read and use scrolling configuration

src/config/config.ts

@@ -12,6 +12,8 @@ type Config = {
     resizeNeighborColumn: boolean,
     reMaximize: boolean,
     skipSwitcher: boolean,
+    scrollingLazy: boolean,
+    scrollingCentered: boolean,
     tiledKeepBelow: boolean,
     floatingKeepAbove: boolean,
     windowRules: string,

src/config/definition.ts

@@ -117,6 +117,16 @@ const configDef = [
         "type": "Bool",
         "default": false
     },
+    {
+        "name": "scrollingLazy",
+        "type": "Bool",
+        "default": true
+    },
+    {
+        "name": "scrollingCentered",
+        "type": "Bool",
+        "default": false
+    },
     {
         "name": "tiledKeepBelow",
         "type": "Bool",

src/layout/Desktop.ts

@@ -8,7 +8,6 @@ class Desktop {
     private dirtyPins: boolean;
     public clientArea: QRect;
     public tilingArea: QRect;
-    public readonly scroller: Desktop.Scroller = new ScrollerLazy();
 
     constructor(desktopNumber: number, pinManager: PinManager, config: Desktop.Config, layoutConfig: LayoutConfig) {
         this.pinManager = pinManager;
@@ -104,7 +103,11 @@ class Desktop {
             return;
         }
 
-        this.scroller.focusColumn(this, focusedColumn);
+        this.focusColumn(focusedColumn);
+    }
+
+    public focusColumn(column: Column) {
+        this.config.scroller.focusColumn(this, column);
     }
 
     private getVisibleRange(scrollX: number) {
@@ -190,6 +193,7 @@ namespace Desktop {
         marginLeft: number,
         marginRight: number,
         overscroll: number,
+        scroller: Desktop.Scroller,
     };
 
     export type Range = {

src/layout/Grid.ts

@@ -277,7 +277,7 @@ class Grid {
             lastFocusedColumn.restoreToTiled();
         }
         this.lastFocusedColumn = column;
-        this.desktop.scroller.focusColumn(this.desktop, column);
+        this.desktop.focusColumn(column);
     }
 
     public onScreenSizeChanged() {

src/world/World.ts

@@ -29,6 +29,9 @@ class World {
                 marginLeft: config.gapsOuterLeft,
                 marginRight: config.gapsOuterRight,
                 overscroll: config.overscroll,
+                scroller: config.scrollingLazy ? new ScrollerLazy() :
+                    config.scrollingCentered ? new ScrollerCentered() :
+                    console.assert(false),
             },
             {
                 gapsInnerHorizontal: config.gapsInnerHorizontal,