Add setting to define previews animation time

Settings.ui

@@ -2158,6 +2158,11 @@
     <property name="step_increment">10</property>
     <property name="page_increment">25</property>
   </object>
+  <object class="GtkAdjustment" id="preview_animation_time_adjustment">
+    <property name="upper">1000</property>
+    <property name="step_increment">10</property>
+    <property name="page_increment">50</property>
+  </object>
   <object class="GtkAdjustment" id="preview_height_adjustment">
     <property name="lower">50</property>
     <property name="upper">500</property>
@@ -2290,6 +2295,50 @@
                 </child>
               </object>
             </child>
+            <child>
+              <object class="GtkListBoxRow" id="listboxrow_animation_time">
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <child>
+                  <object class="GtkGrid" id="grid_animation_time">
+                    <property name="visible">True</property>
+                    <property name="can_focus">False</property>
+                    <property name="margin_left">12</property>
+                    <property name="margin_right">12</property>
+                    <property name="margin_top">12</property>
+                    <property name="margin_bottom">12</property>
+                    <property name="column_spacing">32</property>
+                    <child>
+                      <object class="GtkLabel" id="animation_time_label">
+                        <property name="visible">True</property>
+                        <property name="can_focus">False</property>
+                        <property name="hexpand">True</property>
+                        <property name="label" translatable="yes">Animation time (ms)</property>
+                        <property name="xalign">0</property>
+                      </object>
+                      <packing>
+                        <property name="left_attach">0</property>
+                        <property name="top_attach">0</property>
+                      </packing>
+                    </child>
+                    <child>
+                      <object class="GtkSpinButton" id="animation_time_spinbutton">
+                        <property name="visible">True</property>
+                        <property name="can_focus">True</property>
+                        <property name="width_chars">4</property>
+                        <property name="text">0</property>
+                        <property name="adjustment">preview_animation_time_adjustment</property>
+                        <property name="numeric">True</property>
+                      </object>
+                      <packing>
+                        <property name="left_attach">1</property>
+                        <property name="top_attach">0</property>
+                      </packing>
+                    </child>
+                  </object>
+                </child>
+              </object>
+            </child>
             <child>
               <object class="GtkListBoxRow" id="listbox_preview_middle_click_close">
                 <property name="visible">True</property>

prefs.js

@@ -1061,6 +1061,11 @@ const Settings = new Lang.Class({
                 this._settings.set_int('leave-timeout', widget.get_value());
             }));
 
+            this._builder.get_object('animation_time_spinbutton').set_value(this._settings.get_int('window-preview-animation-time'));
+            this._builder.get_object('animation_time_spinbutton').connect('value-changed', Lang.bind (this, function(widget) {
+                this._settings.set_int('window-preview-animation-time', widget.get_value());
+            }));
+
             this._builder.get_object('peek_mode_opacity_spinbutton').set_value(this._settings.get_int('peek-mode-opacity'));
             this._builder.get_object('peek_mode_opacity_spinbutton').connect('value-changed', Lang.bind (this, function(widget) {
                 this._settings.set_int('peek-mode-opacity', widget.get_value());
@@ -1099,7 +1104,10 @@ const Settings = new Lang.Class({
                     this._builder.get_object('preview_timeout_spinbutton').set_value(this._settings.get_int('show-window-previews-timeout'));
 
                     this._settings.set_value('leave-timeout', this._settings.get_default_value('leave-timeout'));
-                    this._builder.get_object('leave_timeout_spinbutton').set_value(this._settings.get_int('leave-timeout'));   
+                    this._builder.get_object('leave_timeout_spinbutton').set_value(this._settings.get_int('leave-timeout'));
+
+                    this._settings.set_value('window-preview-animation-time', this._settings.get_default_value('window-preview-animation-time'));
+                    this._builder.get_object('animation_time_spinbutton').set_value(this._settings.get_int('window-preview-animation-time'));
 
                     this._settings.set_value('peek-mode', this._settings.get_default_value('peek-mode'));
                     this._settings.set_value('window-preview-show-title', this._settings.get_default_value('window-preview-show-title'));

schemas/org.gnome.shell.extensions.dash-to-panel.gschema.xml

@@ -413,12 +413,17 @@
     <key type="s" name="window-preview-title-font-color">
       <default>"#dddddd"</default>
       <summary>Window previews title font color</summary>
-      <description>This defines the Window previews titles font color.</description>
+      <description>This defines the window preview titles font color.</description>
     </key>
     <key type="i" name="window-preview-title-font-size">
       <default>14</default>
       <summary>Window previews title font size</summary>
-      <description>This defines the Window previews titles font size.</description>
+      <description>This defines the window preview titles font size.</description>
+    </key>
+    <key type="i" name="window-preview-animation-time">
+      <default>300</default>
+      <summary>Window previews animation time</summary>
+      <description>This defines the window previews animation time.</description>
     </key>
     <key name="window-preview-title-font-weight" enum="org.gnome.shell.extensions.dash-to-panel.fontWeight">
       <default>'inherit'</default>

windowPreview.js

@@ -17,7 +17,6 @@
 
 const Clutter = imports.gi.Clutter;
 const Config = imports.misc.config;
-const GLib = imports.gi.GLib;
 const Gtk = imports.gi.Gtk;
 const Main = imports.ui.main;
 const Mainloop = imports.mainloop;
@@ -48,6 +47,7 @@ const PEEK_INDEX_PROP = '_dtpPeekInitialIndex';
 var headerHeight = 0;
 var isLeftButtons = false;
 var scaleFactor = 1;
+var animationTime = 0;
 
 var PreviewMenu = Utils.defineClass({
     Name: 'DashToPanel-PreviewMenu',
@@ -333,6 +333,7 @@ var PreviewMenu = Utils.defineClass({
         isLeftButtons = Meta.prefs_get_button_layout().left_buttons.indexOf(Meta.ButtonFunction.CLOSE) >= 0;
         scaleFactor = St.ThemeContext.get_for_stage(global.stage).scale_factor;
         headerHeight = this._dtpSettings.get_boolean('window-preview-show-title') ? HEADER_HEIGHT * scaleFactor : 0;
+        animationTime = this._dtpSettings.get_int('window-preview-animation-time') * .001;
     },
 
     _resetHiddenState: function() {
@@ -862,7 +863,7 @@ var Preview = Utils.defineClass({
 
 function getTweenOpts(opts) {
     let defaults = {
-        time: Taskbar.DASH_ANIMATION_TIME * 1.5,
+        time: animationTime,
         transition: 'easeInOutQuad'
     };