src/rt/text.c

#ifndef lint
static const char       RCSid[] = "$Id: text.c,v 2.24 2004/02/12 18:55:50 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);


extern int
do_text(
        register 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)
                        scalecolor(r->pcol, m->oargs.farg[9]);
                else
                        scalecolor(r->pcol, m->oargs.farg[10]);
        } else { /* PAT_CTEXT */
                COLOR  cval;
                if (foreground)
                        setcolor(cval, m->oargs.farg[9],
                                        m->oargs.farg[10],
                                        m->oargs.farg[11]);
                else
                        setcolor(cval, m->oargs.farg[12],
                                        m->oargs.farg[13],
                                        m->oargs.farg[14]);
                multcolor(r->pcol, cval);
        }
        return(0);
}


static TLINE *
tlalloc(                        /* allocate and assign text line */
        char  *s
)
{
        register int  siz;
        register 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 */
        register 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;
        register int  i;
        register TLINE  *tlp;
        register 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(USER, 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)]);
                                                /* 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
}


extern void
freetext(                       /* free text structures associated with m */
        OBJREC  *m
)
{
        register TEXT  *tp;
        register 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
)
{
        register TEXT  *tp;
        register TLINE  *tlp;
        FVECT  v;
        double  y, x;
        register 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,
        register GLYPH  *gl
)
{
        int  n, ncross;
        int  xlb, ylb;
        int  tv;
        register 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:	2.25
Committed:	Tue Mar 30 16:13:01 2004 UTC (20 years, 1 month ago) by schorsch
Content type:	text/plain
Branch:	MAIN
CVS Tags:	rad3R7P2, rad3R7P1, rad4R1, rad4R0, rad3R6, rad3R6P1, rad3R8, rad3R9
Changes since 2.24:	+34 -24 lines
Log Message:	Continued ANSIfication. There are only bits and pieces left now.
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	schorsch	2.25	static const char RCSid[] = "$Id: text.c,v 2.24 2004/02/12 18:55:50 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	schorsch	2.25	extern int
86			do_text(
87			register OBJREC *m,
88			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	1.1	if (foreground)
117	greg	1.7	scalecolor(r->pcol, m->oargs.farg[9]);
118	greg	1.1	else
119	greg	1.7	scalecolor(r->pcol, m->oargs.farg[10]);
120	greg	1.1	} else { /* PAT_CTEXT */
121			COLOR cval;
122			if (foreground)
123	greg	1.7	setcolor(cval, m->oargs.farg[9],
124			m->oargs.farg[10],
125			m->oargs.farg[11]);
126	greg	1.1	else
127	greg	1.7	setcolor(cval, m->oargs.farg[12],
128			m->oargs.farg[13],
129			m->oargs.farg[14]);
130	greg	1.1	multcolor(r->pcol, cval);
131			}
132	greg	2.12	return(0);
133	greg	1.1	}
134
135
136	schorsch	2.25	static TLINE *
137			tlalloc( /* allocate and assign text line */
