src/rt/text.c

#ifndef lint
static const char       RCSid[] = "$Id: text.c,v 2.28 2021/11/19 22:51:31 greg Exp $";
#endif
/*
 *  text.c - functions for text patterns and mixtures.
 */

#include "copyright.h"

#include  "ray.h"
#include  "paths.h"
#include  "otypes.h"
#include  "rtotypes.h"
#include  "font.h"

/*
 *      A text pattern is specified as the text (a file or line),
 *  the upper left anchor point, the right motion vector, the down
 *  motion vector, and the foreground and background brightness.
 *  For a file, the description is as follows:
 *
 *      modifier brighttext id
 *      2 fontfile textfile
 *      0
 *      11+
 *              Ax Ay Az
 *              Rx Ry Rz
 *              Dx Dy Dz
 *              foreground background
 *              [spacing]
 *
 *  For a single line, we use:
 *
 *      modifier brighttext id
 *      N+2 fontfile . This is a line with N words...
 *      0
 *      11+
 *              Ax Ay Az
 *              Rx Ry Rz
 *              Dx Dy Dz
 *              foreground background
 *              [spacing]
 *
 *  Colortext is identical, except colors are given rather than
 *  brightnesses.
 *
 *  Mixtext has foreground and background modifiers:
 *
 *      modifier mixtext id
 *      4+ foremod backmod fontfile text..
 *      0
 *      9+
 *              Ax Ay Az
 *              Rx Ry Rz
 *              Dx Dy Dz
 *              [spacing]
 */

#define  fndx(m)        ((m)->otype==MIX_TEXT ? 2 : 0)
#define  tndx(m)        ((m)->otype==MIX_TEXT ? 3 : 1)
#define  sndx(m)        ((m)->otype==PAT_BTEXT ? 11 : \
                                (m)->otype==PAT_CTEXT ? 15 : 9)

typedef struct tline {
        struct tline  *next;            /* pointer to next line */
        short  *spc;                    /* character spacing */
        int  width;                     /* total line width */
                                        /* followed by the string */
}  TLINE;

#define  TLSTR(l)       ((char *)((l)+1))

typedef struct {
        FVECT  right, down;             /* right and down unit vectors */
        FONT  *f;                       /* our font */
        TLINE  tl;                      /* line list */
}  TEXT;

static TLINE * tlalloc(char *s);
static TEXT * gettext(OBJREC *tm);
static int intext(FVECT p, OBJREC *m);
static int inglyph(double x, double y, GLYPH *gl);


int
do_text(
        OBJREC  *m,
        RAY  *r
)
{
        FVECT  v;
        int  foreground;
                                /* get transformed position */
        if (r->rox != NULL)
                multp3(v, r->rop, r->rox->b.xfm);
        else
                VCOPY(v, r->rop);
                                /* check if we are within a text glyph */
        foreground = intext(v, m);
                                /* modify */
        if (m->otype == MIX_TEXT) {
                OBJECT  omod;
                char  *modname = m->oargs.sarg[foreground ? 0 : 1];
                if (!strcmp(modname, VOIDID))
                        omod = OVOID;
                else if ((omod = lastmod(objndx(m), modname)) == OVOID) {
                        sprintf(errmsg, "undefined modifier \"%s\"", modname);
                        objerror(m, USER, errmsg);
                }
                if (rayshade(r, omod)) {
                        if (m->omod != OVOID)
                                objerror(m, USER, "inappropriate modifier");
                        return(1);
                }
        } else if (m->otype == PAT_BTEXT) {
                if (foreground) {
                        scalescolor(r->pcol, m->oargs.farg[9]);
                } else {
                        scalescolor(r->pcol, m->oargs.farg[10]);
                }
        } else { /* PAT_CTEXT */
                SCOLOR  scval;
                if (foreground)
                        setscolor(scval, m->oargs.farg[9],
                                        m->oargs.farg[10],
                                        m->oargs.farg[11]);
                else
                        setscolor(scval, m->oargs.farg[12],
                                        m->oargs.farg[13],
                                        m->oargs.farg[14]);
                smultscolor(r->pcol, scval);
        }
        return(0);
}


