Wire up output mode change events

Add the required machinery to listen to output mode change events:
+ Add required listener in hrt code
+ Add wrappers to wlroots code to hrt and lisp bindings for those
  wrappers.

heart/include/hrt/hrt_output.h

@@ -10,9 +10,11 @@
 struct hrt_output {
   struct wlr_output *wlr_output;
   struct hrt_server *server;
+  void (*mode_change_handler)(struct hrt_output *output);
 
   struct wl_listener frame;
   struct wl_listener destroy;
+  struct wl_listener mode;
 
   // temp background color
   float color[4];
@@ -21,7 +23,14 @@ struct hrt_output {
 struct hrt_output_callbacks {
   void (*output_added)(struct hrt_output *output);
   void (*output_removed)(struct hrt_output *output);
+  void (*output_mode_changed)(struct hrt_output *output);
 };
 
 bool hrt_output_init(struct hrt_server *server, const struct hrt_output_callbacks *callbacks);
+
+/**
+ * Get the effective output resolution of the output that can be used to
+ * set the width and height of views.
+ **/
+void hrt_output_resolution(struct hrt_output *output, int *width, int *height);
 #endif

heart/src/output.c

@@ -1,7 +1,11 @@
+#include "hrt/hrt_server.h"
+#include "wlr/util/log.h"
 #include <time.h>
 #include <stdio.h>
 #include <stdlib.h>
 
+#include <wayland-server-core.h>
+#include <wayland-util.h>
 #include <wlr/render/wlr_renderer.h>
 
 #include <hrt/hrt_output.h>
@@ -24,11 +28,22 @@ static void handle_output_destroy(struct wl_listener *listener, void *data) {
   struct hrt_server *server = output->server;
   server->output_callback->output_removed(output);
 
+  wl_list_remove(&output->frame.link);
+  wl_list_remove(&output->mode.link);
+
   // wlr_output_layout removes the output by itself.
 
   free(output);
 }
 
+static void handle_mode_change(struct wl_listener *listener, void *data) {
+	wlr_log(WLR_DEBUG, "Output mode changed");
+	struct hrt_output *output = wl_container_of(listener, output, mode);
+	if(output->mode_change_handler) {
+		output->mode_change_handler(output);
+	}
+}
+
 // temp random float generator
 static float float_rand()
 {
@@ -40,11 +55,14 @@ static struct hrt_output *hrt_output_create(struct hrt_server *server,
   struct hrt_output *output = calloc(1, sizeof(struct hrt_output));
   output->wlr_output = wlr_output;
   output->server = server;
+  output->mode_change_handler = server->output_callback->output_mode_changed;
 
   wlr_output_init_render(wlr_output, server->allocator, server->renderer);
 
   output->frame.notify = handle_frame_notify;
   wl_signal_add(&wlr_output->events.frame, &output->frame);
+  output->mode.notify = handle_mode_change;
+  wl_signal_add(&wlr_output->events.mode, &output->mode);
 
   // temp background color:
   // {0.730473, 0.554736, 0.665036, 1.000000} is really pretty.
@@ -112,3 +130,7 @@ bool hrt_output_init(struct hrt_server *server, const struct hrt_output_callback
 
   return true;
 }
+
+void hrt_output_resolution(struct hrt_output *output, int *width, int *height) {
+	wlr_output_effective_resolution(output->wlr_output, width, height);
+}

lisp/bindings/hrt-bindings.lisp

@@ -105,18 +105,28 @@ See themes section of man xcursor(3) to find where to find valid cursor names."
 (cffi:defcstruct hrt-output
   (wlr-output :pointer #| (:struct wlr-output) |# )
   (server (:pointer (:struct hrt-server)))
+  (mode-change-handler :pointer #| function ptr void (struct hrt_output *) |#)
   (frame (:struct wl-listener))
   (destroy (:struct wl-listener))
+  (mode (:struct wl-listener))
   (color :float :count 4))
 
 (cffi:defcstruct hrt-output-callbacks
   (output-added :pointer #| function ptr void (struct hrt_output *) |#)
-  (output-removed :pointer #| function ptr void (struct hrt_output *) |#))
+  (output-removed :pointer #| function ptr void (struct hrt_output *) |#)
+  (output-mode-changed :pointer #| function ptr void (struct hrt_output *) |#))
 
