src/cmd/page/ps.c - plan9 - Git at Google

 /*
  * ps.c
  *
  * provide postscript file reading support for page
  */

 #include <u.h>
 #include <libc.h>
 #include <draw.h>
 #include <cursor.h>
 #include <thread.h>
 #include <bio.h>
 #include <ctype.h>
 #include "page.h"

 static int	pswritepage(Document *d, int fd, int page);
 static Image*	psdrawpage(Document *d, int page);
 static char*	pspagename(Document*, int);

 #define R(r) (r).min.x, (r).min.y, (r).max.x, (r).max.y
 Rectangle
 rdbbox(char *p)
 {
 	Rectangle r;
 	int a;
 	char *f[4];
 	while(*p == ':' || *p == ' ' || *p == '\t')
 		p++;
 	if(tokenize(p, f, 4) != 4)
 		return Rect(0,0,0,0);
 	r = Rect(atoi(f[0]), atoi(f[1]), atoi(f[2]), atoi(f[3]));
 	r = canonrect(r);
 	if(Dx(r) <= 0 || Dy(r) <= 0)
 		return Rect(0,0,0,0);

 	if(truetoboundingbox)
 		return r;

 	/* initdraw not called yet, can't use %R */
 	if(chatty) fprint(2, "[%d %d %d %d] -> ", R(r));
 	/*
 	 * attempt to sniff out A4, 8½×11, others
 	 * A4 is 596×842
 	 * 8½×11 is 612×792
 	 */

 	a = Dx(r)*Dy(r);
 	if(a < 300*300){	/* really small, probably supposed to be */
 		/* empty */
 	} else if(Dx(r) <= 596 && r.max.x <= 596 && Dy(r) > 792 && Dy(r) <= 842 && r.max.y <= 842)	/* A4 */
 		r = Rect(0, 0, 596, 842);
 	else {	/* cast up to 8½×11 */
 		if(Dx(r) <= 612 && r.max.x <= 612){
 			r.min.x = 0;
 			r.max.x = 612;
 		}
 		if(Dy(r) <= 792 && r.max.y <= 792){
 			r.min.y = 0;
 			r.max.y = 792;
 		}
 	}
 	if(chatty) fprint(2, "[%d %d %d %d]\n", R(r));
 	return r;
 }

 #define RECT(X) X.min.x, X.min.y, X.max.x, X.max.y

 int
 prefix(char *x, char *y)
 {
 	return strncmp(x, y, strlen(y)) == 0;
 }

 /*
  * document ps is really being printed as n-up pages.
  * we need to treat every n pages as 1.
  */
 void
 repaginate(PSInfo *ps, int n)
 {
 	int i, np, onp;
 	Page *page;

 	page = ps->page;
 	onp = ps->npage;
 	np = (ps->npage+n-1)/n;

 	if(chatty) {
 		for(i=0; i<=onp+1; i++)
 			print("page %d: %d\n", i, page[i].offset);
 	}

 	for(i=0; i<np; i++)
 		page[i] = page[n*i];

 	/* trailer */
 	page[np] = page[onp];

 	/* EOF */
 	page[np+1] = page[onp+1];

 	ps->npage = np;

 	if(chatty) {
 		for(i=0; i<=np+1; i++)
 			print("page %d: %d\n", i, page[i].offset);
 	}

 }

 Document*
 initps(Biobuf *b, int argc, char **argv, uchar *buf, int nbuf)
 {
 	Document *d;
 	PSInfo *ps;
 	char *p;
 	char *q, *r;
 	char eol;
 	char *nargv[1];
 	char fdbuf[20];
 	char tmp[32];
 	int fd;
 	int i;
 	int incomments;
 	int cantranslate;
 	int trailer=0;
 	int nesting=0;
 	int dumb=0;
 	int landscape=0;
 	long psoff;
 	long npage, mpage;
 	Page *page;
 	Rectangle bbox = Rect(0,0,0,0);

 	if(argc > 1) {
 		fprint(2, "can only view one ps file at a time\n");
 		return nil;
 	}

 	fprint(2, "reading through postscript...\n");
 	if(b == nil){	/* standard input; spool to disk (ouch) */
 		fd = spooltodisk(buf, nbuf, nil);
 		sprint(fdbuf, "/dev/fd/%d", fd);
 		b = Bopen(fdbuf, OREAD);
 		if(b == nil){
 			fprint(2, "cannot open disk spool file\n");
 			wexits("Bopen temp");
 		}
 		nargv[0] = fdbuf;
 		argv = nargv;
 	}

