Changed HardwarePalette.ApplyModifiers to be more efficient.

- Add separate ImmutablePalette and MutablePalette classes since the distinction is extremely important to HardwarePalette.
- Keep a cache of palettes in HardwarePalette to avoid reallocation them every time ApplyModifiers is called.
- Palettes that are not allowed to be modified are copied to the buffer once when added, rather than every time ApplyModifiers is called.
- The AdjustPalette method now takes a read-only dictionary to prevent the dictionary being messed with.
- Added a constant for the palette size to remove its usage as a magic number in several areas.
- The ColorPreviewManagerWidget is annoying in that it needs to actually permanently update a palette after it has been added. To allow this, HardwarePalette now allows a palette to be replaced after initialization. The WorldRenderer therefore now also updates the PaletteReference it created earlier with the new palette to prevent stale data being used elsewhere.

OpenRA.Mods.D2k/PaletteFromScaledPalette.cs

@@ -35,15 +35,15 @@ namespace OpenRA.Mods.D2k
 		public object Create(ActorInitializer init) { return new PaletteFromScaledPalette(this); }
 	}
 
-	class PaletteFromScaledPalette : IPalette
+	class PaletteFromScaledPalette : ILoadsPalettes
 	{
 		readonly PaletteFromScaledPaletteInfo info;
 		public PaletteFromScaledPalette(PaletteFromScaledPaletteInfo info) { this.info = info; }
 
-		public void InitPalette(WorldRenderer wr)
+		public void LoadPalettes(WorldRenderer wr)
 		{
 			var remap = new ScaledPaletteRemap(info.Scale, info.Offset);
-			wr.AddPalette(info.Name, new Palette(wr.Palette(info.BasePalette).Palette, remap), info.AllowModifiers);
+			wr.AddPalette(info.Name, new ImmutablePalette(wr.Palette(info.BasePalette).Palette, remap), info.AllowModifiers);
 		}
 	}