GARbro-mirror/ArcFormats/Valkyria/ImageMG2.cs

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2017-02-25 09:42:15 +08:00
//! \file ImageMG2.cs
//! \date Sat Feb 25 03:08:01 2017
//! \brief Valkyria image format.
//
// Copyright (C) 2017 by morkt
//
// 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.
//
using System.ComponentModel.Composition;
using System.IO;
using System.Windows.Media;
using System.Windows.Media.Imaging;
namespace GameRes.Formats.Valkyria
{
internal class Mg2MetaData : ImageMetaData
{
public int ImageLength;
public int AlphaLength;
}
[Export(typeof(ImageFormat))]
public class Mg2Format : ImageFormat
{
public override string Tag { get { return "MG2"; } }
public override string Description { get { return "Valkyria image format"; } }
public override uint Signature { get { return 0x4F43494D; } } // 'MICO'
public override ImageMetaData ReadMetaData (IBinaryStream file)
{
var header = file.ReadHeader (0x10);
if (!header.AsciiEqual (4, "CG01"))
return null;
int length = header.ToInt32 (8);
using (var input = new Mg2EncryptedStream (file.AsStream, 0x10, length))
using (var png = new BinaryStream (input, file.Name))
{
var info = Png.ReadMetaData (png);
if (null == info)
return null;
return new Mg2MetaData
{
Width = info.Width,
Height = info.Height,
OffsetX = info.OffsetX,
OffsetY = info.OffsetY,
BPP = info.BPP,
ImageLength = length,
AlphaLength = header.ToInt32 (12)
};
}
}
public override ImageData Read (IBinaryStream file, ImageMetaData info)
{
var meta = (Mg2MetaData)info;
BitmapSource frame;
using (var input = new Mg2EncryptedStream (file.AsStream, 0x10, meta.ImageLength))
{
var decoder = new PngBitmapDecoder (input, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
frame = decoder.Frames[0];
if (0 == meta.AlphaLength)
{
frame.Freeze();
return new ImageData (frame, info);
}
}
if (frame.Format.BitsPerPixel != 32)
frame = new FormatConvertedBitmap (frame, PixelFormats.Bgr32, null, 0);
int stride = frame.PixelWidth * 4;
var pixels = new byte[stride * (int)meta.Height];
frame.CopyPixels (pixels, stride, 0);
using (var input = new Mg2EncryptedStream (file.AsStream, 0x10+meta.ImageLength, meta.AlphaLength))
{
var decoder = new PngBitmapDecoder (input, BitmapCreateOptions.None, BitmapCacheOption.OnLoad);
BitmapSource alpha_frame = decoder.Frames[0];
if (alpha_frame.PixelWidth != frame.PixelWidth || alpha_frame.PixelHeight != frame.PixelHeight)
return ImageData.Create (info, PixelFormats.Bgr32, null, pixels, stride);
alpha_frame = new FormatConvertedBitmap (alpha_frame, PixelFormats.Gray8, null, 0);
var alpha = new byte[alpha_frame.PixelWidth * alpha_frame.PixelHeight];
alpha_frame.CopyPixels (alpha, alpha_frame.PixelWidth, 0);
int src = 0;
for (int dst = 3; dst < pixels.Length; dst += 4)
{
pixels[dst] = alpha[src++];
}
return ImageData.Create (info, PixelFormats.Bgra32, null, pixels, stride);
}
}
public override void Write (Stream file, ImageData image)
{
throw new System.NotImplementedException ("Mg2Format.Write not implemented");
}
}
internal class Mg2EncryptedStream : StreamRegion
{
readonly int m_threshold;
public Mg2EncryptedStream (Stream main, int offset, int length)
: base (main, offset, length, true)
{
m_threshold = length / 5;
}
public override int Read (byte[] buffer, int offset, int count)
{
int pos = (int)Position;
int read = base.Read (buffer, offset, count);
for (int i = 0; i < read && pos < m_threshold; ++i)
buffer[offset+i] ^= (byte)pos++;
return read;
}
public override int ReadByte ()
{
long pos = Position;
int b = base.ReadByte();
if (b != -1 && pos < m_threshold)
b ^= (byte)pos;
return b;
}
}
}