Implementation of sRGB image support. Overhauls the linearization setup to utilize the sRGB image types, as well as refactors the use of ColorF and ColorI to be properly internally consistent. ColorIs are used only for front-facing/editing/UI settings, and ColorFs, now renamed to LinearColorF to reduce confusion of purpose, are used for color info in the engine itself. This avoids confusing and expensive conversions back and forth between types and avoids botches with linearity. Majority work done by @rextimmy

Engine/source/gfx/bitmap/imageUtils.h

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+//-----------------------------------------------------------------------------
+// Copyright (c) 2016 GarageGames, LLC
+//
+// Permission is hereby granted, free of charge, to any person obtaining a copy
+// of this software and associated documentation files (the "Software"), to
+// deal in the Software without restriction, including without limitation the
+// rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+// sell copies of the Software, and to permit persons to whom the Software is
+// furnished to do so, subject to the following conditions:
+//
+// The above copyright notice and this permission notice shall be included in
+// all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+// IN THE SOFTWARE.
+//-----------------------------------------------------------------------------
+
+#ifndef _IMAGE_UTILS_H_
+#define _IMAGE_UTILS_H_
+
+#ifndef _SWIZZLE_H_
+#include "core/util/swizzle.h"
+#endif
+#ifndef _GFXENUMS_H_
+#include "gfx/gfxEnums.h"
+#endif
+
+struct DDSFile;
+
+namespace ImageUtil
+{
+   enum CompressQuality
+   {
+      LowQuality,
+      MediumQuality,
+      HighQuality
+   };
+
+   // compress raw pixel data, expects rgba format
+   bool rawCompress(const U8 *srcRGBA, U8 *dst, const S32 width, const S32 height, const GFXFormat compressFormat, const CompressQuality compressQuality = LowQuality);
+   // compress DDSFile
+   bool ddsCompress(DDSFile *srcDDS, const GFXFormat compressFormat, const CompressQuality compressQuality = LowQuality);
+   // decompress compressed pixel data, dest data should be rgba format
+   bool decompress(const U8 *src, U8 *dstRGBA, const S32 width, const S32 height, const GFXFormat srcFormat);
+   //swizzle dds file
+   void swizzleDDS(DDSFile *srcDDS, const Swizzle<U8, 4> &swizzle);
+   //check if a GFXFormat is compressed
+   bool isCompressedFormat(const GFXFormat format);
+   bool isSRGBFormat(const GFXFormat format);
+   //check if a GFXFormat has an alpha channel
+   bool isAlphaFormat(const GFXFormat format);
+
+   //convert to sRGB format
+   GFXFormat toSRGBFormat(const GFXFormat format);
+};
+
+#endif