_line ++;
			max_asc = max_desc = 0;
		}
		if (i < text_info.length) {
			glyph_info_t* cur = text_info.glyphs + i;
			if (cur->asc > max_asc)
				max_asc = cur->asc;
			if (cur->desc > max_desc)
				max_desc = cur->desc;
		}
	}
	text_info.height += (text_info.n_lines - 1) * double_to_d6(global_settings->line_spacing);
}

/**
 * \brief rearrange text between lines
 * \param max_text_width maximal text line width in pixels
 * The algo is similar to the one in libvo/sub.c:
 * 1. Place text, wrapping it when current line is full
 * 2. Try moving words from the end of a line to the beginning of the next one while it reduces
 * the difference in lengths between this two lines.
 * The result may not be optimal, but usually is good enough.
 */
static void wrap_lines_smart(int max_text_width)
{
	int i, j;
	glyph_info_t *cur, *s1, *e1, *s2, *s3, *w;
	int last_space;
	int break_type;
	int exit;
	int pen_shift_x;
	int pen_shift_y;
	int cur_line;

	last_space = -1;
	text_info.n_lines = 1;
	break_type = 0;
	s1 = text_info.glyphs; // current line start
	for (i = 0; i < text_info.length; ++i) {
		int break_at, s_offset, len;
		cur = text_info.glyphs + i;
		break_at = -1;
		s_offset = s1->bbox.xMin + s1->pos.x;
		len = (cur->bbox.xMax + cur->pos.x) - s_offset;

		if (cur->symbol == '\n') {
			break_type = 2;
			break_at = i;
			mp_msg(MSGT_ASS, MSGL_DBG2, "forced line break at %d\n", break_at);
		}
		
		if (len >= max_text_width) {
			break_type = 1;
			break_at = last_space;
			if (break_at == -1)
				break_at = i - 1;
			if (break_at == -1)
				break_at = 0;
			mp_msg(MSGT_ASS, MSGL_DBG2, "overfill at %d\n", i);
			mp_msg(MSGT_ASS, MSGL_DBG2, "line break at %d\n", break_at);
		}

		if (break_at != -1) {
			// need to use one more line
			// marking break_at+1 as start of a new line
			int lead = break_at + 1; // the first symbol of the new line
			if (text_info.n_lines >= MAX_LINES) {
				// to many lines ! 
				// no more linebreaks
				for (j = lead; j < text_info.length; ++j)
					text_info.glyphs[j].linebreak = 0;
				break;
			}
			if (lead < text_info.length)
				text_info.glyphs[lead].linebreak = break_type;
			last_space = -1;
			s1 = text_info.glyphs + lead;
			s_offset = s1->bbox.xMin + s1->pos.x;
			text_info.n_lines ++;
		}
		
		if (cur->symbol == ' ')
			last_space = i;

		// make sure the hard linebreak is not forgotten when
		// there was a new soft linebreak just inserted
		if (cur->symbol == '\n' && break_type == 1)
			i--;
	}
#define DIFF(x,y) (((x) < (y)) ? (y - x) : (x - y))
	exit = 0;
	while (!exit) {
		exit = 1;
		w = s3 = text_info.glyphs;
		s1 = s2 = 0;
		for (i = 0; i <= text_info.length; ++i) {
			cur = text_info.glyphs + i;
			if ((i == text_info.length) || cur->linebreak) {
				s1 = s2;
				s2 = s3;
				s3 = cur;
				if (s1 && (s2->linebreak == 1)) { // have at least 2 lines, and linebreak is 'soft'
					int l1, l2, l1_new, l2_new;

					w = s2;
					do { --w; } while ((w > s1) && (w->symbol == ' '));
					while ((w > s1) && (w->symbol != ' ')) { --w; }
					e1 = w;
					while ((e1 > s1) && (e1->symbol == ' ')) { --e1; }
					if (w->symbol == ' ') ++w;

					l1 = ((s2-1)->bbox.xMax + (s2-1)->pos.x) - (s1->bbox.xMin + s1->pos.x);
					l2 = ((s3-1)->bbox.xMax + (s3-1)->pos.x) - (s2->bbox.xMin + s2->pos.x);
					l1_new = (e1->bbox.xMax + e1->pos.x) - (s1->bbox.xMin + s1->pos.x);
					l2_new = ((s3-1)->bbox.xMax + (s3-1)->pos.x) - (w->bbox.xMin + w->pos.x);

					if (DIFF(l1_new, l2_new) < DIFF(l1, l2)) {
						w->linebreak = 1;
						s2->linebreak = 0;
						exit = 0;
					}
				}
			}
			if (i == text_info.length)
				break;
		}
		
