kiwmi_output:usable_area() and :on("usable_area_change")

include/desktop/output.h

@@ -9,6 +9,7 @@
 #define KIWMI_DESKTOP_OUTPUT_H
 
 #include <wayland-server.h>
+#include <wlr/types/wlr_box.h>
 
 struct kiwmi_output {
     struct wl_list link;
@@ -20,10 +21,12 @@ struct kiwmi_output {
     struct wl_listener mode;
 
     struct wl_list layers[4]; // struct kiwmi_layer_surface::link
+    struct wlr_box usable_area;
 
     struct {
         struct wl_signal destroy;
         struct wl_signal resize;
+        struct wl_signal usable_area_change;
     } events;
 };
 

kiwmi/desktop/layer_shell.c

@@ -301,6 +301,12 @@ arrange_layers(struct kiwmi_output *output)
         }
     }
 
+    if (memcmp(&usable_area, &output->usable_area, sizeof(output->usable_area))
+        != 0) {
+        memcpy(&output->usable_area, &usable_area, sizeof(output->usable_area));
+        wl_signal_emit(&output->events.usable_area_change, output);
+    }
+
     struct kiwmi_desktop *desktop = output->desktop;
     struct kiwmi_server *server   = wl_container_of(desktop, server, desktop);
     struct kiwmi_seat *seat       = server->input.seat;

kiwmi/desktop/output.c

@@ -219,6 +219,9 @@ output_create(struct wlr_output *wlr_output, struct kiwmi_desktop *desktop)
     output->wlr_output = wlr_output;
     output->desktop    = desktop;
 
+    output->usable_area.width  = wlr_output->width;
+    output->usable_area.height = wlr_output->height;
+
     output->frame.notify = output_frame_notify;
     wl_signal_add(&wlr_output->events.frame, &output->frame);
 
@@ -280,6 +283,7 @@ new_output_notify(struct wl_listener *listener, void *data)
 
     wl_signal_init(&output->events.destroy);
     wl_signal_init(&output->events.resize);
+    wl_signal_init(&output->events.usable_area_change);
 
     wl_signal_emit(&desktop->events.new_output, output);
 }

kiwmi/luak/kiwmi_output.c

@@ -116,6 +116,35 @@ l_kiwmi_output_size(lua_State *L)
     return 2;
 }
 
+static int
+l_kiwmi_output_usable_area(lua_State *L)
+{
+    struct kiwmi_object *obj =
+        *(struct kiwmi_object **)luaL_checkudata(L, 1, "kiwmi_output");
+
+    if (!obj->valid) {
+        return luaL_error(L, "kiwmi_output no longer valid");
+    }
+
+    struct kiwmi_output *output = obj->object;
+
+    lua_newtable(L);
+
+    lua_pushinteger(L, output->usable_area.x);
+    lua_setfield(L, -2, "x");
+
+    lua_pushinteger(L, output->usable_area.y);
+    lua_setfield(L, -2, "y");
+
+    lua_pushinteger(L, output->usable_area.width);
+    lua_setfield(L, -2, "width");
+
+    lua_pushinteger(L, output->usable_area.height);
+    lua_setfield(L, -2, "height");
+
+    return 1;
+}
+
 static const luaL_Reg kiwmi_output_methods[] = {
     {"auto", l_kiwmi_output_auto},
     {"move", l_kiwmi_output_move},
@@ -123,6 +152,7 @@ static const luaL_Reg kiwmi_output_methods[] = {
     {"on", luaK_callback_register_dispatch},
     {"pos", l_kiwmi_output_pos},
     {"size", l_kiwmi_output_size},
+    {"usable_area", l_kiwmi_output_usable_area},
     {NULL, NULL},
 };
 
@@ -192,6 +222,50 @@ kiwmi_output_on_resize_notify(struct wl_listener *listener, void *data)
     }
 }
 
