config: support window switcher field definitions

<windowSwitcher>
  <fields>
    <field content="type" width="25%" />
    <field content="app_id" width="25%" />
    <field content="title" width="50%" />
  </fields>
</windowSwitcher>

Relates to issues #852 #855 #879

docs/labwc-config.5.scd

@@ -89,6 +89,20 @@ The rest of this man page describes configuration options.
 	*outlines* [yes|no] Draw an outline around the selected window when
 	switching between windows. Default is yes.
 
+*<windowSwitcher><fields><field content="" width="%">*
+	Define window switcher fields.
+
+	*content* defines what the field shows and can be any of:
+
+		- *type* Show view type ("xdg-shell" or "xwayland")
+
+		- *app_id* Show app_id (class for XWayland)
+
+		- *title* Show window title if different to app_id
+
+	*width* defines the width of the field expressed as a percentage of
+	the overall window switcher width. The "%" character is required.
+
 ## RESISTANCE
 
 *<resistance><screenEdgeStrength>*

docs/rc.xml.all

@@ -38,7 +38,13 @@
     </font>
   </theme>
 
-  <windowSwitcher show="yes" preview="yes" outlines="yes" />
+  <windowSwitcher show="yes" preview="yes" outlines="yes">
+    <fields>
+      <field content="type" width="25%" />
+      <field content="app_id" width="25%" />
+      <field content="title" width="50%" />
+    </fields>
+  </windowSwitcher>
 
   <!-- edge strength is in pixels -->
   <resistance>

include/config/rcxml.h

@@ -11,6 +11,19 @@
 #include "config/libinput.h"
 #include "theme.h"
 
+enum window_switcher_field_content {
+	LAB_FIELD_NONE = 0,
+	LAB_FIELD_TYPE,
+	LAB_FIELD_APP_ID,
+	LAB_FIELD_TITLE,
+};
+
+struct window_switcher_field {
+	enum window_switcher_field_content content;
+	int width;
+	struct wl_list link; /* struct rcxml.window_switcher.fields */
+};
+
 struct rcxml {
 	char *config_dir;
 
@@ -65,6 +78,10 @@ struct rcxml {
 
 	/* Regions */
 	struct wl_list regions;  /* struct region.link */
+
+	struct {
+		struct wl_list fields;  /* struct window_switcher_field.link */
+	} window_switcher;
 };
 
 extern struct rcxml rc;

src/config/rcxml.c

@@ -31,6 +31,8 @@ static bool in_regions;
 static bool in_keybind;
 static bool in_mousebind;
 static bool in_libinput_category;
+static bool in_window_switcher_field;
+
 static struct keybind *current_keybind;
 static struct mousebind *current_mousebind;
 static struct libinput_category *current_libinput_category;
@@ -38,6 +40,7 @@ static const char *current_mouse_context;
 static struct action *current_keybind_action;
 static struct action *current_mousebind_action;
 static struct region *current_region;
+static struct window_switcher_field *current_field;
 
 enum font_place {
 	FONT_PLACE_NONE = 0,
@@ -51,6 +54,43 @@ enum font_place {
 static void load_default_key_bindings(void);
 static void load_default_mouse_bindings(void);
 
+static void
+fill_window_switcher_field(char *nodename, char *content)
+{
+	if (!strcasecmp(nodename, "field.fields.windowswitcher")) {
+		current_field = znew(*current_field);
+		wl_list_append(&rc.window_switcher.fields, &current_field->link);
+		return;
+	}
+
+	string_truncate_at_pattern(nodename, ".field.fields.windowswitcher");
+	if (!content) {
+		/* intentionally left empty */
+	} else if (!current_field) {
+		wlr_log(WLR_ERROR, "no <field>");
+	} else if (!strcmp(nodename, "content")) {
+		if (!strcmp(content, "type")) {
+			current_field->content = LAB_FIELD_TYPE;
+		} else if (!strcmp(content, "app_id")) {
+			current_field->content = LAB_FIELD_APP_ID;
+		} else if (!strcmp(content, "title")) {
+			current_field->content = LAB_FIELD_TITLE;
+		} else {
+			wlr_log(WLR_ERROR, "bad windowSwitcher field '%s'", content);
+		}
+	} else if (!strcmp(nodename, "width") && !strchr(content, '%')) {
+		wlr_log(WLR_ERROR, "Removing invalid field, %s='%s' misses"
+			" trailing %%", nodename, content);
+		wl_list_remove(&current_field->link);
+		zfree(current_field);
+	} else if (!strcmp(nodename, "width")) {
+		current_field->width = atoi(content);
+	} else {
+		wlr_log(WLR_ERROR, "Unexpected data in field parser: %s=\"%s\"",
+			nodename, content);
+	}
+}
+
 static void
 fill_region(char *nodename, char *content)
 {
@@ -362,6 +402,10 @@ entry(xmlNode *node, char *nodename, char *content)
 		fill_region(nodename, content);
 		return;
 	}
+	if (in_window_switcher_field) {
+		fill_window_switcher_field(nodename, content);
+		return;
+	}
 
