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@@ -0,0 +1,904 @@
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+using System;
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+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.Xml;
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+using OfficeOpenXml.Drawing;
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+using OfficeOpenXml.Packaging.Ionic.Zlib;
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+
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+namespace Masuit.Tools.Excel;
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+
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+public static class ImageDetector
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+{
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+ private const float MToInch = 39.3700787F;
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+ private const float CmToInch = MToInch * 0.01F;
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+ public const float MmToInch = CmToInch * 0.1F;
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+ private const float HundredthThMmToInch = MmToInch * 0.01F;
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+ internal const float StandardDPI = 96f;
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+
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+ internal struct TifIfd
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+ {
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+ public short Tag;
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+ public short Type;
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+ public int Count;
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+ public int ValueOffset;
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+ }
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+
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+ /// <summary>
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+ /// 获取图像格式
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+ /// </summary>
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+ /// <param name="ms"></param>
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+ /// <returns></returns>
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+ public static ePictureType? GetPictureType(Stream ms)
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+ {
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+ var br = new BinaryReader(ms);
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+ if (IsJpg(br))
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+ {
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+ return ePictureType.Jpg;
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+ }
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+ if (IsBmp(br, out _))
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+ {
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+ return ePictureType.Bmp;
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+ }
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+ else if (IsGif(br))
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+ {
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+ return ePictureType.Gif;
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+ }
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+ else if (IsPng(br))
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+ {
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+ return ePictureType.Png;
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+ }
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+ else if (IsTif(br, out _))
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+ {
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+ return ePictureType.Tif;
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+ }
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+ else if (IsIco(br))
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+ {
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+ return ePictureType.Ico;
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+ }
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+ else if (IsWebP(br))
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+ {
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+ return ePictureType.WebP;
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+ }
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+ else if (IsEmf(br))
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+ {
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+ return ePictureType.Emf;
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+ }
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+ else if (IsWmf(br))
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+ {
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+ return ePictureType.Wmf;
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+ }
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+ else if (IsSvg(ms))
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+ {
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+ return ePictureType.Svg;
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+ }
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+ else if (IsGZip(br))
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+ {
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+ _ = ExtractImage(ToArray(ms), out ePictureType? pt);
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+ return pt;
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+ }
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+ return null;
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+ }
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+
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+ /// <summary>
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+ ///
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+ /// </summary>
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+ /// <param name="stream"></param>
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+ /// <returns></returns>
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+ public static byte[] ToArray(Stream stream)
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+ {
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+ stream.Position = 0;
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+ byte[] bytes = new byte[stream.Length];
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+ stream.Read(bytes, 0, bytes.Length);
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+
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+ // 设置当前流的位置为流的开始
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+ stream.Seek(0, SeekOrigin.Begin);
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+ return bytes;
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+ }
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+
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+ private static bool IsGZip(BinaryReader br)
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+ {
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+ br.BaseStream.Position = 0;
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+ var sign = br.ReadBytes(2);
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+ return IsGZip(sign);
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+ }
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+
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+ private static bool IsGZip(byte[] sign)
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+ {
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+ return sign.Length >= 2 && sign[0] == 0x1F && sign[1] == 0x8B;
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+ }
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+
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+ internal static bool TryGetImageBounds(ePictureType pictureType, MemoryStream ms, ref double width, ref double height, out double horizontalResolution, out double verticalResolution)
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+ {
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+ width = 0;
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+ height = 0;
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+ horizontalResolution = verticalResolution = StandardDPI;
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+ try
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+ {
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+ ms.Seek(0, SeekOrigin.Begin);
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+ if (pictureType == ePictureType.Bmp && IsBmp(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ if (pictureType == ePictureType.Jpg && IsJpg(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ if (pictureType == ePictureType.Gif && IsGif(ms, ref width, ref height))
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+ {
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+ return true;
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+ }
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+ if (pictureType == ePictureType.Png && IsPng(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ if (pictureType == ePictureType.Emf && IsEmf(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ if (pictureType == ePictureType.Wmf && IsWmf(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ else if (pictureType == ePictureType.Svg && IsSvg(ms, ref width, ref height))
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+ {
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+ return true;
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+ }
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+ else if (pictureType == ePictureType.Tif && IsTif(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ else if (pictureType == ePictureType.WebP && IsWebP(ms, ref width, ref height, ref horizontalResolution, ref verticalResolution))
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+ {
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+ return true;
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+ }
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+ else if (pictureType == ePictureType.Ico && IsIcon(ms, ref width, ref height))
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+ {
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+ return true;
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+ }
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+ return false;
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+ }
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+ catch