138			char *s
139			)
140	greg	1.8	{
141	greg	2.4	register int siz;
142	greg	1.8	register TLINE *tl;
143
144	greg	2.4	siz = strlen(s) + 1;
145			if ((tl=(TLINE *)malloc(sizeof(TLINE)+siz)) == NULL \|\|
146			(tl->spc=(short )malloc(sizsizeof(short))) == NULL)
147	greg	1.8	error(SYSTEM, "out of memory in tlalloc");
148			tl->next = NULL;
149			strcpy(TLSTR(tl), s);
150			return(tl);
151			}
152
153
154	schorsch	2.25	static TEXT *
155			gettext( /* get text structure for material */
156			register OBJREC *tm
157			)
158	greg	1.1	{
159	greg	1.7	#define R (tm->oargs.farg+3)
160			#define D (tm->oargs.farg+6)
161			FVECT DxR;
162			double d;
163	greg	1.1	FILE *fp;
164			char linbuf[512];
165	greg	1.8	TEXT *t;
166	greg	1.1	register int i;
167	greg	1.8	register TLINE *tlp;
168	greg	1.1	register char *s;
169
170	greg	1.7	if ((t = (TEXT *)tm->os) != NULL)
171			return(t);
172			/* check arguments */
173	greg	2.4	if (tm->oargs.nsargs - tndx(tm) < 1 \|\| tm->oargs.nfargs < sndx(tm))
174	greg	1.7	objerror(tm, USER, "bad # arguments");
175			if ((t = (TEXT *)malloc(sizeof(TEXT))) == NULL)
176	greg	2.10	error(SYSTEM, "out of memory in gettext");
177	greg	1.7	/* compute vectors */
178			fcross(DxR, D, R);
179			fcross(t->right, DxR, D);
180	gregl	2.17	d = DOT(t->right,t->right);
181	gwlarson	2.19	if (d <= FTINYFTINYFTINY*FTINY)
182	gregl	2.17	objerror(tm, USER, "illegal motion vector");
183			d = DOT(D,D)/d;
184	greg	1.7	for (i = 0; i < 3; i++)
185			t->right[i] *= d;
186			fcross(t->down, R, DxR);
187	greg	1.9	d = DOT(R,R)/DOT(t->down,t->down);
188	greg	1.7	for (i = 0; i < 3; i++)
189			t->down[i] *= d;
190			/* get text */
191	greg	1.8	tlp = &t->tl;
192	greg	1.7	if (tm->oargs.nsargs - tndx(tm) > 1) { /* single line */
193			s = linbuf;
194			for (i = tndx(tm)+1; i < tm->oargs.nsargs; i++) {
195			strcpy(s, tm->oargs.sarg[i]);
196			s += strlen(s);
197			*s++ = ' ';
198	greg	1.1	}
199	greg	1.7	*--s = '\0';
200	greg	1.8	tlp->next = tlalloc(linbuf);
201			tlp = tlp->next;
202	greg	1.7	} else { /* text file */
203			if ((s = getpath(tm->oargs.sarg[tndx(tm)],
204	greg	2.22	getrlibpath(), R_OK)) == NULL) {
205	greg	1.7	sprintf(errmsg, "cannot find text file \"%s\"",
206			tm->oargs.sarg[tndx(tm)]);
207			error(USER, errmsg);
208			}
209			if ((fp = fopen(s, "r")) == NULL) {
210	greg	2.4	sprintf(errmsg, "cannot open text file \"%s\"", s);
211	greg	1.7	error(SYSTEM, errmsg);
212			}
213	greg	1.8	while (fgets(linbuf, sizeof(linbuf), fp) != NULL) {
214	greg	1.7	s = linbuf + strlen(linbuf) - 1;
215			if (*s == '\n')
216			*s = '\0';
217	greg	1.8	tlp->next = tlalloc(linbuf);
218			tlp = tlp->next;
219	greg	1.7	}
220			fclose(fp);
221	greg	1.1	}
222	greg	1.8	tlp->next = NULL;
223	greg	1.7	/* get the font */
224			t->f = getfont(tm->oargs.sarg[fndx(tm)]);
225	greg	2.4	/* compute character spacing */
226			i = sndx(tm);
227			d = i < tm->oargs.nfargs ? tm->oargs.farg[i] : 0.0;
228	greg	2.14	i = d * 255.0;
229	greg	2.6	t->tl.width = 0;
230	greg	2.4	for (tlp = t->tl.next; tlp != NULL; tlp = tlp->next) {
231			if (i < 0)
232			tlp->width = squeeztext(tlp->spc, TLSTR(tlp), t->f, -i);
233			else if (i > 0)
234			tlp->width = proptext(tlp->spc, TLSTR(tlp), t->f, i, 3);
235			else
236			tlp->width = uniftext(tlp->spc, TLSTR(tlp), t->f);
