Don't layout during rendering

nncmpp.c

@@ -1182,9 +1182,6 @@ struct widget;
 /// Draw a widget on the window
 typedef void (*widget_render_fn) (struct widget *self);
 
-/// Extract the contents of container widgets
-typedef struct widget *(*widget_sublayout_fn) (struct widget *self);
-
 /// A minimal abstraction appropriate for both TUI and GUI widgets.
 /// Units for the widget's region are frontend-specific.
 /// Having this as a linked list simplifies layouting and memory management.
@@ -1198,7 +1195,7 @@ struct widget
 	int height;                         ///< Height, initialized by UI methods
 
 	widget_render_fn on_render;         ///< Render callback
-	widget_sublayout_fn on_sublayout;   ///< Optional sublayout callback
+	struct widget *children;            ///< Child widgets of containers
 	chtype attrs;                       ///< Rendition, in Curses terms
 
 	short id;                           ///< Post-layouting identification
@@ -1231,6 +1228,23 @@ struct ui
 	bool have_icons;
 };
 
+static void
+widget_destroy (struct widget *self)
+{
+	LIST_FOR_EACH (struct widget, w, self->children)
+		widget_destroy (w);
+	free (self);
+}
+
+static void
+widget_move (struct widget *w, int dx, int dy)
+{
+	w->x += dx;
+	w->y += dy;
+	LIST_FOR_EACH (struct widget, child, w->children)
+		widget_move (child, dx, dy);
+}
+
 /// Replaces negative widths amongst widgets in the sublist by redistributing
 /// any width remaining after all positive claims are satisfied from "width".
 /// Also unifies heights to the maximum value of the run, and returns it.
@@ -1265,7 +1279,7 @@ widget_redistribute (struct widget *head, int width)
 	int x = 0;
 	LIST_FOR_EACH (struct widget, w, head)
 	{
-		w->x = x;
+		widget_move (w, x - w->x, 0);
 		x += w->width;
 	}
 	return max_height;
@@ -1792,30 +1806,37 @@ app_invalidate (void)
 }
 
 static void
-app_flush_layout_to (struct layout *l, int width, struct layout *dest)
+app_append_layout (struct layout *l, struct layout *dest)
 {
-	hard_assert (l != NULL && l->head != NULL);
-	widget_redistribute (l->head, width);
-
 	struct widget *last = dest->tail;
 	if (!last)
 		*dest = *l;
-	else
+	else if (l->head)
 	{
 		// Assuming there is no unclaimed vertical space.
 		LIST_FOR_EACH (struct widget, w, l->head)
-			w->y = last->y + last->height;
+			widget_move (w, 0, last->y + last->height - w->y);
 
 		last->next = l->head;
 		l->head->prev = last;
 		dest->tail = l->tail;
 	}
+
+	*l = (struct layout) {};
 }
 
 static void
-app_flush_layout (struct layout *l)
+app_flush_layout_full (struct layout *l, int width, struct layout *dest)
 {
-	app_flush_layout_to (l, g.ui_width, &g.widgets);
+	hard_assert (l != NULL && l->head != NULL);
+	widget_redistribute (l->head, width);
+	app_append_layout (l, dest);
+}
+
+static void
+app_flush_layout (struct layout *l, struct layout *out)
+{
+	app_flush_layout_full (l, g.ui_width, out);
 }
 
 static struct widget *
@@ -1836,19 +1857,19 @@ app_push_fill (struct layout *l, struct widget *w)
 /// Write the given UTF-8 string padded with spaces.
 /// @param[in] attrs  Text attributes for the text, including padding.
 static void
-app_layout_text (const char *str, chtype attrs)
+app_layout_text (const char *str, chtype attrs, struct layout *out)
 {
 	struct layout l = {};
 	app_push (&l, g.ui->padding (attrs, 0.25, 1));
 	app_push_fill (&l, g.ui->label (attrs, str));
 	app_push (&l, g.ui->padding (attrs, 0.25, 1));
-	app_flush_layout (&l);
+	app_flush_layout (&l, out);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 
 static void
-app_layout_song_info (void)
+app_layout_song_info (struct layout *out)
 {
 	compact_map_t map;
 	if (!(map = item_list_get (&g.playlist, g.song)))
@@ -1880,7 +1901,7 @@ app_layout_song_info (void)
 		app_push (&l, g.ui->label (attrs[1], title));
 		app_push_fill (&l, g.ui->padding (attrs[0], 0, 1));
 		app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
-		app_flush_layout (&l);
+		app_flush_layout (&l, out);
 	}
 
