From acf2379ba3117ba6eb8c426e85a60ce71a3abe67 Mon Sep 17 00:00:00 2001
From: Jeremy Attali <jeremy.attali@gmail.com>
Date: Sun, 29 Dec 2019 00:07:11 -0500
Subject: [PATCH] fix(render): better handler empty buffer

---
 src/render.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/src/render.c b/src/render.c
index 609bb49..b97d1f2 100644
--- a/src/render.c
+++ b/src/render.c
@@ -150,6 +150,13 @@ static void render_buffer(cairo_t *cr, struct swappy_state *state) {
 
   wl_list_for_each(output, &state->outputs, link) {
     struct swappy_buffer *buffer = output->buffer;
+
+    if (output->buffer == NULL) {
+      g_warning(
+          "screencopy buffer is empty, cannot draw it onto the paint area");
+      continue;
+    }
+
     cairo_format_t format = get_cairo_format(buffer->format);
 
     g_assert(format != CAIRO_FORMAT_INVALID);
@@ -258,6 +265,9 @@ void render_state(struct swappy_state *state) {
 
   cairo_set_source_rgb(cr, 1, 1, 1);
 
+  cairo_set_source_rgb(cr, 0.0, 0.0, 0.0);
+  cairo_paint(cr);
+
   render_buffer(cr, state);
   render_paints(cr, state);