xF: add a scrollbar to the buffer list

And clean this area up.
2026-08-02 22:45:28 +02:00
parent f8ecf7d0f7
commit 8f3df19786
1 changed files with 228 additions and 106 deletions
@@ -267,6 +267,8 @@ enum action
 	ACTION_FORMAT_UNDERLINE,
 	ACTION_SCROLL_UP,
 	ACTION_SCROLL_DOWN,
+	ACTION_BUFFER_LIST_SCROLL_UP,
+	ACTION_BUFFER_LIST_SCROLL_DOWN,
 	ACTION_SUBMIT,
 	ACTION_COMPLETE,
 	ACTION_HISTORY_PREVIOUS,
@@ -357,8 +359,10 @@ enum app_widget_id
 	WIDGET_NONE,
 	WIDGET_BUTTON,
 	WIDGET_BUFFER,
+	WIDGET_BUFFER_LIST,
 	WIDGET_TRANSCRIPT,
-	WIDGET_SCROLLBAR,
+	WIDGET_BUFFER_LIST_SCROLLBAR,
+	WIDGET_TRANSCRIPT_SCROLLBAR,
 };

 struct app_backend
@@ -452,7 +456,8 @@ static struct
 	struct attrs attrs[ATTRIBUTE_COUNT];
 	struct line_editor editor;          ///< Message editor
 	int64_t last_active;                ///< Last ACTIVE command timestamp
-	bool dragging_scrollbar;            ///< Mouse drag updates the viewport
+	int buffer_list_offset;             ///< XUI pixels from the top of the list
+	enum app_widget_id dragged_scrollbar;

 	struct binding *keys;               ///< Parsed xC-style key bindings
 	size_t keys_len;
@@ -882,6 +887,7 @@ app_reset_relay_state (void)
 {
 	g.buffer_current = NULL;
 	g.buffer_last = NULL;
+	g.buffer_list_offset = 0;

 	LIST_FOR_EACH (struct buffer, iter, g.buffers)
 		buffer_destroy (iter);
@@ -940,6 +946,8 @@ relay_process_response (const struct relay_event_data_response *e)

 // ~~~ State synchronization ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

+static void app_buffer_list_ensure_visible (const struct buffer *buffer);
+
 static struct buffer *
 buffer_find (const char *name)
 {
@@ -1143,6 +1151,7 @@ relay_process_buffer_activate (struct buffer *b)
 	if (b)
 	{
 		b->scroll_offset = 0;
+		app_buffer_list_ensure_visible (b);
 		app_editor_set (b->input);
 		g.editor.point = MIN (b->input_point, (int) g.editor.len);
 		app_recheck_current_highlight ();
@@ -1560,6 +1569,23 @@ relay_reconnect_now (void)

 // --- Viewport policy ---------------------------------------------------------

+static int
+app_viewport_height (void)
+{
+	return MAX (0, g_xui.height - 3 * g_xui.vunit);
+}
+
+static int
+app_buffer_list_content_height (void)
+{
+	size_t count = 0;
+	LIST_FOR_EACH (struct buffer, buffer, g.buffers)
+		count++;
+
+	uint64_t height = count * (uint64_t) g_xui.vunit;
+	return MIN ((uint64_t) INT_MAX, height);
+}
+
 static size_t
 app_visible_line_count (const struct buffer *b)
 {
@@ -1570,37 +1596,6 @@ app_visible_line_count (const struct buffer *b)
 	return count;
 }

