From 4a531daef89fadfaf6f8d8822614246a5aed79ce Mon Sep 17 00:00:00 2001
From: Johan Malm <jgm323@gmail.com>
Date: Tue, 6 Jun 2023 19:52:57 +0100
Subject: [PATCH] config: support <margin top="" bottom="" left="" right=""
 output="" />

---
 docs/labwc-config.5.scd |  6 +++++
 docs/rc.xml.all         | 11 +++++++++
 include/config/rcxml.h  | 10 ++++++++
 src/config/rcxml.c      | 51 +++++++++++++++++++++++++++++++++++++++++
 src/layers.c            | 19 +++++++++++++++
 5 files changed, 97 insertions(+)

diff --git a/docs/labwc-config.5.scd b/docs/labwc-config.5.scd
index 0c447fc2..e3bfe5c2 100644
--- a/docs/labwc-config.5.scd
+++ b/docs/labwc-config.5.scd
@@ -239,6 +239,12 @@ Therefore, where multiple objects of the same kind are required (for example
 *<theme><font place=""><weight>*
 	Font weight (normal or bold). Default is normal.
 
+## MARGIN
+
+*<margin top="" bottom="" left="" right="" output="" />*
+	Specify the number of pixels to reserve at the edges of an output.
+	New, maximized and tiled windows will not be placed in these areas.
+
 ## KEYBOARD
 
 *<keyboard><keybind key="">*
diff --git a/docs/rc.xml.all b/docs/rc.xml.all
index aff736aa..20f92a31 100644
--- a/docs/rc.xml.all
+++ b/docs/rc.xml.all
@@ -93,6 +93,17 @@
     </names>
   </desktops>
 
+  <!--
+    # <margin> can be used to reserve space where new/maximized/tiled
+    # windows will not be placed. Clients using layer-shell protocol reserve
+    # space automatically, so <margin> is only intended for other, specialist
+    # cases.
+    #
+    # If output is left empty, the margin will be applied to all outputs.
+
+    <margin top="" bottom="" left="" right="" output="" />
+  -->
+
   <!-- Percent based regions based on output usable area, % char is required -->
   <!--
     <regions>
diff --git a/include/config/rcxml.h b/include/config/rcxml.h
index d7ae5eb8..88a2ee0f 100644
--- a/include/config/rcxml.h
+++ b/include/config/rcxml.h
@@ -6,6 +6,7 @@
 #include <stdio.h>
 #include <wayland-server-core.h>
 
+#include "common/border.h"
 #include "common/buf.h"
 #include "common/font.h"
 #include "config/libinput.h"
@@ -18,6 +19,12 @@ enum window_switcher_field_content {
 	LAB_FIELD_TITLE,
 };
 
+struct usable_area_override {
+	struct border margin;
+	char *output;
+	struct wl_list link; /* struct rcxml.usable_area_overrides */
+};
+
 struct window_switcher_field {
 	enum window_switcher_field_content content;
 	int width;
@@ -47,6 +54,9 @@ struct rcxml {
 	/* Pointer to current theme */
 	struct theme *theme;
 
+	/* <margin top="" bottom="" left="" right="" output="" /> */
+	struct wl_list usable_area_overrides;
+
 	/* keyboard */
 	int repeat_rate;
 	int repeat_delay;
diff --git a/src/config/rcxml.c b/src/config/rcxml.c
index 2073ebf5..633b26bd 100644
--- a/src/config/rcxml.c
+++ b/src/config/rcxml.c
@@ -31,12 +31,14 @@
 #include "workspaces.h"
 
 static bool in_regions;
+static bool in_usable_area_override;
 static bool in_keybind;
 static bool in_mousebind;
 static bool in_libinput_category;
 static bool in_window_switcher_field;
 static bool in_window_rules;
 
+static struct usable_area_override *current_usable_area_override;
 static struct keybind *current_keybind;
 static struct mousebind *current_mousebind;
 static struct libinput_category *current_libinput_category;
@@ -60,6 +62,36 @@ enum font_place {
 static void load_default_key_bindings(void);
 static void load_default_mouse_bindings(void);
 
