If monitors on the compositor side are disable, they are removed as globals client side.

So we need to recreate them after they are turned back on.
Also, used g_object_unref on PangoFontDescription rather than pango_font_description_free which would cause a crash.

src/bar.c

@@ -1,6 +1,5 @@
 #include "bar.h"
 #include "cairo.h"
-#include "config.def.h"
 #include "config.h"
 #include "input.h"
 #include "main.h"
@@ -27,6 +26,7 @@ static void bar_status_render(struct Pipeline *pipeline, struct Bar *bar, cairo_
 static int bar_width(struct Pipeline *pipeline, void *data, unsigned int future_widths);
 
 const struct PipelineListener bar_pipeline_listener = { .render = bar_render, .width = bar_width, };
+const struct HotspotListener bar_hotspot_listener = { .click = bar_click, .bounds = bar_bounds };
 
 void bar_click(struct Monitor *monitor, void *data, uint32_t button, double x, double y) {
     if (!monitor || !data)
@@ -155,8 +155,7 @@ struct Bar *bar_create(struct List *hotspots, struct Pipeline *pipeline) {
 
     pipeline_add(pipeline, &bar_pipeline_listener, bar);
     struct Hotspot *hotspot = list_add(hotspots, ecalloc(1, sizeof(*hotspot)));
-    hotspot->click = bar_click;
-    hotspot->bounds = bar_bounds;
+    hotspot->listener = &bar_hotspot_listener;
     hotspot->data = bar;
 
     bar->x = 0;

src/config.def.h

@@ -35,6 +35,7 @@ static const int *schemes[3][2] = {
 
 /*
  * Tags
+ * Must not exceed 31 tags and amount must match dwl's tagcount.
  */
 static const char *tags[] = { "1", "2", "3", "4", "5", "6", "7", "8", "9" };
 

src/input.c

@@ -15,6 +15,7 @@
 #include <wayland-util.h>
 
 static int button_cmp(const void *left, const void *right);
+static void hotspots_process(struct Monitor* monitor, double x, double y, uint32_t button);
 static void pointer_axis(void *data, struct wl_pointer *wl_pointer, uint32_t time, uint32_t axis, wl_fixed_t value);
 static void pointer_axis_discrete(void *data, struct wl_pointer *wl_pointer, uint32_t axis, int32_t discrete);
 static void pointer_axis_source(void *data, struct wl_pointer *wl_pointer, uint32_t axis_source);
@@ -158,7 +159,7 @@ void pointer_frame(void *data, struct wl_pointer *wl_pointer) {
     if (!monitor) return;
 
     for (int i = 0; i < pointer->buttons->length; i++)
-        process_hotspots(pointer->focused_monitor, pointer->x, pointer->y,
+        hotspots_process(pointer->focused_monitor, pointer->x, pointer->y,
                 *(uint32_t*)pointer->buttons->data[i]);
     list_elements_destroy(pointer->buttons, free);
     pointer->buttons = list_create(0);
@@ -173,14 +174,16 @@ void pointer_process_scroll(struct Pointer *pointer, unsigned int axis_index) {
     struct Axis *axis = &pointer->axis[axis_index];
     if (axis->discrete_steps) {
         for (int i = 0; i < axis->discrete_steps; i++)
-            process_hotspots(pointer->focused_monitor, pointer->x, pointer->y, wl_axis_to_button(axis_index, axis->value));
+            hotspots_process(pointer->focused_monitor, pointer->x, pointer->y, wl_axis_to_button(axis_index, axis->value));
+        axis->value = 0;
+        axis->discrete_steps = 0;
     } else {
         while (abs(axis->value) > SCROLL_THRESHOLD) {
             if (axis->value > 0){
-                process_hotspots(pointer->focused_monitor, pointer->x, pointer->y, wl_axis_to_button(axis_index, SCROLL_THRESHOLD));
+                hotspots_process(pointer->focused_monitor, pointer->x, pointer->y, wl_axis_to_button(axis_index, SCROLL_THRESHOLD));
                 axis->value -= SCROLL_THRESHOLD;
             } else {
-                process_hotspots(pointer->focused_monitor, pointer->x, pointer->y, wl_axis_to_button(axis_index, -SCROLL_THRESHOLD));
+                hotspots_process(pointer->focused_monitor, pointer->x, pointer->y, wl_axis_to_button(axis_index, -SCROLL_THRESHOLD));
                 axis->value += SCROLL_THRESHOLD;
             }
         }
@@ -224,19 +227,19 @@ void pointer_update_cursor(struct Pointer *pointer) {
     wl_surface_commit(pointer->cursor_surface);
 }
 
