[gnome-shell] altTab: Fix window-switcher on HiDPI displays

[Florian Müllner <fmuellner src gnome org>]

commit 80911535a7bba4225ccbe110a39674c45cdcddd1
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Nov 26 00:04:11 2015 +0100

    altTab: Fix window-switcher on HiDPI displays
    
    We need to take the scale factor into account to avoid tiny window
    previews on HiDPI.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=758676

 js/ui/altTab.js |    8 +++++---
 1 files changed, 5 insertions(+), 3 deletions(-)
---
diff --git a/js/ui/altTab.js b/js/ui/altTab.js
index 8765f19..7029bf7 100644
--- a/js/ui/altTab.js
+++ b/js/ui/altTab.js
@@ -685,15 +685,17 @@ const WindowIcon = new Lang.Class({
 
         this._icon.destroy_all_children();
 
+        let scaleFactor = St.ThemeContext.get_for_stage(global.stage).scale_factor;
+
         switch (mode) {
             case AppIconMode.THUMBNAIL_ONLY:
                 size = WINDOW_PREVIEW_SIZE;
-                this._icon.add_actor(_createWindowClone(mutterWindow, WINDOW_PREVIEW_SIZE));
+                this._icon.add_actor(_createWindowClone(mutterWindow, size * scaleFactor));
                 break;
 
             case AppIconMode.BOTH:
                 size = WINDOW_PREVIEW_SIZE;
-                this._icon.add_actor(_createWindowClone(mutterWindow, WINDOW_PREVIEW_SIZE));
+                this._icon.add_actor(_createWindowClone(mutterWindow, size * scaleFactor));
 
                 if (this.app)
                     this._icon.add_actor(this._createAppIcon(this.app,
@@ -705,7 +707,7 @@ const WindowIcon = new Lang.Class({
                 this._icon.add_actor(this._createAppIcon(this.app, size));
         }
 
-        this._icon.set_size(size, size);
+        this._icon.set_size(size * scaleFactor, size * scaleFactor);
     },
 
     _createAppIcon: function(app, size) {