-static const struct buffer_line *
-app_unread_marker_line (const struct buffer *b)
-{
-	if (!buffer_has_unread_marker (b))
-		return NULL;
-
-	uint64_t unread = (uint64_t) b->new_messages + b->new_unimportant_messages;
-	const struct buffer_line *marker = b->lines_tail;
-	while (unread > 1 && marker->prev)
-	{
-		unread--;
-		marker = marker->prev;
-	}
-	return marker;
-}
-
-static int
-app_viewport_height (void)
-{
-	return MAX (0, g_xui.height - 3 * g_xui.vunit);
-}
-
-static int
-app_buffer_content_height (const struct buffer *b)
-{
-	uint64_t height = app_visible_line_count (b) * (uint64_t) g_xui.vunit;
-	if (buffer_has_unread_marker (b))
-		height += UNREAD_MARKER_HEIGHT;
-	return MIN ((uint64_t) INT_MAX, height);
-}
-
 static int
 app_content_height (void)
 {
@@ -1609,7 +1604,15 @@ app_content_height (void)
 		return MIN ((uint64_t) INT_MAX,
 			g.log.lines.len * (uint64_t) g_xui.vunit);
 	}
-	return g.buffer_current ? app_buffer_content_height (g.buffer_current) : 0;
+	if (g.buffer_current)
+	{
+		struct buffer *b = g.buffer_current;
+		uint64_t height = app_visible_line_count (b) * (uint64_t) g_xui.vunit;
+		if (buffer_has_unread_marker (b))
+			height += UNREAD_MARKER_HEIGHT;
+		return MIN ((uint64_t) INT_MAX, height);
+	}
+	return 0;
 }

 static int *
@@ -1617,36 +1620,102 @@ app_content_scroll_offset (void)
 {
 	if (g.log.visible)
 		return &g.log.offset;
-	return g.buffer_current ? &g.buffer_current->scroll_offset : NULL;
+	if (g.buffer_current)
+		return &g.buffer_current->scroll_offset;
+	return NULL;
+}
+
+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+struct app_scroll_view
+{
+	int *offset;                        ///< Pixels from the anchored edge
+	int total;                          ///< Total content height in pixels
+	bool from_bottom;                   ///< The offset is bottom-anchored
+};
+
+static struct app_scroll_view
+app_scroll_view (enum app_widget_id id)
+{
+	if (id == WIDGET_BUFFER_LIST_SCROLLBAR)
+		return (struct app_scroll_view) { &g.buffer_list_offset,
+			app_buffer_list_content_height (), false };
+
+	hard_assert (id == WIDGET_TRANSCRIPT_SCROLLBAR);
+	return (struct app_scroll_view) { app_content_scroll_offset (),
+		app_content_height (), true };
 }

 static int
-app_content_top (void)
+app_scroll_view_origin (struct app_scroll_view *self)
 {
-	int total = app_content_height ();
-	int *offset = app_content_scroll_offset ();
-	return MAX (0, total - app_viewport_height () - (offset ? *offset : 0));
+	if (!self->offset)
+		return 0;
+
+	int maximum = MAX (0, self->total - app_viewport_height ());
+	*self->offset = MAX (0, MIN (maximum, *self->offset));
+	return self->from_bottom
+		? self->total - app_viewport_height () - *self->offset
+		: *self->offset;
 }

 static bool
-app_scroll (int amount)
+app_scroll_view_set_origin (struct app_scroll_view *self, int64_t origin)
 {
-	int *offset = app_content_scroll_offset ();
-	if (!offset)
+	if (!self->offset)
 		return false;

-	int maximum = MAX (0, app_content_height () - app_viewport_height ());
-	int64_t requested = (int64_t) *offset + amount;
-	int updated = MAX (0, MIN ((int64_t) maximum, requested));
-	if (updated == *offset)
+	int maximum = MAX (0, self->total - app_viewport_height ());
+	int updated = MAX (0, MIN ((int64_t) maximum, origin));
+	if (self->from_bottom)
+		updated = maximum - updated;
+	if (updated == *self->offset)
 		return false;

-	*offset = updated;
-	app_recheck_current_highlight ();
+	*self->offset = updated;
+	return true;
+}
+
+static bool
+app_scroll (enum app_widget_id id, int amount)
+{
+	struct app_scroll_view view = app_scroll_view (id);
+	if (!app_scroll_view_set_origin (&view,
+		(int64_t) app_scroll_view_origin (&view) + amount))
+		return false;
+
+	if (view.from_bottom)
+		app_recheck_current_highlight ();
 	xui_invalidate ();
 	return true;
 }

+// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
+
+static void
+app_buffer_list_ensure_visible (const struct buffer *buffer)
+{
+	int visible = app_viewport_height ();
+	if (visible <= 0 || g_xui.vunit <= 0)
+		return;
+
+	int64_t row_top = 0;
+	struct buffer *iter;
+	for (iter = g.buffers; iter && iter != buffer; iter = iter->next)
+		row_top += g_xui.vunit;
+	if (!iter)
+		return;
+
+	struct app_scroll_view view =
+		app_scroll_view (WIDGET_BUFFER_LIST_SCROLLBAR);
+	int64_t origin = app_scroll_view_origin (&view);
+	if (row_top < origin)
+		origin = row_top;
+	else if (row_top + g_xui.vunit > origin + visible)
+		origin = row_top + g_xui.vunit - visible;
+	app_scroll_view_set_origin (&view, origin);
+}
+
 // --- Terminal widgets --------------------------------------------------------

 static void
@@ -1835,6 +1904,25 @@ app_select_backend (void)
 #endif  // WITH_X11
 }

+static struct widget *
+app_make_scrollbar (enum app_widget_id id)
+{
+	struct app_scroll_view view = app_scroll_view (id);
+	int top = MAX (0, app_scroll_view_origin (&view));
+	if (app_viewport_height () <= 0
+	 || view.total <= app_viewport_height ())
+		return NULL;
+
+	struct widget *scrollbar = g_xui.ui->scrollbar
+		(g_attrs[ATTRIBUTE_SCROLLBAR].attrs, top, view.total);
+#ifdef WITH_X11
+	if (g_xui.ui == &x11_ui)
+		scrollbar->on_render = app_x11_render_scrollbar;
+#endif  // WITH_X11
+	scrollbar->widget_id = id;
+	return scrollbar;
+}
+
 // --- Layout and rendering ----------------------------------------------------

 struct layout
@@ -2059,18 +2147,53 @@ app_make_buffer_row (struct buffer *b, int index)
 	return widget;
 }

+static void
+app_on_viewport_allocated (struct widget *self)
+{
+	xui_on_vbox_allocated (self);
+
+	int y = self->y + self->userdata;
+	LIST_FOR_EACH (struct widget, child, self->children)
+	{
+		widget_move (child, self->x - child->x, y - child->y);
+		y += child->height;
+	}
+}
+
 static struct widget *
 app_make_buffer_list (void)
 {
 	struct layout rows = {};
-	int index = 0;
+	struct app_scroll_view view =
+		app_scroll_view (WIDGET_BUFFER_LIST_SCROLLBAR);
+	int top = app_scroll_view_origin (&view);
+	int bottom = top + app_viewport_height ();
+	int index = 0, first = top / g_xui.vunit;
 	LIST_FOR_EACH (struct buffer, buffer, g.buffers)
-		app_push (&rows, app_make_buffer_row (buffer, index++));
+	{
+		int row_top = index * g_xui.vunit;
+		if (index >= first && row_top < bottom)
+			app_push (&rows, app_make_buffer_row (buffer, index));
+		index++;
+	}

 	struct widget *list = xui_vbox (rows.head);
-	list->width = MIN (20 * g_xui.hunit, g_xui.width / 3);
-	list->height = -1;
-	return list;
+	list->on_allocated = app_on_viewport_allocated;
+	list->userdata = -(top % g_xui.vunit);
+	list->width = list->height = -1;
+
+	struct layout viewport = {};
+	app_push (&viewport, list);
+	struct widget *scrollbar =
+		app_make_scrollbar (WIDGET_BUFFER_LIST_SCROLLBAR);
+	if (scrollbar)
+		app_push (&viewport, scrollbar);
+
+	struct widget *viewport_box = xui_hbox (viewport.head);
+	viewport_box->widget_id = WIDGET_BUFFER_LIST;
+	viewport_box->width = MIN (20 * g_xui.hunit, g_xui.width / 3);
+	viewport_box->height = -1;
+	return viewport_box;
 }

