Merge branch 'configurable-alternate-scroll-mode' into master

Closes #135

CHANGELOG.md

@@ -73,6 +73,12 @@
   (https://codeberg.org/dnkl/foot/issues/128).
 * **scrollback-up-line** and **scrollback-down-line** key
   bindings. They scroll up/down a single line in the scrollback.
+* **mouse.alternate-scroll-mode** option to `foot.ini`. This option
+  controls the initial state of the _Alternate Scroll Mode_, and
+  defaults to `yes`. When enabled, mouse scroll events are translated
+  to up/down key events in the alternate screen, letting you scroll in
+  e.g. `less` and other applications without enabling native mouse
+  support in them (https://codeberg.org/dnkl/foot/issues/135).
 
 
 ### Removed

config.c

@@ -764,6 +764,9 @@ parse_section_mouse(const char *key, const char *value, struct config *conf,
     if (strcmp(key, "hide-when-typing") == 0)
         conf->mouse.hide_when_typing = str_to_bool(value);
 
+    else if (strcmp(key, "alternate-scroll-mode") == 0)
+        conf->mouse.alternate_scroll_mode = str_to_bool(value);
+
     else {
         LOG_AND_NOTIFY_ERR("%s:%d: [mouse]: %s: invalid key", path, lineno, key);
         return false;
@@ -1907,6 +1910,7 @@ config_load(struct config *conf, const char *conf_path,
         },
         .mouse = {
             .hide_when_typing = false,
+            .alternate_scroll_mode = true,
         },
         .csd = {
             .preferred = CONF_CSD_PREFER_SERVER,

config.h

@@ -119,6 +119,7 @@ struct config {
 
     struct {
         bool hide_when_typing;
+        bool alternate_scroll_mode;
     } mouse;
 
     struct {

doc/foot.ini.5.scd

@@ -143,6 +143,24 @@ applications can change these at runtime.
 *hide-when-typing*
 	Boolean. When enabled, the mouse cursor is hidden while typing.
 
+*alternate-scroll-mode*
+	Boolean. This option controls the initial value for the _alternate
+	scroll mode_. When this mode is enabled, mouse scroll events are
+	translated to _up_/_down_ key events when displaying the alternate
+	screen.
+	
+	This lets you scroll with the mouse in e.g. pagers (like _less_)
+	without enabling native mouse support in them.
+	
+	Alternate scrolling is *not* used if the application enables
+	native mouse support.
+	
+	This option can be modified by applications at run-time using the
+	escape sequences *CSI ? 1007 h* (enable) and *CSI ? 1007 l*
+	(disable).
+	
+	Default: _yes_.
+
 
 # SECTION: colors
 

foot.ini

@@ -23,6 +23,7 @@
 
 [mouse]
 # hide-when-typing=no
+# alternate-scroll-mode=yes
 
 [colors]
 # alpha=1.0

input.c

@@ -498,6 +498,9 @@ keyboard_keymap(void *data, struct wl_keyboard *wl_keyboard,
     seat->kbd.mod_ctrl = xkb_keymap_mod_get_index(seat->kbd.xkb_keymap, "Control");
     seat->kbd.mod_meta = xkb_keymap_mod_get_index(seat->kbd.xkb_keymap, "Mod4");
 
+    seat->kbd.key_arrow_up = xkb_keymap_key_by_name(seat->kbd.xkb_keymap, "UP");
+    seat->kbd.key_arrow_down = xkb_keymap_key_by_name(seat->kbd.xkb_keymap, "DOWN");
+
     /* Compose (dead keys) */
     seat->kbd.xkb_compose_table = xkb_compose_table_new_from_locale(
         seat->kbd.xkb, setlocale(LC_CTYPE, NULL), XKB_COMPOSE_COMPILE_NO_FLAGS);
@@ -1610,6 +1613,20 @@ wl_pointer_button(void *data, struct wl_pointer *wl_pointer,
     }
 }
 