 (cffi:defcfun ("hrt_output_init" hrt-output-init) :bool
   (server (:pointer (:struct hrt-server)))
   (callbacks (:pointer (:struct hrt-output-callbacks))))
 
+(cffi:defcfun ("hrt_output_resolution" hrt-output-resolution) :void
+  "Get the effective output resolution of the output that can be used to
+set the width and height of views."
+  (output (:pointer (:struct hrt-output)))
+  (width (:pointer :int))
+  (height (:pointer :int)))
+
 ;; next section imported from file build/include/hrt/hrt_server.h
 
 (cffi:defcstruct hrt-server
@@ -153,5 +163,5 @@ See themes section of man xcursor(3) to find where to find valid cursor names."
 (cffi:defcfun ("hrt_server_finish" hrt-server-finish) :void
   (server (:pointer (:struct hrt-server))))
 
-(cffi:defcfun ("hrt_server_scene_tree" hrt-server-scene-tree) :pointer #| (:struct wlr-scene-tree) |#
+(cffi:defcfun ("hrt_server_scene_tree" hrt-server-scene-tree) :pointer #| (:struct wlr-scene-tree) |# 
   (server (:pointer (:struct hrt-server))))

lisp/bindings/package.lisp

@@ -11,8 +11,13 @@
 	   #:hrt-seat
 	   #:hrt-output
 	   #:hrt-keypress-info
+	   ;; output callbacks
 	   #:output-added
 	   #:output-removed
+	   #:output-mode-changed
+	   ;; output methods:
+	   #:output-resolution
+	   ;; seat callbacks
 	   #:button-event #:wheel-event #:keyboard-keypress-event
 	   #:hrt-server
 	   #:hrt-server-scene-tree

lisp/bindings/wrappers.lisp

@@ -0,0 +1,12 @@
+(in-package #:hrt)
+
+(defmacro with-return-by-value (variables &body body)
+  `(cffi:with-foreign-objects ,variables
+     ,@body
+     (values ,@(loop for pair in variables
+		     collect `(cffi:mem-ref ,(first pair) ,(second pair))))))
+
+(defun output-resolution (output)
+  (declare (type cffi:foreign-pointer output))
+  (with-return-by-value ((width :int) (height :int))
+    (hrt-output-resolution output width height)))

lisp/main.lisp

@@ -37,13 +37,15 @@
   (disable-fpu-exceptions)
   (hrt:load-foreign-libraries)
   (log-init :level :trace)
+  (sb-ext:enable-debugger)
   (cffi:with-foreign-objects ((output-callbacks '(:struct hrt-output-callbacks))
 			      (seat-callbacks '(:struct hrt-seat-callbacks))
 			      (view-callbacks '(:struct hrt-view-callbacks))
 			      (server '(:struct hrt-server)))
     (init-callback-struct output-callbacks (:struct hrt-output-callbacks)
       (output-added handle-new-output)
-      (output-removed handle-output-removed))
+      (output-removed handle-output-removed)
+      (output-mode-changed output-mode-change-callback))
     (init-callback-struct seat-callbacks (:struct hrt-seat-callbacks)
       (button-event cursor-callback)
       (wheel-event cursor-callback)

lisp/output.lisp

@@ -11,3 +11,7 @@
   (log-string :trace "Output removed")
   (with-accessors ((outputs mahogany-state-outputs)) *compositor-state*
     (setf outputs (delete output outputs :key #'mahogany-output-hrt-output))))
+
+(cffi:defcallback output-mode-change-callback :void ((output (:pointer (:struct hrt-output))))
+  (multiple-value-bind (width height) (hrt:output-resolution output)
+    (log-string :trace "Output mode changed (w: ~S h: ~S)" width height)))

mahogany.asd

@@ -23,7 +23,8 @@
 			:serial t
 			:components ((:file "package")
 				     (:file "hrt-libs")
-				     (:file "hrt-bindings")))
+				     (:file "hrt-bindings")
+				     (:file "wrappers")))
 	       (:file "package")
 	       (:module interfaces
 			:depends-on ("package")