Use clear-to-end-of-line for flicker-free updates.

1 files changed, 19 insertions, 9 deletions

diff --git a/pw.c b/pw.c
index dd0160e..e533a5e 100644
--- a/pw.c
+++ b/pw.c
@@ -227,6 +227,18 @@ static void usage(const char *name)
   exit(EXIT_FAILURE);
 }
 
+static void clrline()
+{
+  printf("\r\033[J");
+}
+
+static void clreol(int nl)
+{
+  printf("\033[K");
+  if (nl)
+    putchar('\n');
+}
+
 static void drawline(const char *line, int hpos, int columns)
 {
   size_t len = dslen(line);
@@ -238,22 +250,19 @@ static void drawline(const char *line, int hpos, int columns)
       putchar('>');
     }
     if (len < (size_t) columns - 1) {
-      puts(line);
+      fputs(line, stdout);
+      clreol(1);
     } else {
       for (int i = 0; i < columns - 2; i++)
         putchar(line[i]);
       puts("<");
     }
   } else {
-    puts(">");
+    putchar('>');
+    clreol(1);
   }
 }
 
-static void clrline()
-{
-  printf("\r\033[J");
-}
-
 static void drawstatus(int columns, unsigned stat, char *cmd)
 {
   char status[cmdsize] = "", *ptr = status;
@@ -292,6 +301,7 @@ static void drawstatus(int columns, unsigned stat, char *cmd)
   }
 
   fputs(status, stdout);
+  clreol(0);
   fflush(stdout);
 }
 
@@ -307,13 +317,13 @@ static void redraw(char **circbuf, int nlines, int hpos,
        dsdrop(snapshot[i]);
     }
     snaplines = nlines;
-    printf("\r\033[%dA\033[J", nlines);
+    printf("\r\033[%dA", nlines);
     for (int i = 0; i < nlines; i++) {
       drawline(circbuf[i], hpos, columns);
       snapshot[i] = dsref(circbuf[i]);
     }
   } else {
-    printf("\r\033[%dA\033[J", snaplines);
+    printf("\r\033[%dA", snaplines);
     for (int i = 0; i < snaplines; i++)
       drawline(snapshot[i], hpos, columns);
   }