path: root/source/fitz/path.c

#include <assert.h>
#include "mupdf/fitz.h"

fz_path *
fz_new_path(fz_context *ctx)
{
	fz_path *path;

	path = fz_malloc_struct(ctx, fz_path);
	path->len = 0;
	path->cap = 0;
	path->items = NULL;
	path->last = -1;

	return path;
}

fz_path *
fz_clone_path(fz_context *ctx, fz_path *old)
{
	fz_path *path;

	assert(old);
	path = fz_malloc_struct(ctx, fz_path);
	fz_try(ctx)
	{
		path->len = old->len;
		path->cap = old->len;
		path->items = fz_malloc_array(ctx, path->cap, sizeof(fz_path_item));
		memcpy(path->items, old->items, sizeof(fz_path_item) * path->len);
	}
	fz_catch(ctx)
	{
		fz_free(ctx, path);
		fz_rethrow(ctx);
	}

	return path;
}

void
fz_free_path(fz_context *ctx, fz_path *path)
{
	if (path == NULL)
		return;
	fz_free(ctx, path->items);
	fz_free(ctx, path);
}

static void
grow_path(fz_context *ctx, fz_path *path, int n)
{
	int newcap = path->cap;
	if (path->len + n <= path->cap)
	{
		path->last = path->len;
		return;
	}
	while (path->len + n > newcap)
		newcap = newcap + 36;
	path->items = fz_resize_array(ctx, path->items, newcap, sizeof(fz_path_item));
	path->cap = newcap;
	path->last = path->len;
}

fz_point
fz_currentpoint(fz_context *ctx, fz_path *path)
{
	fz_point c, m;
	int i;

	c.x = c.y = m.x = m.y = 0;
	i = 0;

	while (i < path->len)
	{
		switch (path->items[i++].k)
		{
		case FZ_MOVETO:
			m.x = c.x = path->items[i++].v;
			m.y = c.y = path->items[i++].v;
			break;
		case FZ_LINETO:
			c.x = path->items[i++].v;
			c.y = path->items[i++].v;
			break;
		case FZ_CURVETO:
			i += 4;
			c.x = path->items[i++].v;
			c.y = path->items[i++].v;
			break;
		case FZ_CLOSE_PATH:
			c = m;
		}
	}

	return c;
}

void
fz_moveto(fz_context *ctx, fz_path *path, float x, float y)
{
	if (path->last >= 0 && path->items[path->last].k == FZ_MOVETO)
	{
		/* No point in having MOVETO then MOVETO */
		path->len = path->last;
	}
	grow_path(ctx, path, 3);
	path->items[path->len++].k = FZ_MOVETO;
	path->items[path->len++].v = x;
	path->items[path->len++].v = y;
}

void
fz_lineto(fz_context *ctx, fz_path *path, float x, float y)
{
	float x0, y0;

	if (path->last < 0)
	{
		fz_warn(ctx, "lineto with no current point");
		return;
	}
	if (path->items[path->last].k == FZ_CLOSE_PATH)
	{
		x0 = path->items[path->last-2].v;
		y0 = path->items[path->last-1].v;
	}
	else
	{
		x0 = path->items[path->len-2].v;
		y0 = path->items[path->len-1].v;
	}
	/* Anything other than MoveTo followed by LineTo the same place is a nop */
	if (path->items[path->last].k != FZ_MOVETO && x0 == x && y0 == y)
		return;
	grow_path(ctx, path, 3);
	path->items[path->len++].k = FZ_LINETO;
	path->items[path->len++].v = x;
	path->items[path->len++].v = y;
}

void
fz_curveto(fz_context *ctx, fz_path *path,
	float x1, float y1,
	float x2, float y2,
	float x3, float y3)
{
	float x0, y0;

	if (path->last < 0)
	{
		fz_warn(ctx, "curveto with no current point");
		return;
	}
	if (path->items[path->last].k == FZ_CLOSE_PATH)
	{
		x0 = path->items[path->last-2].v;
		y0 = path->items[path->last-1].v;
	}
	else
	{
		x0 = path->items[path->len-2].v;
		y0 = path->items[path->len-1].v;
	}

	/* Check for degenerate cases: */
	if (x0 == x1 && y0 == y1)
	{
		if (x2 == x3 && y2 == y3)
		{
			/* If (x1,y1)==(x2,y2) and prev wasn't a moveto, then skip */
			if (x1 == x2 && y1 == y2 && path->items[path->last].k != FZ_MOVETO)
				return;
			/* Otherwise a line will suffice */
			fz_lineto(ctx, path, x3, y3);
			return;
		}
		if (x1 == x2 && y1 == y2)
		{
			/* A line will suffice */
			fz_lineto(ctx, path, x3, y3);
			return;
		}
	}
	else if (x1 == x2 && y1 == y2 && x2 == x3 && y2 == y3)
	{
		/* A line will suffice */
		fz_lineto(ctx, path, x3, y3);
		return;
	}