	}
	assert(text_info.n_lines >= 1);
#undef DIFF
	
	measure_text();

	pen_shift_x = 0;
	pen_shift_y = 0;
	cur_line = 1;
	for (i = 0; i < text_info.length; ++i) {
		cur = text_info.glyphs + i;
		if (cur->linebreak) {
			int height = text_info.lines[cur_line - 1].desc + text_info.lines[cur_line].asc;
			cur_line ++;
			pen_shift_x = - cur->pos.x;
			pen_shift_y += d6_to_int(height + double_to_d6(global_settings->line_spacing));
			mp_msg(MSGT_ASS, MSGL_DBG2, "shifting from %d to %d by (%d, %d)\n", i, text_info.length - 1, pen_shift_x, pen_shift_y);
		}
		cur->pos.x += pen_shift_x;
		cur->pos.y += pen_shift_y;
	}
}

/**
 * \brief determine karaoke effects
 * Karaoke effects cannot be calculated during parse stage (get_next_char()),
 * so they are done in a separate step.
 * Parse stage: when karaoke style override is found, its parameters are stored in the next glyph's 
 * (the first glyph of the karaoke word)'s effect_type and effect_timing.
 * This function:
 * 1. sets effect_type for all glyphs in the word (_karaoke_ word)
 * 2. sets effect_timing for all glyphs to x coordinate of the border line between the left and right karaoke parts
 * (left part is filled with PrimaryColour, right one - with SecondaryColour).
 */
static void process_karaoke_effects(void)
{
	glyph_info_t *cur, *cur2;
	glyph_info_t *s1, *e1; // start and end of the current word
	glyph_info_t *s2; // start of the next word
	int i;
	int timing; // current timing
	int tm_start, tm_end; // timings at start and end of the current word
	int tm_current;
	double dt;
	int x;
	int x_start, x_end;

	tm_current = frame_context.time - render_context.event->Start;
	timing = 0;
	s1 = s2 = 0;
	for (i = 0; i <= text_info.length; ++i) {
		cur = text_info.glyphs + i;
		if ((i == text_info.length) || (cur->effect_type != EF_NONE)) {
			s1 = s2;
			s2 = cur;
			if (s1) {
				e1 = s2 - 1;
				tm_start = timing + s1->effect_skip_timing;
				tm_end = tm_start + s1->effect_timing;
				timing = tm_end;
				x_start = 1000000;
				x_end = -1000000;
				for (cur2 = s1; cur2 <= e1; ++cur2) {
					x_start = FFMIN(x_start, cur2->bbox.xMin + cur2->pos.x);
					x_end = FFMAX(x_end, cur2->bbox.xMax + cur2->pos.x);
				}

				dt = (tm_current - tm_start);
				if ((s1->effect_type == EF_KARAOKE) || (s1->effect_type == EF_KARAOKE_KO)) {
					if (dt > 0)
						x = x_end + 1;
					else
						x = x_start;
				} else if (s1->effect_type == EF_KARAOKE_KF) {
					dt /= (tm_end - tm_start);
					x = x_start + (x_end - x_start) * dt;
				} else {
					mp_msg(MSGT_ASS, MSGL_ERR, MSGTR_LIBASS_UnknownEffectType_InternalError);
					continue;
				}

				for (cur2 = s1; cur2 <= e1; ++cur2) {
					cur2->effect_type = s1->effect_type;
					cur2->effect_timing = x - cur2->pos.x;
				}
			}
		}
	}
}

/**
 * \brief Calculate base point for positioning and rotation
 * \param bbox text bbox
 * \param alignment alignment
 * \param bx, by out: base point coordinates
 */
static void get_base_point(FT_BBox bbox, int alignment, int* bx, int* by)
{
	const int halign = alignment & 3;
	const int valign = alignment & 12;
	if (bx)
		switch(halign) {
		case HALIGN_LEFT:
			*bx = bbox.xMin;
			break;
		case HALIGN_CENTER:
			*bx = (bbox.xMax + bbox.xMin) / 2;
			break;
		case HALIGN_RIGHT:
			*bx = bbox.xMax;
			break;
		}
	if (by)
		switch(valign) {
		case VALIGN_TOP:
			*by = bbox.yMin;
			break;
		case VALIGN_CENTER:
			*by = (bbox.yMax + bbox.yMin) / 2;
			break;
		case VALIGN_SUB:
			*by = bbox.yMax;
			break;
		}
}

/**
 * \brief Multiply 4-vector by 4-matrix
 * \param a 4-vector
 * \param m 4-matrix]
 * \param b out: 4-vector
 * Calculates a * m and stores result in b
 */
static inline void transform_point_3d(double *a, double *m, double *b)
{
	b[0] = a[0] * m[0] + a[1] * m[4] + a[2] * m[8] +  a[3] * m[12];
	b[1] = a[0] * m[1] + a[1] * m[5] + a[2] * m[9] +  a[3] * m[13];
	b[2] = a[0] * m[2] + a[1] * m[6] + a[2] * m[10] + a[3] * m[14];
	b[3] = a[0] * m[3] + a[1] * m[7] + a[2] * m[11] + a[3] * m[15];
}