static TLINE *
tlalloc(                        /* allocate and assign text line */
        char  *s
)
{
        int  siz;
        TLINE  *tl;

        siz = strlen(s) + 1;
        if ((tl=(TLINE *)malloc(sizeof(TLINE)+siz)) == NULL ||
                        (tl->spc=(short *)malloc(siz*sizeof(short))) == NULL)
                error(SYSTEM, "out of memory in tlalloc");
        tl->next = NULL;
        strcpy(TLSTR(tl), s);
        return(tl);
}


static TEXT *
gettext(                        /* get text structure for material */
        OBJREC  *tm
)
{
#define  R      (tm->oargs.farg+3)
#define  D      (tm->oargs.farg+6)
        FVECT  DxR;
        double  d;
        FILE  *fp;
        char  linbuf[512];
        TEXT  *t;
        int  i;
        TLINE  *tlp;
        char  *s;

        if ((t = (TEXT *)tm->os) != NULL)
                return(t);
                                                /* check arguments */
        if (tm->oargs.nsargs - tndx(tm) < 1 || tm->oargs.nfargs < sndx(tm))
                objerror(tm, USER, "bad # arguments");
        if ((t = (TEXT *)malloc(sizeof(TEXT))) == NULL)
                error(SYSTEM, "out of memory in gettext");
                                                /* compute vectors */
        fcross(DxR, D, R);
        fcross(t->right, DxR, D);
        d = DOT(t->right,t->right);
        if (d <= FTINY*FTINY*FTINY*FTINY)
                objerror(tm, USER, "illegal motion vector");
        d = DOT(D,D)/d;
        for (i = 0; i < 3; i++)
                t->right[i] *= d;
        fcross(t->down, R, DxR);
        d = DOT(R,R)/DOT(t->down,t->down);
        for (i = 0; i < 3; i++)
                t->down[i] *= d;
                                                /* get text */
        tlp = &t->tl;
        if (tm->oargs.nsargs - tndx(tm) > 1) {  /* single line */
                s = linbuf;
                for (i = tndx(tm)+1; i < tm->oargs.nsargs; i++) {
                        strcpy(s, tm->oargs.sarg[i]);
                        s += strlen(s);
                        *s++ = ' ';
                }
                *--s = '\0';
                tlp->next = tlalloc(linbuf);
                tlp = tlp->next;
        } else {                                /* text file */
                if ((s = getpath(tm->oargs.sarg[tndx(tm)],
                                getrlibpath(), R_OK)) == NULL) {
                        sprintf(errmsg, "cannot find text file \"%s\"",
                                        tm->oargs.sarg[tndx(tm)]);
                        error(SYSTEM, errmsg);
                }
                if ((fp = fopen(s, "r")) == NULL) {
                        sprintf(errmsg, "cannot open text file \"%s\"", s);
                        error(SYSTEM, errmsg);
                }
                while (fgets(linbuf, sizeof(linbuf), fp) != NULL) {
                        s = linbuf + strlen(linbuf) - 1;
                        if (*s == '\n')
                                *s = '\0';
                        tlp->next = tlalloc(linbuf);
                        tlp = tlp->next;
                }
                fclose(fp);
        }
        tlp->next = NULL;
                                                /* get the font */
        t->f = getfont(tm->oargs.sarg[fndx(tm)]);
        if (!t->f)
                objerror(tm, USER, "font load error");
                                                /* compute character spacing */
        i = sndx(tm);
        d = i < tm->oargs.nfargs ? tm->oargs.farg[i] : 0.0;
        i = d * 255.0;
        t->tl.width = 0;
        for (tlp = t->tl.next; tlp != NULL; tlp = tlp->next) {
                if (i < 0)
                        tlp->width = squeeztext(tlp->spc, TLSTR(tlp), t->f, -i);
                else if (i > 0)
                        tlp->width = proptext(tlp->spc, TLSTR(tlp), t->f, i, 3);
                else
                        tlp->width = uniftext(tlp->spc, TLSTR(tlp), t->f);
                if (tlp->width > t->tl.width)
                        t->tl.width = tlp->width;
        }
                                                /* we're done */
        tm->os = (char *)t;
        return(t);
#undef  R
#undef  D
}


