From 0900d01ec9fce2e64384ef27111fe1a4d9d45068 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Mon, 25 Oct 2021 19:39:46 +0200
Subject: [PATCH] input: clean up mouse scroll handling
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* Allow scrolling on the normal (non-alt) screen, when application is
  grabbing the mouse (when user presses Shift).
* Use term_mouse_grabbed() instead of explicitly checking for
  MOUSE_NONE tracking.
* Remove mouse tracking check from cmd_scrollback_{up,down}. Caller is
  expected to have done the check.
* Don’t scroll down on mouse wheel tilt events.
---
 commands.c |  6 ------
 input.c    | 29 +++++++++++++++++++++--------
 2 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/commands.c b/commands.c
index e7dafdfc..4b0306aa 100644
--- a/commands.c
+++ b/commands.c
@@ -18,9 +18,6 @@ cmd_scrollback_up(struct terminal *term, int rows)
     if (urls_mode_is_active(term))
         return;
 
-    if (term->mouse_tracking != MOUSE_NONE)
-        return;
-
     rows = min(rows, term->rows);
     xassert(term->grid->offset >= 0);
 
@@ -98,9 +95,6 @@ cmd_scrollback_down(struct terminal *term, int rows)
     if (urls_mode_is_active(term))
         return;
 
-    if (term->mouse_tracking != MOUSE_NONE)
-        return;
-
     if (term->grid->view == term->grid->offset)
         return;
 
diff --git a/input.c b/input.c
index 19ec2cfa..00c4dac1 100644
--- a/input.c
+++ b/input.c
@@ -2091,6 +2091,8 @@ alternate_scroll(struct seat *seat, int amount, int button)
     xassert(seat->mouse_focus != NULL);
     struct terminal *term = seat->mouse_focus;
 
+    assert(button == BTN_BACK || button == BTN_FORWARD);
+
     xkb_keycode_t key = button == BTN_BACK
         ? seat->kbd.key_arrow_up : seat->kbd.key_arrow_down;
 
@@ -2110,19 +2112,30 @@ mouse_scroll(struct seat *seat, int amount, enum wl_pointer_axis axis)
         : amount < 0 ? BTN_WHEEL_LEFT : BTN_WHEEL_RIGHT;
     amount = abs(amount);
 
-    if (term->mouse_tracking == MOUSE_NONE) {
+    if (term_mouse_grabbed(term, seat)) {
         if (term->grid == &term->alt) {
-            if (term->alt_scrolling)
-                alternate_scroll(seat, amount, button);
+            if (term->alt_scrolling) {
+                switch (button) {
+                case BTN_BACK:
+                case BTN_FORWARD:
+                    alternate_scroll(seat, amount, button);
+                    break;
+                }
+            }
         } else {
-            if (button == BTN_BACK)
+            switch (button) {
+            case BTN_BACK:
                 cmd_scrollback_up(term, amount);
-            else
+                break;
+
+            case BTN_FORWARD:
                 cmd_scrollback_down(term, amount);
+                break;
+            }
         }
-    } else if (!term_mouse_grabbed(term, seat) &&
-               seat->mouse.col >= 0 && seat->mouse.row >= 0)
-    {
+    }
+
+    else if (seat->mouse.col >= 0 && seat->mouse.row >= 0) {
         xassert(seat->mouse.col < term->cols);
         xassert(seat->mouse.row < term->rows);