 	/* find %!, perhaps after PCL nonsense */
 	Bseek(b, 0, 0);
 	psoff = 0;
 	eol = 0;
 	for(i=0; i<16; i++){
 		psoff = Boffset(b);
 		if(!(p = Brdline(b, eol='\n')) && !(p = Brdline(b, eol='\r'))) {
 			fprint(2, "cannot find end of first line\n");
 			wexits("initps");
 		}
 		if(p[0]=='\x1B')
 			p++, psoff++;
 		if(p[0] == '%' && p[1] == '!')
 			break;
 	}
 	if(i == 16){
 		werrstr("not ps");
 		return nil;
 	}

 	/* page counting */
 	npage = 0;
 	mpage = 16;
 	page = emalloc(mpage*sizeof(*page));
 	memset(page, 0, mpage*sizeof(*page));

 	cantranslate = goodps;
 	incomments = 1;
 Keepreading:
 	while(p = Brdline(b, eol)) {
 		if(p[0] == '%')
 			if(chatty) fprint(2, "ps %.*s\n", utfnlen(p, Blinelen(b)-1), p);
 		if(npage == mpage) {
 			mpage *= 2;
 			page = erealloc(page, mpage*sizeof(*page));
 			memset(&page[npage], 0, npage*sizeof(*page));
 		}

 		if(p[0] != '%' || p[1] != '%')
 			continue;

 		if(prefix(p, "%%BeginDocument")) {
 			nesting++;
 			continue;
 		}
 		if(nesting > 0 && prefix(p, "%%EndDocument")) {
 			nesting--;
 			continue;
 		}
 		if(nesting)
 			continue;

 		if(prefix(p, "%%EndComment")) {
 			incomments = 0;
 			continue;
 		}
 		if(reverse == -1 && prefix(p, "%%PageOrder")) {
 			/* glean whether we should reverse the viewing order */
 			p[Blinelen(b)-1] = 0;
 			if(strstr(p, "Ascend"))
 				reverse = 0;
 			else if(strstr(p, "Descend"))
 				reverse = 1;
 			else if(strstr(p, "Special"))
 				dumb = 1;
 			p[Blinelen(b)-1] = '\n';
 			continue;
 		} else if(prefix(p, "%%Trailer")) {
 			incomments = 1;
 			page[npage].offset = Boffset(b)-Blinelen(b);
 			trailer = 1;
 			continue;
 		} else if(incomments && prefix(p, "%%Orientation")) {
 			if(strstr(p, "Landscape"))
 				landscape = 1;
 		} else if(incomments && Dx(bbox)==0 && prefix(p, q="%%BoundingBox")) {
 			bbox = rdbbox(p+strlen(q)+1);
 			if(chatty)
 				/* can't use %R because haven't initdraw() */
 				fprint(2, "document bbox [%d %d %d %d]\n",
 					RECT(bbox));
 			continue;
 		}

 		/*
 		 * If they use the initgraphics command, we can't play our translation tricks.
 		 */
 		p[Blinelen(b)-1] = 0;
 		if((q=strstr(p, "initgraphics")) && ((r=strchr(p, '%'))==nil || r > q))
 			cantranslate = 0;
 		p[Blinelen(b)-1] = eol;

 		if(!prefix(p, "%%Page:"))
 			continue;

 		/*
 		 * figure out of the %%Page: line contains a page number
 		 * or some other page description to use in the menu bar.
 		 *
 		 * lines look like %%Page: x y or %%Page: x
 		 * we prefer just x, and will generate our
 		 * own if necessary.
 		 */
 		p[Blinelen(b)-1] = 0;
 		if(chatty) fprint(2, "page %s\n", p);
 		r = p+7;
 		while(*r == ' ' || *r == '\t')
 			r++;
 		q = r;
 		while(*q && *q != ' ' && *q != '\t')
 			q++;
 		free(page[npage].name);
 		if(*r) {
 			if(*r == '"' && *q == '"')
 				r++, q--;
 			if(*q)
 				*q = 0;
 			page[npage].name = estrdup(r);
 			*q = 'x';
 		} else {
 			snprint(tmp, sizeof tmp, "p %ld", npage+1);
 			page[npage].name = estrdup(tmp);
 		}

