Add unmap and workspace switch animation

This will add unmap animation for windows that are hidden (e.g. minimized) and also a custom animation when switching workspace. Also we have two new animations, slide-in and slide-out that are automatically used for workspace switching.

Also with this changes opacity isn't added to the win_image itself but to the whole window so even shadow gets animated when animating windows. 

IMPORTANT: 
* For unmap animation fading needs to be turned on in the picom.conf as otherwise opacity is automatically set to 0 and so even if it animates you don't see it as the window is already transparent.
* For workspace switch animations window manager must set _NET_CURRENT_DESKTOP before doing the hide/show of windows for e.g. here is the change for Fluxbox:
pijulius/fluxbox@83ee4db

New options in settings are:
--animation-for-unmap-window
  Which animation to run when hiding (e.g. minimize) a window.
  Must be one of `auto`, `none`, `fly-in`, `zoom`,
  `slide-down`, `slide-up`, `slide-left`, `slide-right`
  `slide-in`, `slide-out`
  (default: auto).

--animation-for-workspace-switch-in
  Which animation to run on switching workspace for windows
  comming into view.
  IMPORTANT: window manager must set _NET_CURRENT_DESKTOP
  before doing the hide/show of windows
  Must be one of `auto`, `none`, `fly-in`, `zoom`,
  `slide-down`, `slide-up`, `slide-left`, `slide-right`
  `slide-in`, `slide-out`
  (default: auto).

--animation-for-workspace-switch-out
  Which animation to run on switching workspace for windows
  going out of view.
  IMPORTANT: window manager must set _NET_CURRENT_DESKTOP
  before doing the hide/show of windows
  Must be one of `auto`, `none`, `fly-in`, `zoom`,
  `slide-down`, `slide-up`, `slide-left`, `slide-right`
  `slide-in`, `slide-out`
  (default: auto).

also custom animations can be defined for both open and unmap with window types like this:
wintypes:
{
  notification = { animation = "slide-left"; animation-unmap = "zoom"; }
};

src/atom.h

@@ -23,7 +23,8 @@
 	WM_CLIENT_MACHINE, \
 	_NET_ACTIVE_WINDOW, \
 	_COMPTON_SHADOW, \
-	_NET_WM_WINDOW_TYPE
+	_NET_WM_WINDOW_TYPE, \
+	_NET_CURRENT_DESKTOP
 
 #define ATOM_LIST2 \
 	_NET_WM_WINDOW_TYPE_DESKTOP, \

src/common.h

@@ -187,6 +187,10 @@ typedef struct session {
 	int root_height;
 	/// Width of root window.
 	int root_width;
+	/// Current desktop number of root window
+	int root_desktop_num;
+	/// Desktop switch direction
+	int root_desktop_switch_direction;
 	// Damage of root window.
 	// Damage root_damage;
 	/// X Composite overlay window. Used if <code>--paint-on-overlay</code>.