+static void
+alternate_scroll(struct seat *seat, int amount, int button)
+{
+    if (seat->wl_keyboard == NULL)
+        return;
+
+    xkb_keycode_t key = button == BTN_BACK
+        ? seat->kbd.key_arrow_up : seat->kbd.key_arrow_down;
+
+    for (int i = 0; i < amount; i++)
+        keyboard_key(seat, NULL, seat->kbd.serial, 0, key - 8, XKB_KEY_DOWN);
+    keyboard_key(seat, NULL, seat->kbd.serial, 0, key - 8, XKB_KEY_UP);
+}
+
 static void
 mouse_scroll(struct seat *seat, int amount)
 {
@@ -1617,52 +1634,33 @@ mouse_scroll(struct seat *seat, int amount)
     assert(term != NULL);
 
     int button = amount < 0 ? BTN_BACK : BTN_FORWARD;
-
-    void (*scrollback)(struct terminal *term, int rows)
-        = amount < 0 ? &cmd_scrollback_up : &cmd_scrollback_down;
-
     amount = abs(amount);
 
-    if ((button == BTN_BACK || button == BTN_FORWARD) &&
-        term->grid == &term->alt && term->alt_scrolling)
-    {
-        /*
-         * alternateScroll/faux scrolling - translate mouse
-         * "back"/"forward" to up/down keys
-         */
-
-        static xkb_keycode_t key_arrow_up = 0;
-        static xkb_keycode_t key_arrow_down = 0;
-
-        if (key_arrow_up == 0) {
-            key_arrow_up = xkb_keymap_key_by_name(seat->kbd.xkb_keymap, "UP");
-            key_arrow_down = xkb_keymap_key_by_name(seat->kbd.xkb_keymap, "DOWN");
+    if (term->mouse_tracking == MOUSE_NONE) {
+        if (term->grid == &term->alt) {
+            if (term->alt_scrolling)
+                alternate_scroll(seat, amount, button);
+        } else {
+            if (button == BTN_BACK)
+                cmd_scrollback_up(term, amount);
+            else
+                cmd_scrollback_down(term, amount);
         }
+    } else if (!term_mouse_grabbed(term, seat) &&
+               seat->mouse.col >= 0 && seat->mouse.row >= 0)
+    {
+        assert(seat->mouse.col < term->cols);
+        assert(seat->mouse.row < term->rows);
 
-        xkb_keycode_t key = button == BTN_BACK ? key_arrow_up : key_arrow_down;
-
-        for (int i = 0; i < amount; i++)
-            keyboard_key(seat, NULL, seat->kbd.serial, 0, key - 8, XKB_KEY_DOWN);
-        keyboard_key(seat, NULL, seat->kbd.serial, 0, key - 8, XKB_KEY_UP);
-    } else {
-        if (!term_mouse_grabbed(term, seat) &&
-            seat->mouse.col >= 0 && seat->mouse.row >= 0)
-        {
-            assert(seat->mouse.col < term->cols);
-            assert(seat->mouse.row < term->rows);
-
-            for (int i = 0; i < amount; i++) {
-                term_mouse_down(
-                    term, button, seat->mouse.row, seat->mouse.col,
-                    seat->kbd.shift, seat->kbd.alt, seat->kbd.ctrl);
-            }
-
-            term_mouse_up(
+        for (int i = 0; i < amount; i++) {
+            term_mouse_down(
                 term, button, seat->mouse.row, seat->mouse.col,
                 seat->kbd.shift, seat->kbd.alt, seat->kbd.ctrl);
         }
 
-        scrollback(term, amount);
+        term_mouse_up(
+            term, button, seat->mouse.row, seat->mouse.col,
+            seat->kbd.shift, seat->kbd.alt, seat->kbd.ctrl);
     }
 }
 

terminal.c

@@ -964,6 +964,7 @@ term_init(const struct config *conf, struct fdm *fdm, struct reaper *reaper,
         .grid = &term->normal,
         .composed_count = 0,
         .composed = NULL,
+        .alt_scrolling = conf->mouse.alternate_scroll_mode,
         .meta = {
             .esc_prefix = true,
             .eight_bit = true,

wayland.h

@@ -149,6 +149,9 @@ struct seat {
         xkb_mod_index_t mod_ctrl;
         xkb_mod_index_t mod_meta;
 
+        xkb_keycode_t key_arrow_up;
+        xkb_keycode_t key_arrow_down;
+
         /* Enabled modifiers */
         bool shift;
         bool alt;