src/oping.c: Fix pretty ping graph movement.

[liboping.git] / src / oping.c

diff --git a/src/oping.c b/src/oping.c
index a74cd420a8e5567a5907d6faca5db76e4ff4067c..debe23725709b3d278210f2cbc0439dd4bdf3ceb 100644 (file)
--- a/src/oping.c
+++ b/src/oping.c
@@ -979,12 +979,19 @@ static int update_graph_prettyping (ping_context_t *ctx, /* {{{ */
        /* Determine the first index in the history we need to draw
         * the graph. */
        history_offset = 0;
-       if (((size_t) x_max) < ctx->history_size)
+       if (((size_t) x_max) < ctx->history_size) /* window is smaller than history */
        {
                if (ctx->history_index > x_max)
                        history_offset = ctx->history_index - x_max;
                else /* wrap around */
-                       history_offset = ctx->history_index + x_max - ctx->history_size;
+                       history_offset = ctx->history_index + ctx->history_size - x_max;
+       }
+       else /* window is larger than history */
+       {
+               if (ctx->history_index != ctx->history_size) /* no longer growing. */
+                       history_offset = ctx->history_index;
+               else /* start-up */
+                       history_offset = 0;
        }
 
        for (x = 0; x < x_max; x++)