swaybar: synchronize rendering to output frames

1 files changed, 23 insertions, 1 deletions

diff --git a/swaybar/render.c b/swaybar/render.c
index 90e5bac7..dc31a5ea 100644
--- a/swaybar/render.c
+++ b/swaybar/render.c
@@ -473,7 +473,22 @@ static uint32_t render_to_cairo(cairo_t *cairo, struct swaybar_output *output) {
         return max_height > output->height ? max_height : output->height;
 }
 
-void render_frame(struct swaybar *bar, struct swaybar_output *output) {
+static void output_frame_handle_done(void *data, struct wl_callback *callback,
+                uint32_t time) {
+        wl_callback_destroy(callback);
+        struct swaybar_output *output = data;
+        output->frame_scheduled = false;
+        if (output->dirty) {
+                render_frame(output);
+                output->dirty = false;
+        }
+}
+
+static const struct wl_callback_listener output_frame_listener = {
+        .done = output_frame_handle_done
+};
+
+void render_frame(struct swaybar_output *output) {
         assert(output->surface != NULL);
 
         struct swaybar_hotspot *hotspot, *tmp;
@@ -518,6 +533,8 @@ void render_frame(struct swaybar *bar, struct swaybar_output *output) {
                                 output->width * output->scale,
                                 output->height * output->scale);
                 if (!output->current_buffer) {
+                        cairo_surface_destroy(recorder);
+                        cairo_destroy(cairo);
                         return;
                 }
                 cairo_t *shm = output->current_buffer->cairo;
@@ -535,6 +552,11 @@ void render_frame(struct swaybar *bar, struct swaybar_output *output) {
                                 output->current_buffer->buffer, 0, 0);
                 wl_surface_damage(output->surface, 0, 0,
                                 output->width, output->height);
+
+                struct wl_callback *frame_callback = wl_surface_frame(output->surface);
+                wl_callback_add_listener(frame_callback, &output_frame_listener, output);
+                output->frame_scheduled = true;
+
                 wl_surface_commit(output->surface);
         }
         cairo_surface_destroy(recorder);