From 03c675c6e2d9152da363eefcb1a2c3b059aac2ba Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Tue, 16 Feb 2021 19:11:38 +0100
Subject: [PATCH] sixel: implement private mode 8452 - cursor positioning after
 sixel

When disabled (the default), the cursor is positioned on a new line
after emitting a sixel image.

When enabled, the cursor is positioned to the right of the sixel
image.

Closes #363
---
 CHANGELOG.md           |  2 ++
 csi.c                  |  7 +++++++
 doc/foot-ctlseqs.5.scd |  3 +++
 sixel.c                | 24 ++++++++++++++++++++++--
 terminal.h             |  3 +++
 5 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e4a00be3..1473707b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -47,6 +47,8 @@
   (https://codeberg.org/dnkl/foot/issues/347)
 * `DECSET 1070` - sixel private color palette
   (https://codeberg.org/dnkl/foot/issues/362).
+* `DECSET 8452` - position cursor to the right of sixels
+  (https://codeberg.org/dnkl/foot/issues/363).
 
 
 ### Changed
diff --git a/csi.c b/csi.c
index d7a26e3c..b05327b1 100644
--- a/csi.c
+++ b/csi.c
@@ -552,6 +552,10 @@ decset_decrst(struct terminal *term, unsigned param, bool enable)
         term->bracketed_paste = enable;
         break;
 
+    case 8452:
+        term->sixel.cursor_right_of_graphics = enable;
+        break;
+
     case 27127:
         term->modify_escape_key = enable;
         break;
@@ -613,6 +617,7 @@ decrqm(const struct terminal *term, unsigned param, bool *enabled)
     case 1049: *enabled = term->grid == &term->alt; return true;
     case 1079: *enabled = term->sixel.use_private_palette; return true;
     case 2004: *enabled = term->bracketed_paste; return true;
+    case 8452: *enabled = term->sixel.cursor_right_of_graphics; return true;
     case 27127: *enabled = term->modify_escape_key; return true;
     case 737769: *enabled = term_ime_is_enabled(term); return true;
     }
@@ -653,6 +658,7 @@ xtsave(struct terminal *term, unsigned param)
     case 1049: term->xtsave.alt_screen = term->grid == &term->alt; break;
     case 1070: term->xtsave.sixel_private_palette = term->sixel.use_private_palette; break;
     case 2004: term->xtsave.bracketed_paste = term->bracketed_paste; break;
+    case 8452: term->xtsave.sixel_cursor_right_of_graphics = term->sixel.cursor_right_of_graphics; break;
     case 27127: term->xtsave.modify_escape_key = term->modify_escape_key; break;
     case 737769: term->xtsave.ime = term_ime_is_enabled(term); break;
     }
@@ -692,6 +698,7 @@ xtrestore(struct terminal *term, unsigned param)
     case 1049: enable = term->xtsave.alt_screen; break;
     case 1070: enable = term->xtsave.sixel_private_palette; break;
     case 2004: enable = term->xtsave.bracketed_paste; break;
+    case 8452: enable = term->xtsave.sixel_cursor_right_of_graphics; break;
     case 27127: enable = term->xtsave.modify_escape_key; break;
     case 737769: enable = term->xtsave.ime; break;
 
diff --git a/doc/foot-ctlseqs.5.scd b/doc/foot-ctlseqs.5.scd
index 9b459507..8b8d2643 100644
--- a/doc/foot-ctlseqs.5.scd
+++ b/doc/foot-ctlseqs.5.scd
@@ -316,6 +316,9 @@ that corresponds to one of the following modes:
 |  2004
 :  xterm
 :  Wrap pasted text with start/end delimiters (bracketed paste mode)
+|  8452
+:  xterm
+:  Position cursor to the right of sixels, instead of on the next line
 |  737769
 :  foot
 :  Input Method Editor (IME) mode
diff --git a/sixel.c b/sixel.c
index 63ce493b..4f41348c 100644
--- a/sixel.c
+++ b/sixel.c
@@ -767,9 +767,29 @@ sixel_unhook(struct terminal *term)
             {
                 row->cells[col].attrs.clean = 0;
             }
-            term_linefeed(term);
+
+            if (i < image.rows - 1 || !term->sixel.cursor_right_of_graphics)
+                term_linefeed(term);
         }
-        term_carriage_return(term);
+
+        /*
+         * Position cursor
+         *
+         * Private mode 8452 controls where we leave the cursor after
+         * emitting a sixel:
+         *
+         * When disabled (the default), the cursor is positioned on a
+         * new line.
+         *
+         * When enabled, the cursor is positioned to the right of the
+         * sixel.
+         */
+        term_cursor_to(
+            term,
+            term->grid->cursor.point.row,
+            (term->sixel.cursor_right_of_graphics
+             ? min(image.pos.col + image.cols, term->cols - 1)
+             : 0));
 
         _sixel_overwrite_by_rectangle(
             term, image.pos.row, image.pos.col, image.rows, image.cols);
diff --git a/terminal.h b/terminal.h
index 632f6029..898a5770 100644
--- a/terminal.h
+++ b/terminal.h
@@ -361,6 +361,7 @@ struct terminal {
         uint32_t ime:1;
 
         uint32_t sixel_private_palette:1;
+        uint32_t sixel_cursor_right_of_graphics:1;
     } xtsave;
 
     char *window_title;
@@ -538,6 +539,8 @@ struct terminal {
         unsigned param;      /* Currently collecting parameter, for RASTER, COLOR_SPEC and REPEAT */
         unsigned param_idx;  /* Parameters seen */
 
+        bool cursor_right_of_graphics:1;  /* Private mode 8452 */
+
         /* Application configurable */
         unsigned palette_size;  /* Number of colors in palette */
         unsigned max_width;     /* Maximum image width, in pixels */