From 61db5ca69fe045d678c73d01ba150f322b421d61 Mon Sep 17 00:00:00 2001
From: Peter Fajdiga <peter.fajdiga@gmail.com>
Date: Sat, 16 Dec 2023 09:31:03 +0100
Subject: [PATCH] use different implementations of `clampScrollX` in different
 scrollers

---
 src/layout/Desktop.ts          |  8 ++------
 src/layout/ScrollerCentered.ts | 16 ++++++++++++++++
 src/layout/ScrollerGrouped.ts  |  4 ++++
 src/layout/ScrollerLazy.ts     |  9 +++++++++
 4 files changed, 31 insertions(+), 6 deletions(-)

diff --git a/src/layout/Desktop.ts b/src/layout/Desktop.ts
index ce0f181..7f1b3ce 100644
--- a/src/layout/Desktop.ts
+++ b/src/layout/Desktop.ts
@@ -119,12 +119,7 @@ class Desktop {
     }
 
     private clampScrollX(x: number) {
-        let minScroll = 0;
-        let maxScroll = this.grid.getWidth() - this.tilingArea.width;
-        if (maxScroll < 0) {
-            return Math.round(maxScroll / 2);
-        }
-        return clamp(x, minScroll, maxScroll);
+        return this.config.scroller.clampScrollX(this, x);
     }
 
     public setScroll(x: number, force: boolean) {
@@ -233,5 +228,6 @@ namespace Desktop {
 
     export type Scroller = {
         scrollToColumn(desktop: Desktop, column: Column): void;
+        clampScrollX(desktop: Desktop, x: number): number;
     }
 }
diff --git a/src/layout/ScrollerCentered.ts b/src/layout/ScrollerCentered.ts
index 3be76b2..7e86209 100644
--- a/src/layout/ScrollerCentered.ts
+++ b/src/layout/ScrollerCentered.ts
@@ -2,4 +2,20 @@ class ScrollerCentered {
     public scrollToColumn(desktop: Desktop, column: Column) {
         desktop.scrollCenterRange(column);
     }
+
+    public clampScrollX(desktop: Desktop, x: number) {
+        return ScrollerCentered.clampScrollX(desktop, x);
+    }
+
+    public static clampScrollX(desktop: Desktop, x: number) {
+        const firstColumn = desktop.grid.getFirstColumn();
+        if (firstColumn === null) {
+            return 0;
+        }
+        const lastColumn = desktop.grid.getLastColumn()!;
+
+        let minScroll = Math.round((firstColumn.getWidth() - desktop.tilingArea.width) / 2);
+        let maxScroll = Math.round(desktop.grid.getWidth() - (desktop.tilingArea.width + lastColumn.getWidth()) / 2);
+        return clamp(x, minScroll, maxScroll);
+    }
 }
diff --git a/src/layout/ScrollerGrouped.ts b/src/layout/ScrollerGrouped.ts
index af66383..ad876cc 100644
--- a/src/layout/ScrollerGrouped.ts
+++ b/src/layout/ScrollerGrouped.ts
@@ -12,6 +12,10 @@ class ScrollerGrouped {
         columnRange.addNeighbors(visibleRange, this.layoutConfig.gapsInnerHorizontal, false);
         desktop.scrollCenterRange(columnRange);
     }
+
+    public clampScrollX(desktop: Desktop, x: number) {
+        return ScrollerCentered.clampScrollX(desktop, x);
+    }
 }
 
 namespace ScrollerGrouped {
diff --git a/src/layout/ScrollerLazy.ts b/src/layout/ScrollerLazy.ts
index bc511e0..76fead4 100644
--- a/src/layout/ScrollerLazy.ts
+++ b/src/layout/ScrollerLazy.ts
@@ -2,4 +2,13 @@ class ScrollerLazy {
     public scrollToColumn(desktop: Desktop, column: Column) {
         desktop.scrollToRange(column);
     }
+
+    public clampScrollX(desktop: Desktop, x: number) {
+        let minScroll = 0;
+        let maxScroll = desktop.grid.getWidth() - desktop.tilingArea.width;
+        if (maxScroll < 0) {
+            return Math.round(maxScroll / 2);
+        }
+        return clamp(x, minScroll, maxScroll);
+    }
 }