Feature #16: _COMPTON_SHADOW window property support

- Add support for reading _COMPTON_SHADOW property from windows (--respect-attr-shadow). Presently the only defined behavior is, if _COMPTON_SHADOW is set on the highest ancestor below root window of a window (usually the WM frame), it's format is 32-bit, type is CADINAL, value is 0, the window will not get a shadow. The format and behavior could change in the future without prior notification. - Fix an issue in fork_after() that may cause some streams to remain open. My mistake. - Attempt to reduce determine_shadow() calls from map_win() by separating some raw handler functions out.
12 years ago · 295bbf30c2
parent baed7f4b0c
commit 295bbf30c2
2 changed files with 94 additions and 10 deletions
--- a/compton.c
+++ b/compton.c
@ -164,6 +164,7 @@ Atom name_ewmh_atom = None;
 Atom class_atom = None;
 Atom transient_atom = None;
 Atom ewmh_active_win_atom = None;;
+Atom compton_shadow_atom = None;

 Atom win_type_atom;
 Atom win_type[NUM_WINTYPES];
@ -205,6 +206,7 @@ static options_t opts = {
  .clear_shadow = False,
  .shadow_blacklist = NULL,
  .shadow_ignore_shaped = False,
+  .respect_attr_shadow = False,

  .wintype_fade = { False },
  .fade_in_step = 0.028 * OPAQUE,
@ -1958,7 +1960,7 @@ map_win(Display *dpy, Window id,
 #endif

  // Detect if the window is shaped or has rounded corners
-  win_update_shape(dpy, w);
+  win_update_shape_raw(dpy, w);

  // Get window name and class if we are tracking them
  if (opts.track_wdata) {
@ -1983,8 +1985,11 @@ map_win(Display *dpy, Window id,
      w->focused = True;
  }

-  // Window type change and bounding shape state change could affect
-  // shadow
+  // Check for _COMPTON_SHADOW
+  if (opts.respect_attr_shadow)
+    win_update_attr_shadow_raw(dpy, w);
+
+  // Many things above could affect shadow
  determine_shadow(dpy, w);

  // Fading in
@ -2198,6 +2203,18 @@ determine_fade(Display *dpy, win *w) {
  w->fade = opts.wintype_fade[w->window_type];
 }

+/**
+ * Update window-shape.
+ */
+static void
+win_update_shape_raw(Display *dpy, win *w) {
+  if (shape_exists) {
+    w->bounding_shaped = wid_bounding_shaped(dpy, w->id);
+    if (w->bounding_shaped && opts.detect_rounded_corners)
+      win_rounded_corners(dpy, w);
+  }
+}
+
 /**
 * Update window-shape related information.
 */
@ -2206,9 +2223,7 @@ win_update_shape(Display *dpy, win *w) {
  if (shape_exists) {
    // Bool bounding_shaped_old = w->bounding_shaped;

-    w->bounding_shaped = wid_bounding_shaped(dpy, w->id);
-    if (w->bounding_shaped && opts.detect_rounded_corners)
-      win_rounded_corners(dpy, w);
+    win_update_shape_raw(dpy, w);

    // Shadow state could be changed
    determine_shadow(dpy, w);
@ -2222,6 +2237,40 @@ win_update_shape(Display *dpy, win *w) {
  }
 }

+/**
+ * Reread _COMPTON_SHADOW property from a window.
+ *
+ * The property must be set on the outermost window, usually the WM frame.
+ */
+static void
+win_update_attr_shadow_raw(Display *dpy, win *w) {
+  winattr_t attr = wid_get_attr(dpy, w->id, compton_shadow_atom, 1,
+      XA_CARDINAL, 32);
+  
+  if (!attr.nitems) {
+    free_winattr(&attr);
+    w->attr_shadow = -1;
+
+    return;
+  }
+
+  w->attr_shadow = *((long *) attr.data);
+}
+
+/**
+ * Reread _COMPTON_SHADOW property from a window and update related
+ * things.
+ */
+static void
+win_update_attr_shadow(Display *dpy, win *w) {
+  long attr_shadow_old = w->attr_shadow;
+
+  win_update_attr_shadow_raw(dpy, w);
+
+  if (w->attr_shadow != attr_shadow_old)
+    determine_shadow(dpy, w);
+}
+
 /**
 * Determine if a window should have shadow, and update things depending
 * on shadow state.
@ -2233,7 +2282,8 @@ determine_shadow(Display *dpy, win *w) {
  w->shadow = (opts.wintype_shadow[w->window_type]
      && !win_match(w, opts.shadow_blacklist, &w->cache_sblst)
      && !(opts.shadow_ignore_shaped && w->bounding_shaped
-        && !w->rounded_corners));
+        && !w->rounded_corners)
+      && !(opts.respect_attr_shadow && 0 == w->attr_shadow));