	grow_path(ctx, path, 7);
	path->items[path->len++].k = FZ_CURVETO;
	path->items[path->len++].v = x1;
	path->items[path->len++].v = y1;
	path->items[path->len++].v = x2;
	path->items[path->len++].v = y2;
	path->items[path->len++].v = x3;
	path->items[path->len++].v = y3;
}

void
fz_curvetov(fz_context *ctx, fz_path *path, float x2, float y2, float x3, float y3)
{
	float x1, y1;
	if (path->last < 0)
	{
		fz_warn(ctx, "curvetov with no current point");
		return;
	}
	if (path->items[path->last].k == FZ_CLOSE_PATH)
	{
		x1 = path->items[path->last-2].v;
		y1 = path->items[path->last-1].v;
	}
	else
	{
		x1 = path->items[path->len-2].v;
		y1 = path->items[path->len-1].v;
	}
	fz_curveto(ctx, path, x1, y1, x2, y2, x3, y3);
}

void
fz_curvetoy(fz_context *ctx, fz_path *path, float x1, float y1, float x3, float y3)
{
	fz_curveto(ctx, path, x1, y1, x3, y3, x3, y3);
}

void
fz_closepath(fz_context *ctx, fz_path *path)
{
	if (path->last < 0)
	{
		fz_warn(ctx, "closepath with no current point");
		return;
	}
	/* CLOSE following a CLOSE is a NOP */
	if (path->items[path->last].k == FZ_CLOSE_PATH)
		return;
	grow_path(ctx, path, 1);
	path->items[path->len++].k = FZ_CLOSE_PATH;
}

static inline fz_rect *bound_expand(fz_rect *r, const fz_point *p)
{
	if (p->x < r->x0) r->x0 = p->x;
	if (p->y < r->y0) r->y0 = p->y;
	if (p->x > r->x1) r->x1 = p->x;
	if (p->y > r->y1) r->y1 = p->y;
	return r;
}

fz_rect *
fz_bound_path(fz_context *ctx, fz_path *path, const fz_stroke_state *stroke, const fz_matrix *ctm, fz_rect *r)
{
	fz_point p;
	int i = 0;

	/* If the path is empty, return the empty rectangle here - don't wait
	 * for it to be expanded in the stroked case below. */
	if (path->len == 0)
	{
		*r = fz_empty_rect;
		return r;
	}
	/* A path must start with a moveto - and if that's all there is
	 * then the path is empty. */
	if (path->len == 3)
	{
		*r = fz_empty_rect;
		return r;
	}

	p.x = path->items[1].v;
	p.y = path->items[2].v;
	fz_transform_point(&p, ctm);
	r->x0 = r->x1 = p.x;
	r->y0 = r->y1 = p.y;

	while (i < path->len)
	{
		switch (path->items[i++].k)
		{
		case FZ_CURVETO:
			p.x = path->items[i++].v;
			p.y = path->items[i++].v;
			bound_expand(r, fz_transform_point(&p, ctm));
			p.x = path->items[i++].v;
			p.y = path->items[i++].v;
			bound_expand(r, fz_transform_point(&p, ctm));
			p.x = path->items[i++].v;
			p.y = path->items[i++].v;
			bound_expand(r, fz_transform_point(&p, ctm));
			break;
		case FZ_MOVETO:
			if (i + 2 == path->len)
			{
				/* Trailing Moveto - cannot affect bbox */
				i += 2;
				break;
			}
			/* fallthrough */
		case FZ_LINETO:
			p.x = path->items[i++].v;
			p.y = path->items[i++].v;
			bound_expand(r, fz_transform_point(&p, ctm));
			break;
		case FZ_CLOSE_PATH:
			break;
		}
	}

	if (stroke)
	{
		fz_adjust_rect_for_stroke(r, stroke, ctm);
	}

	return r;
}

fz_rect *
fz_adjust_rect_for_stroke(fz_rect *r, const fz_stroke_state *stroke, const fz_matrix *ctm)
{
	float expand;

	if (!stroke)
		return r;

	expand = stroke->linewidth;
	if (expand == 0)
		expand = 1.0f;
	expand *= fz_matrix_max_expansion(ctm);
	if ((stroke->linejoin == FZ_LINEJOIN_MITER || stroke->linejoin == FZ_LINEJOIN_MITER_XPS) && stroke->miterlimit > 1)
		expand *= stroke->miterlimit;

	r->x0 -= expand;
	r->y0 -= expand;
	r->x1 += expand;
	r->y1 += expand;
	return r;
}

void
fz_transform_path(fz_context *ctx, fz_path *path, const fz_matrix *ctm)
{
	int k, i = 0;

	while (i < path->len)
	{
		switch (path->items[i++].k)
		{
		case FZ_CURVETO:
			for (k = 0; k < 3; k++)
			{
				fz_transform_point((fz_point *)(void *)&path->items[i].v, ctm);
				i += 2;
			}
			break;
		case FZ_MOVETO:
		case FZ_LINETO:
			fz_transform_point((fz_point *)(void *)&path->items[i].v, ctm);
			i += 2;
			break;
		case FZ_CLOSE_PATH:
			break;
		}
	}
}

