+
+/*
+ * Updates the MOTIF_WM_HINTS. The container's border style should be set to
+ * `motif_border_style' if border style is not BS_NORMAL.
+ *
+ * i3 only uses this hint when it specifies a window should have no
+ * title bar, or no decorations at all, which is how most window managers
+ * handle it.
+ *
+ * The EWMH spec intended to replace Motif hints with _NET_WM_WINDOW_TYPE, but
+ * it is still in use by popular widget toolkits such as GTK+ and Java AWT.
+ *
+ */
+void window_update_motif_hints(i3Window *win, xcb_get_property_reply_t *prop, border_style_t *motif_border_style) {
+/* This implementation simply mirrors Gnome's Metacity. Official
+ * documentation of this hint is nowhere to be found.
+ * For more information see:
+ * https://people.gnome.org/~tthurman/docs/metacity/xprops_8h-source.html
+ * https://stackoverflow.com/questions/13787553/detect-if-a-x11-window-has-decorations
+ */
+#define MWM_HINTS_FLAGS_FIELD 0
+#define MWM_HINTS_DECORATIONS_FIELD 2
+
+#define MWM_HINTS_DECORATIONS (1 << 1)
+#define MWM_DECOR_ALL (1 << 0)
+#define MWM_DECOR_BORDER (1 << 1)
+#define MWM_DECOR_TITLE (1 << 3)
+
+ if (motif_border_style != NULL)
+ *motif_border_style = BS_NORMAL;
+
+ if (prop == NULL || xcb_get_property_value_length(prop) == 0) {
+ FREE(prop);
+ return;
+ }
+
+ /* The property consists of an array of 5 uint32_t's. The first value is a
+ * bit mask of what properties the hint will specify. We are only interested
+ * in MWM_HINTS_DECORATIONS because it indicates that the third value of the
+ * array tells us which decorations the window should have, each flag being
+ * a particular decoration. Notice that X11 (Xlib) often mentions 32-bit
+ * fields which in reality are implemented using unsigned long variables
+ * (64-bits long on amd64 for example). On the other hand,
+ * xcb_get_property_value() behaves strictly according to documentation,
+ * i.e. returns 32-bit data fields. */
+ uint32_t *motif_hints = (uint32_t *)xcb_get_property_value(prop);
+
+ if (motif_border_style != NULL &&
+ motif_hints[MWM_HINTS_FLAGS_FIELD] & MWM_HINTS_DECORATIONS) {
+ if (motif_hints[MWM_HINTS_DECORATIONS_FIELD] & MWM_DECOR_ALL ||
+ motif_hints[MWM_HINTS_DECORATIONS_FIELD] & MWM_DECOR_TITLE)
+ *motif_border_style = BS_NORMAL;
+ else if (motif_hints[MWM_HINTS_DECORATIONS_FIELD] & MWM_DECOR_BORDER)
+ *motif_border_style = BS_PIXEL;
+ else
+ *motif_border_style = BS_NONE;
+ }
+
+ FREE(prop);
+
+#undef MWM_HINTS_FLAGS_FIELD
+#undef MWM_HINTS_DECORATIONS_FIELD
+#undef MWM_HINTS_DECORATIONS
+#undef MWM_DECOR_ALL
+#undef MWM_DECOR_BORDER
+#undef MWM_DECOR_TITLE
+}