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+ {
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+ return false;
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+ }
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+ }
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+
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+ internal static byte[] ExtractImage(byte[] img, out ePictureType? type)
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+ {
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+ if (IsGZip(img))
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+ {
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+ try
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+ {
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+ var ms = new MemoryStream(img);
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+ var msOut = new MemoryStream();
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+ const int bufferSize = 4096;
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+ var buffer = new byte[bufferSize];
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+ using (var z = new GZipStream(ms, CompressionMode.Decompress))
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+ {
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+ int size = 0;
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+ do
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+ {
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+ size = z.Read(buffer, 0, bufferSize);
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+ if (size > 0)
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+ {
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+ msOut.Write(buffer, 0, size);
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+ }
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+ }
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+ while (size == bufferSize);
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+ msOut.Position = 0;
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+ var br = new BinaryReader(msOut);
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+ if (IsEmf(br))
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+ {
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+ type = ePictureType.Emf;
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+ }
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+ else if (IsWmf(br))
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+ {
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+ type = ePictureType.Wmf;
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+ }
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+ else
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+ {
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+ type = null;
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+ }
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+ msOut.Position = 0;
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+ return msOut.ToArray();
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+ }
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+ }
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+ catch
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+ {
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+ type = null;
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+ return img;
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+ }
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+ }
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+ type = null;
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+ return img;
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+ }
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+
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+ private static bool IsJpg(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
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+ {
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+ using (var br = new BinaryReader(ms))
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+ {
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+ if (IsJpg(br))
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+ {
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+ float xDensity = 1, yDensity = 1;
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+ while (ms.Position < ms.Length)
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+ {
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+ var id = GetUInt16BigEndian(br);
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+ var length = (int)GetInt16BigEndian(br);
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+ switch (id)
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+ {
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+ case 0xFFE0:
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+ var identifier = br.ReadBytes(5); //JFIF\0
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+ var version = br.ReadBytes(2);
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+ var unit = br.ReadByte();
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+ xDensity = (int)GetInt16BigEndian(br);
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+ yDensity = (int)GetInt16BigEndian(br);
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+
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+ if (unit == 1)
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+ {
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+ horizontalResolution = xDensity;
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+ verticalResolution = yDensity;
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+ }
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+ else if (unit == 2)
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+ {
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+ horizontalResolution = xDensity * CmToInch;
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+ verticalResolution = yDensity * CmToInch;
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+ }
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+
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+ ms.Position += length - 14;
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+ break;
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+
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+ case 0xFFE1:
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+ var pos = ms.Position;
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+ identifier = br.ReadBytes(6); //EXIF\0\0 or //EXIF\FF\FF
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+ double w = 0, h = 0;
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+ ReadTiffHeader(br, ref w, ref h, ref horizontalResolution, ref verticalResolution);
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+ ms.Position = pos + length - 2;
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+ break;
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+
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+ case 0xFFC0:
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+ case 0xFFC1:
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+ case 0xFFC2:
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+ var precision = br.ReadByte(); //Bits
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+ height = GetUInt16BigEndian(br);
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+ width = GetUInt16BigEndian(br);
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+ br.Close();
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+ return true;
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+
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+ case 0xFFD9:
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+ return height != 0 && width != 0;
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+
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+ default:
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+ ms.Position += length - 2;
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+ break;
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+ }
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+ }
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+ }
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+ return false;
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+ }
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+ }
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+
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+ private static bool IsJpg(BinaryReader br)
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+ {
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+ br.BaseStream.Position = 0;
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+ var sign = br.ReadBytes(2); //FF D8
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+ return sign.Length >= 2 && sign[0] == 0xFF && sign[1] == 0xD8;
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+ }
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+
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+ private static bool IsGif(MemoryStream ms, ref double width, ref double height)
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+ {
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+ using (var br = new BinaryReader(ms))
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+ {
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+ if (IsGif(br))
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+ {
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+ width = br.ReadUInt16();
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+ height = br.ReadUInt16();
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+ br.Close();
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+ return true;
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+ }
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+ }
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+ return false;
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+ }
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+
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+ private static bool IsGif(BinaryReader br)
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+ {
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+ br.BaseStream.Seek(0, SeekOrigin.Begin);
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+ var b = br.ReadBytes(6);
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+ return b[0] == 0x47 && b[1] == 0x49 && b[2] == 0x46; //byte 4-6 contains the version, but we don't check them here.