 	// Showing a blank line is better than having the controls jump around
@@ -1919,7 +1940,7 @@ app_layout_song_info (void)
 
 	app_push_fill (&l, g.ui->padding (attrs[0], 0, 1));
 	app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
-	app_flush_layout (&l);
+	app_flush_layout (&l, out);
 }
 
 static char *
@@ -1939,11 +1960,11 @@ app_time_string (int seconds)
 }
 
 static void
-app_layout_status (void)
+app_layout_status (struct layout *out)
 {
 	bool stopped = g.state == PLAYER_STOPPED;
 	if (!stopped)
-		app_layout_song_info ();
+		app_layout_song_info (out);
 
 	chtype attrs[2] = { APP_ATTR (NORMAL), APP_ATTR (HIGHLIGHT) };
 	struct layout l = {};
@@ -2014,11 +2035,11 @@ app_layout_status (void)
 	str_free (&volume);
 
 	app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
-	app_flush_layout (&l);
+	app_flush_layout (&l, out);
 }
 
 static void
-app_layout_tabs (void)
+app_layout_tabs (struct layout *out)
 {
 	chtype attrs[2] = { APP_ATTR (TAB_BAR), APP_ATTR (TAB_ACTIVE) };
 	struct layout l = {};
@@ -2053,30 +2074,30 @@ app_layout_tabs (void)
 	}
 #endif  // WITH_FFTW
 
-	app_flush_layout (&l);
+	app_flush_layout (&l, out);
 }
 
 static void
-app_layout_header (void)
+app_layout_header (struct layout *out)
 {
 	if (g.client.state == MPD_CONNECTED)
 	{
 		struct layout lt = {};
 		app_push_fill (&lt, g.ui->padding (APP_ATTR (NORMAL), 0, 0.125));
-		app_flush_layout (&lt);
+		app_flush_layout (&lt, out);
 
-		app_layout_status ();
+		app_layout_status (out);
 
 		struct layout lb = {};
 		app_push_fill (&lb, g.ui->padding (APP_ATTR (NORMAL), 0, 0.125));
-		app_flush_layout (&lb);
+		app_flush_layout (&lb, out);
 	}
 
-	app_layout_tabs ();
+	app_layout_tabs (out);
 
 	const char *header = g.active_tab->header;
 	if (header)
-		app_layout_text (header, APP_ATTR (HEADER));
+		app_layout_text (header, APP_ATTR (HEADER), out);
 }
 
 static struct widget *
@@ -2169,50 +2190,37 @@ app_layout_row (struct tab *tab, int item_index)
 	return l;
 }
 
-// XXX: This isn't a very clean design, in that part of layouting
-//   is done during the rendering stage.
-static struct widget *
-app_sublayout_list (struct widget *list)
+static void
+app_layout_view (struct layout *out, int height)
 {
+	struct layout l = {};
+	struct widget *list = app_push_fill (&l, g.ui->list ());
+	list->id = WIDGET_LIST;
+	list->height = height;
+	list->width = g.ui_width;
+
 	struct tab *tab = g.active_tab;
+	if ((int) tab->item_count * g.ui_vunit > list->height)
+	{
+		struct widget *scrollbar = g.ui->scrollbar (APP_ATTR (SCROLLBAR));
+		list->width -= scrollbar->width;
+		app_push (&l, scrollbar)->id = WIDGET_SCROLLBAR;
+	}
+
 	int to_show = MIN ((int) tab->item_count - tab->item_top,
 		ceil ((double) list->height / g.ui_vunit));
 
-	struct layout l = {};
+	struct layout children = {};
 	for (int row = 0; row < to_show; row++)
 	{
 		int item_index = tab->item_top + row;
 		struct layout subl = app_layout_row (tab, item_index);
-		app_flush_layout_to (&subl, list->width, &l);
+		// TODO: Change layouting so that we don't need to know list->width.
+		app_flush_layout_full (&subl, list->width, &children);
 	}
-	LIST_FOR_EACH (struct widget, w, l.head)
-	{
-		w->x += list->x;
-		w->y += list->y;
-	}
-	return l.head;
-}
+	list->children = children.head;
 
-static void
-app_layout_view (void)
-{
-	// XXX: Expecting the status bar to always be there, one row tall.
-	struct widget *last = g.widgets.tail;
-	int unavailable_height = last->y + last->height + g.ui_vunit;
-
-	struct layout l = {};
-	struct widget *w = app_push_fill (&l, g.ui->list ());
-	w->id = WIDGET_LIST;
-	w->height = g.ui_height - unavailable_height;
-
-	struct tab *tab = g.active_tab;
-	if ((int) tab->item_count * g.ui_vunit > w->height)
-	{
-		app_push (&l, g.ui->scrollbar (APP_ATTR (SCROLLBAR)))
-			->id = WIDGET_SCROLLBAR;
-	}
-
-	app_flush_layout (&l);
+	app_flush_layout (&l, out);
 }
 
 static void
@@ -2258,7 +2266,7 @@ app_layout_mpd_status_playlist (struct layout *l, chtype attrs)
 }
 
 static void
-app_layout_mpd_status (void)
+app_layout_mpd_status (struct layout *out)
 {
 	struct layout l = {};
 	chtype attrs[2] = { APP_ATTR (NORMAL), APP_ATTR (HIGHLIGHT) };
@@ -2311,11 +2319,11 @@ app_layout_mpd_status (void)
 	}
 
 	app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
-	app_flush_layout (&l);
+	app_flush_layout (&l, out);
 }
 
 static void
-app_layout_statusbar (void)
+app_layout_statusbar (struct layout *out)
 {
 	struct layout l = {};
 	chtype attrs[2] = { APP_ATTR (NORMAL), APP_ATTR (HIGHLIGHT) };
@@ -2331,7 +2339,7 @@ app_layout_statusbar (void)
 		}
 		app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
 