void
freetext(                       /* free text structures associated with m */
        OBJREC  *m
)
{
        TEXT  *tp;
        TLINE  *tlp;

        tp = (TEXT *)m->os;
        if (tp == NULL)
                return;
        while ((tlp = tp->tl.next) != NULL) {
                tp->tl.next = tlp->next;
                free((void *)tlp->spc);
                free((void *)tlp);
        }
        freefont(tp->f);        /* release font reference */
        free((void *)tp);
        m->os = NULL;
}


static int
intext(                 /* check to see if p is in text glyph */
        FVECT  p,
        OBJREC  *m
)
{
        TEXT  *tp;
        TLINE  *tlp;
        FVECT  v;
        double  y, x;
        int  i, h;
                                /* first, compute position in text */
        tp = gettext(m);
        v[0] = p[0] - m->oargs.farg[0];
        v[1] = p[1] - m->oargs.farg[1];
        v[2] = p[2] - m->oargs.farg[2];
        x = DOT(v, tp->right);
        i = sndx(m);
        if (i < m->oargs.nfargs)
                x *= tp->f->mwidth + 255.*fabs(m->oargs.farg[i]);
        else
                x *= 255.;
        h = x;
        i = y = DOT(v, tp->down);
        if (x < 0.0 || y < 0.0)
                return(0);
        x -= (double)h;
        y = ((i+1) - y)*255.;
                                /* find the line position */
        for (tlp = tp->tl.next; tlp != NULL; tlp = tlp->next)
                if (--i < 0)
                        break;
        if (tlp == NULL || h >= tlp->width)
                return(0);
        for (i = 0; (h -= tlp->spc[i]) >= 0; i++)
                if (h < 255 && inglyph(h+x, y,
                                tp->f->fg[TLSTR(tlp)[i]&0xff]))
                        return(1);
        return(0);
}


static int
inglyph(                /* (x,y) within font glyph gl? */
        double  x,              /* real coordinates in range [0,255) */
        double  y,
        GLYPH  *gl
)
{
        int  n, ncross;
        int  xlb, ylb;
        int  tv;
        GORD  *p0, *p1;

