示例#1
0
        private void WriteIFD(MemoryStream stream, Dictionary <ExifTag, ExifProperty> ifd, IFD ifdtype, long tiffoffset, bool preserveMakerNote)
        {
            BitConverterEx conv = new BitConverterEx(BitConverterEx.ByteOrder.System, ByteOrder);

            // Create a queue of fields to write
            Queue <ExifProperty> fieldqueue = new Queue <ExifProperty>();

            foreach (ExifProperty prop in ifd.Values)
            {
                if (prop.Tag != ExifTag.MakerNote)
                {
                    fieldqueue.Enqueue(prop);
                }
            }
            // Push the maker note data to the end
            if (ifd.ContainsKey(ExifTag.MakerNote))
            {
                fieldqueue.Enqueue(ifd[ExifTag.MakerNote]);
            }

            // Offset to start of field data from start of TIFF header
            uint dataoffset         = (uint)(2 + ifd.Count * 12 + 4 + stream.Position - tiffoffset);
            uint currentdataoffset  = dataoffset;
            long absolutedataoffset = stream.Position + (2 + ifd.Count * 12 + 4);

            bool makernotewritten = false;

            // Field count
            stream.Write(conv.GetBytes((ushort)ifd.Count), 0, 2);
            // Fields
            while (fieldqueue.Count != 0)
            {
                ExifProperty         field   = fieldqueue.Dequeue();
                ExifInterOperability interop = field.Interoperability;

                uint fillerbytecount = 0;

                // Try to preserve the makernote data offset
                if (!makernotewritten &&
                    !makerNoteProcessed &&
                    makerNoteOffset != 0 &&
                    ifdtype == IFD.EXIF &&
                    field.Tag != ExifTag.MakerNote &&
                    interop.Data.Length > 4 &&
                    currentdataoffset + interop.Data.Length > makerNoteOffset &&
                    ifd.ContainsKey(ExifTag.MakerNote))
                {
                    // Delay writing this field until we write makernote data
                    fieldqueue.Enqueue(field);
                    continue;
                }
                else if (field.Tag == ExifTag.MakerNote)
                {
                    makernotewritten = true;
                    // We may need to write filler bytes to preserve maker note offset
                    if (preserveMakerNote && !makerNoteProcessed)
                    {
                        fillerbytecount = makerNoteOffset - currentdataoffset;
                    }
                    else
                    {
                        fillerbytecount = 0;
                    }
                }

                // Tag
                stream.Write(conv.GetBytes(interop.TagID), 0, 2);
                // Type
                stream.Write(conv.GetBytes(interop.TypeID), 0, 2);
                // Count
                stream.Write(conv.GetBytes(interop.Count), 0, 4);
                // Field data
                byte[] data = interop.Data;
                if (ByteOrder != BitConverterEx.SystemByteOrder)
                {
                    if (interop.TypeID == 1 || interop.TypeID == 3 || interop.TypeID == 4 || interop.TypeID == 9)
                    {
                        Array.Reverse(data);
                    }
                    else if (interop.TypeID == 5 || interop.TypeID == 10)
                    {
                        Array.Reverse(data, 0, 4);
                        Array.Reverse(data, 4, 4);
                    }
                }

                // Fields containing offsets to other IFDs
                // Just store their offets, we will write the values later on when we know the lengths of IFDs
                if (ifdtype == IFD.Zeroth && interop.TagID == 0x8769)
                {
                    exifIFDFieldOffset = stream.Position;
                }
                else if (ifdtype == IFD.Zeroth && interop.TagID == 0x8825)
                {
                    gpsIFDFieldOffset = stream.Position;
                }
                else if (ifdtype == IFD.EXIF && interop.TagID == 0xa005)
                {
                    interopIFDFieldOffset = stream.Position;
                }
                else if (ifdtype == IFD.First && interop.TagID == 0x201)
                {
                    thumbOffsetLocation = stream.Position;
                }
                else if (ifdtype == IFD.First && interop.TagID == 0x202)
                {
                    thumbSizeLocation = stream.Position;
                }

                // Write 4 byte field value or field data
                if (data.Length <= 4)
                {
                    stream.Write(data, 0, data.Length);
                    for (int i = data.Length; i < 4; i++)
                    {
                        stream.WriteByte(0);
                    }
                }
                else
                {
                    // Pointer to data area relative to TIFF header
                    stream.Write(conv.GetBytes(currentdataoffset + fillerbytecount), 0, 4);
                    // Actual data
                    long currentoffset = stream.Position;
                    stream.Seek(absolutedataoffset, SeekOrigin.Begin);
                    // Write filler bytes
                    for (int i = 0; i < fillerbytecount; i++)
                    {
                        stream.WriteByte(0xFF);
                    }
                    stream.Write(data, 0, data.Length);
                    stream.Seek(currentoffset, SeekOrigin.Begin);
                    // Increment pointers
                    currentdataoffset  += fillerbytecount + (uint)data.Length;
                    absolutedataoffset += fillerbytecount + data.Length;
                }
            }
            // Offset to 1st IFD
            // We will write zeros for now. This will be filled after we write all IFDs
            if (ifdtype == IFD.Zeroth)
            {
                firstIFDFieldOffset = stream.Position;
            }
            stream.Write(new byte[] { 0, 0, 0, 0 }, 0, 4);