-		app_flush_layout (&l);
+		app_flush_layout (&l, out);
 		LIST_FOR_EACH (struct widget, w, l.head)
 			w->id = WIDGET_MESSAGE;
 	}
@@ -2340,14 +2348,14 @@ app_layout_statusbar (void)
 		app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
 		app_push (&l, g.ui->editor (attrs[1]));
 		app_push (&l, g.ui->padding (attrs[0], 0.25, 1));
-		app_flush_layout (&l);
+		app_flush_layout (&l, out);
 	}
 	else if (g.client.state == MPD_CONNECTED)
-		app_layout_mpd_status ();
+		app_layout_mpd_status (out);
 	else if (g.client.state == MPD_CONNECTING)
-		app_layout_text ("Connecting to MPD...", attrs[0]);
+		app_layout_text ("Connecting to MPD...", attrs[0], out);
 	else if (g.client.state == MPD_DISCONNECTED)
-		app_layout_text ("Disconnected", attrs[0]);
+		app_layout_text ("Disconnected", attrs[0], out);
 }
 
 // - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
@@ -2393,14 +2401,23 @@ app_on_refresh (void *user_data)
 	(void) user_data;
 	poller_idle_reset (&g.refresh_event);
 
+	struct layout top = {}, bottom = {};
+	app_layout_header (&top);
+	app_layout_statusbar (&bottom);
+
+	int available_height = g.ui_height;
+	if (top.tail)
+		available_height -= top.tail->y + top.tail->height;
+	if (bottom.tail)
+		available_height -= bottom.tail->y + bottom.tail->height;
+
 	LIST_FOR_EACH (struct widget, w, g.widgets.head)
-		free (w);
+		widget_destroy (w);
 
 	g.widgets = (struct layout) {};
-
-	app_layout_header ();
-	app_layout_view ();
-	app_layout_statusbar ();
+	app_append_layout (&top, &g.widgets);
+	app_layout_view (&g.widgets, available_height);
+	app_append_layout (&bottom, &g.widgets);
 
 	app_fix_view_range();
 
@@ -2633,7 +2650,7 @@ incremental_search_on_changed (void)
 		LIST_FOR_EACH (struct widget, w, tab->on_item_layout (index).head)
 		{
 			str_append (&s, w->text);
-			free (w);
+			widget_destroy (w);
 		}
 
 		size_t len;
@@ -5694,11 +5711,8 @@ tui_make_scrollbar (chtype attrs)
 static void
 tui_render_list (struct widget *self)
 {
-	LIST_FOR_EACH (struct widget, w, self->on_sublayout (self))
-	{
+	LIST_FOR_EACH (struct widget, w, self->children)
 		w->on_render (w);
-		free (w);
-	}
 }
 
 static struct widget *
@@ -5708,7 +5722,6 @@ tui_make_list (void)
 	w->width = -1;
 	w->height = g.active_tab->item_count;
 	w->on_render = tui_render_list;
-	w->on_sublayout = app_sublayout_list;
 	return w;
 }
 
@@ -6478,11 +6491,8 @@ x11_render_list (struct widget *self)
 		&(XRectangle) { self->x, self->y, self->width, self->height }, 1);
 
 	x11_render_padding (self);
-	LIST_FOR_EACH (struct widget, w, self->on_sublayout (self))
-	{
+	LIST_FOR_EACH (struct widget, w, self->children)
 		w->on_render (w);
-		free (w);
-	}
 
 	XftDrawSetClip (g.xft_draw, None);
 }
@@ -6492,7 +6502,6 @@ x11_make_list (void)
 {
 	struct widget *w = xcalloc (1, sizeof *w + 1);
 	w->on_render = x11_render_list;
-	w->on_sublayout = app_sublayout_list;
 	return w;
 }
 
@@ -6770,15 +6779,9 @@ x11_find_text (struct widget *list, int x, int y)
 	if (!target)
 		return NULL;
 
-	if (target->on_sublayout)
-	{
-		struct widget *sublist = target->on_sublayout (target);
-		char *result = x11_find_text (sublist, x, y);
-		LIST_FOR_EACH (struct widget, w, sublist)
-			free (w);
-		if (result)
-			return result;
-	}
+	char *result = x11_find_text (target->children, x, y);
+	if (result)
+		return result;
 	return xstrdup (target->text);
 }