-void process_hotspots(struct Monitor* monitor, double x, double y, uint32_t button) {
+void hotspots_process(struct Monitor* monitor, double x, double y, uint32_t button) {
     struct Hotspot *hotspot;
     for (int i = 0; i < monitor->hotspots->length; i++) {
         hotspot = monitor->hotspots->data[i];
 
         double hotspot_x = 0, hotspot_y = 0, hotspot_width = 0, hotspot_height = 0;
-        hotspot->bounds(hotspot->data, &hotspot_x, &hotspot_y, &hotspot_width, &hotspot_height);
+        hotspot->listener->bounds(hotspot->data, &hotspot_x, &hotspot_y, &hotspot_width, &hotspot_height);
 
         if (!( x > hotspot_x && y > hotspot_y &&
                     x < (hotspot_x+hotspot_width) && y < (hotspot_y+hotspot_height)))
             continue;
 
-        hotspot->click(monitor, hotspot->data, button, x, y);
+        hotspot->listener->click(monitor, hotspot->data, button, x, y);
         return;
     }
 }
@@ -389,7 +392,7 @@ void touch_up(void *data, struct wl_touch *wl_touch, uint32_t serial, uint32_t t
     if (!point) return;
 
     uint32_t button = touch_point_to_button(point, time);
-    process_hotspots(point->focused_monitor, point->x, point->y, button);
+    hotspots_process(point->focused_monitor, point->x, point->y, button);
 }
 
 uint32_t wl_axis_to_button(int axis, wl_fixed_t value) {

src/input.h

@@ -51,15 +51,18 @@ struct Seat {
     struct wl_list link;
 };
 
-struct Hotspot {
+struct HotspotListener {
     void (*click)(struct Monitor *monitor, void *data, uint32_t button, double x, double y);
     void (*bounds)(void *data, double *x, double *y, double *width, double *height);
+};
+
+struct Hotspot {
+    const struct HotspotListener *listener;
     void *data;
 };
 
 extern const struct wl_seat_listener seat_listener;
 
-void process_hotspots(struct Monitor* monitor, double x, double y, uint32_t button);
 void seat_destroy(struct Seat *seat);
 
 #endif // INPUT_H_

src/main.c

@@ -35,6 +35,7 @@ static void fifo_setup(void);
 static void monitor_destroy(struct Monitor *monitor);
 static struct Monitor *monitor_from_name(const char *name);
 struct Monitor *monitor_from_surface(const struct wl_surface *surface);
+static void monitor_initialize(struct Monitor *monitor);
 static void monitor_update(struct Monitor *monitor);
 static void pipe_in(int fd, short mask, void *data);
 static void registry_global_add(void *data, struct wl_registry *registry, uint32_t name,
@@ -195,9 +196,9 @@ void monitor_destroy(struct Monitor *monitor) {
     if (!monitor)
         return;
 
-    wl_list_remove(&monitor->link);
     free(monitor->xdg_name);
-    wl_output_release(monitor->wl_output);
+    if (wl_output_get_version(monitor->wl_output) >= WL_OUTPUT_RELEASE_SINCE_VERSION)
+        wl_output_release(monitor->wl_output);
     list_elements_destroy(monitor->hotspots, free);
     pipeline_destroy(monitor->pipeline);
     bar_destroy(monitor->bar);
@@ -224,6 +225,17 @@ struct Monitor *monitor_from_surface(const struct wl_surface *surface) {
     return NULL;
 }
 
