From 1178a7763bb16c6f128174adca6813aea9321f08 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Daniel=20Ekl=C3=B6f?= <daniel@ekloef.se>
Date: Fri, 3 Jan 2020 21:53:38 +0100
Subject: [PATCH] wayland: window: optimize: set opaque region

When background alpha is 1.0 (0xffff), i.e. completely opaque, tell
the compositor this, via wl_surface_set_opaque_region().

This allows it to optimize drawing of surfaces _behind_ our window.
---
 wayland.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/wayland.c b/wayland.c
index abe7329f..c0b305ca 100644
--- a/wayland.c
+++ b/wayland.c
@@ -850,6 +850,17 @@ wayl_win_init(struct terminal *term)
         goto out;
     }
 
+    if (term->colors.alpha == 0xffff) {
+        struct wl_region *region = wl_compositor_create_region(
+            term->wl->compositor);
+
+        if (region != NULL) {
+            wl_region_add(region, 0, 0, INT32_MAX, INT32_MAX);
+            wl_surface_set_opaque_region(win->surface, region);
+            wl_region_destroy(region);
+        }
+    }
+
     wl_surface_add_listener(win->surface, &surface_listener, win);
 
     win->xdg_surface = xdg_wm_base_get_xdg_surface(wayl->shell, win->surface);