sidebar: statuses wear italic instead of an indent, and can wear colour

Three columns of indent is a fifth of a sixteen-column sidebar, spent
saying 'this belongs to the row above'. The slant says it in none: a
status now starts in the same column its tab's name starts in, and is
set in italic. That also survives the monochrome themes in contrib,
where a colour-only distinction would have had nothing to spend.

tab_status_fg / tab_status_bg are there for themes that do have colour
to spend. The fg follows tab_count when a theme does not name it -- the
same declared/derived split apply_scrolled makes -- so the six themes
in contrib get coherent status rows without a line added to any of
them. The bg is unset by default, because a band is opt-in and 'none'
is what a translucent terminal wants; the row is padded so a band that
*is* set covers the row rather than the words on it.

Two things fell out. The padding loop existed three times and is now
pad_cells. And cb_color wrote #000000 for an unset colour, so
 quietly pinned attach_bg -- 'gray
ink on the terminal's own background', says its comment -- to a black
band. Unset colours are now written commented out, the same trick the
states block uses for what it wants re-derived rather than pinned.

2 files changed, 8 insertions, 0 deletions

diff --git a/include/app_internal.h b/include/app_internal.h
index 11f96b4..94a92cf 100644
--- a/include/app_internal.h
+++ b/include/app_internal.h
@@ -392,6 +392,8 @@ extern config_t CFG;
 #define PREFIX_FG (CFG.prefix_fg)
 #define PREFIX_BG (CFG.prefix_bg)
 #define TAB_COUNT (CFG.tab_count)
+#define TAB_STATUS_FG (CFG.tab_status_fg)
+#define TAB_STATUS_BG (CFG.tab_status_bg)
 #define STATUS_C (CFG.status)
 #define STATUS_STATE (CFG.status_state)
 #define FINDER_FG (CFG.finder_fg)
diff --git a/include/config.h b/include/config.h
index 1849014..f7caeba 100644
--- a/include/config.h
+++ b/include/config.h
@@ -438,6 +438,12 @@ typedef struct {
   color_t tab_idle, tab_hover;
   color_t prefix_fg, prefix_bg; /* the "C-a" badge */
   color_t tab_count;            /* how many panes in the session */
+  /* The sidebar's status rows. Their distinction from the labels above them
+   * is carried by the slant (see draw_tab_sidebar), because a monochrome
+   * theme has no colour to spend on it; these are for themes that do. A bg of
+   * none leaves the terminal's own background alone, which is what a
+   * translucent one wants. */
+  color_t tab_status_fg, tab_status_bg;
 
   /* the line along the bottom */
   color_t status, status_state;