mirror of
https://github.com/MrUnknownDE/VRCX.git
synced 2026-05-05 06:16:05 +02:00
Screenshot metadata dialog (#490)
* docs: Add json schema for screenshot metadata * feat(.NET): Add function to open a file and read screenshot metadata to AppApi * refactor(.NET): Check initial file dialog directory before set Paranoia is fun * refactor(.NET): Stop reading entire png files into memory to check 8 bytes * refactor(.NET): Handle endianness and keyword encoding correctly for screenshots * docs: Add xmldocs and some comments to parts of the screenshot helper * screenshot metadata dialog * screenshot metadata dialog 1 * fix: file dialog open bool not resetting properly * screenshot metadata dialog 2 * fix: Stop png parser from dying on bad files Parser would keep reading past a file's IEND chunk, and it finally found one that had junk data past IEND. It died. This fixes that. It also encapsulates the Read function in a try/catch so VRCX doesn't crash if it fails due to a corrupted file. * fix: buggy carousel transition animation --------- Co-authored-by: Teacup <git@teadev.xyz>
This commit is contained in:
Natsumi
GitHub
+279
-33
@@ -3,25 +3,35 @@ using System.Collections.Generic;
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using System.IO;
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using System.Linq;
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using System.Text;
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using System.Threading.Tasks;
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using Newtonsoft.Json.Linq;
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namespace VRCX
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{
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internal static class ScreenshotHelper
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{
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private static byte[] pngSignatureBytes = new byte[] { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
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private static readonly byte[] pngSignatureBytes = { 0x89, 0x50, 0x4E, 0x47, 0x0D, 0x0A, 0x1A, 0x0A };
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/// <summary>
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/// Writes a text description into a PNG file at the specified path.
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/// Creates an iTXt PNG chunk in the target file, using the Description tag, with the specified text.
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/// </summary>
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/// <param name="path">The file path of the PNG file in which the description is to be written.</param>
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/// <param name="text">The text description that is to be written into the PNG file.</param>
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/// <returns>
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/// <c>true</c> if the text description is successfully written to the PNG file;
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/// otherwise, <c>false</c>.
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/// </returns>
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public static bool WritePNGDescription(string path, string text)
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{
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if (!File.Exists(path) || !IsPNGFile(path)) return false;
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var png = File.ReadAllBytes(path);
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int newChunkIndex = FindChunk(png, "IHDR");
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var newChunkIndex = FindEndOfChunk(png, "IHDR");
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if (newChunkIndex == -1) return false;
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// If this file already has a text chunk, chances are it got logged twice for some reason. Stop.
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int existingiTXt = FindChunk(png, "iTXt");
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var existingiTXt = FindChunkIndex(png, "iTXt");
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if (existingiTXt != -1) return false;
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var newChunk = new PNGChunk("iTXt");
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@@ -35,37 +45,230 @@ namespace VRCX
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return true;
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}
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public static bool IsPNGFile(string path)
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/// <summary>
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/// Reads a text description from a PNG file at the specified path.
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/// Reads any existing iTXt PNG chunk in the target file, using the Description tag.
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/// </summary>
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/// <param name="path">The file path of the PNG file in which the description is to be read from.</param>
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/// <returns>
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/// The text description that is read from the PNG file.
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/// </returns>
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public static string ReadPNGDescription(string path)
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{
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if (!File.Exists(path) || !IsPNGFile(path)) return null;
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var png = File.ReadAllBytes(path);
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var pngSignature = png.Take(8).ToArray();
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return pngSignatureBytes.SequenceEqual(pngSignature);
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var existingiTXt = FindChunk(png, "iTXt");
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if (existingiTXt == null) return null;
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var text = existingiTXt.GetText("Description");
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return text;
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}
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static int FindChunk(byte[] png, string type)
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/// <summary>
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/// Determines whether the specified file is a PNG file. We do this by checking if the first 8 bytes in the file path match the PNG signature.
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/// </summary>
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/// <param name="path">The path of the file to check.</param>
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/// <returns></returns>
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public static bool IsPNGFile(string path)
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{
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int index = 8;
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// Read only the first 8 bytes of the file to check if it's a PNG file instead of reading the entire thing into memory just to see check a couple bytes.
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using (var fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
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{
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if (fs.Length < 33) return false;
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var signature = new byte[8];
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fs.Read(signature, 0, 8);
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return signature.SequenceEqual(pngSignatureBytes);
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}
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}
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/// <summary>
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/// Finds the index of the first byte of the specified chunk type in the specified PNG file.
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/// </summary>
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/// <param name="png">Array of bytes representing a PNG file.</param>
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/// <param name="type">Type of PMG chunk to find</param>
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/// <returns></returns>
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private static int FindChunkIndex(byte[] png, string type)
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{
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// The first 8 bytes of the file are the png signature, so we can skip them.
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var index = 8;
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while (index < png.Length)
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{
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byte[] chunkLength = new byte[4];
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var chunkLength = new byte[4];
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Array.Copy(png, index, chunkLength, 0, 4);
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Array.Reverse(chunkLength);
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int length = BitConverter.ToInt32(chunkLength, 0);
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byte[] chunkName = new byte[4];
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// BitConverter wants little endian(unless your system is big endian for some reason), PNG multi-byte integers are big endian. So we reverse the array.
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if (BitConverter.IsLittleEndian) Array.Reverse(chunkLength);
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var length = BitConverter.ToInt32(chunkLength, 0);
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// We don't need to reverse strings since UTF-8 strings aren't affected by endianess, given that they're a sequence of bytes.
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var chunkName = new byte[4];
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Array.Copy(png, index + 4, chunkName, 0, 4);
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string name = Encoding.ASCII.GetString(chunkName);
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var name = Encoding.UTF8.GetString(chunkName);
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if (name == type)
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{
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return index + length + 12;
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return index;
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}
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if (name == "IEND") // Nothing should exist past IEND in a normal png file, so we should stop parsing here to avoid trying to parse junk data.
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{
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return -1;
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}
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// The chunk length is 4 bytes, the chunk name is 4 bytes, the chunk data is length bytes, and the chunk CRC is 4 bytes.
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index += length + 12;
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}
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return -1;
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}
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/// <summary>
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/// Finds the index of the end of the specified chunk type in the specified PNG file.
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/// </summary>
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/// <param name="png">Array of bytes representing a PNG file.</param>
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/// <param name="type">Type of PMG chunk to find</param>
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/// <returns></returns>
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private static int FindEndOfChunk(byte[] png, string type)
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{
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var index = FindChunkIndex(png, type);
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if (index == -1) return index;
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var chunkLength = new byte[4];
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Array.Copy(png, index, chunkLength, 0, 4);
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Array.Reverse(chunkLength);
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var length = BitConverter.ToInt32(chunkLength, 0);
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return index + length + 12;
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}
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/// <summary>
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/// Finds the specified chunk type in the specified PNG file and returns it as a PNGChunk.
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/// </summary>
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/// <param name="png">Array of bytes representing a PNG file</param>
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/// <param name="type">Type of PMG chunk to find</param>
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/// <returns>PNGChunk</returns>
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private static PNGChunk FindChunk(byte[] png, string type)
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{
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var index = FindChunkIndex(png, type);
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if (index == -1) return null;
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var chunkLength = new byte[4];
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Array.Copy(png, index, chunkLength, 0, 4);
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Array.Reverse(chunkLength);
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var length = BitConverter.ToInt32(chunkLength, 0);
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var chunkData = new byte[length];
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Array.Copy(png, index + 8, chunkData, 0, length);
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return new PNGChunk(type, chunkData);
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}
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// parse LFS screenshot PNG metadata
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public static JObject ParseLfsPicture(string metadataString)
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{
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var metadata = new JObject();
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// lfs|2|author:usr_032383a7-748c-4fb2-94e4-bcb928e5de6b,Natsumi-sama|world:wrld_b016712b-5ce6-4bcb-9144-c8ed089b520f,35372,pet park test|pos:-60.49379,-0.002925932,5.805772|players:usr_9d73bff9-4543-4b6f-a004-9e257869ff50,-0.85,-0.17,-0.58,Olivia.;usr_3097f91e-a816-4c7a-a625-38fbfdee9f96,12.30,13.72,0.08,Zettai Ryouiki;usr_032383a7-748c-4fb2-94e4-bcb928e5de6b,0.68,0.32,-0.28,Natsumi-sama;usr_7525f45f-517e-442b-9abc-fbcfedb29f84,0.51,0.64,0.70,Weyoun
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// lfs|2|author:usr_8c0a2f22-26d4-4dc9-8396-2ab40e3d07fc,knah|world:wrld_fb4edc80-6c48-43f2-9bd1-2fa9f1345621,35341,Luminescent Ledge|pos:8.231676,0.257298,-0.1983307|rq:2|players:usr_65b9eeeb-7c91-4ad2-8ce4-addb1c161cd6,0.74,0.59,1.57,Jakkuba;usr_6a50647f-d971-4281-90c3-3fe8caf2ba80,8.07,9.76,0.16,SopwithPup;usr_8c0a2f22-26d4-4dc9-8396-2ab40e3d07fc,0.26,1.03,-0.28,knah;usr_7f593ad1-3e9e-4449-a623-5c1c0a8d8a78,0.15,0.60,1.46,NekOwneD
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var lfs = metadataString.Split('|');
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var version = int.Parse(lfs[1]);
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var application = lfs[0];
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metadata.Add("application", application);
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metadata.Add("version", version);
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if (application == "screenshotmanager")
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{
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// screenshotmanager|0|author:usr_290c03d6-66cc-4f0e-b782-c07f5cfa8deb,VirtualTeacup|wrld_6caf5200-70e1-46c2-b043-e3c4abe69e0f,47213,The Great Pug
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var author = lfs[2].Split(',');
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metadata.Add("author", new JObject
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{
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{ "id", author[0] },
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{ "displayName", author[1] }
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});
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var world = lfs[3].Split(',');
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metadata.Add("world", new JObject
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{
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{ "id", world[0] },
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{ "name", world[2] },
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{ "instanceId", world[1] }
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});
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return metadata;
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}
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for (var i = 2; i < lfs.Length; i++)
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{
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var split = lfs[i].Split(':');
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switch (split[0])
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{
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case "author":
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var author = split[1].Split(',');
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metadata.Add("author", new JObject
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{
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{ "id", author[0] },
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{ "displayName", author[1] }
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});
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break;
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case "world":
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if (version == 1)
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{
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metadata.Add("world", new JObject
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{
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{ "id", "" },
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{ "name", split[1] },
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{ "instanceId", "" }
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});
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}
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else
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{
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var world = split[1].Split(',');
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metadata.Add("world", new JObject
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{
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{ "id", world[0] },
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{ "name", world[2] },
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{ "instanceId", world[0] }
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});
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}
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break;
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case "pos":
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var pos = split[1].Split(',');
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metadata.Add("pos", new JObject
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{
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{ "x", pos[0] },
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{ "y", pos[1] },
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{ "z", pos[2] }
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});
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break;
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case "rq":
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metadata.Add("rq", split[1]);
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break;
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case "players":
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var players = split[1].Split(';');
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var playersArray = new JArray();
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foreach (var player in players)
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{
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var playerSplit = player.Split(',');
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playersArray.Add(new JObject
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{
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{ "id", playerSplit[0] },
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{ "x", playerSplit[1] },
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{ "y", playerSplit[2] },
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{ "z", playerSplit[3] },
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{ "displayName", playerSplit[4] }
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});
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}
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metadata.Add("players", playersArray);
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break;
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}
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}
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return metadata;
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}
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}
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// See http://www.libpng.org/pub/png/spec/1.2/PNG-Chunks.html 4.2.3
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@@ -75,28 +278,42 @@ namespace VRCX
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// Proper practice here for arbitrary image processing would be to check the PNG file being passed for any existing iTXt chunks with the same keyword that we're trying to use; If we find one, we replace that chunk's data instead of creating a new chunk.
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// Luckily, VRChat should never do this! Bugs notwithstanding, we should never re-process a png file either. So we're just going to skip that logic.
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// This code would be HORRIBLE for general parsing of PNG files/metadata. It's not really meant to do that, it's just meant to do exactly what we need it to do.
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internal class PNGChunk
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{
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public string ChunkType;
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public List<byte> ChunkDataBytes;
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public int ChunkDataLength;
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// crc lookup table
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private static uint[] crcTable;
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// init lookup table and store crc for iTXt
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private static uint tEXtCRC = Crc32(new byte[] { (byte)'i', (byte)'T', (byte)'X', (byte)'t' }, 0, 4, 0);
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private static readonly uint iTXtCrc = Crc32(new[] { (byte)'i', (byte)'T', (byte)'X', (byte)'t' }, 0, 4, 0);
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private readonly Encoding keywordEncoding = Encoding.GetEncoding("ISO-8859-1"); // ISO-8859-1/Latin1 is the encoding used for the keyword in text chunks.
