Attach dialogs to windows with visual effects

Override the new mutter preference /apps/mutter/general/attach_modal_dialogs
to attach modal dialogs to their parent window. Animate the modal dialogs
expanding from the top of the parent window. Slowly dim the parent window
after the dialog comes up.
https://bugzilla.gnome.org/show_bug.cgi?id=612726

js/ui/windowManager.js

@@ -1,6 +1,8 @@
 /* -*- mode: js2; js2-basic-offset: 4; indent-tabs-mode: nil -*- */
 
 const Clutter = imports.gi.Clutter;
+const GLib = imports.gi.GLib;
+const Gio = imports.gi.Gio;
 const Lang = imports.lang;
 const Meta = imports.gi.Meta;
 const St = imports.gi.St;
@@ -11,6 +13,68 @@ const Main = imports.ui.main;
 const Tweener = imports.ui.tweener;
 
 const WINDOW_ANIMATION_TIME = 0.25;
+const DIM_TIME = 0.500;
+const UNDIM_TIME = 0.250;
+
+var dimShader = undefined;
+
+function getDimShader() {
+    if (dimShader === null)
+        return null;
+    if (!dimShader) {
+        let [success, source, length] = GLib.file_get_contents(global.datadir +
+                                                               '/shaders/dim-window.glsl');
+        try {
+            let shader = new Clutter.Shader();
+            shader.set_fragment_source(source, -1);
+            shader.compile();
+
+            dimShader = shader;
+        } catch (e) {
+            log(e.message);
+            dimShader = null;
+        }
+    }
+    return dimShader;
+}
+
+function WindowDimmer(actor) {
+    this._init(actor);
+}
+
+WindowDimmer.prototype = {
+    _init: function(actor) {
+        this.actor = actor;
+    },
+
+    set dimFraction(fraction) {
+        this._dimFraction = fraction;
+        let shader = getDimShader();
+        if (!Meta.prefs_get_attach_modal_dialogs() || !shader) {
+            this.actor.set_shader(null);
+            return;
+        }
+        if (fraction > 0.01) {
+            this.actor.set_shader(shader);
+            this.actor.set_shader_param_float('height', this.actor.get_height());
+            this.actor.set_shader_param_float('fraction', fraction);
+        } else
+            this.actor.set_shader(null);
+    },
+
+    get dimFraction() {
+        return this._dimFraction;
+    },
+
+    _dimFraction: 0.0
+};
+
+function getWindowDimmer(texture) {
+    if (!texture._windowDimmer)
+        texture._windowDimmer = new WindowDimmer(texture);
+
+    return texture._windowDimmer;
+}
 
 function WindowManager() {
     this._init();
@@ -147,7 +211,75 @@ WindowManager.prototype = {
     _unmaximizeWindowDone : function(shellwm, actor) {
     },
 
+    _parentHasOtherAttachedDialog: function(parent, self) {
+        var count = 0;
+        parent.foreach_transient(function(win) {
+            if (win.get_window_type() == Meta.CompWindowType.MODAL_DIALOG && win != self)
+                count++;
+            return false;
+        });
+        return count != 0;
+    },
+
+    _dimParentWindow: function(actor) {
+        let meta = actor.get_meta_window();
+        let parent = meta.get_transient_for();
+        if (!parent)
+            return;
+        let parentActor = parent.get_compositor_private();
+        if (!parentActor)
+            return;
+        if (!this._parentHasOtherAttachedDialog(parent, meta)) {
+            let texture = parentActor.get_texture();
+            Tweener.addTween(getWindowDimmer(texture),
+                             { dimFraction: 1.0,
+                               time: DIM_TIME,
+                               transition: 'linear'
+                             });
+        }
+    },
+
+    _undimParentWindow: function(actor) {
+        let meta = actor.get_meta_window();
+        let parent = meta.get_transient_for();
+        if (!parent)
+            return;
+        let parentActor = parent.get_compositor_private();
+        if (!parentActor)
+            return;
+        if (!this._parentHasOtherAttachedDialog(parent, meta)) {
+            let texture = parentActor.get_texture();
+            Tweener.addTween(getWindowDimmer(texture),
+                             { dimFraction: 0.0,
+                               time: UNDIM_TIME,
+                               transition: 'linear'
+                             });
+        }
+    },
+
     _mapWindow : function(shellwm, actor) {
+        if (this._shouldAnimate() && actor
+            && actor.get_window_type() == Meta.CompWindowType.MODAL_DIALOG
+            && Meta.prefs_get_attach_modal_dialogs()
+            && actor.get_meta_window().get_transient_for()) {
+            actor.set_scale(1.0, 0.0);
+            actor.show();
+            this._mapping.push(actor);
+
+            Tweener.addTween(actor,
+                             { scale_y: 1,
+                               time: WINDOW_ANIMATION_TIME,
+                               transition: "easeOutQuad",
+                               onComplete: this._mapWindowDone,
+                               onCompleteScope: this,
+                               onCompleteParams: [shellwm, actor],
+                               onOverwrite: this._mapWindowOverwrite,
+                               onOverwriteScope: this,
+                               onOverwriteParams: [shellwm, actor]
+                             });
+            this._dimParentWindow(actor);
+            return;
+        }
         if (!this._shouldAnimate(actor)) {
             shellwm.completed_map(actor);
             return;
@@ -185,11 +317,46 @@ WindowManager.prototype = {
         }
     },
 
-    _destroyWindow : function(shellwm, actor) {
+    _destroyWindowOverwrite : function(shellwm, actor) {
+        if (this._removeEffect(this._mapping, actor)) {
+            shellwm.completed_destroy(actor);
+        }
+    },
+
+     _destroyWindow : function(shellwm, actor) {
+        while (actor && this._shouldAnimate()
+               && actor.get_window_type() == Meta.CompWindowType.MODAL_DIALOG
+               && actor.get_meta_window().get_transient_for()) {
+            this._undimParentWindow(actor);
+            if (!Meta.prefs_get_attach_modal_dialogs())
+                break;
+            actor.set_scale(1.0, 1.0);
+            actor.show();
+            this._mapping.push(actor);
+
+            Tweener.addTween(actor,
+                             { scale_y: 0,
+                               time: WINDOW_ANIMATION_TIME,
+                               transition: "easeOutQuad",
+                               onComplete: this._destroyWindowDone,
+                               onCompleteScope: this,
+                               onCompleteParams: [shellwm, actor],
+                               onOverwrite: this._destroyWindowOverwrite,
+                               onOverwriteScope: this,
+                               onOverwriteParams: [shellwm, actor]
+                             });
+            return;
+        }
         shellwm.completed_destroy(actor);
     },
-    
+
     _destroyWindowDone : function(shellwm, actor) {
+        if (actor && actor.get_window_type() == Meta.CompWindowType.MODAL_DIALOG &&
+            actor.get_meta_window().get_transient_for()) {
+            if (this._removeEffect(this._mapping, actor)) {
+                shellwm.completed_destroy(actor);
+            }
+        }
     },
 
     _switchWorkspace : function(shellwm, from, to, direction) {