From 1a3f02702c6a8461ee401c0f3d0d66c895b69831 Mon Sep 17 00:00:00 2001
From: Hans Petter Jansson <hpj@hpjansson.org>
Date: Sat, 17 Jun 2023 22:35:50 +0200
Subject: [PATCH] seqs: Add seqs to enable/disable the alt screen

---
 chafa/chafa-term-db.c      |  4 ++++
 chafa/chafa-term-info.c    |  2 ++
 chafa/chafa-term-seq-def.h | 34 ++++++++++++++++++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/chafa/chafa-term-db.c b/chafa/chafa-term-db.c
index 0b449d62..73c3ed86 100644
--- a/chafa/chafa-term-db.c
+++ b/chafa/chafa-term-db.c
@@ -86,6 +86,10 @@ static const SeqStr vt220_seqs [] =
     { CHAFA_TERM_SEQ_SAVE_CURSOR_POS, "\033[s" },
     { CHAFA_TERM_SEQ_RESTORE_CURSOR_POS, "\033[u" },
 
+    /* These are actually xterm seqs, but we'll allow it */
+    { CHAFA_TERM_SEQ_ENABLE_ALT_SCREEN, "\033[1049h" },
+    { CHAFA_TERM_SEQ_DISABLE_ALT_SCREEN, "\033[1049l" },
+
     { CHAFA_TERM_SEQ_MAX, NULL }
 };
 
diff --git a/chafa/chafa-term-info.c b/chafa/chafa-term-info.c
index a8ff7ec4..02944263 100644
--- a/chafa/chafa-term-info.c
+++ b/chafa/chafa-term-info.c
@@ -181,6 +181,8 @@
  * @CHAFA_TERM_SEQ_RESTORE_CURSOR_POS: Move cursor to the last saved position.
  * @CHAFA_TERM_SEQ_ENABLE_ADVANCE_DOWN_AFTER_SIXEL: After showing a sixel image, leave cursor below the first column.
  * @CHAFA_TERM_SEQ_ENABLE_ADVANCE_RIGHT_AFTER_SIXEL: After showing a sixel image, leave cursor to the right of the last row.
+ * @CHAFA_TERM_SEQ_ENABLE_ALT_SCREEN: Switch to the alternate screen buffer.
+ * @CHAFA_TERM_SEQ_DISABLE_ALT_SCREEN: Switch back to the regular screen buffer.
  * @CHAFA_TERM_SEQ_MAX: Last control sequence plus one.
  *
  * An enumeration of the control sequences supported by #ChafaTermInfo.
diff --git a/chafa/chafa-term-seq-def.h b/chafa/chafa-term-seq-def.h
index 40e06540..7d1024c8 100644
--- a/chafa/chafa-term-seq-def.h
+++ b/chafa/chafa-term-seq-def.h
@@ -2533,6 +2533,40 @@ CHAFA_TERM_SEQ_DEF(enable_advance_down_after_sixel, ENABLE_ADVANCE_DOWN_AFTER_SI
  **/
 CHAFA_TERM_SEQ_DEF(enable_advance_right_after_sixel, ENABLE_ADVANCE_RIGHT_AFTER_SIXEL, 0, none, char)
 
+/**
+ * chafa_term_info_emit_enable_alt_screen:
+ * @term_info: A #ChafaTermInfo
+ * @dest: String destination
+ *
+ * Prints the control sequence for #CHAFA_TERM_SEQ_ENABLE_ALT_SCREEN.
+ *
+ * @dest must have enough space to hold
+ * #CHAFA_TERM_SEQ_LENGTH_MAX bytes, even if the emitted sequence is
+ * shorter. The output will not be zero-terminated.
+ *
+ * Returns: Pointer to first byte after emitted string
+ *
+ * Since: 1.14
+ **/
+CHAFA_TERM_SEQ_DEF(enable_alt_screen, ENABLE_ALT_SCREEN, 0, none, char)
+
+/**
+ * chafa_term_info_emit_disable_alt_screen:
+ * @term_info: A #ChafaTermInfo
+ * @dest: String destination
+ *
+ * Prints the control sequence for #CHAFA_TERM_SEQ_DISABLE_ALT_SCREEN.
+ *
+ * @dest must have enough space to hold
+ * #CHAFA_TERM_SEQ_LENGTH_MAX bytes, even if the emitted sequence is
+ * shorter. The output will not be zero-terminated.
+ *
+ * Returns: Pointer to first byte after emitted string
+ *
+ * Since: 1.14
+ **/
+CHAFA_TERM_SEQ_DEF(disable_alt_screen, DISABLE_ALT_SCREEN, 0, none, char)
+
 #undef CHAFA_TERM_SEQ_AVAILABILITY
 
 #undef CHAFA_TERM_SEQ_ARGS