From fbfb21ce79308d054326b1268ccc22629363dc93 Mon Sep 17 00:00:00 2001
From: Nicholas Marriott <nicm@cvs.openbsd.org>
Date: Wed, 28 Sep 2022 07:59:51 +0000
Subject: Add scroll-top and scroll-bottom commands to scroll so cursor is at
 top or bottom. From Anindya Mukherjee, GitHub issue 3334.

---
 usr.bin/tmux/window-copy.c | 58 ++++++++++++++++++++++++++++++++++++++++------
 1 file changed, 51 insertions(+), 7 deletions(-)

(limited to 'usr.bin/tmux/window-copy.c')

diff --git a/usr.bin/tmux/window-copy.c b/usr.bin/tmux/window-copy.c
index 56551d24430..401d7fcaa74 100644
--- a/usr.bin/tmux/window-copy.c
+++ b/usr.bin/tmux/window-copy.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: window-copy.c,v 1.339 2022/08/23 08:14:19 nicm Exp $ */
+/* $OpenBSD: window-copy.c,v 1.340 2022/09/28 07:59:50 nicm Exp $ */
 
 /*
  * Copyright (c) 2007 Nicholas Marriott <nicholas.marriott@gmail.com>
@@ -1250,20 +1250,23 @@ window_copy_cmd_cursor_right(struct window_copy_cmd_state *cs)
 	return (WINDOW_COPY_CMD_NOTHING);
 }
 
+/* Scroll line containing the cursor to the given position. */
 static enum window_copy_cmd_action
-window_copy_cmd_scroll_middle(struct window_copy_cmd_state *cs)
+window_copy_cmd_scroll_to(struct window_copy_cmd_state *cs, u_int to)
 {
 	struct window_mode_entry	*wme = cs->wme;
 	struct window_copy_mode_data	*data = wme->data;
-	u_int				 mid_value, oy, delta;
+	u_int				 oy, delta;
 	int				 scroll_up; /* >0 up, <0 down */
 
-	mid_value = (screen_size_y(&data->screen) - 1) / 2;
-	scroll_up = data->cy - mid_value;
+	scroll_up = data->cy - to;
 	delta = abs(scroll_up);
-	oy = screen_hsize(data->backing) + data->cy - data->oy;
+	oy = screen_hsize(data->backing) - data->oy;
 
-	log_debug ("XXX %u %u %u %d %u", mid_value, oy, delta, scroll_up, data->oy);
+	/*
+	 * oy is the maximum scroll down amount, while data->oy is the maximum
+	 * scroll up amount.
+	 */
 	if (scroll_up > 0 && data->oy >= delta) {
 		window_copy_scroll_up(wme, delta);
 		data->cy -= delta;
@@ -1276,6 +1279,35 @@ window_copy_cmd_scroll_middle(struct window_copy_cmd_state *cs)
 	return (WINDOW_COPY_CMD_REDRAW);
 }
 
+/* Scroll line containing the cursor to the bottom. */
+static enum window_copy_cmd_action
+window_copy_cmd_scroll_bottom(struct window_copy_cmd_state *cs)
+{
+	struct window_copy_mode_data	*data = cs->wme->data;
+	u_int				 bottom;
+
+	bottom = screen_size_y(&data->screen) - 1;
+	return (window_copy_cmd_scroll_to(cs, bottom));
+}
+
+/* Scroll line containing the cursor to the middle. */
+static enum window_copy_cmd_action
+window_copy_cmd_scroll_middle(struct window_copy_cmd_state *cs)
+{
+	struct window_copy_mode_data	*data = cs->wme->data;
+	u_int				 mid_value;
+
+	mid_value = (screen_size_y(&data->screen) - 1) / 2;
+	return (window_copy_cmd_scroll_to(cs, mid_value));
+}
+
+/* Scroll line containing the cursor to the top. */
+static enum window_copy_cmd_action
+window_copy_cmd_scroll_top(struct window_copy_cmd_state *cs)
+{
+	return (window_copy_cmd_scroll_to(cs, 0));
+}
+
 static enum window_copy_cmd_action
 window_copy_cmd_cursor_up(struct window_copy_cmd_state *cs)
 {
@@ -2794,6 +2826,12 @@ static const struct {
 	  .clear = WINDOW_COPY_CMD_CLEAR_ALWAYS,
 	  .f = window_copy_cmd_refresh_from_pane
 	},
+	{ .command = "scroll-bottom",
+	  .minargs = 0,
+	  .maxargs = 0,
+	  .clear = WINDOW_COPY_CMD_CLEAR_ALWAYS,
+	  .f = window_copy_cmd_scroll_bottom
+	},
 	{ .command = "scroll-down",
 	  .minargs = 0,
 	  .maxargs = 0,
@@ -2812,6 +2850,12 @@ static const struct {
 	  .clear = WINDOW_COPY_CMD_CLEAR_ALWAYS,
 	  .f = window_copy_cmd_scroll_middle
 	},
+	{ .command = "scroll-top",
+	  .minargs = 0,
+	  .maxargs = 0,
+	  .clear = WINDOW_COPY_CMD_CLEAR_ALWAYS,
+	  .f = window_copy_cmd_scroll_top
+	},
 	{ .command = "scroll-up",
 	  .minargs = 0,
 	  .maxargs = 0,
-- 
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