+static void
+kiwmi_output_on_usable_area_change_notify(
+    struct wl_listener *listener,
+    void *data)
+{
+    struct kiwmi_lua_callback *lc = wl_container_of(listener, lc, listener);
+    struct kiwmi_server *server   = lc->server;
+    lua_State *L                  = server->lua->L;
+    struct kiwmi_output *output   = data;
+
+    lua_rawgeti(L, LUA_REGISTRYINDEX, lc->callback_ref);
+
+    lua_newtable(L);
+
+    lua_pushcfunction(L, luaK_kiwmi_output_new);
+    lua_pushlightuserdata(L, server->lua);
+    lua_pushlightuserdata(L, output);
+
+    if (lua_pcall(L, 2, 1, 0)) {
+        wlr_log(WLR_ERROR, "%s", lua_tostring(L, -1));
+        lua_pop(L, 1);
+        return;
+    }
+
+    lua_setfield(L, -2, "output");
+
+    lua_pushinteger(L, output->usable_area.x);
+    lua_setfield(L, -2, "x");
+
+    lua_pushinteger(L, output->usable_area.y);
+    lua_setfield(L, -2, "y");
+
+    lua_pushinteger(L, output->usable_area.width);
+    lua_setfield(L, -2, "width");
+
+    lua_pushinteger(L, output->usable_area.height);
+    lua_setfield(L, -2, "height");
+
+    if (lua_pcall(L, 1, 0, 0)) {
+        wlr_log(WLR_ERROR, "%s", lua_tostring(L, -1));
+        lua_pop(L, 1);
+    }
+}
+
 static int
 l_kiwmi_output_on_destroy(lua_State *L)
 {
@@ -252,9 +326,40 @@ l_kiwmi_output_on_resize(lua_State *L)
     return 0;
 }
 
+static int
+l_kiwmi_output_on_usable_area_change(lua_State *L)
+{
+    struct kiwmi_object *obj =
+        *(struct kiwmi_object **)luaL_checkudata(L, 1, "kiwmi_output");
+    luaL_checktype(L, 2, LUA_TFUNCTION);
+
+    if (!obj->valid) {
+        return luaL_error(L, "kiwmi_output no longer valid");
+    }
+
+    struct kiwmi_output *output   = obj->object;
+    struct kiwmi_desktop *desktop = output->desktop;
+    struct kiwmi_server *server   = wl_container_of(desktop, server, desktop);
+
+    lua_pushcfunction(L, luaK_kiwmi_lua_callback_new);
+    lua_pushlightuserdata(L, server);
+    lua_pushvalue(L, 2);
+    lua_pushlightuserdata(L, kiwmi_output_on_usable_area_change_notify);
+    lua_pushlightuserdata(L, &output->events.usable_area_change);
+    lua_pushlightuserdata(L, obj);
+
+    if (lua_pcall(L, 5, 0, 0)) {
+        wlr_log(WLR_ERROR, "%s", lua_tostring(L, -1));
+        return 0;
+    }
+
+    return 0;
+}
+
 static const luaL_Reg kiwmi_output_events[] = {
     {"destroy", l_kiwmi_output_on_destroy},
     {"resize", l_kiwmi_output_on_resize},
+    {"usable_area_change", l_kiwmi_output_on_usable_area_change},
     {NULL, NULL},
 };
 

lua_docs.md

@@ -225,6 +225,10 @@ Returns two parameters: `x` and `y`.
 Get the size of the output.
 Returns two parameters: `width` and `height`.
 
+#### output:usable_area()
+
+Returns a table containing the `x`, `y`, `width` and `height` of the output's usable area, relative to the output's top left corner.
+
 ### Events
 
 #### destroy
@@ -237,6 +241,11 @@ Callback receives the output.
 The output is being resized.
 Callback receives a table containing the `output`, the new `width`, and the new `height`.
 
+#### usable_area_change
+
+The usable area of this output has changed, e.g. because the output was resized or the bars around it changed.
+Callback receives a table containing the `output` and the new `x`, `y`, `width` and `height`.
+
 ## kiwmi_renderer
 
 Represents a rendering context, to draw on the output.