c2: add new pre-defined target "group_focused"

This matches when the focused window is in the same window group as the
window being matched.

Signed-off-by: Yuxuan Shui <yshuiv7@gmail.com>

CHANGELOG.md

@@ -34,6 +34,7 @@
 * Marginally improve performance when resizing/opening/closing windows. (#1190)
 * Type and format specifiers are no longer used in rules. These specifiers are what you put after the colon (':') in rules, e.g. the `:32c` in `"_GTK_FRAME_EXTENTS@:32c"`. Now this information is ignored and the property is matched regardless of format or type.
 * `backend` is now a required option. picom will not start if one is not specified explicitly.
+* New predefined target for conditions: `group_focused`. This target indicate whether the focused window is in the same window group as the window being matched.
 
 ## Deprecated features
 

man/picom.1.adoc

@@ -301,7 +301,7 @@ With greater-than/less-than operators it looks like:
 
 _NEGATION_ (optional) is one or more exclamation marks;
 
-_TARGET_ is either a predefined target name, or the name of a window property to match. Supported predefined targets are `x`, `y`, `x2` (`x` + `widthb`), `y2` (like `x2`), `width`, `height`, `widthb` (`width` + 2 * `border_width`), `heightb` (like `widthb`), `border_width`, `fullscreen`, `override_redirect`, `argb` (whether the window has an ARGB visual), `focused`, `wmwin` (whether the window looks like a WM window, i.e. has no child window with `WM_STATE` and is not override-redirected), `bounding_shaped`, `rounded_corners` (requires *--detect-rounded-corners*, note this has no relation to *--corner-radius*), `window_type` (window type in string), `name`, `class_g` (= `WM_CLASS[1]`), `class_i` (= `WM_CLASS[0]`), and `role`.
+_TARGET_ is either a predefined target name, or the name of a window property to match. Supported predefined targets are `x`, `y`, `x2` (`x` + `widthb`), `y2` (like `x2`), `width`, `height`, `widthb` (`width` + 2 * `border_width`), `heightb` (like `widthb`), `border_width`, `fullscreen`, `override_redirect`, `argb` (whether the window has an ARGB visual), `focused`, `group_focused` (whether the window belongs to the focused window group), `wmwin` (whether the window looks like a WM window, i.e. has no child window with `WM_STATE` and is not override-redirected), `bounding_shaped`, `rounded_corners` (requires *--detect-rounded-corners*, note this has no relation to *--corner-radius*), `window_type` (window type in string), `name`, `class_g` (= `WM_CLASS[1]`), `class_i` (= `WM_CLASS[0]`), and `role`.
 
 _CLIENT/FRAME_ is a single `@` if the window attribute should be be looked up on client window, nothing if on frame window;
 

src/c2.c

@@ -173,6 +173,7 @@ struct _c2_l {
 		C2_L_POVREDIR,
 		C2_L_PARGB,
 		C2_L_PFOCUSED,
+		C2_L_PGROUPFOCUSED,
 		C2_L_PWMWIN,
 		C2_L_PBSHAPED,
 		C2_L_PROUNDED,
@@ -235,30 +236,31 @@ static struct {
 	bool is_string;
 	bool deprecated;
 } C2_PREDEFS[] = {
-    [C2_L_PID]         = { "id", false, true },
-    [C2_L_PX]          = { "x", false, },
-    [C2_L_PY]          = { "y", false, },
-    [C2_L_PX2]         = { "x2", false, },
-    [C2_L_PY2]         = { "y2", false, },
-    [C2_L_PWIDTH]      = { "width", false, },
-    [C2_L_PHEIGHT]     = { "height", false, },
-    [C2_L_PWIDTHB]     = { "widthb", false, },
-    [C2_L_PHEIGHTB]    = { "heightb", false, },
-    [C2_L_PBDW]        = { "border_width", false, },
-    [C2_L_PFULLSCREEN] = { "fullscreen", false, },
-    [C2_L_POVREDIR]    = { "override_redirect", false, },
-    [C2_L_PARGB]       = { "argb", false, },
-    [C2_L_PFOCUSED]    = { "focused", false, },
-    [C2_L_PWMWIN]      = { "wmwin", false, },
-    [C2_L_PBSHAPED]    = { "bounding_shaped", false, },
-    [C2_L_PROUNDED]    = { "rounded_corners", false, },
-    [C2_L_PCLIENT]     = { "client", false, true },
-    [C2_L_PWINDOWTYPE] = { "window_type", true, },
-    [C2_L_PLEADER]     = { "leader", false, true },
-    [C2_L_PNAME]       = { "name", true, },
-    [C2_L_PCLASSG]     = { "class_g", true, },
-    [C2_L_PCLASSI]     = { "class_i", true, },
-    [C2_L_PROLE]       = { "role", true, },
+    [C2_L_PID]           = { "id", false, true },
+    [C2_L_PX]            = { "x", false, },
+    [C2_L_PY]            = { "y", false, },
+    [C2_L_PX2]           = { "x2", false, },
+    [C2_L_PY2]           = { "y2", false, },
+    [C2_L_PWIDTH]        = { "width", false, },
+    [C2_L_PHEIGHT]       = { "height", false, },
+    [C2_L_PWIDTHB]       = { "widthb", false, },
+    [C2_L_PHEIGHTB]      = { "heightb", false, },
+    [C2_L_PBDW]          = { "border_width", false, },
+    [C2_L_PFULLSCREEN]   = { "fullscreen", false, },
+    [C2_L_POVREDIR]      = { "override_redirect", false, },
+    [C2_L_PARGB]         = { "argb", false, },
+    [C2_L_PFOCUSED]      = { "focused", false, },
+    [C2_L_PGROUPFOCUSED] = { "group_focused", false, },
+    [C2_L_PWMWIN]        = { "wmwin", false, },
+    [C2_L_PBSHAPED]      = { "bounding_shaped", false, },
+    [C2_L_PROUNDED]      = { "rounded_corners", false, },
+    [C2_L_PCLIENT]       = { "client", false, true },
+    [C2_L_PWINDOWTYPE]   = { "window_type", true, },
+    [C2_L_PLEADER]       = { "leader", false, true },
+    [C2_L_PNAME]         = { "name", true, },
+    [C2_L_PCLASSG]       = { "class_g", true, },
+    [C2_L_PCLASSI]       = { "class_i", true, },
+    [C2_L_PROLE]         = { "role", true, },
 };
 // clang-format on
 
@@ -1610,6 +1612,10 @@ static bool c2_match_once_leaf_int(const struct win *w, const c2_l_t *leaf) {
 			predef_target =
 			    w->a.map_state == XCB_MAP_STATE_VIEWABLE && w->is_focused;
 			break;
+		case C2_L_PGROUPFOCUSED:
+			predef_target = w->a.map_state == XCB_MAP_STATE_VIEWABLE &&
+			                w->is_group_focused;
+			break;
 		case C2_L_PWMWIN: predef_target = win_is_wmwin(w); break;
 		case C2_L_PBSHAPED: predef_target = w->bounding_shaped; break;
 		case C2_L_PROUNDED: predef_target = w->rounded_corners; break;