        if (gl == NULL)
                return(0);
        xlb = x;
        ylb = y;
        if (gl->left > xlb || gl->right <= xlb ||       /* check extent */
                        gl->bottom > ylb || gl->top <= ylb)
                return(0);
        xlb = xlb<<1 | 1;               /* add 1/2 to test points... */
        ylb = ylb<<1 | 1;               /* ...so no equal comparisons */
        n = gl->nverts;                 /* get # of vertices */
        p0 = gvlist(gl) + 2*(n-1);      /* connect last to first */
        p1 = gvlist(gl);
        ncross = 0;
                                        /* positive x axis cross test */
        while (n--) {
                if ((p0[1]<<1 > ylb) ^ (p1[1]<<1 > ylb)) {
                        tv = (p0[0]<<1 > xlb) | ((p1[0]<<1 > xlb) << 1);
                        if (tv == 03)
                                ncross++;
                        else if (tv)
                                ncross += (p1[1] > p0[1]) ^
                                                ((p0[1]-y)*(p1[0]-x) >
                                                (p0[0]-x)*(p1[1]-y));
                }
                p0 = p1;
                p1 += 2;
        }
        return(ncross & 01);
}
Revision:	2.29
Committed:	Wed Nov 15 18:02:53 2023 UTC (6 months ago) by greg
Content type:	text/plain
Branch:	MAIN
CVS Tags:	HEAD
Changes since 2.28:	+10 -9 lines
Log Message:	feat(rpict,rtrace,rcontrib,rtpict): Hyperspectral rendering (except photon map)
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.29	static const char RCSid[] = "$Id: text.c,v 2.28 2021/11/19 22:51:31 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* text.c - functions for text patterns and mixtures.
6			*/
7
8	greg	2.21	#include "copyright.h"
9	greg	2.20
10	greg	1.1	#include "ray.h"
11	greg	2.24	#include "paths.h"
12	greg	1.1	#include "otypes.h"
13	schorsch	2.25	#include "rtotypes.h"
14	greg	2.2	#include "font.h"
15
16	greg	1.1	/*
17			* A text pattern is specified as the text (a file or line),
18			* the upper left anchor point, the right motion vector, the down
19			* motion vector, and the foreground and background brightness.
20			* For a file, the description is as follows:
21			*
22			* modifier brighttext id
23			* 2 fontfile textfile
24			* 0
25	greg	2.4	* 11+
26	greg	1.1	* Ax Ay Az
27			* Rx Ry Rz
28			* Dx Dy Dz
29			* foreground background
30	greg	2.4	* [spacing]
31	greg	1.1	*
32			* For a single line, we use:
33			*
34			* modifier brighttext id
35			* N+2 fontfile . This is a line with N words...
36			* 0
37	greg	2.4	* 11+
38	greg	1.1	* Ax Ay Az
39			* Rx Ry Rz
40			* Dx Dy Dz
41			* foreground background
42	greg	2.4	* [spacing]
43	greg	1.1	*
44			* Colortext is identical, except colors are given rather than
45	greg	2.15	* brightnesses.
46	greg	1.1	*
47	greg	2.15	* Mixtext has foreground and background modifiers:
48			*
49	greg	1.1	* modifier mixtext id
50			* 4+ foremod backmod fontfile text..
51			* 0
52	greg	2.4	* 9+
53	greg	1.1	* Ax Ay Az
54			* Rx Ry Rz
55			* Dx Dy Dz
56	greg	2.4	* [spacing]