#ifndef NDEBUG
void
fz_print_path(fz_context *ctx, FILE *out, fz_path *path, int indent)
{
	float x, y;
	int i = 0;
	int n;
	while (i < path->len)
	{
		for (n = 0; n < indent; n++)
			fputc(' ', out);
		switch (path->items[i++].k)
		{
		case FZ_MOVETO:
			x = path->items[i++].v;
			y = path->items[i++].v;
			fprintf(out, "%g %g m\n", x, y);
			break;
		case FZ_LINETO:
			x = path->items[i++].v;
			y = path->items[i++].v;
			fprintf(out, "%g %g l\n", x, y);
			break;
		case FZ_CURVETO:
			x = path->items[i++].v;
			y = path->items[i++].v;
			fprintf(out, "%g %g ", x, y);
			x = path->items[i++].v;
			y = path->items[i++].v;
			fprintf(out, "%g %g ", x, y);
			x = path->items[i++].v;
			y = path->items[i++].v;
			fprintf(out, "%g %g c\n", x, y);
			break;
		case FZ_CLOSE_PATH:
			fprintf(out, "h\n");
			break;
		}
	}
}
#endif

fz_stroke_state *
fz_keep_stroke_state(fz_context *ctx, fz_stroke_state *stroke)
{
	if (!stroke)
		return NULL;

	fz_lock(ctx, FZ_LOCK_ALLOC);
	if (stroke->refs > 0)
		stroke->refs++;
	fz_unlock(ctx, FZ_LOCK_ALLOC);
	return stroke;
}

void
fz_drop_stroke_state(fz_context *ctx, fz_stroke_state *stroke)
{
	int drop;

	if (!stroke)
		return;

	fz_lock(ctx, FZ_LOCK_ALLOC);
	drop = (stroke->refs > 0 ? --stroke->refs == 0 : 0);
	fz_unlock(ctx, FZ_LOCK_ALLOC);
	if (drop)
		fz_free(ctx, stroke);
}

fz_stroke_state *
fz_new_stroke_state_with_len(fz_context *ctx, int len)
{
	fz_stroke_state *state;

	len -= nelem(state->dash_list);
	if (len < 0)
		len = 0;

	state = Memento_label(fz_malloc(ctx, sizeof(*state) + sizeof(state->dash_list[0]) * len), "fz_stroke_state");
	state->refs = 1;
	state->start_cap = FZ_LINECAP_BUTT;
	state->dash_cap = FZ_LINECAP_BUTT;
	state->end_cap = FZ_LINECAP_BUTT;
	state->linejoin = FZ_LINEJOIN_MITER;
	state->linewidth = 1;
	state->miterlimit = 10;
	state->dash_phase = 0;
	state->dash_len = 0;
	memset(state->dash_list, 0, sizeof(state->dash_list[0]) * (len + nelem(state->dash_list)));

	return state;
}

fz_stroke_state *
fz_new_stroke_state(fz_context *ctx)
{
	return fz_new_stroke_state_with_len(ctx, 0);
}

fz_stroke_state *
fz_unshare_stroke_state_with_len(fz_context *ctx, fz_stroke_state *shared, int len)
{
	int single, unsize, shsize, shlen, drop;
	fz_stroke_state *unshared;

	fz_lock(ctx, FZ_LOCK_ALLOC);
	single = (shared->refs == 1);
	fz_unlock(ctx, FZ_LOCK_ALLOC);

	shlen = shared->dash_len - nelem(shared->dash_list);
	if (shlen < 0)
		shlen = 0;
	shsize = sizeof(*shared) + sizeof(shared->dash_list[0]) * shlen;
	len -= nelem(shared->dash_list);
	if (len < 0)
		len = 0;
	if (single && shlen >= len)
		return shared;
	unsize = sizeof(*unshared) + sizeof(unshared->dash_list[0]) * len;
	unshared = Memento_label(fz_malloc(ctx, unsize), "fz_stroke_state");
	memcpy(unshared, shared, (shsize > unsize ? unsize : shsize));
	unshared->refs = 1;
	fz_lock(ctx, FZ_LOCK_ALLOC);
	drop = (shared->refs > 0 ? --shared->refs == 0 : 0);
	fz_unlock(ctx, FZ_LOCK_ALLOC);
	if (drop)
		fz_free(ctx, shared);
	return unshared;
}

fz_stroke_state *
fz_unshare_stroke_state(fz_context *ctx, fz_stroke_state *shared)
{
	return fz_unshare_stroke_state_with_len(ctx, shared, shared->dash_len);
}