From 39335bc210ec091a13c6574d00b0c3257a550987 Mon Sep 17 00:00:00 2001
From: nick black <dankamongmen@gmail.com>
Date: Wed, 14 Apr 2021 00:48:16 -0400
Subject: [PATCH] [sixel_wipe] set SIXEL_P2_TRANS #1527

---
 src/lib/sixel.c    | 11 +++++++++++
 src/lib/terminfo.c |  1 +
 2 files changed, 12 insertions(+)

diff --git a/src/lib/sixel.c b/src/lib/sixel.c
index c8c6e1b28..1b1090c89 100644
--- a/src/lib/sixel.c
+++ b/src/lib/sixel.c
@@ -540,3 +540,14 @@ int sprite_sixel_init(int fd){
   // the upper left corner of the screen).
   return tty_emit("\e[?80;8452h", fd);
 }
+
+// we return -1 because we're not doing a proper wipe -- that's not possible
+// using sixel. we just mark it as partially transparent, so that if it's
+// redrawn, it's redrawn using P2=1.
+int sixel_wipe(const notcurses* nc, sprixel* s, int ycell, int xcell){
+  (void)nc;
+  (void)ycell;
+  (void)xcell;
+  change_p2(s->glyph, SIXEL_P2_TRANS);
+  return -1;
+}
diff --git a/src/lib/terminfo.c b/src/lib/terminfo.c
index 2471fe39d..28dd444a8 100644
--- a/src/lib/terminfo.c
+++ b/src/lib/terminfo.c
@@ -338,6 +338,7 @@ setup_sixel(tinfo* ti){
   ti->sixel_maxx = 4096; // whee!
   ti->sixel_maxy = 4096;
   ti->pixel_destroy = sixel_delete;
+  ti->pixel_cell_wipe = sixel_wipe;
 }
 
 // query for Sixel support