237	greg	2.6	if (tlp->width > t->tl.width)
238			t->tl.width = tlp->width;
239	greg	2.4	}
240	greg	1.7	/* we're done */
241			tm->os = (char *)t;
242			return(t);
243			#undef R
244			#undef D
245	greg	1.1	}
246
247
248	schorsch	2.25	extern void
249			freetext( /* free text structures associated with m */
250			OBJREC *m
251			)
252	greg	1.7	{
253	greg	2.9	register TEXT *tp;
254			register TLINE *tlp;
255	greg	1.7
256			tp = (TEXT *)m->os;
257			if (tp == NULL)
258			return;
259	greg	2.9	while ((tlp = tp->tl.next) != NULL) {
260			tp->tl.next = tlp->next;
261	greg	2.20	free((void *)tlp->spc);
262			free((void *)tlp);
263	greg	2.4	}
264	greg	2.20	freefont(tp->f); /* release font reference */
265			free((void *)tp);
266	greg	1.7	m->os = NULL;
267			}
268
269
270	schorsch	2.25	static int
271			intext( /* check to see if p is in text glyph */
272			FVECT p,
273			OBJREC *m
274			)
275	greg	1.7	{
276			register TEXT *tp;
277	greg	1.8	register TLINE *tlp;
278	greg	1.10	FVECT v;
279			double y, x;
280	greg	2.4	register int i, h;
281	greg	1.7	/* first, compute position in text */
282	greg	1.9	tp = gettext(m);
283	greg	1.7	v[0] = p[0] - m->oargs.farg[0];
284			v[1] = p[1] - m->oargs.farg[1];
285			v[2] = p[2] - m->oargs.farg[2];
286	greg	2.6	x = DOT(v, tp->right);
287			i = sndx(m);
288			if (i < m->oargs.nfargs)
289	greg	2.14	x = tp->f->mwidth + 255.fabs(m->oargs.farg[i]);
290	greg	2.6	else
291	greg	2.14	x *= 255.;
292	greg	2.6	h = x;
293	greg	2.4	i = y = DOT(v, tp->down);
294	greg	1.7	if (x < 0.0 \|\| y < 0.0)
295			return(0);
296	greg	2.4	x -= (double)h;
297	greg	2.14	y = ((i+1) - y)*255.;
298	greg	2.4	/* find the line position */
299	greg	1.8	for (tlp = tp->tl.next; tlp != NULL; tlp = tlp->next)
300	greg	2.4	if (--i < 0)
301	greg	1.8	break;
302	greg	2.4	if (tlp == NULL \|\| h >= tlp->width)
303	greg	1.7	return(0);
304	greg	2.4	for (i = 0; (h -= tlp->spc[i]) >= 0; i++)
305	greg	2.14	if (h < 255 && inglyph(h+x, y,
306	greg	2.4	tp->f->fg[TLSTR(tlp)[i]&0xff]))
307			return(1);
308			return(0);
309	greg	1.7	}
310
311
312	schorsch	2.25	static int
313			inglyph( /* (x,y) within font glyph gl? */
314			double x, /* real coordinates in range [0,255) */
315			double y,
316			register GLYPH *gl
317			)
318	greg	1.1	{
319			int n, ncross;
320	greg	2.5	int xlb, ylb;
321			int tv;
322	greg	2.2	register GORD p0, p1;
323	greg	1.1
324	greg	1.7	if (gl == NULL)
325	greg	1.1	return(0);
326	greg	2.5	xlb = x;
327			ylb = y;
328			if (gl->left > xlb \|\| gl->right <= xlb \|\| /* check extent */
329			gl->bottom > ylb \|\| gl->top <= ylb)
330			return(0);
331			xlb = xlb<<1 \| 1; /* add 1/2 to test points... */
332			ylb = ylb<<1 \| 1; /* ...so no equal comparisons */
333	greg	2.2	n = gl->nverts; /* get # of vertices */
334			p0 = gvlist(gl) + 2(n-1); / connect last to first */
335			p1 = gvlist(gl);
336	greg	1.1	ncross = 0;
337			/* positive x axis cross test */
338			while (n--) {
339	greg	2.5	if ((p0[1]<<1 > ylb) ^ (p1[1]<<1 > ylb)) {
340	schorsch	2.23	tv = (p0[0]<<1 > xlb) \| ((p1[0]<<1 > xlb) << 1);
341	greg	2.5	if (tv == 03)
342	greg	1.1	ncross++;
343	greg	2.5	else if (tv)
344	greg	1.1	ncross += (p1[1] > p0[1]) ^
345			((p0[1]-y)*(p1[0]-x) >
346			(p0[0]-x)*(p1[1]-y));
347	greg	2.5	}
348	greg	1.1	p0 = p1;
349			p1 += 2;
350			}
351			return(ncross & 01);
352			}