src/config.c

@@ -504,6 +504,18 @@ void set_default_winopts(options_t *opt, win_option_mask_t *mask, bool shadow_en
 			mask[i].animation = OPEN_WINDOW_ANIMATION_INVALID;
 			opt->wintype_option[i].animation = OPEN_WINDOW_ANIMATION_INVALID;
 		}
+		if (!mask[i].animation_unmap) {
+			mask[i].animation_unmap = OPEN_WINDOW_ANIMATION_INVALID;
+			opt->wintype_option[i].animation_unmap = OPEN_WINDOW_ANIMATION_INVALID;
+		}
+		if (!mask[i].animation_workspace_in) {
+			mask[i].animation_workspace_in = OPEN_WINDOW_ANIMATION_INVALID;
+			opt->wintype_option[i].animation_workspace_in = OPEN_WINDOW_ANIMATION_INVALID;
+		}
+		if (!mask[i].animation_workspace_out) {
+			mask[i].animation_workspace_out = OPEN_WINDOW_ANIMATION_INVALID;
+			opt->wintype_option[i].animation_workspace_out = OPEN_WINDOW_ANIMATION_INVALID;
+		}
 		if (!mask[i].clip_shadow_above) {
 			mask[i].clip_shadow_above = true;
 			opt->wintype_option[i].clip_shadow_above = false;
@@ -514,6 +526,8 @@ void set_default_winopts(options_t *opt, win_option_mask_t *mask, bool shadow_en
 enum open_window_animation parse_open_window_animation(const char *src) {
 	if (strcmp(src, "none") == 0) {
 		return OPEN_WINDOW_ANIMATION_NONE;
+	}else if (strcmp(src, "auto") == 0) {
+		return OPEN_WINDOW_ANIMATION_AUTO;
 	} else if (strcmp(src, "fly-in") == 0) {
 		return OPEN_WINDOW_ANIMATION_FLYIN;
 	} else if (strcmp(src, "zoom") == 0) {
@@ -578,6 +592,9 @@ char *parse_config(options_t *opt, const char *config_file, bool *shadow_enable,
 	    .animations = false,
 	    .animation_for_open_window = OPEN_WINDOW_ANIMATION_NONE,
 	    .animation_for_transient_window = OPEN_WINDOW_ANIMATION_NONE,
+	    .animation_for_unmap_window = OPEN_WINDOW_ANIMATION_AUTO,
+	    .animation_for_workspace_switch_in = OPEN_WINDOW_ANIMATION_AUTO,
+	    .animation_for_workspace_switch_out = OPEN_WINDOW_ANIMATION_AUTO,
 	    .animation_stiffness = 200.0,
 	    .animation_window_mass = 1.0,
 	    .animation_dampening = 25,

src/config.h

@@ -39,12 +39,15 @@ enum backend {
 
 enum open_window_animation {
 	OPEN_WINDOW_ANIMATION_NONE = 0,
+	OPEN_WINDOW_ANIMATION_AUTO,
 	OPEN_WINDOW_ANIMATION_FLYIN,
 	OPEN_WINDOW_ANIMATION_ZOOM,
 	OPEN_WINDOW_ANIMATION_SLIDE_UP,
 	OPEN_WINDOW_ANIMATION_SLIDE_DOWN,
 	OPEN_WINDOW_ANIMATION_SLIDE_LEFT,
 	OPEN_WINDOW_ANIMATION_SLIDE_RIGHT,
+	OPEN_WINDOW_ANIMATION_SLIDE_IN,
+	OPEN_WINDOW_ANIMATION_SLIDE_OUT,
 	OPEN_WINDOW_ANIMATION_INVALID,
 };
 
@@ -58,6 +61,9 @@ typedef struct win_option_mask {
 	bool opacity : 1;
 	bool clip_shadow_above : 1;
 	enum open_window_animation animation;
+	enum open_window_animation animation_unmap;
+	enum open_window_animation animation_workspace_in;
+	enum open_window_animation animation_workspace_out;
 } win_option_mask_t;
 
 typedef struct win_option {
@@ -70,6 +76,9 @@ typedef struct win_option {
 	double opacity;
 	bool clip_shadow_above;
 	enum open_window_animation animation;
+	enum open_window_animation animation_unmap;
+	enum open_window_animation animation_workspace_in;
+	enum open_window_animation animation_workspace_out;
 } win_option_t;
 
 enum blur_method {
@@ -193,6 +202,13 @@ typedef struct options {
 	enum open_window_animation animation_for_open_window;
 	/// Which animation to run when opening a transient window
 	enum open_window_animation animation_for_transient_window;
+	/// Which animation to run when unmapping (e.g. minimizing) a window
+	enum open_window_animation animation_for_unmap_window;
+	/// Which animation to run when switching workspace
+	/// IMPORTANT: will only work if window manager updates
+	/// _NET_CURRENT_DESKTOP before doing the hide/show of windows
+	enum open_window_animation animation_for_workspace_switch_in;
+	enum open_window_animation animation_for_workspace_switch_out;
 	/// Spring stiffness for animation
 	double animation_stiffness;
 	/// Window mass for animation

