[gnome-shell] workspacesView: Scale inactive workspaces

[Marge Bot <marge-bot src gnome org>]

commit 4cf5b4a6d8eeb33aab019a25a25bca634b4d71b7
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Thu Dec 31 14:19:43 2020 -0300

    workspacesView: Scale inactive workspaces
    
    As per the latest mockups, then horizontally snapping, the active
    workspace should be highlighted. Because WorkspacesView clips to
    allocation, we cannot simply scale up the active one. Instead,
    scale down the inactive ones.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1613>

 js/ui/workspace.js      |  3 ++-
 js/ui/workspacesView.js | 20 ++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletion(-)
---
diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index f9e7fad4bb..8a9faf4ead 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -1,7 +1,7 @@
 // -*- mode: js; js-indent-level: 4; indent-tabs-mode: nil -*-
 /* exported Workspace */
 
-const { Clutter, GLib, GObject, Meta, St } = imports.gi;
+const { Clutter, GLib, GObject, Graphene, Meta, St } = imports.gi;
 
 const Background = imports.ui.background;
 const DND = imports.ui.dnd;
@@ -936,6 +936,7 @@ class Workspace extends St.Widget {
     _init(metaWorkspace, monitorIndex) {
         super._init({
             style_class: 'window-picker',
+            pivot_point: new Graphene.Point({ x: 0.5, y: 0.5 }),
             layout_manager: new WorkspaceLayout(metaWorkspace, monitorIndex),
             reactive: true,
         });
diff --git a/js/ui/workspacesView.js b/js/ui/workspacesView.js
index ac0729dd07..ab8c78c5f6 100644
--- a/js/ui/workspacesView.js
+++ b/js/ui/workspacesView.js
@@ -17,6 +17,8 @@ const MUTTER_SCHEMA = 'org.gnome.mutter';
 const WORKSPACE_MIN_SPACING = 24;
 const WORKSPACE_MAX_SPACING = 80;
 
+const WORKSPACE_INACTIVE_SCALE = 0.94;
+
 var WorkspacesViewBase = GObject.registerClass({
     GTypeFlags: GObject.TypeFlags.ABSTRACT,
 }, class WorkspacesViewBase extends St.Widget {
@@ -83,6 +85,7 @@ class WorkspacesView extends WorkspacesViewBase {
         this._fitModeAdjustment = fitModeAdjustment;
         this._fitModeNotifyId = this._fitModeAdjustment.connect('notify::value', () => {
             this._updateVisibility();
+            this._updateWorkspacesState();
             this.queue_relayout();
         });
 
@@ -212,6 +215,20 @@ class WorkspacesView extends WorkspacesViewBase {
         return Math.clamp(spacing, WORKSPACE_MIN_SPACING, WORKSPACE_MAX_SPACING);
     }
 
+    _updateWorkspacesState() {
+        const adj = this._scrollAdjustment;
+
+        // Fade and scale inactive workspaces
+        this._workspaces.forEach((w, index) => {
+            const distanceToCurrentWorkspace = Math.abs(adj.value - index);
+
+            const progress = 1 - Math.clamp(distanceToCurrentWorkspace, 0, 1);
+
+            const scale = Util.lerp(WORKSPACE_INACTIVE_SCALE, 1, progress);
+            w.set_scale(scale, scale);
+        });
+    }
+
     vfunc_allocate(box) {
         this.set_allocation(box);
 
@@ -349,6 +366,8 @@ class WorkspacesView extends WorkspacesViewBase {
             this._workspaces[j].destroy();
             this._workspaces.splice(j, 1);
         }
+
+        this._updateWorkspacesState();
     }
 
     _activeWorkspaceChanged(_wm, _from, _to, _direction) {
@@ -411,6 +430,7 @@ class WorkspacesView extends WorkspacesViewBase {
             metaWorkspace.activate(global.get_current_time());
         }
 
+        this._updateWorkspacesState();
         this.queue_relayout();
     }
 });