  // Window extents need update on shadow state change
  if (w->shadow != shadow_old) {
@ -2387,6 +2437,7 @@ add_win(Display *dpy, Window id, Window prev, Bool override_redirect) {
  new->need_configure = False;
  new->window_type = WINTYPE_UNKNOWN;
  new->mode = WINDOW_TRANS;
+  new->attr_shadow = -1;

  new->prev_trans = NULL;

@ -3182,6 +3233,13 @@ ev_property_notify(XPropertyEvent *ev) {
      determine_shadow(dpy, w);
    }
  }
+
+  // If _COMPTON_SHADOW changes
+  if (opts.respect_attr_shadow && compton_shadow_atom == ev->atom) {
+    win *w = find_win(ev->window);
+    if (w)
+      win_update_attr_shadow(dpy, w);
+  }
 }

 inline static void
@ -3438,6 +3496,9 @@ usage(void) {
    "--use-ewmh-active-win\n"
    "  Use _NET_WM_ACTIVE_WINDOW on the root window to determine which\n"
    "  window is focused instead of using FocusIn/Out events.\n"
+    "--respect-attr-shadow\n"
+    "  Respect _COMPTON_SHADOW. This a prototype-level feature, which\n"
+    "  you must not rely on.\n"
    "\n"
    "Format of a condition:\n"
    "\n"
@ -3560,9 +3621,12 @@ fork_after(void) {
  setsid();

  // Mainly to suppress the _FORTIFY_SOURCE warning
-  if (!freopen("/dev/null", "r", stdin)
-      || !freopen("/dev/null", "w", stdout)
-      || !freopen("/dev/null", "w", stderr))
+  bool success = freopen("/dev/null", "r", stdin);
+  success = freopen("/dev/null", "w", stdout) && success;
+  if (!success)
+    fprintf(stderr, "fork_after(): freopen() failed.");
+  success = freopen("/dev/null", "w", stderr);
+  if (!success)
    fprintf(stderr, "fork_after(): freopen() failed.");
 }

@ -3865,6 +3929,7 @@ get_cfg(int argc, char *const *argv) {
    { "sw-opti", no_argument, NULL, 274 },
    { "vsync-aggressive", no_argument, NULL, 275 },
    { "use-ewmh-active-win", no_argument, NULL, 276 },
+    { "respect-attr-shadow", no_argument, NULL, 277 },
    // Must terminate with a NULL entry
    { NULL, 0, NULL, 0 },
  };
@ -4055,6 +4120,10 @@ get_cfg(int argc, char *const *argv) {
        // --use-ewmh-active-win
        opts.use_ewmh_active_win = True;
        break;
+      case 277:
+        // --respect-attr-shadow
+        opts.respect_attr_shadow = True;
+        break;
      default:
        usage();
        break;
@ -4116,6 +4185,7 @@ get_atoms(void) {
  class_atom = XA_WM_CLASS;
  transient_atom = XA_WM_TRANSIENT_FOR;
  ewmh_active_win_atom = XInternAtom(dpy, "_NET_ACTIVE_WINDOW", False);
+  compton_shadow_atom = XInternAtom(dpy, "_COMPTON_SHADOW", False);

  win_type_atom = XInternAtom(dpy,
    "_NET_WM_WINDOW_TYPE", False);
--- a/compton.h
+++ b/compton.h
@ -318,6 +318,9 @@ typedef struct _win {
  Picture shadow_pict;
  /// Alpha mask Picture to render shadow. Affected by shadow opacity.
  Picture shadow_alpha_pict;
+  /// The value of _COMPTON_SHADOW attribute of the window. Below 0 for
+  /// none.
+  long attr_shadow;

  // Dim-related members
  /// Whether the window is to be dimmed.
@ -391,6 +394,8 @@ typedef struct _options {
  wincond *shadow_blacklist;
  /// Whether bounding-shaped window should be ignored.
  Bool shadow_ignore_shaped;
+  /// Whether to respect _COMPTON_SHADOW.
+  Bool respect_attr_shadow;

  // Fading
  Bool wintype_fade[NUM_WINTYPES];
@ -1063,9 +1068,18 @@ set_focused(Display *dpy, win *w, Bool focused) {
 static void
 determine_fade(Display *dpy, win *w);

+static void
+win_update_shape_raw(Display *dpy, win *w);
+
 static void
 win_update_shape(Display *dpy, win *w);

+static void
+win_update_attr_shadow_raw(Display *dpy, win *w);
+
+static void
+win_update_attr_shadow(Display *dpy, win *w);
+
 static void
 determine_shadow(Display *dpy, win *w);