# HG changeset patch
# User nobody_special
# Date 1618276338 14400
# Node ID aa698b41897d6eb1323cce718c7dc8bd290ac174
# Parent  85895476fecf64c5c4ad3334fb6fa4430aae5816
scat(7): get DSS plates from the web

diff -r 85895476fecf -r aa698b41897d sys/src/cmd/scat/display.c
--- a/sys/src/cmd/scat/display.c	Tue Mar 02 22:56:58 2021 -0500
+++ b/sys/src/cmd/scat/display.c	Mon Apr 12 21:12:18 2021 -0400
@@ -4,6 +4,66 @@
 #include <draw.h>
 #include "sky.h"
 
+char *dssfmt = "https://archive.stsci.edu/cgi-bin/dss_search?v=poss2ukstu_red&r=%s&d=%s&e=J2000&h=%s&w=%s&f=gif";
+
+/* BUGS: Plenty more than what's listed here.
+ * - foolishly hardcoded block sizes to malloc(),
+ * - web connection is discarded but perhaps it should be kept persistent,
+ * - retreived plate is grayscale. DSS red and blue filters could potentially 
+ *   be combined (with an interpolated green channel) to create false-color 
+ *   plates.
+ */
+void
+webplate(char *ra, char *dec, char *h, char *w)
+{
+	char *url, *ndir, *path;
+	int fd, many;
+	Dir *wdir;
+
+	wdir = dirstat("/mnt/web/");
+
+	if(!wdir) {
+		fprint(2, "webfs expected at /mnt/web/\n");
+		goto webOut;
+	}
+	
+	if((fd = open("/mnt/web/clone", ORDWR)) < 0) {
+		fprint(2, "failed to clone web connection.\n");
+		goto webOut;
+	}
+
+	ndir = malloc(6);
+	many = read(fd, ndir, 6);
+	ndir[many-1] = '\0';
+
+	url = malloc(250);
+	path = malloc(250);
+	sprint(url, dssfmt, ra, dec, h, w);
+	sprint(path, "/mnt/web/%s/body", ndir);
+	
+	print("Fetching plate from:\n%s\n", url);
+
+	fprint(fd, "url %s", url);
+
+	switch(rfork(RFPROC|RFFDG|RFNOTEG|RFNOWAIT)){
+	case -1:
+		fprint(2, "fork failed retreiving plate from web: %r\n");
+		break;
+	case 0:
+		execl("/bin/page", "page", "-w", path, nil);
+		fprint(2, "exec failed: %r\n");
+		exits("exec page");
+	default:
+		break;
+	}
+
+	free(url);
+	free(ndir);
+	free(path);
+webOut:
+	free(wdir);
+}
+
 void
 displaypic(Picture *pic)
 {
diff -r 85895476fecf -r aa698b41897d sys/src/cmd/scat/scat.c
--- a/sys/src/cmd/scat/scat.c	Tue Mar 02 22:56:58 2021 -0500
+++ b/sys/src/cmd/scat/scat.c	Mon Apr 12 21:12:18 2021 -0400
@@ -988,12 +988,27 @@
 	Bprint(&bout, " x %s\n", ms(decsize));
 	Bflush(&bout);
 	flatten();
+
+/* drag scat(7) into the 21st century */
+	if(rasize <= 0 || decsize <=0) {
+		Bprint(&bout, "Plate too small, expanding to 15'x15'\n");
+		rasize = RAD(0.25);
+		decsize = RAD(0.25);
+	}
+	
+	Bflush(&bout);
+
+	webplate(hms(racenter), dms(deccenter), ms(rasize), ms(decsize));
+
+/* Skip old codepath for calling up DSS plates from jukebox */
+/*
 	pic = image(racenter, deccenter, rasize, decsize);
 	if(pic == 0)
 		return;
 	Bprint(&bout, "plate %s locn %d %d %d %d\n", pic->name, pic->minx, pic->miny, pic->maxx, pic->maxy);
 	Bflush(&bout);
 	displaypic(pic);
+*/
 }
 
 void
diff -r 85895476fecf -r aa698b41897d sys/src/cmd/scat/sky.h
--- a/sys/src/cmd/scat/sky.h	Tue Mar 02 22:56:58 2021 -0500
+++ b/sys/src/cmd/scat/sky.h	Mon Apr 12 21:12:18 2021 -0400
@@ -391,6 +391,7 @@
 extern Angle	getdec(char*);
 extern void	getplates(void);
 extern Img*	dssread(char*);
+extern void webplate(char*, char*, char*, char*);
 extern void	hinv(Pix*, int, int);
 extern int	input_bit(Biobuf*);
 extern int	input_nbits(Biobuf*, int);