sidebar: air between tabs (tab_gap)

A tab carrying three rows of wrapped status and the tab under it carrying
three more read as one column of text: the labels are in there, but the list
has stopped looking like a list. tab_gap is the blank rows between them, 0 by
default, which is exactly what the sidebar has always drawn.

It is the space *between* tabs and nothing else. Above the first tab is
tab_bar_pad's and before the button is newtab_pad's, so the gap is applied
before each label except the first and none of the three is ever paid twice.

Given up a row at a time when the list is short of room, ahead of every label
and the button, which is the same order the pad and the statuses already
follow: a gap that pushed a tab off the bottom would be spacing costing you
the thing it spaces. Paint rather than layout, so tuning it repaints without
reflowing any pane. Sidebars only -- the top strip is one row, and the space
between tabs there is the label's own padding.

1 files changed, 8 insertions, 0 deletions

diff --git a/include/config.h b/include/config.h
index d0aeccd..b6cbc86 100644
--- a/include/config.h
+++ b/include/config.h
@@ -339,6 +339,14 @@ typedef struct {
    * own window buttons when the multiplexer fills a borderless window.
    * Ignored for top, which has exactly one row and no air to give. */
   uint16_t tab_bar_pad;
+  /* Blank rows between one tab and the next, so a list of tabs each carrying
+   * a paragraph of status reads as separate entries rather than as one
+   * column of text. Sidebars only: the top strip is a single row, where the
+   * space between tabs is the label's own padding and there is none to give.
+   * Paint, not layout -- the panes' rectangle is the same at 0 as at 3 --
+   * and dropped a row at a time when the list is short of room, because the
+   * gap must never be what costs you the tab it was separating. */
+  uint16_t tab_gap;
   /* Status rows under each of a sidebar's tabs: what the panes inside said
    * through OSC 5577 (or how they died), at most this many rows per tab with
    * an ellipsis when there was more. The sidebar is what makes this possible