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+ }
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+
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+ private static bool IsBmp(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
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+ {
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+ using (var br = new BinaryReader(ms))
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+ {
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+ if (IsBmp(br, out string sign))
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+ {
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+ var size = br.ReadInt32();
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+ var reserved = br.ReadBytes(4);
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+ var offsetData = br.ReadInt32();
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+
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+ //Info Header
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+ var ihSize = br.ReadInt32(); //Should be 40
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+ width = br.ReadInt32();
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+ height = br.ReadInt32();
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+
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+ if (sign == "BM")
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+ {
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+ br.ReadBytes(12);
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+ horizontalResolution = br.ReadInt32() / MToInch;
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+ verticalResolution = br.ReadInt32() / MToInch;
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+ }
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+ else
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+ {
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+ horizontalResolution = verticalResolution = 1;
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+ }
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+
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+ return true;
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+ }
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+ }
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+ return false;
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+ }
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+
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+ internal static bool IsBmp(BinaryReader br, out string sign)
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+ {
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+ try
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+ {
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+ br.BaseStream.Seek(0, SeekOrigin.Begin);
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+ sign = Encoding.ASCII.GetString(br.ReadBytes(2)); //BM for a Windows bitmap
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+ return (sign == "BM" || sign == "BA" || sign == "CI" || sign == "CP" || sign == "IC" || sign == "PT");
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+ }
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+ catch
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+ {
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+ sign = null;
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+ return false;
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+ }
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+ }
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+
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+ #region Ico
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+
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+ private static bool IsIcon(MemoryStream ms, ref double width, ref double height)
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+ {
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+ using (var br = new BinaryReader(ms))
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+ {
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+ if (IsIco(br))
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+ {
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+ var imageCount = br.ReadInt16();
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+ width = br.ReadByte();
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+ if (width == 0) width = 256;
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+ height = br.ReadByte();
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+ if (height == 0) height = 256;
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+ br.Close();
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+ return true;
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+ }
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+ br.Close();
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+ return false;
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+ }
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+ }
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+
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+ internal static bool IsIco(BinaryReader br)
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+ {
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+ br.BaseStream.Seek(0, SeekOrigin.Begin);
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+ var type0 = br.ReadInt16();
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+ var type1 = br.ReadInt16();
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+ return type0 == 0 && type1 == 1;
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+ }
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+
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+ #endregion Ico
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+
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+ #region WebP
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+
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+ private static bool IsWebP(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
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+ {
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+ width = height = 0;
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+ horizontalResolution = verticalResolution = StandardDPI * (1 + 1 / 3); //Excel seems to render webp at 1 1/3 size.
