[gnome-shell] overviewControls: Make AppDisplay rise from the bottom

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

commit 87645652e5fa65ad7d217b69c2935339f56599cf
Author: Georges Basile Stavracas Neto <georges stavracas gmail com>
Date:   Wed Jan 20 19:25:13 2021 -0300

    overviewControls: Make AppDisplay rise from the bottom
    
    It makes more sense in a spatial overview that the app grid
    comes and goes to somewhere in the screen, instead of fading
    in and out into the void.
    
    Make the app grid rise from the bottom of the screen.
    
    Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1624>

 js/ui/overviewControls.js | 47 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 8 deletions(-)
---
diff --git a/js/ui/overviewControls.js b/js/ui/overviewControls.js
index e640564a56..efb3fd9fbf 100644
--- a/js/ui/overviewControls.js
+++ b/js/ui/overviewControls.js
@@ -69,6 +69,31 @@ class ControlsManagerLayout extends Clutter.BoxLayout {
         return workspaceBox;
     }
 
+    _getAppDisplayBoxForState(state, box, searchHeight, dashHeight, appGridBox) {
+        const [width, height] = box.get_size();
+        const appDisplayBox = new Clutter.ActorBox();
+        const { spacing } = this;
+
+        switch (state) {
+        case ControlsState.HIDDEN:
+        case ControlsState.WINDOW_PICKER:
+            appDisplayBox.set_origin(0, box.y2);
+            break;
+        case ControlsState.APP_GRID:
+            appDisplayBox.set_origin(0,
+                searchHeight + spacing + appGridBox.get_height());
+            break;
+        }
+
+        appDisplayBox.set_size(width,
+            height -
+            searchHeight - spacing -
+            appGridBox.get_height() - spacing -
+            dashHeight);
+
+        return appDisplayBox;
+    }
+
     vfunc_set_container(container) {
         this._container = container;
         this.hookup_style(container);
@@ -112,7 +137,7 @@ class ControlsManagerLayout extends Clutter.BoxLayout {
         }
 
         // Workspaces
-        const params = [box, searchHeight, dashHeight, thumbnailsHeight];
+        let params = [box, searchHeight, dashHeight, thumbnailsHeight];
         const transitionParams = this._stateAdjustment.getStateTransitionParams();
 
         let workspacesBox;
@@ -133,14 +158,20 @@ class ControlsManagerLayout extends Clutter.BoxLayout {
         const workspaceAppGridBox =
             this._getWorkspacesBoxForState(ControlsState.APP_GRID, ...params);
 
-        childBox.set_origin(0, searchHeight + spacing + workspaceAppGridBox.get_height());
-        childBox.set_size(width,
-            height -
-            searchHeight - spacing -
-            workspaceAppGridBox.get_height() - spacing -
-            dashHeight);
+        params = [box, searchHeight, dashHeight, workspaceAppGridBox];
+        let appDisplayBox;
+        if (!transitionParams.transitioning) {
+            appDisplayBox =
+                this._getAppDisplayBoxForState(transitionParams.currentState, ...params);
+        } else {
+            const initialBox =
+                this._getAppDisplayBoxForState(transitionParams.initialState, ...params);
+            const finalBox =
+                this._getAppDisplayBoxForState(transitionParams.finalState, ...params);
 
-        this._appDisplay.allocate(childBox);
+            appDisplayBox = initialBox.interpolate(finalBox, transitionParams.progress);
+        }
+        this._appDisplay.allocate(appDisplayBox);
 
         // ViewSelector
         childBox.set_origin(0, searchHeight + spacing);