From 792a3a728beadd4662beced61f009ef0cfbbe8ea Mon Sep 17 00:00:00 2001
From: Phap Dieu Duong <ddphap@gmail.com>
Date: Fri, 31 Jan 2025 20:54:15 +0700
Subject: [PATCH] fixed: Image Booster does not pre load images before
 switching between images #1482

---
 .../Photoing/Services/ImageBooster.cs         | 31 ++++++++++++++-----
 Source/ImageGlass/FrmMain.cs                  |  3 ++
 2 files changed, 27 insertions(+), 7 deletions(-)

diff --git a/Source/Components/ImageGlass.Base/Photoing/Services/ImageBooster.cs b/Source/Components/ImageGlass.Base/Photoing/Services/ImageBooster.cs
index 766b0fa53..3dbf4e3a6 100644
--- a/Source/Components/ImageGlass.Base/Photoing/Services/ImageBooster.cs
+++ b/Source/Components/ImageGlass.Base/Photoing/Services/ImageBooster.cs
@@ -205,12 +205,17 @@ await img.LoadAsync(ReadOptions with
     /// Add index of the image to queue list
     /// </summary>
     /// <param name="index">Current index of image list</param>
-    private List<int> GetQueueList(int index)
+    /// <param name="includeCurrentIndex">Include current index in the queue list</param>
+    private List<int> GetQueueList(int index, bool includeCurrentIndex)
     {
         // check valid index
         if (index < 0 || index >= ImgList.Count) return [];
 
-        var list = new HashSet<int> { index };
+        var list = new HashSet<int>();
+        if (includeCurrentIndex)
+        {
+            list.Add(index);
+        }
 
         var maxCachedItems = (MaxQueue * 2) + 1;
         var iRight = index;
@@ -366,8 +371,8 @@ await ImgList[index].LoadAsync(ReadOptions with
         // get image data from cache
         else
         {
-            // update queue list according to index
-            var queueItems = GetQueueList(index);
+            // get queue list according to index
+            var queueItems = GetQueueList(index, true);
 
             if (!queueItems.Contains(index))
             {
@@ -405,6 +410,20 @@ await ImgList[index].LoadAsync(ReadOptions with
     }
 
 
+    /// <summary>
+    /// Start caching images.
+    /// </summary>
+    /// <param name="index">Current index of image list</param>
+    /// <param name="includeCurrentIndex">Include current index in the queue list</param>
+    public void StartCaching(int index, bool includeCurrentIndex)
+    {
+        // get queue list according to index
+        var queueItems = GetQueueList(index, includeCurrentIndex);
+
+        QueuedList.Clear();
+        QueuedList.AddRange(queueItems);
+    }
+
 
     /// <summary>
     /// Adds a file path
@@ -603,7 +622,7 @@ public void UpdateCache()
             .Select(item => item.Index)
             .ToList();
 
-        // release the cachced images
+        // release the cached images
         foreach (var index in cachedIndexList)
         {
             ImgList[index].Dispose();
@@ -617,8 +636,6 @@ public void UpdateCache()
     /// <summary>
     /// Check if the folder path of input filename exists in the list
     /// </summary>
-    /// <param name="filename"></param>
-    /// <returns></returns>
     public bool ContainsDirPathOf(string filename)
     {
         var target = Path.GetDirectoryName(filename)?.ToUpperInvariant();
diff --git a/Source/ImageGlass/FrmMain.cs b/Source/ImageGlass/FrmMain.cs
index 8f3358bec..a5ca1cf7a 100644
--- a/Source/ImageGlass/FrmMain.cs
+++ b/Source/ImageGlass/FrmMain.cs
@@ -1169,6 +1169,9 @@ private void HandleImageList_Loaded(ImageListLoadedEventArgs e)
 
         LoadImageInfo(ImageInfoUpdateTypes.ListCount);
 
+        // start image caching, don't cache the current index
+        Local.Images.StartCaching(Local.CurrentIndex, false);
+
         // Load thumnbnail
         BHelper.RunAsThread(LoadGallery);
     }