From 5ad137d1f985e0633e7bf5d3d3bc3c8e04f0137e Mon Sep 17 00:00:00 2001
From: Daniel van Vugt <daniel.van.vugt@canonical.com>
Date: Fri, 21 Jan 2022 19:20:07 +0800
Subject: [PATCH] workspace: Use the original overviewAdjustment on
 WorkspaceBackground

Using `layoutManager.stateAdjustment` would treat
`ControlsState.HIDDEN` the same as `ControlsState.APP_GRID`:

| `ControlsState` | `stateAdjustment` | Rounded corners  |
| --------------- | ----------------- | ---------------- |
| HIDDEN:0        | 0.0               | No               |
| WINDOW_PICKER:1 | 1.0               | Yes              |
| APP_GRID:2      | 0.0               | No (issue #4096) |

and so rounded corners were accidentally lost for `ControlsState.APP_GRID`
(issue #4096).

But it's not as simple as treating `ControlsState.APP_GRID` the same as
`ControlsState.WINDOW_PICKER` because that would break `allocate` which
only needs its downscaling algorithm enabled for
`ControlsState.WINDOW_PICKER` (because `ControlsState.APP_GRID` is already
downscaled by the parent allocation).

So we now map those two problems separately:

| `ControlsState` | Rounded corners  | Downscale from parent |
| --------------- | ---------------- | --------------------- |
| HIDDEN:0        | No               | No                    |
| WINDOW_PICKER:1 | Yes              | Yes                   |
| APP_GRID:2      | Yes              | No                    |

Fixes: https://gitlab.gnome.org/GNOME/gnome-shell/-/issues/4096
---
 js/ui/workspace.js               | 8 ++++++--
 src/shell-workspace-background.c | 6 ++++--
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/js/ui/workspace.js b/js/ui/workspace.js
index 4787cdf0e..6aec58588 100644
--- a/js/ui/workspace.js
+++ b/js/ui/workspace.js
@@ -1005,8 +1005,12 @@ class WorkspaceBackground extends Shell.WorkspaceBackground {
         const cornerRadius = scaleFactor * BACKGROUND_CORNER_RADIUS_PIXELS;
 
         const backgroundContent = this._bgManager.backgroundActor.content;
+
+        // Map ControlsState {0, 1, 2} to progress {0.0, 1.0, 1.0}
+        const roundedCornerProgress =
+            Math.clamp(this._stateAdjustment.value, 0, 1);
         backgroundContent.rounded_clip_radius =
-            Util.lerp(0, cornerRadius, this._stateAdjustment.value);
+            Util.lerp(0, cornerRadius, roundedCornerProgress);
     }
 
     _updateRoundedClipBounds() {
@@ -1048,7 +1052,7 @@ class Workspace extends St.Widget {
 
         // Background
         this._background =
-            new WorkspaceBackground(monitorIndex, layoutManager.stateAdjustment);
+            new WorkspaceBackground(monitorIndex, overviewAdjustment);
         this.add_child(this._background);
 
         // Window previews
diff --git a/src/shell-workspace-background.c b/src/shell-workspace-background.c
index 290441ac8..d99911929 100644
--- a/src/shell-workspace-background.c
+++ b/src/shell-workspace-background.c
@@ -70,6 +70,7 @@ shell_workspace_background_allocate (ClutterActor          *actor,
   int left_offset, right_offset;
   int top_offset, bottom_offset;
   int scale_factor;
+  float progress;
 
   scale_factor = st_theme_context_get_scale_factor (context);
 
@@ -81,8 +82,9 @@ shell_workspace_background_allocate (ClutterActor          *actor,
   scaled_box.y1 = box->y1 + (height - scaled_height) / 2;
   clutter_actor_box_set_size (&scaled_box, scaled_width, scaled_height);
 
-  clutter_actor_box_interpolate(box, &scaled_box,
-                                self->state_adjustment_value, &my_box);
+  // Map ControlsState {0, 1, 2} to progress {0.0, 1.0, 0.0}
+  progress = 1.f - fabs (1.f - self->state_adjustment_value);
+  clutter_actor_box_interpolate(box, &scaled_box, progress, &my_box);
 
   clutter_actor_set_allocation (actor, &my_box);