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+ using (var br = new BinaryReader(ms))
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+ {
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+ if (IsWebP(br))
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+ {
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+ var vp8 = Encoding.ASCII.GetString(br.ReadBytes(4));
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+ switch (vp8)
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+ {
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+ case "VP8 ":
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+ var b = br.ReadBytes(10);
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+ var w = br.ReadInt16();
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+ width = w & 0x3FFF;
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+ var hScale = w >> 14;
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+ var h = br.ReadInt16();
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+ height = h & 0x3FFF;
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+ hScale = h >> 14;
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+ break;
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+
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+ case "VP8X":
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+ br.ReadBytes(8);
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+ b = br.ReadBytes(6);
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+ width = BitConverter.ToInt32(new byte[] { b[0], b[1], b[2], 0 }, 0) + 1;
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+ height = BitConverter.ToInt32(new byte[] { b[3], b[4], b[5], 0 }, 0) + 1;
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+ break;
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+
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+ case "VP8L":
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+ br.ReadBytes(5);
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+ b = br.ReadBytes(4);
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+ width = (b[0] | (b[1] & 0x3F) << 8) + 1;
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+ height = (b[1] >> 6 | b[2] << 2 | (b[3] & 0x0F) << 10) + 1;
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+ break;
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+ }
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+ }
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+ }
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+ return width != 0 && height != 0;
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+ }
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+
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+ internal static bool IsWebP(BinaryReader br)
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+ {
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+ try
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+ {
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+ br.BaseStream.Seek(0, SeekOrigin.Begin);
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+ var riff = Encoding.ASCII.GetString(br.ReadBytes(4));
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+ var length = GetInt32BigEndian(br);
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+ var webP = Encoding.ASCII.GetString(br.ReadBytes(4));
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+
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|
+ return riff == "RIFF" && webP == "WEBP";
|
|
|
+ }
|
|
|
+ catch
|
|
|
+ {
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ #endregion WebP
|
|
|
+
|
|
|
+ #region Tiff
|
|
|
+
|
|
|
+ private static bool IsTif(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
|
|
|
+ {
|
|
|
+ using (var br = new BinaryReader(ms))
|
|
|
+ {
|
|
|