/**
 * \brief Apply 3d transformation to a vector
 * \param v FreeType vector (2d)
 * \param m 4-matrix
 * Transforms v by m, projects the result back to the screen plane
 * Result is returned in v.
 */
static inline void transform_vector_3d(FT_Vector* v, double *m) {
	const double camera = 2500 * frame_context.border_scale; // camera distance
	double a[4], b[4];
	a[0] = d6_to_double(v->x);
	a[1] = d6_to_double(v->y);
	a[2] = 0.;
	a[3] = 1.;
	transform_point_3d(a, m, b);
	/* Apply perspective projection with the following matrix:
	   2500     0     0     0
	      0  2500     0     0
	      0     0     0     0
	      0     0     8     2500
	   where 2500 is camera distance, 8 - z-axis scale.
	   Camera is always located in (org_x, org_y, -2500). This means
	   that different subtitle events can be displayed at the same time
	   using different cameras. */
	b[0] *= camera;
	b[1] *= camera;
	b[3] = 8 * b[2] + camera;
	if (b[3] < 0.001 && b[3] > -0.001)
		b[3] = b[3] < 0. ? -0.001 : 0.001;
	v->x = double_to_d6(b[0] / b[3]);
	v->y = double_to_d6(b[1] / b[3]);
}

/**
 * \brief Apply 3d transformation to a glyph
 * \param glyph FreeType glyph
 * \param m 4-matrix
 * Transforms glyph by m, projects the result back to the screen plane
 * Result is returned in glyph.
 */
static inline void transform_glyph_3d(FT_Glyph glyph, double *m, FT_Vector shift) {
	int i;
	FT_Outline* outline = &((FT_OutlineGlyph)glyph)->outline;
	FT_Vector* p = outline->points;

	for (i=0; i<outline->n_points; i++) {
		p[i].x += shift.x;
		p[i].y += shift.y;
		transform_vector_3d(p + i, m);
		p[i].x -= shift.x;
		p[i].y -= shift.y;
	}

	//transform_vector_3d(&glyph->advance, m);
}

/**
 * \brief Apply 3d transformation to several objects
 * \param shift FreeType vector
 * \param glyph FreeType glyph
 * \param glyph2 FreeType glyph
 * \param frx x-axis rotation angle
 * \param fry y-axis rotation angle
 * \param frz z-axis rotation angle
 * Rotates both glyphs by frx, fry and frz. Shift vector is added before rotation and subtracted after it.
 */
static void transform_3d(FT_Vector shift, FT_Glyph* glyph, FT_Glyph* glyph2, double frx, double fry, double frz)
{
	fry = - fry; // FreeType's y axis goes in the opposite direction
	if (frx != 0. || fry != 0. || frz != 0.) {
		double m[16];
		double sx = sin(frx);
		double sy = sin(fry);
 		double sz = sin(frz);
		double cx = cos(frx);
		double cy = cos(fry);
		double cz = cos(frz);
		m[0] = cy * cz;            m[1] = cy*sz;              m[2]  = -sy;    m[3] = 0.0;
		m[4] = -cx*sz + sx*sy*cz;  m[5] = cx*cz + sx*sy*sz;   m[6]  = sx*cy;  m[7] = 0.0;
		m[8] = sx*sz + cx*sy*cz;   m[9] = -sx*cz + cx*sy*sz;  m[10] = cx*cy;  m[11] = 0.0;
		m[12] = 0.0;               m[13] = 0.0;               m[14] = 0.0;    m[15] = 1.0;

		if (glyph && *glyph)
			transform_glyph_3d(*glyph, m, shift);

		if (glyph2 && *glyph2)
			transform_glyph_3d(*glyph2, m, shift);
	}
}

/**
 * \brief Main ass rendering function, glues everything together
 * \param event event to render
 * Process event, appending resulting ass_image_t's to images_root.
 */
static int ass_render_event(ass_event_t* event, event_images_t* event_images)
{
	char* p;
	FT_UInt previous; 
	FT_UInt num_glyphs;
	FT_Vector pen;
	unsigned code;
	FT_BBox bbox;
	int i, j;
	FT_Vector shift;
	int MarginL, MarginR, MarginV;
	int last_break;
	int alignment, halign, valign;
	int device_x = 0, device_y = 0;

	if (event->Style >= frame_context.track->n_styles) {
		mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_NoStyleFound);
		return 1;
	}
	if (!event->Text) {
		mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_EmptyEvent);
		return 1;
	}

	init_render_context(event);

	text_info.length = 0;
	pen.x = 0;
	pen.y = 0;
	previous = 0;
	num_glyphs = 0;
	p = event->Text;
	// Event parsing.
	while (1) {
		// get next char, executing style override
		// this affects render_context
		code = get_next_char(&p);
		
		// face could have been changed in get_next_char
		if (!render_context.font) {
			free_render_context();
			return 1;
		}

		if (code == 0)
			break;

		if (text_info.length >= MAX_GLYPHS) {
			mp_msg(MSGT_ASS, MSGL_WARN, MSGTR_LIBASS_MAX_GLYPHS_Reached, 
					(int)(event - frame_context.track->events), event->Start, event->Duration, event->Text);
			break;
		}

		if ( previous && code ) {
			FT_Vector delta;
			delta = ass_font_get_kerning(render_context.font, previous, code);
			pen.x += delta.x * render_context.scale_x;
			pen.y += delta.y * render_context.scale_y;
		}