1 files changed, 52 insertions, 5 deletions

diff --git a/desktop/modules/appearance/WallEngine.qml b/desktop/modules/appearance/WallEngine.qml
index fe45f7b..54705f6 100644
--- a/desktop/modules/appearance/WallEngine.qml
+++ b/desktop/modules/appearance/WallEngine.qml
@@ -33,7 +33,6 @@ Singleton {
     function listed(path, which) { return list(which).indexOf(path) >= 0; }
     // A gallery folder by its Wallpapers.groups key, "" for the hearted list.
     function folder(which) { return which === "V" ? cfg.folderV : cfg.folderH; }
-    function setFolder(which, key) { Prefs.setWallEngine(which === "V" ? { folderV: key } : { folderH: key }); }
     // What a tick draws from. A folder that is no longer in the gallery
     // gives nothing, so that screen is left alone rather than falling back
     // to the list behind the user's back.
@@ -65,9 +64,46 @@ Singleton {
         }
     }
 
-    function setMinutes(m) {
-        if (Number.isInteger(m) && m >= 1 && m !== cfg.minutes) Prefs.setWallEngine({ minutes: m });
+    // The page's draft, like every settings page: the interval and the two
+    // sources change here and reach Prefs on Start or Apply. Reset binds
+    // them back to what is saved. Hearts are not drafted: the picker writes
+    // them as they are clicked.
+    property int draftMinutes: cfg.minutes
+    property string draftFolderH: cfg.folderH
+    property string draftFolderV: cfg.folderV
+    readonly property bool dirty: draftMinutes !== cfg.minutes
+        || draftFolderH !== cfg.folderH || draftFolderV !== cfg.folderV
+    function draftFolder(which) { return which === "V" ? draftFolderV : draftFolderH; }
+    function setDraftFolder(which, key) {
+        if (which === "V") draftFolderV = key;
+        else draftFolderH = key;
     }
+    function setDraftMinutes(m) {
+        if (Number.isInteger(m) && m >= 1) draftMinutes = m;
+    }
+    function reset() {
+        draftMinutes = Qt.binding(() => cfg.minutes);
+        draftFolderH = Qt.binding(() => cfg.folderH);
+        draftFolderV = Qt.binding(() => cfg.folderV);
+    }
+    function commit() {
+        Prefs.setWallEngine({ minutes: draftMinutes, folderH: draftFolderH, folderV: draftFolderV });
+        reset();
+    }
+
+    // Start changes the wallpapers at once: the first timer change would
+    // otherwise be a whole interval away, which read as the engine not
+    // working.
+    function start() {
+        commit();
+        setOn(true);
+        next();
+    }
+    function apply() {
+        commit();
+        restartTimer();
+    }
+    function stop() { setOn(false); }
 
     // ponytail: in memory, so a restart starts a new round.
     property var bagH: []
@@ -88,7 +124,15 @@ Singleton {
 
     function next() {
         tick();
+        restartTimer();
+    }
+
+    // When the timer next fires, for the page's header; 0 while off. Timer
+    // has no such property, so it is kept beside it.
+    property double nextAt: 0
+    function restartTimer() {
         timer.restart();
+        nextAt = Date.now() + timer.interval;
     }
 
     // A switch-off during a run cannot start its own; it goes when that run
@@ -106,7 +150,10 @@ Singleton {
         interval: root.cfg.minutes * 60000
         repeat: true
         running: root.on
-        onTriggered: root.tick()
+        onTriggered: { root.nextAt = Date.now() + interval; root.tick(); }
+        // A running Timer restarts on a new interval.
+        onIntervalChanged: if (running) root.nextAt = Date.now() + interval
+        onRunningChanged: root.nextAt = running ? Date.now() + interval : 0
     }
 
     Connections {
@@ -116,7 +163,7 @@ Singleton {
             if (!root.on) return;
             Prefs.setWallEngine({ homeH: h !== "" ? h : root.cfg.homeH,
                                   homeV: v !== "" ? v : root.cfg.homeV });
-            timer.restart();
+            root.restartTimer();
         }
         function onFinished() {
             if (!root.homeWaiting || root.on) return;