+ return ReadTiffHeader(br, ref width, ref height, ref horizontalResolution, ref verticalResolution);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool ReadTiffHeader(BinaryReader br, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
|
|
|
+ {
|
|
|
+ var ms = br.BaseStream;
|
|
|
+ var pos = ms.Position;
|
|
|
+ if (IsTif(br, out bool isBigEndian, false))
|
|
|
+ {
|
|
|
+ var offset = GetTifInt32(br, isBigEndian);
|
|
|
+ ms.Position = pos + offset;
|
|
|
+ var numberOfIdf = GetTifInt16(br, isBigEndian);
|
|
|
+ var ifds = new List<TifIfd>();
|
|
|
+ for (int i = 0; i < numberOfIdf; i++)
|
|
|
+ {
|
|
|
+ var ifd = new TifIfd()
|
|
|
+ {
|
|
|
+ Tag = GetTifInt16(br, isBigEndian),
|
|
|
+ Type = GetTifInt16(br, isBigEndian),
|
|
|
+ Count = GetTifInt32(br, isBigEndian),
|
|
|
+ };
|
|
|
+ if (ifd.Type == 1 || ifd.Type == 2 || ifd.Type == 6 || ifd.Type == 7)
|
|
|
+ {
|
|
|
+ ifd.ValueOffset = br.ReadByte();
|
|
|
+ br.ReadBytes(3);
|
|
|
+ }
|
|
|
+ else if (ifd.Type == 3 || ifd.Type == 8)
|
|
|
+ {
|
|
|
+ ifd.ValueOffset = GetTifInt16(br, isBigEndian);
|
|
|
+ br.ReadBytes(2);
|
|
|
+ }
|
|
|
+ else
|
|
|
+ {
|
|
|
+ ifd.ValueOffset = GetTifInt32(br, isBigEndian);
|
|
|
+ }
|
|
|
+ ifds.Add(ifd);
|
|
|
+ }
|
|
|
+
|
|
|
+ int resolutionUnit = 2;
|
|
|
+ foreach (var ifd in ifds)
|
|
|
+ {
|
|
|
+ switch (ifd.Tag)
|
|
|
+ {
|
|
|
+ case 0x100:
|
|
|
+ width = ifd.ValueOffset;
|
|
|
+ break;
|
|
|
+
|
|
|
+ case 0x101:
|
|
|
+ height = ifd.ValueOffset;
|
|
|
+ break;
|
|
|
+
|
|
|
+ case 0x11A:
|
|
|
+ ms.Position = ifd.ValueOffset + pos;
|
|
|
+ var l1 = GetTifInt32(br, isBigEndian);
|
|
|
+ var l2 = GetTifInt32(br, isBigEndian);
|
|
|
+ horizontalResolution = l1 / l2;
|
|
|
+ break;
|
|
|
+
|
|
|
+ case 0x11B:
|
|
|
+ ms.Position = ifd.ValueOffset + pos;
|
|
|
+ l1 = GetTifInt32(br, isBigEndian);
|
|
|
+ l2 = GetTifInt32(br, isBigEndian);
|
|
|
+ verticalResolution = l1 / l2;
|
|
|
+ break;
|
|
|
+
|
|
|
+ case 0x128:
|
|
|
+ resolutionUnit = ifd.ValueOffset;
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ if (resolutionUnit == 1)
|
|
|
+ {
|
|
|
+ horizontalResolution *= CmToInch;
|
|
|
+ verticalResolution *= CmToInch;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ return width != 0 && height != 0;
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool IsTif(BinaryReader br, out bool isBigEndian, bool resetPos = false)
|
|
|
+ {
|
|
|
+ try
|
|
|
+ {
|
|
|
+ if (resetPos)
|
|
|
+ {
|
|
|
+ br.BaseStream.Position = 0;
|
|
|
+ }
|
|
|
+ var b = br.ReadBytes(2);
|
|
|
+ isBigEndian = Encoding.ASCII.GetString(b) == "MM";
|
|
|
+ var identifier = GetTifInt16(br, isBigEndian);
|
|
|
+ if (identifier == 42)
|
|
|
+ {
|
|
|
+ return true;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ catch
|
|
|
+ {
|
|
|
+ isBigEndian = false;
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+
|
|
|
+ private static short GetTifInt16(BinaryReader br, bool isBigEndian)
|
|
|
+ {
|
|
|
+ if (isBigEndian)
|
|
|
+ {
|
|
|
+ return GetInt16BigEndian(br);
|
|
|
+ }
|
|
|
+ else
|
|
|
+ {
|
|
|
+ return br.ReadInt16();
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ private static int GetTifInt32(BinaryReader br, bool isBigEndian)
|
|
|
+ {
|
|
|
+ if (isBigEndian)
|
|
|
+ {
|
|
|
+ return GetInt32BigEndian(br);
|
|
|
+ }
|
|
|
+ else
|
|
|
+ {
|
|
|
+ return br.ReadInt32();
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ #endregion Tiff
|
|
|
+
|
|
|
+ #region Emf
|
|
|
+
|
|
|
+ private static bool IsEmf(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
|
|
|
+ {
|
|
|
+ using (var br = new BinaryReader(ms))
|
|
|
+ {
|
|
|
+ if (IsEmf(br))
|
|
|
+ {
|
|
|
+ var length = br.ReadInt32();
|
|
|
+ var bounds = new int[4];
|
|
|
+ bounds[0] = br.ReadInt32();
|
|
|
+ bounds[1] = br.ReadInt32();
|
|
|
+ bounds[2] = br.ReadInt32();
|
|
|
+ bounds[3] = br.ReadInt32();
|
|
|
+ var frame = new int[4];
|
|
|
+ frame[0] = br.ReadInt32();
|
|
|
+ frame[1] = br.ReadInt32();
|
|
|