 		/*
 		 * store the offset info for later viewing
 		 */
 		trailer = 0;
 		p[Blinelen(b)-1] = eol;
 		page[npage++].offset = Boffset(b)-Blinelen(b);
 	}
 	if(Blinelen(b) > 0){
 		fprint(2, "page: linelen %d\n", Blinelen(b));
 		Bseek(b, Blinelen(b), 1);
 		goto Keepreading;
 	}

 	if(Dx(bbox) == 0 || Dy(bbox) == 0)
 		bbox = Rect(0,0,612,792);	/* 8½×11 */
 	/*
 	 * if we didn't find any pages, assume the document
 	 * is one big page
 	 */
 	if(npage == 0) {
 		dumb = 1;
 		if(chatty) fprint(2, "don't know where pages are\n");
 		reverse = 0;
 		goodps = 0;
 		trailer = 0;
 		page[npage].name = "p 1";
 		page[npage++].offset = 0;
 	}

 	if(npage+2 > mpage) {
 		mpage += 2;
 		page = erealloc(page, mpage*sizeof(*page));
 		memset(&page[mpage-2], 0, 2*sizeof(*page));
 	}

 	if(!trailer)
 		page[npage].offset = Boffset(b);

 	Bseek(b, 0, 2); /* EOF */
 	page[npage+1].offset = Boffset(b);

 	d = emalloc(sizeof(*d));
 	ps = emalloc(sizeof(*ps));
 	ps->page = page;
 	ps->npage = npage;
 	ps->bbox = bbox;
 	ps->psoff = psoff;

 	d->extra = ps;
 	d->npage = ps->npage;
 	d->b = b;
 	d->drawpage = psdrawpage;
 	d->pagename = pspagename;

 	d->fwdonly = ps->clueless = dumb;
 	d->docname = argv[0];
 	/*
 	 * "tag" the doc as an image for now since there still is the "blank page"
 	 * problem for ps files.
 	 */
 	d->type = Tgfx;

 	if(spawngs(&ps->gs, "-dSAFER") < 0)
 		return nil;

 	if(!cantranslate)
 		bbox.min = ZP;
 	setdim(&ps->gs, bbox, ppi, landscape);

 	if(goodps){
 		/*
 		 * We want to only send the page (i.e. not header and trailer) information
 	 	 * for each page, so initialize the device by sending the header now.
 		 */
 		pswritepage(d, ps->gs.gsfd, -1);
 		waitgs(&ps->gs);
 	}

 	if(dumb) {
 		fprint(ps->gs.gsfd, "(%s) run\n", argv[0]);
 		fprint(ps->gs.gsfd, "(/dev/fd/3) (w) file dup (THIS IS NOT A PLAN9 BITMAP 01234567890123456789012345678901234567890123456789\\n) writestring flushfile\n");
 	}

 	ps->bbox = bbox;

 	return d;
 }

 static int
 pswritepage(Document *d, int fd, int page)
 {
 	Biobuf *b = d->b;
 	PSInfo *ps = d->extra;
 	int t, n, i;
 	long begin, end;
 	char buf[8192];

 	if(page == -1)
 		begin = ps->psoff;
 	else
 		begin = ps->page[page].offset;

 	end = ps->page[page+1].offset;

 	if(chatty) {
 		fprint(2, "writepage(%d)... from #%ld to #%ld...\n",
 			page, begin, end);
 	}
 	Bseek(b, begin, 0);

 	t = end-begin;
 	n = sizeof(buf);
 	if(n > t) n = t;
 	while(t > 0 && (i=Bread(b, buf, n)) > 0) {
 		if(write(fd, buf, i) != i)
 			return -1;
 		t -= i;
 		if(n > t)
 			n = t;
 	}
 	return end-begin;
 }

 static Image*
 psdrawpage(Document *d, int page)
 {
 	PSInfo *ps = d->extra;
 	Image *im;

 	if(ps->clueless)
 		return convert(&ps->gs.g);

 	waitgs(&ps->gs);

 	if(goodps)
 		pswritepage(d, ps->gs.gsfd, page);
 	else {
 		pswritepage(d, ps->gs.gsfd, -1);
 		pswritepage(d, ps->gs.gsfd, page);
 		pswritepage(d, ps->gs.gsfd, d->npage);
 	}
 	/*
 	 * If last line terminator is \r, gs will read ahead to check for \n
 	 * so send one to avoid deadlock.
 	 */
 	write(ps->gs.gsfd, "\n", 1);
 	im = convert(&ps->gs.g);
 	if(im == nil) {
 		fprint(2, "fatal: readimage error %r\n");
 		wexits("readimage");
 	}
 	waitgs(&ps->gs);

 	return im;
 }

 static char*
 pspagename(Document *d, int page)
 {
 	PSInfo *ps = (PSInfo *) d->extra;
 	return ps->page[page].name;
 }
	/*
	* ps.c
	*
	* provide postscript file reading support for page
	*/

