New + command to increase display height.

2 files changed, 17 insertions, 1 deletions

diff --git a/pw.1 b/pw.1
index 7fe38a4..c09bd2c 100644
--- a/pw.1
+++ b/pw.1
@@ -217,6 +217,12 @@ recall using the up and down arrow keys or
 and
 .BR Ctrl-N .
 
+.IP \fB+\fP
+Increases the display size by one line. This doesn't come into effect
+immediately; the newly opened position must be filled by a line of data
+from standard input. There is no way to reduce the size dynamically.
+Resizing beyond the terminal height is not permitted, if the height is known.
+
 .IP \fBCtrl-Z\fI
 Suspends
 .IR pw ,
@@ -372,7 +378,7 @@ The program uses hard-coded ANSI sequences, so it doesn't support interesting
 old terminals. On the other hand, it carries no dependency on any
 terminal abstraction library/data.
 
-The intervals and number of lines cannot be dynamically adjusted.
+The intervals cannot be dynamically adjusted.
 
 There is no support for unwrapping long lines, which would be useful for
 copy and paste.
diff --git a/pw.c b/pw.c
index eb4c425..d695ad9 100644
--- a/pw.c
+++ b/pw.c
@@ -692,6 +692,16 @@ int main(int argc, char **argv)
             cmdbuf[1] = 0;
             curcmd = cmdbuf;
             break;
+          case '+':
+            if (ws.ws_row && maxlines >= ws.ws_row - 1)
+              break;
+            maxlines++;
+            if ((circbuf = realloc(circbuf, sizeof *circbuf * maxlines)) == 0)
+              panic("out of memory");
+            if ((snapshot = realloc(snapshot, sizeof *snapshot * maxlines)) == 0)
+              panic("out of memory");
+            snapshot[maxlines-1] = circbuf[maxlines-1] = 0;
+            break;
           }
           break;
         case kbd_esc: