325 lines
8.5 KiB
C#
325 lines
8.5 KiB
C#
#region Copyright & License Information
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/*
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* Copyright 2007-2019 The OpenRA Developers (see AUTHORS)
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* This file is part of OpenRA, which is free software. It is made
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* available to you under the terms of the GNU General Public License
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* as published by the Free Software Foundation, either version 3 of
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* the License, or (at your option) any later version. For more
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* information, see COPYING.
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*/
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#endregion
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using System;
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using System.Collections.Generic;
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using System.Drawing;
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using System.Drawing.Imaging;
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using System.IO;
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using System.Linq;
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using System.Net;
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using System.Runtime.InteropServices;
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using System.Text;
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using ICSharpCode.SharpZipLib.Checksums;
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using ICSharpCode.SharpZipLib.Zip.Compression.Streams;
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namespace OpenRA.FileFormats
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{
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public class Png
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{
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public int Width { get; set; }
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public int Height { get; set; }
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public Color[] Palette { get; set; }
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public byte[] Data { get; set; }
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public Dictionary<string, string> EmbeddedData = new Dictionary<string, string>();
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public Png(Stream s)
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{
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if (!Verify(s))
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throw new InvalidDataException("PNG Signature is bogus");
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s.Position += 8;
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var headerParsed = false;
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var isPaletted = false;
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var data = new List<byte>();
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for (;;)
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{
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var length = IPAddress.NetworkToHostOrder(s.ReadInt32());
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var type = Encoding.UTF8.GetString(s.ReadBytes(4));
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var content = s.ReadBytes(length);
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/*var crc = */s.ReadInt32();
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if (!headerParsed && type != "IHDR")
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throw new InvalidDataException("Invalid PNG file - header does not appear first.");
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using (var ms = new MemoryStream(content))
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{
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switch (type)
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{
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case "IHDR":
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{
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if (headerParsed)
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throw new InvalidDataException("Invalid PNG file - duplicate header.");
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Width = IPAddress.NetworkToHostOrder(ms.ReadInt32());
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Height = IPAddress.NetworkToHostOrder(ms.ReadInt32());
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var bitDepth = ms.ReadUInt8();
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var colorType = (PngColorType)ms.ReadByte();
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isPaletted = IsPaletted(bitDepth, colorType);
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var dataLength = Width * Height;
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if (!isPaletted)
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dataLength *= 4;
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Data = new byte[dataLength];
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var compression = ms.ReadByte();
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/*var filter = */ms.ReadByte();
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var interlace = ms.ReadByte();
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if (compression != 0)
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throw new InvalidDataException("Compression method not supported");
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if (interlace != 0)
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throw new InvalidDataException("Interlacing not supported");
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headerParsed = true;
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break;
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}
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case "PLTE":
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{
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Palette = new Color[256];
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for (var i = 0; i < length / 3; i++)
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{
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var r = ms.ReadByte(); var g = ms.ReadByte(); var b = ms.ReadByte();
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Palette[i] = Color.FromArgb(r, g, b);
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}
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break;
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}
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case "tRNS":
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{
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if (Palette == null)
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throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
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for (var i = 0; i < length; i++)
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Palette[i] = Color.FromArgb(ms.ReadByte(), Palette[i]);
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break;
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}
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case "IDAT":
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{
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data.AddRange(content);
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break;
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}
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case "tEXt":
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{
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var key = ms.ReadASCIIZ();
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EmbeddedData.Add(key, ms.ReadASCII(length - key.Length - 1));
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break;
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}
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case "IEND":
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{
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using (var ns = new MemoryStream(data.ToArray()))
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{
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using (var ds = new InflaterInputStream(ns))
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{
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var pxStride = isPaletted ? 1 : 4;
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var stride = Width * pxStride;
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var prevLine = new byte[stride];
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for (var y = 0; y < Height; y++)
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{
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var filter = (PngFilter)ds.ReadByte();
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var line = ds.ReadBytes(stride);
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for (var i = 0; i < stride; i++)
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line[i] = i < pxStride
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? UnapplyFilter(filter, line[i], 0, prevLine[i], 0)
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: UnapplyFilter(filter, line[i], line[i - pxStride], prevLine[i], prevLine[i - pxStride]);
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Array.Copy(line, 0, Data, y * stride, line.Length);
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prevLine = line;
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}
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}
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}
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if (isPaletted && Palette == null)
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throw new InvalidDataException("Non-Palette indexed PNG are not supported.");
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return;
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}
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}
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}
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}
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}
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public static bool Verify(Stream s)
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{
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var pos = s.Position;
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var signature = new[] { 0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a };
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var isPng = signature.Aggregate(true, (current, t) => current && s.ReadUInt8() == t);
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s.Position = pos;
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return isPng;
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}
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static byte UnapplyFilter(PngFilter f, byte x, byte a, byte b, byte c)
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{
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switch (f)
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{
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case PngFilter.None: return x;
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case PngFilter.Sub: return (byte)(x + a);
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case PngFilter.Up: return (byte)(x + b);
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case PngFilter.Average: return (byte)(x + (a + b) / 2);
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case PngFilter.Paeth: return (byte)(x + Paeth(a, b, c));
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default:
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throw new InvalidOperationException("Unsupported Filter");
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}
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}
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static byte Paeth(byte a, byte b, byte c)
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{
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var p = a + b - c;
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var pa = Math.Abs(p - a);
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var pb = Math.Abs(p - b);
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var pc = Math.Abs(p - c);
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return (pa <= pb && pa <= pc) ? a :
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(pb <= pc) ? b : c;
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}
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[Flags]
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enum PngColorType { Indexed = 1, Color = 2, Alpha = 4 }
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enum PngFilter { None, Sub, Up, Average, Paeth }
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static bool IsPaletted(byte bitDepth, PngColorType colorType)
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{
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if (bitDepth == 8 && colorType == (PngColorType.Indexed | PngColorType.Color))
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return true;
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if (bitDepth == 8 && colorType == (PngColorType.Color | PngColorType.Alpha))
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return false;
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throw new InvalidDataException("Unknown pixel format");
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}
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public byte[] Save()
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{
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var pixelFormat = Palette != null ? PixelFormat.Format8bppIndexed : PixelFormat.Format32bppArgb;
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// Save to a memory stream that we can then parse to add the embedded data
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using (var bitmapStream = new MemoryStream())
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{
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using (var bitmap = new Bitmap(Width, Height, pixelFormat))
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{
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if (Palette != null)
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{
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// Setting bitmap.Palette.Entries directly doesn't work
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var bPal = bitmap.Palette;
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for (var i = 0; i < 256; i++)
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bPal.Entries[i] = Palette[i];
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bitmap.Palette = bPal;
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var bd = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.WriteOnly,
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pixelFormat);
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for (var i = 0; i < Height; i++)
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Marshal.Copy(Data, i * Width, IntPtr.Add(bd.Scan0, i * bd.Stride), Width);
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bitmap.UnlockBits(bd);
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}
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else
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{
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unsafe
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{
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var bd = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.WriteOnly, pixelFormat);
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var colors = (int*)bd.Scan0;
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for (var y = 0; y < Height; y++)
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{
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for (var x = 0; x < Width; x++)
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{
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var i = y * Width + x;
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// Convert RGBA to ARGB
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colors[i] = Color.FromArgb(Data[4 * i + 3], Data[4 * i + 0], Data[4 * i + 1],
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Data[4 * i + 2]).ToArgb();
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}
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}
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bitmap.UnlockBits(bd);
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}
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}
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bitmap.Save(bitmapStream, ImageFormat.Png);
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}
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if (!EmbeddedData.Any())
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return bitmapStream.ToArray();
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// Add embedded metadata to the end of the image
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bitmapStream.Position = 0;
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var outputStream = new MemoryStream();
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using (var bw = new BinaryWriter(outputStream))
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{
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bw.Write(bitmapStream.ReadBytes(8));
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var crc32 = new Crc32();
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for (;;)
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{
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var length = IPAddress.NetworkToHostOrder(bitmapStream.ReadInt32());
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var type = Encoding.UTF8.GetString(bitmapStream.ReadBytes(4));
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var content = bitmapStream.ReadBytes(length);
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var crc = bitmapStream.ReadUInt32();
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switch (type)
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{
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case "tEXt":
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break;
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case "IEND":
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bitmapStream.Close();
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foreach (var kv in EmbeddedData)
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{
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bw.Write(IPAddress.NetworkToHostOrder(kv.Key.Length + 1 + kv.Value.Length));
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bw.Write("tEXt".ToCharArray());
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bw.Write(kv.Key.ToCharArray());
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bw.Write((byte)0x00);
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bw.Write(kv.Value.ToCharArray());
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crc32.Reset();
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crc32.Update(Encoding.ASCII.GetBytes("tEXt"));
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crc32.Update(Encoding.ASCII.GetBytes(kv.Key + (char)0x00 + kv.Value));
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bw.Write((uint)IPAddress.NetworkToHostOrder((int)crc32.Value));
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}
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bw.Write(0);
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bw.Write(type.ToCharArray());
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bw.Write(crc);
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return outputStream.ToArray();
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default:
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bw.Write(IPAddress.NetworkToHostOrder(length));
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bw.Write(type.ToCharArray());
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bw.Write(content);
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bw.Write(crc);
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break;
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}
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}
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}
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}
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}
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public void Save(string path)
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{
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File.WriteAllBytes(path, Save());
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}
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}
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}
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