	#include <u.h>
	#include <libc.h>
	#include <draw.h>
	#include <cursor.h>
	#include <thread.h>
	#include <bio.h>
	#include <ctype.h>
	#include "page.h"

	static int pswritepage(Document *d, int fd, int page);
	static Image* psdrawpage(Document *d, int page);
	static char* pspagename(Document*, int);

	#define R(r) (r).min.x, (r).min.y, (r).max.x, (r).max.y
	Rectangle
	rdbbox(char *p)
	{
	Rectangle r;
	int a;
	char *f[4];
	while(p == ':' \|\| p == ' ' \|\| *p == '\t')
	p++;
	if(tokenize(p, f, 4) != 4)
	return Rect(0,0,0,0);
	r = Rect(atoi(f[0]), atoi(f[1]), atoi(f[2]), atoi(f[3]));
	r = canonrect(r);
	if(Dx(r) <= 0 \|\| Dy(r) <= 0)
	return Rect(0,0,0,0);

	if(truetoboundingbox)
	return r;

	/* initdraw not called yet, can't use %R */
	if(chatty) fprint(2, "[%d %d %d %d] -> ", R(r));
	/*
	* attempt to sniff out A4, 8½×11, others
	* A4 is 596×842
	* 8½×11 is 612×792
	*/

	a = Dx(r)*Dy(r);
	if(a < 300300){ / really small, probably supposed to be */
	/* empty */
	} else if(Dx(r) <= 596 && r.max.x <= 596 && Dy(r) > 792 && Dy(r) <= 842 && r.max.y <= 842) /* A4 */
	r = Rect(0, 0, 596, 842);
	else { /* cast up to 8½×11 */
	if(Dx(r) <= 612 && r.max.x <= 612){
	r.min.x = 0;
	r.max.x = 612;
	}
	if(Dy(r) <= 792 && r.max.y <= 792){
	r.min.y = 0;
	r.max.y = 792;
	}
	}
	if(chatty) fprint(2, "[%d %d %d %d]\n", R(r));
	return r;
	}

	#define RECT(X) X.min.x, X.min.y, X.max.x, X.max.y

	int
	prefix(char x, char y)
	{
	return strncmp(x, y, strlen(y)) == 0;
	}

	/*
	* document ps is really being printed as n-up pages.
	* we need to treat every n pages as 1.
	*/
	void
	repaginate(PSInfo *ps, int n)
	{
	int i, np, onp;
	Page *page;

	page = ps->page;
	onp = ps->npage;
	np = (ps->npage+n-1)/n;

	if(chatty) {
	for(i=0; i<=onp+1; i++)
	print("page %d: %d\n", i, page[i].offset);
	}

	for(i=0; i<np; i++)
	page[i] = page[n*i];

	/* trailer */
	page[np] = page[onp];

	/* EOF */
	page[np+1] = page[onp+1];

	ps->npage = np;

	if(chatty) {
	for(i=0; i<=np+1; i++)
	print("page %d: %d\n", i, page[i].offset);
	}

	}

	Document*
	initps(Biobuf b, int argc, char argv, uchar buf, int nbuf)
	{
	Document *d;
	PSInfo *ps;
	char *p;
	char q, r;
	char eol;
	char *nargv[1];
	char fdbuf[20];
	char tmp[32];
	int fd;
	int i;
	int incomments;
	int cantranslate;
	int trailer=0;
	int nesting=0;
	int dumb=0;
	int landscape=0;
	long psoff;
	long npage, mpage;
	Page *page;
	Rectangle bbox = Rect(0,0,0,0);

	if(argc > 1) {
	fprint(2, "can only view one ps file at a time\n");
	return nil;
	}

	fprint(2, "reading through postscript...\n");
	if(b == nil){ /* standard input; spool to disk (ouch) */
	fd = spooltodisk(buf, nbuf, nil);
	sprint(fdbuf, "/dev/fd/%d", fd);
	b = Bopen(fdbuf, OREAD);
	if(b == nil){
	fprint(2, "cannot open disk spool file\n");
	wexits("Bopen temp");
	}
	nargv[0] = fdbuf;
	argv = nargv;
	}