src/config_libconfig.c

@@ -296,6 +296,30 @@ static inline void parse_wintype_config(const config_t *cfg, const char *member_
 			o->animation = animation;
 			mask->animation = OPEN_WINDOW_ANIMATION_INVALID;
 		}
+		if (config_setting_lookup_string(setting, "animation-unmap", &sval)) {
+			enum open_window_animation animation = parse_open_window_animation(sval);
+			if (animation >= OPEN_WINDOW_ANIMATION_INVALID)
+				animation = OPEN_WINDOW_ANIMATION_NONE;
+
+			o->animation_unmap = animation;
+			mask->animation_unmap = OPEN_WINDOW_ANIMATION_INVALID;
+		}
+		if (config_setting_lookup_string(setting, "animation-workspace-in", &sval)) {
+			enum open_window_animation animation = parse_open_window_animation(sval);
+			if (animation >= OPEN_WINDOW_ANIMATION_INVALID)
+				animation = OPEN_WINDOW_ANIMATION_NONE;
+
+			o->animation_workspace_in = animation;
+			mask->animation_workspace_in = OPEN_WINDOW_ANIMATION_INVALID;
+		}
+		if (config_setting_lookup_string(setting, "animation-workspace-out", &sval)) {
+			enum open_window_animation animation = parse_open_window_animation(sval);
+			if (animation >= OPEN_WINDOW_ANIMATION_INVALID)
+				animation = OPEN_WINDOW_ANIMATION_NONE;
+
+			o->animation_workspace_out = animation;
+			mask->animation_workspace_out = OPEN_WINDOW_ANIMATION_INVALID;
+		}
 
 		double fval;
 		if (config_setting_lookup_float(setting, "opacity", &fval)) {
@@ -546,11 +570,38 @@ char *parse_config_libconfig(options_t *opt, const char *config_file, bool *shad
 	if (config_lookup_string(&cfg, "animation-for-transient-window", &sval)) {
 		enum open_window_animation animation = parse_open_window_animation(sval);
 		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
-			log_fatal("Invalid open-window animation %s", sval);
+			log_fatal("Invalid transient-window animation %s", sval);
 			goto err;
 		}
 		opt->animation_for_transient_window = animation;
 	}
+	// --animation-for-unmap-window
+	if (config_lookup_string(&cfg, "animation-for-unmap-window", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid unmap-window animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_unmap_window = animation;
+	}
+	// --animation-for-workspace-switch-in
+	if (config_lookup_string(&cfg, "animation-for-workspace-switch-in", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid workspace-switch-in animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_workspace_switch_in = animation;
+	}
+	// --animation-for-workspace-switch-out
+	if (config_lookup_string(&cfg, "animation-for-workspace-switch-out", &sval)) {
+		enum open_window_animation animation = parse_open_window_animation(sval);
+		if (animation >= OPEN_WINDOW_ANIMATION_INVALID) {
+			log_fatal("Invalid workspace-switch-out animation %s", sval);
+			goto err;
+		}
+		opt->animation_for_workspace_switch_out = animation;
+	}
 	// --animation-stiffness
 	config_lookup_float(&cfg, "animation-stiffness", &opt->animation_stiffness);
 	// --animation-window-mass

src/event.c

@@ -449,6 +449,17 @@ static inline void ev_property_notify(session_t *ps, xcb_property_notify_event_t
 	}
 
 	if (ps->root == ev->window) {
+		// If desktop number property changes
+		if (ev->atom == ps->atoms->a_NET_CURRENT_DESKTOP) {
+			auto prop = x_get_prop(ps->c, ps->root, ps->atoms->a_NET_CURRENT_DESKTOP,
+							1L, XCB_ATOM_CARDINAL, 32);
+
+			if (prop.nitems) {
+				ps->root_desktop_switch_direction = ((int)*prop.c32) - ps->root_desktop_num;
+				ps->root_desktop_num = (int)*prop.c32;
+			}
+		}
+
 		if (ps->o.use_ewmh_active_win && ps->atoms->a_NET_ACTIVE_WINDOW == ev->atom) {
 			// to update focus
 			ps->pending_updates = true;