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public List<byte> ChunkBytes;
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public List<byte> ChunkDataBytes;
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public int ChunkDataLength;
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public string ChunkType;
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public PNGChunk(string chunkType)
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{
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this.ChunkType = chunkType;
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this.ChunkDataBytes = new List<byte>();
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ChunkType = chunkType;
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ChunkDataBytes = new List<byte>();
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}
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// Construct iTXt chunk data
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public PNGChunk(string chunkType, byte[] bytes)
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{
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ChunkType = chunkType;
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ChunkDataBytes = bytes.ToList();
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ChunkDataLength = bytes.Length;
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}
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/// <summary>
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/// Initializes this PNGChunk's data in the format of an iTXt chunk with the specified keyword and text.
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/// </summary>
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/// <param name="keyword">Keyword for text chunk</param>
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/// <param name="text">Text data for text chunk</param>
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public void InitializeTextChunk(string keyword, string text)
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{
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// Create our chunk data byte array
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ChunkDataBytes.AddRange(Encoding.UTF8.GetBytes(keyword)); // keyword
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ChunkDataBytes.AddRange(keywordEncoding.GetBytes(keyword)); // keyword
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ChunkDataBytes.Add(0x0); // Null separator
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ChunkDataBytes.Add(0x0); // Compression flag
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ChunkDataBytes.Add(0x0); // Compression method
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@@ -107,19 +324,45 @@ namespace VRCX
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ChunkDataLength = ChunkDataBytes.Count;
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}
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// Construct & return PNG chunk
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/// <summary>
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/// Constructs and returns a full, coherent PNG chunk from this PNGChunk's data.
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/// </summary>
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/// <returns>PNG chunk byte array</returns>
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public byte[] ConstructChunkByteArray()
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{
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List<byte> chunk = new List<byte>();
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var chunk = new List<byte>();
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chunk.AddRange(BitConverter.GetBytes(ChunkDataLength).Reverse()); // add data length
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chunk.AddRange(Encoding.ASCII.GetBytes(ChunkType)); // add chunk type
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var chunkLengthBytes = BitConverter.GetBytes(ChunkDataLength);
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var chunkCRCBytes = BitConverter.GetBytes(Crc32(ChunkDataBytes.ToArray(), 0, ChunkDataLength, iTXtCrc));
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// Reverse the chunk length bytes/CRC bytes if system is little endian since PNG integers are big endian
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if (BitConverter.IsLittleEndian)
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{
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Array.Reverse(chunkLengthBytes);
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Array.Reverse(chunkCRCBytes);
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}
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chunk.AddRange(chunkLengthBytes); // add data length
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chunk.AddRange(Encoding.UTF8.GetBytes(ChunkType)); // add chunk type
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chunk.AddRange(ChunkDataBytes); // Add chunk data
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chunk.AddRange(BitConverter.GetBytes(Crc32(ChunkDataBytes.ToArray(), 0, ChunkDataLength, tEXtCRC)).Reverse()); // Add chunk CRC32 hash
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chunk.AddRange(chunkCRCBytes); // Add chunk CRC32 hash.
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return chunk.ToArray();
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}
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/// <summary>
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/// Gets the text from an iTXt chunk
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/// </summary>
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/// <param name="keyword">Keyword of the text chunk</param>
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/// <returns>Text from chunk.</returns>
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public string GetText(string keyword)
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{
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var offset = keywordEncoding.GetByteCount(keyword) + 5;
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// Read string from PNG chunk
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return Encoding.UTF8.GetString(ChunkDataBytes.ToArray(), offset, ChunkDataBytes.Count - offset);
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}
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// Crc32 implementation from
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// https://web.archive.org/web/20150825201508/http://upokecenter.dreamhosters.com/articles/png-image-encoder-in-c/
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private static uint Crc32(byte[] stream, int offset, int length, uint crc)
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{
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@@ -135,18 +378,21 @@ namespace VRCX
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if ((c & 1) == 1)
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c = 0xEDB88320 ^ ((c >> 1) & 0x7FFFFFFF);
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else
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c = ((c >> 1) & 0x7FFFFFFF);
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c = (c >> 1) & 0x7FFFFFFF;
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}
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crcTable[n] = c;
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}
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}
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c = crc ^ 0xffffffff;
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var endOffset = offset + length;
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for (var i = offset; i < endOffset; i++)
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{
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c = crcTable[(c ^ stream[i]) & 255] ^ ((c >> 8) & 0xFFFFFF);
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}
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return c ^ 0xffffffff;
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}
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}
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}
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}
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