	/* find %!, perhaps after PCL nonsense */
	Bseek(b, 0, 0);
	psoff = 0;
	eol = 0;
	for(i=0; i<16; i++){
	psoff = Boffset(b);
	if(!(p = Brdline(b, eol='\n')) && !(p = Brdline(b, eol='\r'))) {
	fprint(2, "cannot find end of first line\n");
	wexits("initps");
	}
	if(p[0]=='\x1B')
	p++, psoff++;
	if(p[0] == '%' && p[1] == '!')
	break;
	}
	if(i == 16){
	werrstr("not ps");
	return nil;
	}

	/* page counting */
	npage = 0;
	mpage = 16;
	page = emalloc(mpagesizeof(page));
	memset(page, 0, mpagesizeof(page));

	cantranslate = goodps;
	incomments = 1;
	Keepreading:
	while(p = Brdline(b, eol)) {
	if(p[0] == '%')
	if(chatty) fprint(2, "ps %.*s\n", utfnlen(p, Blinelen(b)-1), p);
	if(npage == mpage) {
	mpage *= 2;
	page = erealloc(page, mpagesizeof(page));
	memset(&page[npage], 0, npagesizeof(page));
	}

	if(p[0] != '%' \|\| p[1] != '%')
	continue;

	if(prefix(p, "%%BeginDocument")) {
	nesting++;
	continue;
	}
	if(nesting > 0 && prefix(p, "%%EndDocument")) {
	nesting--;
	continue;
	}
	if(nesting)
	continue;

	if(prefix(p, "%%EndComment")) {
	incomments = 0;
	continue;
	}
	if(reverse == -1 && prefix(p, "%%PageOrder")) {
	/* glean whether we should reverse the viewing order */
	p[Blinelen(b)-1] = 0;
	if(strstr(p, "Ascend"))
	reverse = 0;
	else if(strstr(p, "Descend"))
	reverse = 1;
	else if(strstr(p, "Special"))
	dumb = 1;
	p[Blinelen(b)-1] = '\n';
	continue;
	} else if(prefix(p, "%%Trailer")) {
	incomments = 1;
	page[npage].offset = Boffset(b)-Blinelen(b);
	trailer = 1;
	continue;
	} else if(incomments && prefix(p, "%%Orientation")) {
	if(strstr(p, "Landscape"))
	landscape = 1;
	} else if(incomments && Dx(bbox)==0 && prefix(p, q="%%BoundingBox")) {
	bbox = rdbbox(p+strlen(q)+1);
	if(chatty)
	/* can't use %R because haven't initdraw() */
	fprint(2, "document bbox [%d %d %d %d]\n",
	RECT(bbox));
	continue;
	}

	/*
	* If they use the initgraphics command, we can't play our translation tricks.
	*/
	p[Blinelen(b)-1] = 0;
	if((q=strstr(p, "initgraphics")) && ((r=strchr(p, '%'))==nil \|\| r > q))
	cantranslate = 0;
	p[Blinelen(b)-1] = eol;

	if(!prefix(p, "%%Page:"))
	continue;

	/*
	* figure out of the %%Page: line contains a page number
	* or some other page description to use in the menu bar.
	*
	* lines look like %%Page: x y or %%Page: x
	* we prefer just x, and will generate our
	* own if necessary.
	*/
	p[Blinelen(b)-1] = 0;
	if(chatty) fprint(2, "page %s\n", p);
	r = p+7;
	while(r == ' ' \|\| r == '\t')
	r++;
	q = r;
	while(q && q != ' ' && *q != '\t')
	q++;
	free(page[npage].name);
	if(*r) {
	if(r == '"' && q == '"')
	r++, q--;
	if(*q)
	*q = 0;
	page[npage].name = estrdup(r);
	*q = 'x';
	} else {
	snprint(tmp, sizeof tmp, "p %ld", npage+1);
	page[npage].name = estrdup(tmp);
	}

