Make sure SHM pixmap always gets alpha channellibxcwm-20140606work

Promote the depth with which the SHM pixmap image will be requested from 24-bit
to 32-bit to ensure it has an alpha channel (otherwise it seems that the alpha
channel can be lost on a 64-bit host)

1 files changed, 5 insertions, 0 deletions

diff --git a/src/libxcwm/context.c b/src/libxcwm/context.c
index f982557..d63c223 100644
--- a/src/libxcwm/context.c
+++ b/src/libxcwm/context.c
@@ -122,6 +122,11 @@ xcwm_context_open(char *display, xcwm_context_flags_t flags)
     if (!(flags & XCWM_DISABLE_SHM)) {
         context->has_shm = (_xcwm_init_extension(conn, "MIT-SHM") != NULL);
         context->depth = xcb_aux_get_depth(conn, root_screen);
+
+        /* Promote 24-bit root window to 32-bit, as we want alpha as well */
+        if (context->depth == 24) {
+            context->depth = 32;
+        }
     }
 
     _xcwm_atoms_init(context);