add ScrollerGrouped

package/contents/ui/config.ui

@@ -267,6 +267,13 @@
                                                 </property>
                                             </widget>
                                         </item>
+                                        <item>
+                                            <widget class="QRadioButton" name="kcfg_scrollingGrouped">
+                                                <property name="text">
+                                                    <string>Prevent needlessly obscuring columns</string>
+                                                </property>
+                                            </widget>
+                                        </item>
                                     </layout>
                                 </widget>
                             </item>

src/config/config.ts

@@ -14,6 +14,7 @@ type Config = {
     skipSwitcher: boolean,
     scrollingLazy: boolean,
     scrollingCentered: boolean,
+    scrollingGrouped: boolean,
     tiledKeepBelow: boolean,
     floatingKeepAbove: boolean,
     windowRules: string,

src/config/definition.ts

@@ -127,6 +127,11 @@ const configDef = [
         "type": "Bool",
         "default": false
     },
+    {
+        "name": "scrollingGrouped",
+        "type": "Bool",
+        "default": false
+    },
     {
         "name": "tiledKeepBelow",
         "type": "Bool",

src/layout/ScrollerGrouped.ts

@@ -0,0 +1,83 @@
+class ScrollerGrouped {
+    private readonly layoutConfig: LayoutConfig;
+
+    constructor(layoutConfig: LayoutConfig) {
+        this.layoutConfig = layoutConfig;
+    }
+
+    public focusColumn(desktop: Desktop, column: Column) {
+        const columnRange = new ScrollerGrouped.ColumnRange(column);
+        const visibleRange = desktop.getCurrentVisibleRange();
+        columnRange.addNeighbors(visibleRange, this.layoutConfig.gapsInnerHorizontal, true);
+        columnRange.addNeighbors(visibleRange, this.layoutConfig.gapsInnerHorizontal, false);
+        desktop.scrollCenterRange(columnRange);
+    }
+}
+
+namespace ScrollerGrouped {
+    import Range = Desktop.Range;
+
+    export class ColumnRange {
+        private left: Column;
+        private right: Column;
+        private width: number;
+
+        constructor(initialColumn: Column) {
+            this.left = initialColumn;
+            this.right = initialColumn;
+            this.width = initialColumn.getWidth();
+        }
+
+        public addNeighbors(visibleRange: Range, gap: number, requireVisible: boolean) {
+            const grid = this.left.grid;
+
+            let leftColumn: Column|null = this.left;
+            while (true) {
+                leftColumn = grid.getPrevColumn(leftColumn);
+                if (
+                    leftColumn === null ||
+                    requireVisible && !leftColumn.isVisible(visibleRange, true) ||
+                    this.width + gap + leftColumn.getWidth() > visibleRange.getWidth()
+                ) {
+                    break;
+                }
+                this.addLeft(leftColumn, gap);
+            }
+
+            let rightColumn: Column|null = this.right;
+            while (true) {
+                rightColumn = grid.getNextColumn(rightColumn);
+                if (
+                    rightColumn === null ||
+                    requireVisible && !rightColumn.isVisible(visibleRange, true) ||
+                    this.width + gap + rightColumn.getWidth() > visibleRange.getWidth()
+                ) {
+                    break;
+                }
+                this.addRight(rightColumn, gap);
+            }
+        }
+
+        public addLeft(column: Column, gap: number) {
+            this.left = column;
+            this.width += column.getWidth() + gap;
+        }
+
+        public addRight(column: Column, gap: number) {
+            this.right = column;
+            this.width += column.getWidth() + gap;
+        }
+
+        public getLeft() {
+            return this.left.getLeft();
+        }
+
+        public getRight() {
+            return this.right.getRight();
+        }
+
+        public getWidth() {
+            return this.width;
+        }
+    }
+}

src/world/World.ts

@@ -21,6 +21,17 @@ class World {
 
         this.pinManager = new PinManager();
 
+        const layoutConfig = {
+            gapsInnerHorizontal: config.gapsInnerHorizontal,
+            gapsInnerVertical: config.gapsInnerVertical,
+            stackColumnsByDefault: config.stackColumnsByDefault,
+            resizeNeighborColumn: config.resizeNeighborColumn,
+            reMaximize: config.reMaximize,
+            skipSwitcher: config.skipSwitcher,
+            tiledKeepBelow: config.tiledKeepBelow,
+            maximizedKeepAbove: config.floatingKeepAbove,
+        };
+
         this.desktopManager = new DesktopManager(
             this.pinManager,
             {
@@ -31,18 +42,10 @@ class World {
                 overscroll: config.overscroll,
                 scroller: config.scrollingLazy ? new ScrollerLazy() :
                     config.scrollingCentered ? new ScrollerCentered() :
+                    config.scrollingGrouped ? new ScrollerGrouped(layoutConfig) :
                     console.assert(false),
             },
-            {
-                gapsInnerHorizontal: config.gapsInnerHorizontal,
-                gapsInnerVertical: config.gapsInnerVertical,
-                stackColumnsByDefault: config.stackColumnsByDefault,
-                resizeNeighborColumn: config.resizeNeighborColumn,
-                reMaximize: config.reMaximize,
-                skipSwitcher: config.skipSwitcher,
-                tiledKeepBelow: config.tiledKeepBelow,
-                maximizedKeepAbove: config.floatingKeepAbove,
-            },
+            layoutConfig,
             workspace.currentActivity,
         );
         this.clientManager = new ClientManager(config, this, this.desktopManager, this.pinManager);