 static enum app_attribute
@@ -2200,20 +2323,15 @@ struct transcript_slice
 static struct transcript_slice
 app_make_transcript_slice (void)
 {
-	int *scroll_offset = app_content_scroll_offset ();
-	hard_assert (scroll_offset);
-
-	int total = app_content_height ();
+	struct app_scroll_view view =
+		app_scroll_view (WIDGET_TRANSCRIPT_SCROLLBAR);
 	int viewport = app_viewport_height ();
-	int maximum = MAX (0, total - viewport);
-	*scroll_offset = MAX (0, MIN (*scroll_offset, maximum));
-
-	int view_top = total - viewport - *scroll_offset;
+	int view_top = app_scroll_view_origin (&view);
 	return (struct transcript_slice)
 	{
 		.view_top = view_top,
 		.clip_top = MAX (0, view_top),
-		.clip_bottom = MIN (total, view_top + viewport),
+		.clip_bottom = MIN (view.total, view_top + viewport),
 		.first_y = -1,
 	};
 }
@@ -2251,6 +2369,22 @@ app_append_log_rows (struct layout *rows)
 	return app_transcript_slice_offset (&slice);
 }

+static const struct buffer_line *
+app_unread_marker_line (const struct buffer *b)
+{
+	if (!buffer_has_unread_marker (b))
+		return NULL;
+
+	uint64_t unread = (uint64_t) b->new_messages + b->new_unimportant_messages;
+	const struct buffer_line *marker = b->lines_tail;
+	while (unread > 1 && marker->prev)
+	{
+		unread--;
+		marker = marker->prev;
+	}
+	return marker;
+}
+
 static int
 app_append_buffer_rows (struct layout *rows)
 {
@@ -2274,19 +2408,6 @@ app_append_buffer_rows (struct layout *rows)

 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -

-static void
-app_on_transcript_allocated (struct widget *self)
-{
-	xui_on_vbox_allocated (self);
-
-	int y = self->y + self->userdata;
-	LIST_FOR_EACH (struct widget, child, self->children)
-	{
-		widget_move (child, self->x - child->x, y - child->y);
-		y += child->height;
-	}
-}
-
 static struct widget *
 app_make_transcript (void)
 {
@@ -2296,7 +2417,7 @@ app_make_transcript (void)
 		: app_append_buffer_rows (&rows);

 	struct widget *transcript = xui_vbox (rows.head);
-	transcript->on_allocated = app_on_transcript_allocated;
+	transcript->on_allocated = app_on_viewport_allocated;
 	transcript->widget_id = WIDGET_TRANSCRIPT;
 	transcript->userdata = offset;
 	transcript->width = transcript->height = -1;
@@ -2311,19 +2432,9 @@ app_make_middle (void)

 	struct layout viewport = {};
 	app_push (&viewport, app_make_transcript ());
-	int viewport_height = app_viewport_height ();
-	if (viewport_height > 0 && app_content_height () > viewport_height)
-	{
-		struct widget *scrollbar = g_xui.ui->scrollbar
-			(g_attrs[ATTRIBUTE_SCROLLBAR].attrs,
-				app_content_top (), app_content_height ());
-#ifdef WITH_X11
-		if (g_xui.ui == &x11_ui)
-			scrollbar->on_render = app_x11_render_scrollbar;
-#endif  // WITH_X11
-		scrollbar->widget_id = WIDGET_SCROLLBAR;
+	struct widget *scrollbar = app_make_scrollbar (WIDGET_TRANSCRIPT_SCROLLBAR);
+	if (scrollbar)
 		app_push (&viewport, scrollbar);
-	}

 	struct widget *viewport_box = xui_hbox (viewport.head);
 	viewport_box->width = viewport_box->height = -1;
@@ -2594,19 +2705,15 @@ app_scrollbar_seek (struct widget *scrollbar, int y)
 	if (!scrollbar || scrollbar->height <= 0)
 		return false;

-	int total = app_content_height ();
-	int visible = app_viewport_height ();
-	int maximum = MAX (0, total - visible);
+	struct app_scroll_view view = app_scroll_view (scrollbar->widget_id);
 	int top = (double) MAX (0, MIN (scrollbar->height, y))
-		/ scrollbar->height * total - visible / 2;
-	top = MAX (0, MIN (maximum, top));
-
-	int *offset = app_content_scroll_offset ();
-	if (!offset)
+		/ scrollbar->height * view.total - app_viewport_height () / 2;
+	if (!view.offset)
 		return false;

