Rename thumbnails type

ApplicationView/ApplicationController.cs

@@ -292,7 +292,7 @@ namespace MatterHackers.MatterControl
 
 		private List<SceneSelectionOperation> registeredSceneOperations;
 
-		public ThumbnailCache Thumbnails { get; } = new ThumbnailCache();
+		public ThumbnailsConfig Thumbnails { get; } = new ThumbnailsConfig();
 
 		private void RebuildSceneOperations(ThemeConfig theme)
 		{

ApplicationView/ThumbnailsConfig.cs

@@ -0,0 +1,168 @@
+/*
+Copyright (c) 2018, Lars Brubaker, John Lewin
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+The views and conclusions contained in the software and documentation are those
+of the authors and should not be interpreted as representing official policies,
+either expressed or implied, of the FreeBSD Project.
+*/
+
+namespace MatterHackers.MatterControl
+{
+	using System;
+	using System.Collections.Generic;
+	using System.IO;
+	using System.Threading;
+	using System.Threading.Tasks;
+	using MatterHackers.Agg.Image;
+	using MatterHackers.Agg.Platform;
+	using MatterHackers.MatterControl.Library;
+
+	public class ThumbnailsConfig
+	{
+		private readonly static object thumbsLock = new object();
+
+		private Queue<Func<Task>> queuedThumbCallbacks = new Queue<Func<Task>>();
+
+		public Dictionary<Type, ImageBuffer> OperationIcons { get; internal set; }
+
+		public ImageBuffer DefaultThumbnail { get; } = AggContext.StaticData.LoadIcon("cube.png");
+
+		public ImageBuffer LoadCachedImage(string cacheId, int width, int height)
+		{
+			ImageBuffer cachedItem = LoadImage(this.CachePath(cacheId, width, height));
+			if (cachedItem != null)
+			{
+				return cachedItem;
+			}
+
+			if (width < 100
+				&& height < 100)
+			{
+				// check for a 100x100 image
+				var cachedAt100x100 = LoadImage(this.CachePath(cacheId, 100, 100));
+				if (cachedAt100x100 != null)
+				{
+					return cachedAt100x100.CreateScaledImage(width, height);
+				}
+			}
+
+			return null;
+		}
+
+		public string CachePath(string cacheId)
+		{
+			// TODO: Use content SHA
+			return ApplicationController.CacheablePath("ItemThumbnails", $"{cacheId}.png");
+		}
+
+		public string CachePath(string id, int width, int height)
+		{
+			return ApplicationController.CacheablePath("ItemThumbnails", $"{id}-{width}x{height}.png");
+		}
+
+		private AutoResetEvent thumbGenResetEvent = new AutoResetEvent(false);
+
+		private Task thumbnailGenerator = null;
+
+		internal void QueueForGeneration(Func<Task> func)
+		{
+			lock (thumbsLock)
+			{
+				if (thumbnailGenerator == null)
+				{
+					// Spin up a new thread once needed
+					thumbnailGenerator = Task.Run((Action)ThumbGeneration);
+				}
+
+				queuedThumbCallbacks.Enqueue(func);
+				thumbGenResetEvent.Set();
+			}
+		}
+
+		private async void ThumbGeneration()
+		{
+			Thread.CurrentThread.Name = $"ThumbnailGeneration";
+
+			while (!ApplicationController.Instance.ApplicationExiting)
+			{
+				Thread.Sleep(100);
+
+				try
+				{
+					if (queuedThumbCallbacks.Count > 0)
+					{
+						Func<Task> callback;
+						lock (thumbsLock)
+						{
+							callback = queuedThumbCallbacks.Dequeue();
+						}
+
+						await callback();
+					}
+					else
+					{
+						// Process until queuedThumbCallbacks is empty then wait for new tasks via QueueForGeneration
+						thumbGenResetEvent.WaitOne();
+					}
+				}
+				catch (AppDomainUnloadedException)
+				{
+					return;
+				}
+				catch (ThreadAbortException)
+				{
+					return;
+				}
+				catch (Exception ex)
+				{
+					Console.WriteLine("Error generating thumbnail: " + ex.Message);
+				}
+			}
+
+			// Null task reference on exit
+			thumbnailGenerator = null;
+		}
+
+
+		private static ImageBuffer LoadImage(string filePath)
+		{
+			try
+			{
+				if (File.Exists(filePath))
+				{
+					return AggContext.ImageIO.LoadImage(filePath).SetPreMultiply();
+				}
+			}
+			catch { } // Suppress exceptions, return null on any errors
+
+			return null;
+		}
+
+		public void Shutdown()
+		{
+			// Release the waiting ThumbnailGeneration task so it can shutdown gracefully
+			thumbGenResetEvent?.Set();
+		}
+	}
+}

MatterControl.csproj

@@ -75,6 +75,7 @@
     <Compile Include="AboutPage\CheckForUpdatesPage.cs" />
     <Compile Include="AboutPage\ContactFormPage.cs" />
     <Compile Include="ApplicationView\LogoSpinner.cs" />
+    <Compile Include="ApplicationView\ThumbnailsConfig.cs" />
     <Compile Include="ConfigurationPage\PrintLeveling\LevelingPlan.cs" />
     <Compile Include="ConfigurationPage\PrintLeveling\LevelingWizardPage.cs" />
     <Compile Include="ConfigurationPage\PrintLeveling\LevelingWizardRootPage.cs" />
@@ -106,7 +107,6 @@
     <Compile Include="DesignTools\Primitives\HalfCylinderObject3D.cs" />
     <Compile Include="DesignTools\Primitives\HalfWedgeObject3D.cs" />
     <Compile Include="Library\ContentProviders\ImageContentProvider.cs" />
-    <Compile Include="ApplicationView\ThumbnailCache.cs" />
     <Compile Include="Library\Providers\MatterControl\LibraryCollectionContainer.cs" />
     <Compile Include="Library\Providers\MatterControl\PartHistoryContainer.cs" />
     <Compile Include="Library\Providers\MatterControl\RootHistoryContainer.cs" />