+ frame[2] = br.ReadInt32();
|
|
|
+ frame[3] = br.ReadInt32();
|
|
|
+
|
|
|
+ var signatureBytes = br.ReadBytes(4);
|
|
|
+ var signature = Encoding.ASCII.GetString(signatureBytes);
|
|
|
+ if (signature.Trim() == "EMF")
|
|
|
+ {
|
|
|
+ var version = br.ReadUInt32();
|
|
|
+ var size = br.ReadUInt32();
|
|
|
+ var records = br.ReadUInt32();
|
|
|
+ var handles = br.ReadUInt16();
|
|
|
+ var reserved = br.ReadUInt16();
|
|
|
+
|
|
|
+ var nDescription = br.ReadUInt32();
|
|
|
+ var offDescription = br.ReadUInt32();
|
|
|
+ var nPalEntries = br.ReadUInt32();
|
|
|
+ var device = new uint[2];
|
|
|
+ device[0] = br.ReadUInt32();
|
|
|
+ device[1] = br.ReadUInt32();
|
|
|
+
|
|
|
+ var mm = new uint[2];
|
|
|
+ mm[0] = br.ReadUInt32();
|
|
|
+ mm[1] = br.ReadUInt32();
|
|
|
+
|
|
|
+ //Extension 1
|
|
|
+ var cbPixelFormat = br.ReadUInt32();
|
|
|
+ var offPixelFormat = br.ReadUInt32();
|
|
|
+ var bOpenGL = br.ReadUInt32();
|
|
|
+
|
|
|
+ //Extension 2
|
|
|
+ var hr = br.ReadUInt32();
|
|
|
+ var vr = br.ReadUInt32();
|
|
|
+
|
|
|
+ var id = br.ReadInt32();
|
|
|
+ var size2 = br.ReadInt32();
|
|
|
+
|
|
|
+ width = (bounds[2] - bounds[0] + 1);
|
|
|
+ height = (bounds[3] - bounds[1] + 1);
|
|
|
+
|
|
|
+ horizontalResolution = width / ((frame[2] - frame[0]) * HundredthThMmToInch * StandardDPI) * StandardDPI;
|
|
|
+ verticalResolution = height / ((frame[3] - frame[1]) * HundredthThMmToInch * StandardDPI) * StandardDPI;
|
|
|
+
|
|
|
+ return true;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ }
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool IsEmf(BinaryReader br)
|
|
|
+ {
|
|
|
+ br.BaseStream.Position = 0;
|
|
|
+ var type = br.ReadInt32();
|
|
|
+ return type == 1;
|
|
|
+ }
|
|
|
+
|
|
|
+ #endregion Emf
|
|
|
+
|
|
|
+ #region Wmf
|
|
|
+
|
|
|
+ private const double PIXELS_PER_TWIPS = 1D / 15D;
|
|
|
+ private const double DEFAULT_TWIPS = 1440D;
|
|
|
+
|
|
|
+ private static bool IsWmf(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
|
|
|
+ {
|
|
|
+ using (var br = new BinaryReader(ms))
|
|
|
+ {
|
|
|
+ if (IsWmf(br))
|
|
|
+ {
|
|
|
+ var HWmf = br.ReadInt16();
|
|
|
+ var bounds = new ushort[4];
|
|
|
+ bounds[0] = br.ReadUInt16();
|
|
|
+ bounds[1] = br.ReadUInt16();
|
|
|
+ bounds[2] = br.ReadUInt16();
|
|
|
+ bounds[3] = br.ReadUInt16();
|
|
|
+
|
|
|
+ var inch = br.ReadInt16();
|
|
|
+ width = bounds[2] - bounds[0];
|
|
|
+ height = bounds[3] - bounds[1];
|
|
|
+ if (inch != 0)
|
|
|
+ {
|
|
|
+ width *= (DEFAULT_TWIPS / inch) * PIXELS_PER_TWIPS;
|
|
|
+ height *= (DEFAULT_TWIPS / inch) * PIXELS_PER_TWIPS;
|
|
|
+ }
|
|
|
+ return width != 0 && height != 0;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool IsWmf(BinaryReader br)
|
|
|
+ {
|
|
|
+ br.BaseStream.Position = 0;
|
|
|
+ var key = br.ReadUInt32();
|
|
|
+ return key == 0x9AC6CDD7;
|
|
|
+ }
|
|
|
+
|
|
|
+ #endregion Wmf
|
|
|
+
|
|
|
+ #region Png
|
|
|
+
|
|
|
+ private static bool IsPng(MemoryStream ms, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution)
|
|
|
+ {
|
|
|
+ using (var br = new BinaryReader(ms))
|
|
|
+ {
|
|
|
+ return IsPng(br, ref width, ref height, ref horizontalResolution, ref verticalResolution);
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool IsPng(BinaryReader br, ref double width, ref double height, ref double horizontalResolution, ref double verticalResolution, long fileEndPosition = long.MinValue)
|
|
|
+ {
|
|
|
+ if (IsPng(br))
|
|
|
+ {
|
|
|
+ if (fileEndPosition == long.MinValue)
|
|
|
+ {
|
|
|
+ fileEndPosition = br.BaseStream.Length;
|
|
|
+ }
|
|
|
+ while (br.BaseStream.Position < fileEndPosition)
|
|
|
+ {
|
|
|
+ var chunkType = ReadPngChunkHeader(br, out int length);
|
|
|
+ switch (chunkType)
|
|
|
+ {
|
|
|
+ case "IHDR":
|
|
|
+ width = GetInt32BigEndian(br);
|
|
|
+ height = GetInt32BigEndian(br);
|
|
|
+ br.ReadBytes(5); //Ignored bytes, Depth compression etc.
