PNG spritesheet support, along with PaletteFromPng.

Cursor palette loader can now be specified via yaml.

OpenRA.Mods.Common/Traits/World/PaletteFromPng.cs

@@ -0,0 +1,75 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2018 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation, either version 3 of
+ * the License, or (at your option) any later version. For more
+ * information, see COPYING.
+ */
+#endregion
+
+using System.Collections.Generic;
+using OpenRA.FileFormats;
+using OpenRA.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	[Desc("Load a PNG and use its embedded palette.")]
+	class PaletteFromPngInfo : ITraitInfo
+	{
+		[FieldLoader.Require, PaletteDefinition]
+		[Desc("Internal palette name")]
+		public readonly string Name = null;
+
+		[Desc("If defined, load the palette only for this tileset.")]
+		public readonly string Tileset = null;
+
+		[FieldLoader.Require]
+		[Desc("Filename to load")]
+		public readonly string Filename = null;
+
+		[Desc("Map listed indices to shadow. Ignores previous color.")]
+		public readonly int[] ShadowIndex = { };
+
+		public readonly bool AllowModifiers = true;
+
+		public object Create(ActorInitializer init) { return new PaletteFromPng(init.World, this); }
+	}
+
+	class PaletteFromPng : ILoadsPalettes, IProvidesAssetBrowserPalettes
+	{
+		readonly World world;
+		readonly PaletteFromPngInfo info;
+		public PaletteFromPng(World world, PaletteFromPngInfo info)
+		{
+			this.world = world;
+			this.info = info;
+		}
+
+		public void LoadPalettes(WorldRenderer wr)
+		{
+			if (info.Tileset != null && info.Tileset.ToLowerInvariant() != world.Map.Tileset.ToLowerInvariant())
+				return;
+
+			var png = new Png(world.Map.Open(info.Filename));
+			var colors = new uint[Palette.Size];
+
+			for (var i = 0; i < png.Palette.Length; i++)
+				colors[i] = (uint)png.Palette[i].ToArgb();
+
+			wr.AddPalette(info.Name, new ImmutablePalette(colors), info.AllowModifiers);
+		}
+
+		public IEnumerable<string> PaletteNames
+		{
+			get
+			{
+				// Only expose the palette if it is available for the shellmap's tileset (which is a requirement for its use).
+				if (info.Tileset == null || info.Tileset == world.Map.Rules.TileSet.Id)
+					yield return info.Name;
+			}
+		}
+	}
+}