 	/* handle nodes without content, e.g. <keyboard><default /> */
 	if (!strcmp(nodename, "default.keyboard")) {
@@ -448,6 +492,14 @@ entry(xmlNode *node, char *nodename, char *content)
 	} else if (strstr(nodename, "windowswitcher.core")) {
 		wlr_log(WLR_ERROR, "<windowSwitcher> should not be child of <core>");
 
+	/* The following three are for backward compatibility only */
+	} else if (!strcasecmp(nodename, "show.windowSwitcher.core")) {
+		rc.cycle_view_osd = get_bool(content);
+	} else if (!strcasecmp(nodename, "preview.windowSwitcher.core")) {
+		rc.cycle_preview_contents = get_bool(content);
+	} else if (!strcasecmp(nodename, "outlines.windowSwitcher.core")) {
+		rc.cycle_preview_outlines = get_bool(content);
+
 	/* The following three are for backward compatibility only */
 	} else if (!strcasecmp(nodename, "cycleViewOSD.core")) {
 		rc.cycle_view_osd = get_bool(content);
@@ -531,6 +583,12 @@ xml_tree_walk(xmlNode *node)
 			in_regions = false;
 			continue;
 		}
+		if (!strcasecmp((char *)n->name, "fields")) {
+			in_window_switcher_field = true;
+			traverse(n);
+			in_window_switcher_field = false;
+			continue;
+		}
 		traverse(n);
 	}
 }
@@ -568,6 +626,7 @@ rcxml_init(void)
 		wl_list_init(&rc.libinput_categories);
 		wl_list_init(&rc.workspace_config.workspaces);
 		wl_list_init(&rc.regions);
+		wl_list_init(&rc.window_switcher.fields);
 	}
 	has_run = true;
 
@@ -784,6 +843,29 @@ deduplicate_key_bindings(void)
 	}
 }
 
+static struct {
+	enum window_switcher_field_content content;
+	int width;
+} fields[] = {
+	{ LAB_FIELD_TYPE, 25 },
+	{ LAB_FIELD_APP_ID, 25 },
+	{ LAB_FIELD_TITLE, 50 },
+	{ LAB_FIELD_NONE, 0 },
+};
+
+static void
+load_default_window_switcher_fields(void)
+{
+	struct window_switcher_field *field;
+
+	for (int i = 0; fields[i].content != LAB_FIELD_NONE; i++) {
+		field = znew(*field);
+		field->content = fields[i].content;
+		field->width = fields[i].width;
+		wl_list_append(&rc.window_switcher.fields, &field->link);
+	}
+}
+
 static void
 post_processing(void)
 {
@@ -846,6 +928,11 @@ post_processing(void)
 			free(region);
 		}
 	}
+
+	if (!wl_list_length(&rc.window_switcher.fields)) {
+		wlr_log(WLR_INFO, "load default window switcher fields");
+		load_default_window_switcher_fields();
+	}
 }
 
 static void
@@ -953,6 +1040,12 @@ rcxml_finish(void)
 
 	regions_destroy(NULL, &rc.regions);
 
+	struct window_switcher_field *field, *field_tmp;
+	wl_list_for_each_safe(field, field_tmp, &rc.window_switcher.fields, link) {
+		wl_list_remove(&field->link);
+		zfree(field);
+	}
+
 	/* Reset state vars for starting fresh when Reload is triggered */
 	current_keybind = NULL;
 	current_mousebind = NULL;
@@ -961,4 +1054,5 @@ rcxml_finish(void)
 	current_keybind_action = NULL;
 	current_mousebind_action = NULL;
 	current_region = NULL;
+	current_field = NULL;
 }

src/osd.c

@@ -21,8 +21,6 @@
 #define OSD_ITEM_WIDTH (600)
 #define OSD_ITEM_PADDING (10)
 #define OSD_BORDER_WIDTH (6)
-#define OSD_TAB1 (120)
-#define OSD_TAB2 (300)
 
 /* is title different from app_id/class? */
 static int
@@ -243,11 +241,52 @@ preview_cycled_view(struct view *view)
 	wlr_scene_node_raise_to_top(osd_state->preview_node);
 }
 
