Correctly initialize altscreen when defaultbg is not 0.

The alternate screen is not properly initialized when st starts. To see
this, set defaultbg in config.h to anything other than 0 (for example, swap
defaultfg and defaultbg), and run:

./st -e sh -c 'tput smcup; read'

You should see that the top-left 80x24 rectangle is black (or whatever
colorname[0] is), while the rest of the screen (if any) has the desired
colorname[defaultbg] color.

The attached patch fixes this by initializing term.c.attr in tnew() before
calling tresize(). It also removes the unnecessary xcalloc() calls, which
misled me on this bug hunt since it is really tclearregion() which
initializes term.lines and term.alt in tresize().

1 files changed, 3 insertions, 14 deletions

diff --git a/st.c b/st.c
index c751aa1..0fa0c86 100644
--- a/st.c
+++ b/st.c
@@ -420,7 +420,6 @@ static int isfullutf8(char *, int);
 static ssize_t xwrite(int, char *, size_t);
 static void *xmalloc(size_t);
 static void *xrealloc(void *, size_t);
-static void *xcalloc(size_t, size_t);
 
 static void (*handler[LASTEvent])(XEvent *) = {
 	[KeyPress] = kpress,
@@ -509,16 +508,6 @@ xrealloc(void *p, size_t len) {
 	return p;
 }
 
-void *
-xcalloc(size_t nmemb, size_t size) {
-	void *p = calloc(nmemb, size);
-
-	if(!p)
-		die("Out of memory\n");
-
-	return p;
-}
-
 int
 utf8decode(char *s, long *u) {
 	uchar c;
@@ -1370,7 +1359,7 @@ treset(void) {
 
 void
 tnew(int col, int row) {
-	memset(&term, 0, sizeof(Term));
+	term = (Term){ .c = { .attr = { .fg = defaultfg, .bg = defaultbg } } };
 	tresize(col, row);
 	term.numlock = 1;
 
@@ -2536,8 +2525,8 @@ tresize(int col, int row) {
 	/* allocate any new rows */
 	for(/* i == minrow */; i < row; i++) {
 		term.dirty[i] = 1;
-		term.line[i] = xcalloc(col, sizeof(Glyph));
-		term.alt [i] = xcalloc(col, sizeof(Glyph));
+		term.line[i] = xmalloc(col * sizeof(Glyph));
+		term.alt[i] = xmalloc(col * sizeof(Glyph));
 	}
 	if(col > term.col) {
 		bp = term.tabs + term.col;