            // Seek to end of IFD
            stream.Seek(absolutedataoffset, SeekOrigin.Begin);

            // Write thumbnail data
            if (ifdtype == IFD.First)
            {
                if (Thumbnail != null)
                {
                    MemoryStream ts = new MemoryStream();
                    Thumbnail.Save(ts);
                    ts.Close();
                    byte[] thumb = ts.ToArray();
                    thumbOffsetValue = (uint)(stream.Position - tiffoffset);
                    thumbSizeValue   = (uint)thumb.Length;
                    stream.Write(thumb, 0, thumb.Length);
                    ts.Dispose();
                }
                else
                {
                    thumbOffsetValue = 0;
                    thumbSizeValue   = 0;
                }
            }
        }
示例#2
0
        /// <summary>
        /// Returns a System.Drawing.Bitmap created with image data.
        /// </summary>
        //public Bitmap ToBitmap()
        //{
        //    return file.ToBitmap();
        //}
        #endregion

        #region "Private Helper Methods"
        /// <summary>
        /// Reads the APP1 section containing Exif metadata.
        /// </summary>
        private void ReadAPP1()
        {
            // Find the APP1 section containing Exif metadata
            app1 = file.Sections.Find(a => (a.Marker == JPEGMarker.APP1) &&
                                      (Encoding.ASCII.GetString(a.Header, 0, 6) == "Exif\0\0"));

            // If there is no APP1 section, add a new one after the last APP0 section (if any).
            if (app1 == null)
            {
                int insertionIndex = file.Sections.FindLastIndex(a => a.Marker == JPEGMarker.APP0);
                if (insertionIndex == -1)
                {
                    insertionIndex = 0;
                }
                insertionIndex++;
                ByteOrder = BitConverterEx.ByteOrder.BigEndian;
                app1      = new JPEGSection(JPEGMarker.APP1);
                file.Sections.Insert(insertionIndex, app1);
                return;
            }
#if DEBUG__
            mMap = new MemoryBinStream();
            mMap.Seek(0, SeekOrigin.Begin);
            mMap.Write(new Bin("Exif Marker", 3, 6));
#endif

            byte[] header = app1.Header;
            SortedList <int, IFD> ifdqueue = new SortedList <int, IFD>();
            makerNoteOffset = 0;

            // TIFF header
            int tiffoffset = 6;
            if (header[tiffoffset] == 0x49)
            {
                ByteOrder = BitConverterEx.ByteOrder.LittleEndian;
            }
            else
            {
                ByteOrder = BitConverterEx.ByteOrder.BigEndian;
            }
            BitConverterEx conv = new BitConverterEx(ByteOrder, BitConverterEx.ByteOrder.System);

            // Offset to 0th IFD
            int ifd0offset = (int)conv.ToUInt32(header, tiffoffset + 4);
            ifdqueue.Add(ifd0offset, IFD.Zeroth);

            int thumboffset = -1;
            int thumblength = 0;
            int thumbtype   = -1;
#if DEBUG__
            mMap.Write(new Bin("Byte Order: " + ByteOrder.ToString(), 4, 2));
            mMap.Write(new Bin("TIFF ID: 0x00, 0x2A", 4, 2));
            mMap.Write(new Bin("Offset to 0th IFD: " + ifd0offset.ToString(), 4, 4));
#endif
            // Read IFDs
            while (ifdqueue.Count != 0)
            {
                int ifdoffset  = tiffoffset + ifdqueue.Keys[0];
                IFD currentifd = ifdqueue.Values[0];
                ifdqueue.RemoveAt(0);

                // Field count
                ushort fieldcount = conv.ToUInt16(header, ifdoffset);
#if DEBUG__
                mMap.Seek(ifdoffset, SeekOrigin.Begin);
                mMap.Write(new Bin(currentifd.ToString() + " IFD Field Count: " + fieldcount.ToString(), 5, 2));
#endif
                for (short i = 0; i < fieldcount; i++)
                {
                    // Read field info
                    int    fieldoffset = ifdoffset + 2 + 12 * i;
                    ushort tag         = conv.ToUInt16(header, fieldoffset);
                    ushort type        = conv.ToUInt16(header, fieldoffset + 2);
                    uint   count       = conv.ToUInt32(header, fieldoffset + 4);
                    byte[] value       = new byte[4];
                    Array.Copy(header, fieldoffset + 8, value, 0, 4);