+static const char *
+get_type(struct view *view)
+{
+	switch (view->type) {
+	case LAB_XDG_SHELL_VIEW:
+		return "[xdg-shell]";
+#if HAVE_XWAYLAND
+	case LAB_XWAYLAND_VIEW:
+		return "[xwayland]";
+#endif
+	}
+	return "";
+}
+
+static const char *
+get_app_id(struct view *view)
+{
+	switch (view->type) {
+	case LAB_XDG_SHELL_VIEW:
+		return get_formatted_app_id(view);
+#if HAVE_XWAYLAND
+	case LAB_XWAYLAND_VIEW:
+		return view_get_string_prop(view, "class");
+#endif
+	}
+	return "";
+}
+
+static const char *
+get_title(struct view *view)
+{
+	if (is_title_different(view)) {
+		return view_get_string_prop(view, "title");
+	} else {
+		return "";
+	}
+}
+
 static void
-render_osd(cairo_t *cairo, int w, int h, struct wl_list *node_list,
-		struct view *cycle_view, struct theme *theme, bool show_workspace,
+render_osd(struct server *server, cairo_t *cairo, int w, int h,
+		struct wl_list *node_list, bool show_workspace,
 		const char *workspace_name)
 {
+	struct view *cycle_view = server->osd_state.cycle_view;
+	struct theme *theme = server->theme;
+
 	struct wlr_scene_node *node;
 	cairo_surface_t *surf = cairo_get_target(cairo);
 
@@ -270,11 +309,6 @@ render_osd(cairo_t *cairo, int w, int h, struct wl_list *node_list,
 	PangoFontDescription *desc = font_to_pango_desc(&rc.font_osd);
 	pango_layout_set_font_description(layout, desc);
 
-	PangoTabArray *tabs = pango_tab_array_new_with_positions(2, TRUE,
-		PANGO_TAB_LEFT, OSD_TAB1, PANGO_TAB_LEFT, OSD_TAB2);
-	pango_layout_set_tabs(layout, tabs);
-	pango_tab_array_free(tabs);
-
 	pango_cairo_update_layout(cairo, layout);
 
 	int y = OSD_BORDER_WIDTH;
@@ -313,31 +347,31 @@ render_osd(cairo_t *cairo, int w, int h, struct wl_list *node_list,
 		if (!isfocusable(view)) {
 			continue;
 		}
-		buf.len = 0;
-		cairo_move_to(cairo, OSD_BORDER_WIDTH + OSD_ITEM_PADDING, y);
 
-		switch (view->type) {
-		case LAB_XDG_SHELL_VIEW:
-			buf_add(&buf, "[xdg-shell]\t");
-			buf_add(&buf, get_formatted_app_id(view));
-			buf_add(&buf, "\t");
-			break;
-#if HAVE_XWAYLAND
-		case LAB_XWAYLAND_VIEW:
-			buf_add(&buf, "[xwayland]\t");
-			buf_add(&buf, view_get_string_prop(view, "class"));
-			buf_add(&buf, "\t");
-			break;
-#endif
+		int x = OSD_BORDER_WIDTH + OSD_ITEM_PADDING;
+		struct window_switcher_field *field;
+		wl_list_for_each(field, &rc.window_switcher.fields, link) {
+			buf.len = 0;
+			cairo_move_to(cairo, x, y);
+
+			switch (field->content) {
+			case LAB_FIELD_TYPE:
+				buf_add(&buf, get_type(view));
+				break;
+			case LAB_FIELD_APP_ID:
+				buf_add(&buf, get_app_id(view));
+				break;
+			case LAB_FIELD_TITLE:
+				buf_add(&buf, get_title(view));
+				break;
+			default:
+				break;
+			}
+			pango_layout_set_text(layout, buf.buf, -1);
+			pango_cairo_show_layout(cairo, layout);
+			x += field->width / 100.0 * OSD_ITEM_WIDTH;
 		}
 
-		if (is_title_different(view)) {
-			buf_add(&buf, view_get_string_prop(view, "title"));
-		}
-
-		pango_layout_set_text(layout, buf.buf, -1);
-		pango_cairo_show_layout(cairo, layout);
-
 		if (view == cycle_view) {
 			/* Highlight current window */
 			cairo_rectangle(cairo, OSD_BORDER_WIDTH, y - y_offset,
@@ -378,8 +412,7 @@ display_osd(struct output *output)
 
 	/* Render OSD image */
 	cairo_t *cairo = output->osd_buffer->cairo;
-	render_osd(cairo, w, h, node_list, server->osd_state.cycle_view,
-		server->theme, show_workspace, workspace_name);
+	render_osd(server, cairo, w, h, node_list, show_workspace, workspace_name);
 
 	struct wlr_scene_buffer *scene_buffer = wlr_scene_buffer_create(
 		output->osd_tree, &output->osd_buffer->base);