window-switcher: show the previews over the wallpaper, faded in

The full-screen dim over the live windows is replaced by DP-1's own
wallpaper, read from ~/.config/wallp/wall_h on each open and drawn
opaque, so the previews sit on what looks like an empty desktop the way
Mission Control does it. A light 40% Theme.base layer stays on top of
it, because a bright wallpaper at full strength glared behind the
previews.

The overlay fades in over 220ms instead of appearing at once. The fade
waits for the image to decode (or to fail, or for there to be no
wallp file), otherwise Theme.base would flash first. Opacity is
derived from the image status rather than starting at 1, so the
initial Null status cannot play a 1-to-0 animation. Closing is still
instant: fading out would keep the layer surface alive past the 60ms
focus timer.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

2 files changed, 33 insertions, 3 deletions

diff --git a/window-switcher/README.md b/window-switcher/README.md
index 3a32bc5..faefeb1 100644
--- a/window-switcher/README.md
+++ b/window-switcher/README.md
@@ -1,6 +1,6 @@
 # window-switcher
 
-Every open window as a live preview, scattered over a dimmed DP-1 the way
+Every open window as a live preview, scattered over DP-1's wallpaper, lightly dimmed, the way
 macOS Mission Control does it. ALT+TAB or the top-right corner of DP-1 opens
 it, a click picks a window, Escape drops it. It replaced a uniform grid, which
 replaced a rofi list.
@@ -33,7 +33,7 @@ theme with `Quickshell.iconPath`. Hot reload does not follow the symlink, so
 after editing `Workspaces.qml` reload both. A named workspace, or one past eight, has no
 icon and falls back to `[name]`.
 
-With nothing to switch to it says so, because a full-screen dim with nothing in
+With nothing to switch to it says so, because an empty desktop with nothing in
 it reads as a hang.
 
 ## Running it
diff --git a/window-switcher/Switcher.qml b/window-switcher/Switcher.qml
index 3bc6a86..88924d8 100644
--- a/window-switcher/Switcher.qml
+++ b/window-switcher/Switcher.qml
@@ -10,6 +10,7 @@
 // GNU General Public License for more details.
 
 import Quickshell
+import Quickshell.Io
 import Quickshell.Wayland
 import QtQuick
 import "Expose.js" as Expose
@@ -94,9 +95,38 @@ Scope {
                 Keys.onUpPressed: scatter.move(0, -1)
                 Keys.onDownPressed: scatter.move(0, 1)
 
+                // The bare desktop: DP-1's wallpaper, lightly dimmed, drawn opaque over the
+                // real windows, so the previews sit on an empty screen rather
+                // than a dim. Theme.base stands in without wallp. The whole
+                // overlay fades in once the picture is decoded, so the real
+                // windows dissolve into it instead of being swapped out.
                 Rectangle {
                     anchors.fill: parent
-                    color: Qt.rgba(Theme.base.r, Theme.base.g, Theme.base.b, 0.82)
+                    color: Theme.base
+                    opacity: wallImage.status === Image.Ready || wallImage.status === Image.Error || wallImage.source == "" ? 1 : 0
+                    Behavior on opacity { NumberAnimation { duration: 220; easing.type: Easing.OutCubic } }
+
+                    Image {
+                        id: wallImage
+                        anchors.fill: parent
+                        source: wallFile.text().trim() !== "" ? "file://" + wallFile.text().trim() : ""
+                        fillMode: Image.PreserveAspectCrop
+                        asynchronous: true
+                        cache: false
+                    }
+
+                    // A light dim over the wallpaper: a bright picture at full
+                    // strength glares behind the previews.
+                    Rectangle {
+                        anchors.fill: parent
+                        color: Qt.rgba(Theme.base.r, Theme.base.g, Theme.base.b, 0.4)
+                    }
+
+                    FileView {
+                        id: wallFile
+                        path: Quickshell.env("HOME") + "/.config/wallp/wall_h"
+                        blockLoading: true
+                    }
 
                     MouseArea {
                         anchors.fill: parent