Add MC for a single line

This sequence print the current line. It is different to the
'printer on' sequence, where all the characters that arrive to the
terminal are printer. Here only the ascii characters are printed.

st.c

@@ -356,6 +356,8 @@ static void strparse(void);
 static void strreset(void);
 
 static int tattrset(int);
+static void tprinter(char *s, size_t len);
+static void tdumpline(int);
 static void tclearregion(int, int, int, int);
 static void tcursor(int);
 static void tdeletechar(int);
@@ -470,7 +472,7 @@ static STREscape strescseq;
 static int cmdfd;
 static pid_t pid;
 static Selection sel;
-static int iofd;
+static int iofd = STDOUT_FILENO;
 static char **opt_cmd = NULL;
 static char *opt_io = NULL;
 static char *opt_title = NULL;
@@ -1985,6 +1987,8 @@ csihandle(void) {
 		switch(csiescseq.arg[0]) {
 		case 0:
 		case 1:
+			tdumpline(term.c.y);
+			break;
 		case 4:
 			term.mode &= ~MODE_PRINT;
 			break;
@@ -2265,6 +2269,31 @@ strreset(void) {
 	memset(&strescseq, 0, sizeof(strescseq));
 }
 
+void
+tprinter(char *s, size_t len) {
+	if(iofd != -1 && xwrite(iofd, s, len) < 0) {
+		fprintf(stderr, "Error writing in %s:%s\n",
+			opt_io, strerror(errno));
+		close(iofd);
+		iofd = -1;
+	}
+}
+
+void
+tdumpline(int n) {
+	Glyph *bp, *end;
+
+	bp = &term.line[n][0];
+	end = &bp[term.col-1];
+	while(end > bp && !strcmp(" ", end->c))
+		--end;
+	if(bp != end || strcmp(bp->c, " ")) {
+		for( ;bp <= end; ++bp)
+			tprinter(bp->c, strlen(bp->c));
+	}
+	tprinter("\n", 1);
+}
+
 void
 tputtab(bool forward) {
 	uint x = term.c.x;
@@ -2346,14 +2375,8 @@ tputc(char *c, int len) {
 		width = wcwidth(u8char);
 	}
 
-	if(IS_SET(MODE_PRINT) && iofd != -1) {
-		if(xwrite(iofd, c, len) < 0) {
-			fprintf(stderr, "Error writing in %s:%s\n",
-				opt_io, strerror(errno));
-			close(iofd);
-			iofd = -1;
-		}
-	}
+	if(IS_SET(MODE_PRINT))
+		tprinter(c, len);
 
 	/*
 	 * STR sequences must be checked before anything else