+void monitor_initialize(struct Monitor *monitor) {
+    if (!monitor) return;
+
+    monitor->hotspots = list_create(1);
+    monitor->pipeline = pipeline_create();
+    monitor->bar = bar_create(monitor->hotspots, monitor->pipeline);
+    if (!monitor->pipeline || !monitor->bar)
+        panic("Failed to create a pipline or bar for monitor: %s", monitor->xdg_name);
+    monitor_update(monitor);
+}
+
 void monitor_update(struct Monitor *monitor) {
     if (!monitor)
         return;
@@ -257,12 +269,6 @@ void registry_global_add(void *data, struct wl_registry *registry, uint32_t name
         monitor->wl_name = name;
         monitor->xdg_name = NULL;
         monitor->xdg_output = NULL;
-        monitor->hotspots = list_create(1);
-        monitor->pipeline = pipeline_create();
-        monitor->bar = bar_create(monitor->hotspots, monitor->pipeline);
-
-        if (!monitor->pipeline || !monitor->bar)
-            return;
 
         wl_list_insert(&monitors, &monitor->link);
 
@@ -271,6 +277,9 @@ void registry_global_add(void *data, struct wl_registry *registry, uint32_t name
 
         monitor->xdg_output = zxdg_output_manager_v1_get_xdg_output(output_manager, monitor->wl_output);
         zxdg_output_v1_add_listener(monitor->xdg_output, &xdg_output_listener, monitor);
+
+        if (!running) return;
+        monitor_initialize(monitor);
     }
     else if (STRING_EQUAL(interface, wl_seat_interface.name)) {
         struct Seat *seat = ecalloc(1, sizeof(*seat));
@@ -378,6 +387,11 @@ void setup(void) {
 
     wl_display_roundtrip(display);
 
+    struct Monitor *monitor;
+    wl_list_for_each(monitor, &monitors, link) {
+        monitor_initialize(monitor);
+    }
+
     if (fcntl(STDIN_FILENO, F_SETFL, O_NONBLOCK) < 0)
         panic("STDIN_FILENO O_NONBLOCK");
 

src/render.c

@@ -134,7 +134,7 @@ void pipeline_destroy(struct Pipeline *pipeline) {
 
     list_elements_destroy(pipeline->callbacks, free);
     g_object_unref(pipeline->context);
-    g_object_unref(pipeline->font->description);
+    pango_font_description_free(pipeline->font->description);
     free(pipeline->font);
     shm_destroy(pipeline->shm);
     wl_surface_destroy(pipeline->surface);

src/shm.c

@@ -45,9 +45,7 @@ static struct Buffer buffer_create(struct MemoryMapping *map, struct wl_shm_pool
 
 void buffer_destroy(struct Buffer *buffer) {
     if (!buffer) return;
-
     wl_buffer_destroy(buffer->buffer);
-    free(buffer);
 }
 
 struct MemoryMapping memory_mapping_create(int fd, int pool_size) {
@@ -67,9 +65,7 @@ struct MemoryMapping memory_mapping_create(int fd, int pool_size) {
 
 void memory_mapping_destroy(struct MemoryMapping *map) {
     if (!map) return;
-
     munmap(map->ptr, map->size);
-    free(map);
 }
 
 struct Shm *shm_create(int width, int height, enum wl_shm_format format) {

src/util.c

@@ -102,7 +102,7 @@ void list_resize(struct List *list) {
         return;
 
     list->allocated *= 2;
-    list->data = realloc(list->data, list->allocated);
+    list->data = realloc(list->data, sizeof(void*) * list->allocated);
 }
 
 char *string_create(const char *fmt, ...) {

src/util.h

@@ -6,7 +6,7 @@
 #include <wayland-util.h>
 
 #define STRING_EQUAL(string1, string2) strcmp(string1, string2) == 0
-#define STRINGN_EQUAL(string1, string2, n) strcmp(string1, string2, n) == 0
+#define STRINGN_EQUAL(string1, string2, n) strncmp(string1, string2, n) == 0
 #define LENGTH(X) (sizeof X / sizeof X[0] )
 
 struct List {