|
|
|
+ break;
|
|
|
+
|
|
|
+ case "pHYs":
|
|
|
+ horizontalResolution = GetInt32BigEndian(br);
|
|
|
+ verticalResolution = GetInt32BigEndian(br);
|
|
|
+ var unitSpecifier = br.ReadByte();
|
|
|
+ if (unitSpecifier == 1)
|
|
|
+ {
|
|
|
+ horizontalResolution /= MToInch;
|
|
|
+ verticalResolution /= MToInch;
|
|
|
+ }
|
|
|
+
|
|
|
+ br.Close();
|
|
|
+ return true;
|
|
|
+
|
|
|
+ default:
|
|
|
+ br.ReadBytes(length);
|
|
|
+ break;
|
|
|
+ }
|
|
|
+ var crc = br.ReadInt32();
|
|
|
+ }
|
|
|
+ }
|
|
|
+ br.Close();
|
|
|
+ return width != 0 && height != 0;
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool IsPng(BinaryReader br)
|
|
|
+ {
|
|
|
+ br.BaseStream.Position = 0;
|
|
|
+ var signature = br.ReadBytes(8);
|
|
|
+ return signature.SequenceEqual(new byte[] { 137, 80, 78, 71, 13, 10, 26, 10 });
|
|
|
+ }
|
|
|
+
|
|
|
+ private static string ReadPngChunkHeader(BinaryReader br, out int length)
|
|
|
+ {
|
|
|
+ length = GetInt32BigEndian(br);
|
|
|
+ var b = br.ReadBytes(4);
|
|
|
+ var type = Encoding.ASCII.GetString(b);
|
|
|
+ return type;
|
|
|
+ }
|
|
|
+
|
|
|
+ #endregion Png
|
|
|
+
|
|
|
+ #region Svg
|
|
|
+
|
|
|
+ private static bool IsSvg(MemoryStream ms, ref double width, ref double height)
|
|
|
+ {
|
|
|
+ try
|
|
|
+ {
|
|
|
+ using (var reader = new XmlTextReader(ms))
|
|
|
+ {
|
|
|
+ while (reader.Read())
|
|
|
+ {
|
|
|
+ if (reader.LocalName == "svg" && reader.NodeType == XmlNodeType.Element)
|
|
|
+ {
|
|
|
+ var w = reader.GetAttribute("width");
|
|
|
+ var h = reader.GetAttribute("height");
|
|
|
+ var vb = reader.GetAttribute("viewBox");
|
|
|
+ reader.Close();
|
|
|
+ if (w == null || h == null)
|
|
|
+ {
|
|
|
+ if (vb == null)
|
|
|
+ {
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ var bounds = vb.Split(new char[] { ' ', ',' }, StringSplitOptions.RemoveEmptyEntries);
|
|
|
+ if (bounds.Length < 4)
|
|
|
+ {
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ if (string.IsNullOrEmpty(w))
|
|
|
+ {
|
|
|
+ w = bounds[2];
|
|
|
+ }
|
|
|
+ if (string.IsNullOrEmpty(h))
|
|
|
+ {
|
|
|
+ h = bounds[3];
|
|
|
+ }
|
|
|
+ }
|
|
|
+ width = GetSvgUnit(w);
|
|
|
+ if (double.IsNaN(width)) return false;
|
|
|
+ height = GetSvgUnit(h);
|
|
|
+ if (double.IsNaN(height)) return false;
|
|
|
+ return true;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ }
|
|
|
+ catch
|
|
|
+ {
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ private static bool IsSvg(Stream ms)
|
|
|
+ {
|
|
|
+ try
|
|
|
+ {
|
|
|
+ ms.Position = 0;
|
|
|
+ using var reader = new XmlTextReader(ms);
|
|
|
+ while (reader.Read())
|
|
|
+ {
|
|
|
+ if (reader.LocalName == "svg" && reader.NodeType == XmlNodeType.Element)
|
|
|
+ {
|
|
|
+ return true;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ catch
|
|
|
+ {
|
|
|
+ return false;
|
|
|
+ }
|
|
|
+ }
|
|
|
+
|
|
|
