sl0ppty: three ways back from a painted pane

    printf '\033]5577;1;shader;\033\\'                  # from the program
    sl0ppty cmd '{"cmd":"clear-shaders","id":0}'   # from outside it
    bind "z" "clear-shaders"                       # from the keyboard

`app_clear_pane_shaders` empties both of a pane's chains and says whether
there was anything there, which is what lets a key answer "shaders cleared"
or "no shaders on this pane" instead of maybe having done something.

In-band it is not a new verb: naming no rect means all of them. `shader;`
sits under `shader;chrome;` and `shader;content;` as the degenerate case of
"which rect", so a program puts a pane back in one exchange and cannot leave
it half done. `contrib/shader-repl`'s `:both` now uses that rather than two.

**None of the three is gated on `in_band_shaders`.** A chain outlives the
setting that allowed it -- paint a pane, then turn the setting off, and the
paint is still there, because a chain belongs to the pane and not to the file
(there is a test that reloads with it off and clears anyway). A way out that
the setting can take away is not a way out. The operator path matters for the
same reason: the program that made a pane unreadable is not always in a state
to put it back.

They clear what the *pane* set. The config's chains and the session's own
dimming are not this pane's doing and are derived every frame anyway.

The action is bound to nothing, like `scroll-up`: it is in the palette, which
is what the palette is for, and the docs say to bind it if you leave the
setting on. Which is where a second bug turned up -- the palette truncates a
label at 26 characters, so "undo this pane's own shaders" read as "undo this
pane's own shade" on screen. Renamed to fit, and `tests/test_palette.py` now
checks every label against the column, since nothing failed for that: it just
looked like a typo in front of someone.

1 files changed, 4 insertions, 0 deletions

diff --git a/src/config.c b/src/config.c
index 70667ba..24837cb 100644
--- a/src/config.c
+++ b/src/config.c
@@ -24,6 +24,7 @@ static const struct {
     {"resize-left", ACT_RESIZE_LEFT}, {"resize-right", ACT_RESIZE_RIGHT},
     {"resize-up", ACT_RESIZE_UP},     {"resize-down", ACT_RESIZE_DOWN},
     {"equalize", ACT_EQUALIZE},
+    {"clear-shaders", ACT_CLEAR_SHADERS},
     {"rotate-layout", ACT_ROTATE_LAYOUT},
     {"scroll-up", ACT_SCROLL_UP},     {"scroll-down", ACT_SCROLL_DOWN},
     {"scroll-page-up", ACT_SCROLL_PAGE_UP},
@@ -829,6 +830,9 @@ static const struct {
     /* Short enough to fit the palette's label column, which truncates at 26 —
      * "give every pane an even share" read as "give every pane an even sh". */
     {ACT_EQUALIZE, "size", "even out every split"},
+    /* Under `panes`, not `size`: it undoes what the program in the pane did to
+     * the pane, which is a fact about that pane and not about the layout. */
+    {ACT_CLEAR_SHADERS, "panes", "clear this pane's shaders"},
     {ACT_ROTATE_LAYOUT, "size", "turn the layout a quarter"},
 
     {ACT_NEW_TAB, "tabs", "new tab"},