57	greg	1.1	*/
58
59			#define fndx(m) ((m)->otype==MIX_TEXT ? 2 : 0)
60			#define tndx(m) ((m)->otype==MIX_TEXT ? 3 : 1)
61	greg	2.4	#define sndx(m) ((m)->otype==PAT_BTEXT ? 11 : \
62			(m)->otype==PAT_CTEXT ? 15 : 9)
63	greg	1.1
64	greg	1.8	typedef struct tline {
65			struct tline next; / pointer to next line */
66	greg	2.4	short spc; / character spacing */
67			int width; /* total line width */
68	greg	1.8	/* followed by the string */
69			} TLINE;
70
71	greg	1.9	#define TLSTR(l) ((char *)((l)+1))
72	greg	1.8
73	greg	1.7	typedef struct {
74			FVECT right, down; /* right and down unit vectors */
75			FONT f; / our font */
76	greg	1.8	TLINE tl; /* line list */
77	greg	1.7	} TEXT;
78
79	schorsch	2.25	static TLINE * tlalloc(char *s);
80			static TEXT * gettext(OBJREC *tm);
81			static int intext(FVECT p, OBJREC *m);
82			static int inglyph(double x, double y, GLYPH *gl);
83	greg	1.8
84	greg	1.1
85	greg	2.26	int
86	schorsch	2.25	do_text(
87	greg	2.26	OBJREC *m,
88	schorsch	2.25	RAY *r
89			)
90	greg	1.1	{
91	greg	1.10	FVECT v;
92	greg	1.1	int foreground;
93	greg	1.7	/* get transformed position */
94	greg	1.4	if (r->rox != NULL)
95			multp3(v, r->rop, r->rox->b.xfm);
96			else
97			VCOPY(v, r->rop);
98	greg	1.7	/* check if we are within a text glyph */
99			foreground = intext(v, m);
100	greg	1.1	/* modify */
101			if (m->otype == MIX_TEXT) {
102			OBJECT omod;
103			char *modname = m->oargs.sarg[foreground ? 0 : 1];
104			if (!strcmp(modname, VOIDID))
105			omod = OVOID;
106	gwlarson	2.18	else if ((omod = lastmod(objndx(m), modname)) == OVOID) {
107	greg	1.1	sprintf(errmsg, "undefined modifier \"%s\"", modname);
108			objerror(m, USER, errmsg);
109			}
110	greg	2.12	if (rayshade(r, omod)) {
111			if (m->omod != OVOID)
112			objerror(m, USER, "inappropriate modifier");
113			return(1);
114			}
115	greg	2.15	} else if (m->otype == PAT_BTEXT) {
116	greg	2.29	if (foreground) {
117			scalescolor(r->pcol, m->oargs.farg[9]);
118			} else {
119			scalescolor(r->pcol, m->oargs.farg[10]);
120			}
121	greg	1.1	} else { /* PAT_CTEXT */
122	greg	2.29	SCOLOR scval;
123	greg	1.1	if (foreground)
124	greg	2.29	setscolor(scval, m->oargs.farg[9],
125	greg	1.7	m->oargs.farg[10],
126			m->oargs.farg[11]);
127	greg	1.1	else
128	greg	2.29	setscolor(scval, m->oargs.farg[12],
129	greg	1.7	m->oargs.farg[13],
130			m->oargs.farg[14]);
131	greg	2.29	smultscolor(r->pcol, scval);
132	greg	1.1	}
133	greg	2.12	return(0);
134	greg	1.1	}
135
136
137	schorsch	2.25	static TLINE *
138			tlalloc( /* allocate and assign text line */
139			char *s
140			)
141	greg	1.8	{
142	greg	2.26	int siz;
143			TLINE *tl;
144	greg	1.8
145	greg	2.4	siz = strlen(s) + 1;
146			if ((tl=(TLINE *)malloc(sizeof(TLINE)+siz)) == NULL \|\|
147			(tl->spc=(short )malloc(sizsizeof(short))) == NULL)
148	greg	1.8	error(SYSTEM, "out of memory in tlalloc");
149			tl->next = NULL;
150			strcpy(TLSTR(tl), s);
151			return(tl);
152			}
153
154
155	schorsch	2.25	static TEXT *
156			gettext( /* get text structure for material */
157	greg	2.26	OBJREC *tm