-	*offset = maximum - top;
-	app_recheck_current_highlight ();
+	app_scroll_view_set_origin (&view, top);
+	if (view.from_bottom)
+		app_recheck_current_highlight ();
 	xui_invalidate ();
 	return true;
 }
@@ -2844,9 +2951,13 @@ app_process_action (enum action action)
 		app_editor_insert (0x1f);
 		return true;
 	case ACTION_SCROLL_UP:
-		return app_scroll (+page);
+		return app_scroll (WIDGET_TRANSCRIPT_SCROLLBAR, -page);
 	case ACTION_SCROLL_DOWN:
-		return app_scroll (-page);
+		return app_scroll (WIDGET_TRANSCRIPT_SCROLLBAR, +page);
+	case ACTION_BUFFER_LIST_SCROLL_UP:
+		return app_scroll (WIDGET_BUFFER_LIST_SCROLLBAR, -page);
+	case ACTION_BUFFER_LIST_SCROLL_DOWN:
+		return app_scroll (WIDGET_BUFFER_LIST_SCROLLBAR, +page);
 	case ACTION_SUBMIT:
 		app_submit_input ();
 		return true;
@@ -2875,15 +2986,16 @@ app_process_mouse (termo_mouse_event_t type, int x, int y, int button,
 	app_notify_active ();
 	if (type == TERMO_MOUSE_RELEASE)
 	{
-		g.dragging_scrollbar = false;
+		g.dragged_scrollbar = WIDGET_NONE;
 		return true;
 	}
 	if (type == TERMO_MOUSE_DRAG)
 	{
-		if (!g.dragging_scrollbar)
+		if (!g.dragged_scrollbar)
 			return true;
+
 		struct widget *scrollbar =
-			app_widget_by_id (g_xui.widgets, WIDGET_SCROLLBAR);
+			app_widget_by_id (g_xui.widgets, g.dragged_scrollbar);
 		return app_scrollbar_seek (scrollbar,
 			scrollbar ? y - scrollbar->y : 0);
 	}
@@ -2892,18 +3004,26 @@ app_process_mouse (termo_mouse_event_t type, int x, int y, int button,

 	if (button == 4 || button == 5)
 	{
+		int amount = (button == 4 ? -1 : 1) * 3 * g_xui.vunit;
+
+		struct widget *buffer_list =
+			app_widget_by_id (g_xui.widgets, WIDGET_BUFFER_LIST);
+		if (buffer_list && app_widget_contains (buffer_list, x, y))
+			return app_scroll (WIDGET_BUFFER_LIST_SCROLLBAR, amount);
+
 		struct widget *transcript =
 			app_widget_by_id (g_xui.widgets, WIDGET_TRANSCRIPT);
 		return transcript && app_widget_contains (transcript, x, y)
-			&& app_scroll ((button == 4 ? 1 : -1) * 3 * g_xui.vunit);
+			&& app_scroll (WIDGET_TRANSCRIPT_SCROLLBAR, amount);
 	}
 	if (button != 1)
 		return false;

 	struct widget *target = app_interactive_widget_at (g_xui.widgets, x, y);
-	if (target && target->widget_id == WIDGET_SCROLLBAR)
+	if (target && (target->widget_id == WIDGET_BUFFER_LIST_SCROLLBAR
+		|| target->widget_id == WIDGET_TRANSCRIPT_SCROLLBAR))
 	{
-		g.dragging_scrollbar = true;
+		g.dragged_scrollbar = target->widget_id;
 		return app_scrollbar_seek (target, y - target->y);
 	}
 	if (target && target->widget_id == WIDGET_BUTTON)
@@ -2951,6 +3071,8 @@ g_default_bindings[] =
 	{ "M-m",        ACTION_FORMAT                 },
 	{ "PageUp",     ACTION_SCROLL_UP              },
 	{ "PageDown",   ACTION_SCROLL_DOWN            },
+	{ "S-PageUp",   ACTION_BUFFER_LIST_SCROLL_UP   },
+	{ "S-PageDown", ACTION_BUFFER_LIST_SCROLL_DOWN },
 	{ "Enter",      ACTION_SUBMIT                 },
 	{ "C-j",        ACTION_SUBMIT                 },
 	{ "Tab",        ACTION_COMPLETE               },