	/*
	* store the offset info for later viewing
	*/
	trailer = 0;
	p[Blinelen(b)-1] = eol;
	page[npage++].offset = Boffset(b)-Blinelen(b);
	}
	if(Blinelen(b) > 0){
	fprint(2, "page: linelen %d\n", Blinelen(b));
	Bseek(b, Blinelen(b), 1);
	goto Keepreading;
	}

	if(Dx(bbox) == 0 \|\| Dy(bbox) == 0)
	bbox = Rect(0,0,612,792); /* 8½×11 */
	/*
	* if we didn't find any pages, assume the document
	* is one big page
	*/
	if(npage == 0) {
	dumb = 1;
	if(chatty) fprint(2, "don't know where pages are\n");
	reverse = 0;
	goodps = 0;
	trailer = 0;
	page[npage].name = "p 1";
	page[npage++].offset = 0;
	}

	if(npage+2 > mpage) {
	mpage += 2;
	page = erealloc(page, mpagesizeof(page));
	memset(&page[mpage-2], 0, 2sizeof(page));
	}

	if(!trailer)
	page[npage].offset = Boffset(b);

	Bseek(b, 0, 2); /* EOF */
	page[npage+1].offset = Boffset(b);

	d = emalloc(sizeof(*d));
	ps = emalloc(sizeof(*ps));
	ps->page = page;
	ps->npage = npage;
	ps->bbox = bbox;
	ps->psoff = psoff;

	d->extra = ps;
	d->npage = ps->npage;
	d->b = b;
	d->drawpage = psdrawpage;
	d->pagename = pspagename;

	d->fwdonly = ps->clueless = dumb;
	d->docname = argv[0];
	/*
	* "tag" the doc as an image for now since there still is the "blank page"
	* problem for ps files.
	*/
	d->type = Tgfx;

	if(spawngs(&ps->gs, "-dSAFER") < 0)
	return nil;

	if(!cantranslate)
	bbox.min = ZP;
	setdim(&ps->gs, bbox, ppi, landscape);

	if(goodps){
	/*
	* We want to only send the page (i.e. not header and trailer) information
	* for each page, so initialize the device by sending the header now.
	*/
	pswritepage(d, ps->gs.gsfd, -1);
	waitgs(&ps->gs);
	}

	if(dumb) {
	fprint(ps->gs.gsfd, "(%s) run\n", argv[0]);
	fprint(ps->gs.gsfd, "(/dev/fd/3) (w) file dup (THIS IS NOT A PLAN9 BITMAP 01234567890123456789012345678901234567890123456789\\n) writestring flushfile\n");
	}

	ps->bbox = bbox;

	return d;
	}

	static int
	pswritepage(Document *d, int fd, int page)
	{
	Biobuf *b = d->b;
	PSInfo *ps = d->extra;
	int t, n, i;
	long begin, end;
	char buf[8192];

	if(page == -1)
	begin = ps->psoff;
	else
	begin = ps->page[page].offset;

	end = ps->page[page+1].offset;

	if(chatty) {
	fprint(2, "writepage(%d)... from #%ld to #%ld...\n",
	page, begin, end);
	}
	Bseek(b, begin, 0);

	t = end-begin;
	n = sizeof(buf);
	if(n > t) n = t;
	while(t > 0 && (i=Bread(b, buf, n)) > 0) {
	if(write(fd, buf, i) != i)
	return -1;
	t -= i;
	if(n > t)
	n = t;
	}
	return end-begin;
	}

	static Image*
	psdrawpage(Document *d, int page)
	{
	PSInfo *ps = d->extra;
	Image *im;

	if(ps->clueless)
	return convert(&ps->gs.g);

	waitgs(&ps->gs);

	if(goodps)
	pswritepage(d, ps->gs.gsfd, page);
	else {
	pswritepage(d, ps->gs.gsfd, -1);
	pswritepage(d, ps->gs.gsfd, page);
	pswritepage(d, ps->gs.gsfd, d->npage);
	}
	/*
	* If last line terminator is \r, gs will read ahead to check for \n
	* so send one to avoid deadlock.
	*/
	write(ps->gs.gsfd, "\n", 1);
	im = convert(&ps->gs.g);
	if(im == nil) {
	fprint(2, "fatal: readimage error %r\n");
	wexits("readimage");
	}
	waitgs(&ps->gs);

	return im;
	}

	static char*
	pspagename(Document *d, int page)
	{
	PSInfo ps = (PSInfo ) d->extra;
	return ps->page[page].name;
	}