158	schorsch	2.25	)
159	greg	1.1	{
160	greg	1.7	#define R (tm->oargs.farg+3)
161			#define D (tm->oargs.farg+6)
162			FVECT DxR;
163			double d;
164	greg	1.1	FILE *fp;
165			char linbuf[512];
166	greg	1.8	TEXT *t;
167	greg	2.26	int i;
168			TLINE *tlp;
169			char *s;
170	greg	1.1
171	greg	1.7	if ((t = (TEXT *)tm->os) != NULL)
172			return(t);
173			/* check arguments */
174	greg	2.4	if (tm->oargs.nsargs - tndx(tm) < 1 \|\| tm->oargs.nfargs < sndx(tm))
175	greg	1.7	objerror(tm, USER, "bad # arguments");
176			if ((t = (TEXT *)malloc(sizeof(TEXT))) == NULL)
177	greg	2.10	error(SYSTEM, "out of memory in gettext");
178	greg	1.7	/* compute vectors */
179			fcross(DxR, D, R);
180			fcross(t->right, DxR, D);
181	gregl	2.17	d = DOT(t->right,t->right);
182	gwlarson	2.19	if (d <= FTINYFTINYFTINY*FTINY)
183	gregl	2.17	objerror(tm, USER, "illegal motion vector");
184			d = DOT(D,D)/d;
185	greg	1.7	for (i = 0; i < 3; i++)
186			t->right[i] *= d;
187			fcross(t->down, R, DxR);
188	greg	1.9	d = DOT(R,R)/DOT(t->down,t->down);
189	greg	1.7	for (i = 0; i < 3; i++)
190			t->down[i] *= d;
191			/* get text */
192	greg	1.8	tlp = &t->tl;
193	greg	1.7	if (tm->oargs.nsargs - tndx(tm) > 1) { /* single line */
194			s = linbuf;
195			for (i = tndx(tm)+1; i < tm->oargs.nsargs; i++) {
196			strcpy(s, tm->oargs.sarg[i]);
197			s += strlen(s);
198			*s++ = ' ';
199	greg	1.1	}
200	greg	1.7	*--s = '\0';
201	greg	1.8	tlp->next = tlalloc(linbuf);
202			tlp = tlp->next;
203	greg	1.7	} else { /* text file */
204			if ((s = getpath(tm->oargs.sarg[tndx(tm)],
205	greg	2.22	getrlibpath(), R_OK)) == NULL) {
206	greg	1.7	sprintf(errmsg, "cannot find text file \"%s\"",
207			tm->oargs.sarg[tndx(tm)]);
208	greg	2.27	error(SYSTEM, errmsg);
209	greg	1.7	}
210			if ((fp = fopen(s, "r")) == NULL) {
211	greg	2.4	sprintf(errmsg, "cannot open text file \"%s\"", s);
212	greg	1.7	error(SYSTEM, errmsg);
213			}
214	greg	1.8	while (fgets(linbuf, sizeof(linbuf), fp) != NULL) {
215	greg	1.7	s = linbuf + strlen(linbuf) - 1;
216			if (*s == '\n')
217			*s = '\0';
218	greg	1.8	tlp->next = tlalloc(linbuf);
219			tlp = tlp->next;
220	greg	1.7	}
221			fclose(fp);
222	greg	1.1	}
223	greg	1.8	tlp->next = NULL;
224	greg	1.7	/* get the font */
225			t->f = getfont(tm->oargs.sarg[fndx(tm)]);
226	greg	2.28	if (!t->f)
227			objerror(tm, USER, "font load error");
228	greg	2.4	/* compute character spacing */
229			i = sndx(tm);
230			d = i < tm->oargs.nfargs ? tm->oargs.farg[i] : 0.0;
231	greg	2.14	i = d * 255.0;
232	greg	2.6	t->tl.width = 0;
233	greg	2.4	for (tlp = t->tl.next; tlp != NULL; tlp = tlp->next) {
234			if (i < 0)
235			tlp->width = squeeztext(tlp->spc, TLSTR(tlp), t->f, -i);
236			else if (i > 0)
237			tlp->width = proptext(tlp->spc, TLSTR(tlp), t->f, i, 3);
238			else
239			tlp->width = uniftext(tlp->spc, TLSTR(tlp), t->f);
240	greg	2.6	if (tlp->width > t->tl.width)
241			t->tl.width = tlp->width;
242	greg	2.4	}
243	greg	1.7	/* we're done */
244			tm->os = (char *)t;
245			return(t);
246			#undef R
247			#undef D
248	greg	1.1	}
249
250