+ private static double GetSvgUnit(string v)
|
|
|
+ {
|
|
|
+ var factor = 1D;
|
|
|
+ if (v.EndsWith("px", StringComparison.OrdinalIgnoreCase))
|
|
|
+ {
|
|
|
+ v = v.Substring(0, v.Length - 2);
|
|
|
+ }
|
|
|
+ else if (v.EndsWith("pt", StringComparison.OrdinalIgnoreCase))
|
|
|
+ {
|
|
|
+ factor = 1.25;
|
|
|
+ v = v.Substring(0, v.Length - 2);
|
|
|
+ }
|
|
|
+ else if (v.EndsWith("pc", StringComparison.OrdinalIgnoreCase))
|
|
|
+ {
|
|
|
+ factor = 15;
|
|
|
+ v = v.Substring(0, v.Length - 2);
|
|
|
+ }
|
|
|
+ else if (v.EndsWith("mm", StringComparison.OrdinalIgnoreCase))
|
|
|
+ {
|
|
|
+ factor = 3.543307;
|
|
|
+ v = v.Substring(0, v.Length - 2);
|
|
|
+ }
|
|
|
+ else if (v.EndsWith("cm", StringComparison.OrdinalIgnoreCase))
|
|
|
+ {
|
|
|
+ factor = 35.43307;
|
|
|
+ v = v.Substring(0, v.Length - 2);
|
|
|
+ }
|
|
|
+ else if (v.EndsWith("in", StringComparison.OrdinalIgnoreCase))
|
|
|
+ {
|
|
|
+ factor = 90;
|
|
|
+ v = v.Substring(0, v.Length - 2);
|
|
|
+ }
|
|
|
+ if (double.TryParse(v, out double value))
|
|
|
+ {
|
|
|
+ return value * factor;
|
|
|
+ }
|
|
|
+ return double.NaN;
|
|
|
+ }
|
|
|
+
|
|
|
+ #endregion Svg
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+
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+ private static ushort GetUInt16BigEndian(BinaryReader br)
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+ {
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+ var b = br.ReadBytes(2);
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+ return BitConverter.ToUInt16(new byte[] { b[1], b[0] }, 0);
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|
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+ }
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+
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+ private static short GetInt16BigEndian(BinaryReader br)
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|
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+ {
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|
|
+ var b = br.ReadBytes(2);
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|
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+ return BitConverter.ToInt16(new byte[] { b[1], b[0] }, 0);
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|
|
+ }
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+
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+ private static int GetInt32BigEndian(BinaryReader br)
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|
|
+ {
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|
|
+ var b = br.ReadBytes(4);
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|
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+ return BitConverter.ToInt32(new byte[] { b[3], b[2], b[1], b[0] }, 0);
|
|
|
+ }
|
|
|
+}
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懒得勤快