src/options.c

@@ -86,6 +86,33 @@ static void usage(const char *argv0, int ret) {
 	    "  `slide-down`, `slide-up`, `slide-left`, `slide-right`\n"
 	    "  (default: none).\n"
 	    "\n"
+	    "--animation-for-unmap-window\n"
+	    "  Which animation to run when hiding (e.g. minimize) a window.\n"
+	    "  Must be one of `auto`, `none`, `fly-in`, `zoom`,\n"
+	    "  `slide-down`, `slide-up`, `slide-left`, `slide-right`\n"
+	    "  `slide-in`, `slide-out`\n"
+	    "  (default: auto).\n"
+	    "\n"
+	    "--animation-for-workspace-switch-in\n"
+	    "  Which animation to run on switching workspace for windows\n"
+	    "  comming into view.\n"
+	    "  IMPORTANT: window manager must set _NET_CURRENT_DESKTOP\n"
+	    "  before doing the hide/show of windows\n"
+	    "  Must be one of `auto`, `none`, `fly-in`, `zoom`,\n"
+	    "  `slide-down`, `slide-up`, `slide-left`, `slide-right`\n"
+	    "  `slide-in`, `slide-out`\n"
+	    "  (default: auto).\n"
+	    "\n"
+	    "--animation-for-workspace-switch-out\n"
+	    "  Which animation to run on switching workspace for windows\n"
+	    "  going out of view.\n"
+	    "  IMPORTANT: window manager must set _NET_CURRENT_DESKTOP\n"
+	    "  before doing the hide/show of windows\n"
+	    "  Must be one of `auto`, `none`, `fly-in`, `zoom`,\n"
+	    "  `slide-down`, `slide-up`, `slide-left`, `slide-right`\n"
+	    "  `slide-in`, `slide-out`\n"
+	    "  (default: auto).\n"
+	    "\n"
 	    "--animation-stiffness\n"
 	    "  Stiffness (a.k.a. tension) parameter for animation (default: 200.0).\n"
 	    "\n"

src/picom.c

@@ -560,6 +560,14 @@ static void configure_root(session_t *ps) {
 	ps->root_width = r->width;
 	ps->root_height = r->height;
 
+	auto prop = x_get_prop(ps->c, ps->root, ps->atoms->a_NET_CURRENT_DESKTOP,
+					1L, XCB_ATOM_CARDINAL, 32);
+
+	ps->root_desktop_switch_direction = 0;
+	if (prop.nitems) {
+		ps->root_desktop_num = (int)*prop.c32;
+	}
+
 	rebuild_screen_reg(ps);
 	rebuild_shadow_exclude_reg(ps);
 
@@ -654,6 +662,7 @@ paint_preprocess(session_t *ps, bool *fade_running, bool *animation_running) {
 		ps->animation_time = now;
 
 	double delta_secs = (double)(now - ps->animation_time) / 1000;
+	if (!delta_secs || delta_secs > 0.01) delta_secs = 0.01;
 
 	// First, let's process fading
 	win_stack_foreach_managed_safe(w, &ps->window_stack) {
@@ -663,7 +672,7 @@ paint_preprocess(session_t *ps, bool *fade_running, bool *animation_running) {
 
 		// IMPORTANT: These window animation steps must happen before any other
 		// [pre]processing. This is because it changes the window's geometry.
-		if (ps->o.animations && 
+		if (ps->o.animations &&
 			!isnan(w->animation_progress) && w->animation_progress != 1.0 &&
 			ps->o.wintype_option[w->window_type].animation != 0 &&
 			win_is_mapped_in_x(w))
@@ -804,6 +813,27 @@ paint_preprocess(session_t *ps, bool *fade_running, bool *animation_running) {
 				w->animation_velocity_h = 0.0;
 			}
 
+			if (!ps->root_desktop_switch_direction) {
+				if (w->state == WSTATE_UNMAPPING) {
+					steps = 0;
+					double new_opacity = clamp(
+									w->opacity_target_old-w->animation_progress,
+									w->opacity_target, 1);
+
+					if (new_opacity < w->opacity)
+						w->opacity = new_opacity;
+
+				} else if (w->state == WSTATE_MAPPING) {
+					steps = 0;
+					double new_opacity = clamp(
+										w->animation_progress,
+										0.0, w->opacity_target);
+
+					if (new_opacity > w->opacity)
+						w->opacity = new_opacity;
+				}
+			}
+
 			*animation_running = true;
 		}
 
@@ -1729,6 +1759,7 @@ static void draw_callback_impl(EV_P_ session_t *ps, int revents attr_unused) {
 	}
 	if (!animation_running) {
 		ps->animation_time = 0L;
+		ps->root_desktop_switch_direction = 0;
 	}
 
 	// TODO(yshui) Investigate how big the X critical section needs to be. There are