+static void
+fill_usable_area_override(char *nodename, char *content)
+{
+	if (!strcasecmp(nodename, "margin")) {
+		current_usable_area_override = znew(*current_usable_area_override);
+		wl_list_append(&rc.usable_area_overrides, &current_usable_area_override->link);
+		return;
+	}
+	string_truncate_at_pattern(nodename, ".margin");
+	if (!content) {
+		/* nop */
+	} else if (!current_usable_area_override) {
+		wlr_log(WLR_ERROR, "no usable-area-override object");
+	} else if (!strcmp(nodename, "output")) {
+		free(current_usable_area_override->output);
+		current_usable_area_override->output = xstrdup(content);
+	} else if (!strcmp(nodename, "left")) {
+		current_usable_area_override->margin.left = atoi(content);
+	} else if (!strcmp(nodename, "right")) {
+		current_usable_area_override->margin.right = atoi(content);
+	} else if (!strcmp(nodename, "top")) {
+		current_usable_area_override->margin.top = atoi(content);
+	} else if (!strcmp(nodename, "bottom")) {
+		current_usable_area_override->margin.bottom = atoi(content);
+	} else {
+		wlr_log(WLR_ERROR, "Unexpected data usable-area-override parser: %s=\"%s\"",
+			nodename, content);
+	}
+}
+
 /* Does a boolean-parse but also allows 'default' */
 static void
 set_property(const char *str, enum property *variable)
@@ -478,6 +510,9 @@ entry(xmlNode *node, char *nodename, char *content)
 		printf("%s: %s\n", nodename, content);
 	}
 
+	if (in_usable_area_override) {
+		fill_usable_area_override(nodename, content);
+	}
 	if (in_keybind) {
 		fill_keybind(nodename, content);
 	}
@@ -564,6 +599,7 @@ entry(xmlNode *node, char *nodename, char *content)
 	} else if (!strcasecmp(nodename, "name.context.mouse")) {
 		current_mouse_context = content;
 		current_mousebind = NULL;
+
 	} else if (!strcasecmp(nodename, "repeatRate.keyboard")) {
 		rc.repeat_rate = atoi(content);
 	} else if (!strcasecmp(nodename, "repeatDelay.keyboard")) {
@@ -656,6 +692,12 @@ xml_tree_walk(xmlNode *node)
 		if (!strcasecmp((char *)n->name, "comment")) {
 			continue;
 		}
+		if (!strcasecmp((char *)n->name, "margin")) {
+			in_usable_area_override = true;
+			traverse(n);
+			in_usable_area_override = false;
+			continue;
+		}
 		if (!strcasecmp((char *)n->name, "keybind")) {
 			in_keybind = true;
 			traverse(n);
@@ -724,6 +766,7 @@ rcxml_init(void)
 	static bool has_run;
 
 	if (!has_run) {
+		wl_list_init(&rc.usable_area_overrides);
 		wl_list_init(&rc.keybinds);
 		wl_list_init(&rc.mousebinds);
 		wl_list_init(&rc.libinput_categories);
@@ -1185,6 +1228,13 @@ rcxml_finish(void)
 	zfree(rc.font_osd.name);
 	zfree(rc.theme_name);
 
+	struct usable_area_override *area, *area_tmp;
+	wl_list_for_each_safe(area, area_tmp, &rc.usable_area_overrides, link) {
+		wl_list_remove(&area->link);
+		zfree(area->output);
+		zfree(area);
+	}
+
 	struct keybind *k, *k_tmp;
 	wl_list_for_each_safe(k, k_tmp, &rc.keybinds, link) {
 		wl_list_remove(&k->link);
@@ -1228,6 +1278,7 @@ rcxml_finish(void)
 	}
 
 	/* Reset state vars for starting fresh when Reload is triggered */
+	current_usable_area_override = NULL;
 	current_keybind = NULL;
 	current_mousebind = NULL;
 	current_libinput_category = NULL;
diff --git a/src/layers.c b/src/layers.c
index bd0b0e17..2d750f22 100644
--- a/src/layers.c
+++ b/src/layers.c
@@ -10,15 +10,32 @@
 #include <stdbool.h>
 #include <stdlib.h>
 #include <string.h>
+#include <strings.h>
 #include <wayland-server.h>
 #include <wlr/types/wlr_layer_shell_v1.h>
 #include <wlr/util/log.h>
 #include "common/list.h"
 #include "common/mem.h"
+#include "config/rcxml.h"
 #include "layers.h"
 #include "labwc.h"
 #include "node.h"
 
+static void
+apply_override(struct output *output, struct wlr_box *usable_area)
+{
+	struct usable_area_override *override;
+	wl_list_for_each(override, &rc.usable_area_overrides, link) {
+		if (override->output && strcasecmp(override->output, output->wlr_output->name)) {
+			continue;
+		}
+		usable_area->x += override->margin.left;
+		usable_area->y += override->margin.top;
+		usable_area->width -= override->margin.left + override->margin.right;
+		usable_area->height -= override->margin.top + override->margin.bottom;
+	}
+}
+
 static void
 arrange_one_layer(struct output *output, const struct wlr_box *full_area,
 		struct wlr_box *usable_area, struct wlr_scene_tree *tree,
@@ -49,6 +66,8 @@ layers_arrange(struct output *output)
 		&full_area.width, &full_area.height);
 	struct wlr_box usable_area = full_area;
 
+	apply_override(output, &usable_area);
+
 	struct server *server = output->server;
 	struct wlr_scene_output *scene_output =
 		wlr_scene_get_scene_output(server->scene, output->wlr_output);