251	greg	2.26	void
252	schorsch	2.25	freetext( /* free text structures associated with m */
253			OBJREC *m
254			)
255	greg	1.7	{
256	greg	2.26	TEXT *tp;
257			TLINE *tlp;
258	greg	1.7
259			tp = (TEXT *)m->os;
260			if (tp == NULL)
261			return;
262	greg	2.9	while ((tlp = tp->tl.next) != NULL) {
263			tp->tl.next = tlp->next;
264	greg	2.20	free((void *)tlp->spc);
265			free((void *)tlp);
266	greg	2.4	}
267	greg	2.20	freefont(tp->f); /* release font reference */
268			free((void *)tp);
269	greg	1.7	m->os = NULL;
270			}
271
272
273	schorsch	2.25	static int
274			intext( /* check to see if p is in text glyph */
275			FVECT p,
276			OBJREC *m
277			)
278	greg	1.7	{
279	greg	2.26	TEXT *tp;
280			TLINE *tlp;
281	greg	1.10	FVECT v;
282			double y, x;
283	greg	2.26	int i, h;
284	greg	1.7	/* first, compute position in text */
285	greg	1.9	tp = gettext(m);
286	greg	1.7	v[0] = p[0] - m->oargs.farg[0];
287			v[1] = p[1] - m->oargs.farg[1];
288			v[2] = p[2] - m->oargs.farg[2];
289	greg	2.6	x = DOT(v, tp->right);
290			i = sndx(m);
291			if (i < m->oargs.nfargs)
292	greg	2.14	x = tp->f->mwidth + 255.fabs(m->oargs.farg[i]);
293	greg	2.6	else
294	greg	2.14	x *= 255.;
295	greg	2.6	h = x;
296	greg	2.4	i = y = DOT(v, tp->down);
297	greg	1.7	if (x < 0.0 \|\| y < 0.0)
298			return(0);
299	greg	2.4	x -= (double)h;
300	greg	2.14	y = ((i+1) - y)*255.;
301	greg	2.4	/* find the line position */
302	greg	1.8	for (tlp = tp->tl.next; tlp != NULL; tlp = tlp->next)
303	greg	2.4	if (--i < 0)
304	greg	1.8	break;
305	greg	2.4	if (tlp == NULL \|\| h >= tlp->width)
306	greg	1.7	return(0);
307	greg	2.4	for (i = 0; (h -= tlp->spc[i]) >= 0; i++)
308	greg	2.14	if (h < 255 && inglyph(h+x, y,
309	greg	2.4	tp->f->fg[TLSTR(tlp)[i]&0xff]))
310			return(1);
311			return(0);
312	greg	1.7	}
313
314
315	schorsch	2.25	static int
316			inglyph( /* (x,y) within font glyph gl? */
317			double x, /* real coordinates in range [0,255) */
318			double y,
319	greg	2.26	GLYPH *gl
320	schorsch	2.25	)
321	greg	1.1	{
322			int n, ncross;
323	greg	2.5	int xlb, ylb;
324			int tv;
325	greg	2.26	GORD p0, p1;
326	greg	1.1
327	greg	1.7	if (gl == NULL)
328	greg	1.1	return(0);
329	greg	2.5	xlb = x;
330			ylb = y;
331			if (gl->left > xlb \|\| gl->right <= xlb \|\| /* check extent */
332			gl->bottom > ylb \|\| gl->top <= ylb)
333			return(0);
334			xlb = xlb<<1 \| 1; /* add 1/2 to test points... */
335			ylb = ylb<<1 \| 1; /* ...so no equal comparisons */
336	greg	2.2	n = gl->nverts; /* get # of vertices */
337			p0 = gvlist(gl) + 2(n-1); / connect last to first */
338			p1 = gvlist(gl);
339	greg	1.1	ncross = 0;
340			/* positive x axis cross test */
341			while (n--) {
342	greg	2.5	if ((p0[1]<<1 > ylb) ^ (p1[1]<<1 > ylb)) {
343	schorsch	2.23	tv = (p0[0]<<1 > xlb) \| ((p1[0]<<1 > xlb) << 1);
344	greg	2.5	if (tv == 03)
345	greg	1.1	ncross++;
346	greg	2.5	else if (tv)
347	greg	1.1	ncross += (p1[1] > p0[1]) ^
348			((p0[1]-y)*(p1[0]-x) >
349			(p0[0]-x)*(p1[1]-y));
350	greg	2.5	}
351	greg	1.1	p0 = p1;
352			p1 += 2;
353			}
354			return(ncross & 01);
355			}