                    // Fields containing offsets to other IFDs
                    if (currentifd == IFD.Zeroth && tag == 0x8769)
                    {
                        int exififdpointer = (int)conv.ToUInt32(value, 0);
                        ifdqueue.Add(exififdpointer, IFD.EXIF);
                    }
                    else if (currentifd == IFD.Zeroth && tag == 0x8825)
                    {
                        int gpsifdpointer = (int)conv.ToUInt32(value, 0);
                        ifdqueue.Add(gpsifdpointer, IFD.GPS);
                    }
                    else if (currentifd == IFD.EXIF && tag == 0xa005)
                    {
                        int interopifdpointer = (int)conv.ToUInt32(value, 0);
                        ifdqueue.Add(interopifdpointer, IFD.Interop);
                    }

                    // Save the offset to maker note data
                    if (currentifd == IFD.EXIF && tag == 37500)
                    {
                        makerNoteOffset = conv.ToUInt32(value, 0);
                    }

                    // Calculate the bytes we need to read
                    uint baselength = 0;
                    if (type == 1 || type == 2 || type == 7)
                    {
                        baselength = 1;
                    }
                    else if (type == 3)
                    {
                        baselength = 2;
                    }
                    else if (type == 4 || type == 9)
                    {
                        baselength = 4;
                    }
                    else if (type == 5 || type == 10)
                    {
                        baselength = 8;
                    }
                    uint totallength = count * baselength;

                    // If field value does not fit in 4 bytes
                    // the value field is an offset to the actual
                    // field value
                    int fieldposition = 0;
                    if (totallength > 4)
                    {
                        fieldposition = tiffoffset + (int)conv.ToUInt32(value, 0);
                        value         = new byte[totallength];
                        Array.Copy(header, fieldposition, value, 0, totallength);
                    }

                    // Compressed thumbnail data
                    if (currentifd == IFD.First && tag == 0x201)
                    {
                        thumbtype   = 0;
                        thumboffset = (int)conv.ToUInt32(value, 0);
                    }
                    else if (currentifd == IFD.First && tag == 0x202)
                    {
                        thumblength = (int)conv.ToUInt32(value, 0);
                    }

                    // Uncompressed thumbnail data
                    if (currentifd == IFD.First && tag == 0x111)
                    {
                        thumbtype = 1;
                        // Offset to first strip
                        if (type == 3)
                        {
                            thumboffset = (int)conv.ToUInt16(value, 0);
                        }
                        else
                        {
                            thumboffset = (int)conv.ToUInt32(value, 0);
                        }
                    }
                    else if (currentifd == IFD.First && tag == 0x117)
                    {
                        thumblength = 0;
                        for (int j = 0; j < count; j++)
                        {
                            if (type == 3)
                            {
                                thumblength += (int)conv.ToUInt16(value, 0);
                            }
                            else
                            {
                                thumblength += (int)conv.ToUInt32(value, 0);
                            }
                        }
                    }

                    // Create the exif property from the interop data
                    ExifProperty prop = ExifPropertyFactory.Get(tag, type, count, value, ByteOrder, currentifd);
                    if (!Properties.ContainsKey(prop.Tag))
                    {
                        Properties.Add(prop.Tag, prop);

#if DEBUG__
                        mMap.Seek(fieldoffset, SeekOrigin.Begin);
                        mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " ID: " + tag.ToString(), 6, 2, prop));
                        mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Type: " + type.ToString(), 6, 2, prop));
                        mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Count: " + count.ToString(), 6, 4, prop));
                        mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Value: " + string.Format("[0x{0:x2}, 0x{1:x2}, 0x{2:x2}, 0x{3:x2}]", value[0], value[1], value[2], value[3]), 6, 4, prop));
                        if (totallength > 4)
                        {
                            mMap.Seek(fieldposition, SeekOrigin.Begin);
                            mMap.Write(new Bin(ExifTagFactory.GetTagName(currentifd, tag) + " Data", 7, totallength, prop));
                        }
#endif
                    }
                    else
                    {
                        Properties[prop.Tag] = prop;
                    }
                }

                // 1st IFD pointer
                int firstifdpointer = (int)conv.ToUInt32(header, ifdoffset + 2 + 12 * fieldcount);
                if (firstifdpointer != 0)
                {
                    ifdqueue.Add(firstifdpointer, IFD.First);
                }
#if DEBUG__
                mMap.Seek(ifdoffset + 2 + 12 * fieldcount, SeekOrigin.Begin);
                mMap.Write(new Bin("1st IFD Pointer: " + firstifdpointer.ToString(), 5, 4));
#endif
                // Read thumbnail
                if (thumboffset != -1 && thumblength != 0 && Thumbnail == null)
                {
                    if (thumbtype == 0)
                    {
                        using (MemoryStream ts = new MemoryStream(header, tiffoffset + thumboffset, thumblength))
                        {
                            Thumbnail = new JPEGFile(ts);
                        }
                    }
#if DEBUG__
                    mMap.Seek(tiffoffset + thumboffset, SeekOrigin.Begin);
                    mMap.Write(new Bin("Thumbnail", 8, thumblength));
#endif
                }
            }
        }