BeaverBlog

A lot of people saw the cool drag ‘n drop features on the Google Wave demonstration a few weeks ago and started wondering how to create that stuff yourselves. Being in the middle of my work on Imager Gallery.Net I was really excited about it and started looking at it. There are a few samples out there but some doesn’t work and one was even obfuscated. I’ve assembled the following sample which just takes the dropped file and shows a thumbnail (if an image, a generic icon else) of it. Later on it will be extended to upload files aswell and if successful also rewritten as a jQuery plugin. The current sample works with IE and Firefox with Google Gears 0.5.32 installed.

http://blog.crazybeavers.se/wp-content/demos/Google.Gears/drop.html

This is mostly a small note to myself. I keep having problems with the input language changing when working with an application run via Citrix, seems like the guys (or gals for that matter) over at IT-services didn’t uninstall the default languages (I’m Swedish and sincerely miss some of the Swedish letters when writing) so I keep hitting this hotkey-combination that I can’t ever remember. Next time I’ll just look here.

To change language (when you can’t or don’t want to use the Language Bar) you press the following:

Left ALT + SHIFT

I’m still putting quite a lot of work into Imager Gallery.Net. I have a alpha up an running at www.kallesbildarkiv.se though it still lacks quite a lot of features.

Keeping my earlier commitment to release interesting code created for the project I can now present you with my next piece of code. I’ve had problems with finding a good class to read EXIF-information from images that isn’t written in VB.Net, really poorly written or licensed under GPL so I decided I had to write my own. After looking into the subject I found that it would be quite easy to implement this as extension methods on the regular Image class. I’ve decided to release the code under the Creative Commons Attribution-Share Alike license to allow people to use it anywhere as long as they can admit that they are using it.

/*
 * Creative Commons Attribution-Share Alike 3.0 Unported
 * You are free:
 *   to Share — to copy, distribute and transmit the work
 *   to Remix — to adapt the work
 *
 * Under the following conditions:
 *   Attribution — You must attribute the work in the manner
 *   specified by the author or licensor (but not in any way
 *   that suggests that they endorse you or your use of the work).
 *
 *   Share Alike — If you alter, transform, or build upon this work,
 *   you may distribute the resulting work only under the same, similar
 *   or a compatible license.
 *
 * For more information, see http://creativecommons.org/licenses/by-sa/3.0/
 */
using System;
using System.Collections.Generic;
using System.Drawing.Imaging;
using System.Text;
using System.Drawing;

/*
 * This class is completely based on the documentation
 * of the EXIF format found here: http://www.exif.org/Exif2-2.PDF
 */

namespace CrazyBeavers.Extensions
{
    public static partial class ImageExtensions
    {
        #region Enumerations
        #pragma warning disable 1591

        private enum PropertyType
        {
            ByteArray = 1,
            AsciiString = 2,
            UnsignedShort = 3,
            UnsignedLong = 4,
            UnsignedLongPair = 5,
            Any = 6,
            SignedLongArray = 7,
            UnsignedLongPairArray = 10
        }

        public enum PropertyTag
        {
            ImageWidth = 0x100,
            ImageLength = 0x101,
            NBitsPerSample = 0x102,
            Compression = 0x103,
            PhotometricInterpretation = 0x106,
            Orientation = 0x112,
            SamplesPerPixel = 0x115,
            PlanarConfiguration = 0x11C,
            YCbCrSubSampling = 0x212,
            YCbCrPositioning = 0x213,
            XResolution = 0x11A,
            YResolution = 0x11B,
            ResolutionUnit = 0x128,
            StripOffsets = 0x111,
            RowsPerStrip = 0x116,
            StripByteCounts = 0x117,
            JPEGInterchangeFormat = 0x201,
            JPEGInterchangeFormatLength = 0x202,
            TransferFunction = 0x12D,
            WhitePoint = 0x13E,
            PrimaryChromaticities = 0x13F,
            YCbCrCoefficients = 0x211,
            ReferenceBlackWhite = 0x214,
            DateTime = 0x132,
            ImageDescription = 0x10E,
            Make = 0x10F,
            Model = 0x110,
            Software = 0x131,
            Artist = 0x13B,
            Copyright = 0x8298,
            ExifVersion = 0x9000,
            FlashpixVersion = 0xA000,
            ColorSpace = 0xA001,
            ComponentsConfiguration = 0x9101,
            CompressedBitsPerPixel = 0x9102,
            PixelXDimension = 0xA002,
            PixelYDimension = 0xA003,
            MakerNote = 0x927C,
            UserComment = 0x9286,
            RelatedSoundFile = 0xA004,
            DateTimeOriginal = 0x9003,
            DateTimeDigitized = 0x9004,
            SubSecTime = 0x9290,
            SubSecTimeOriginal = 0x9291,
            SubSecTimeDigitized = 0x9292,
            ImageUniqueID = 0xA420,
            ExposureTime = 0x829A,
            FNumber = 0x829D,
            ExposureProgram = 0x8822,
            SpectralSensitivity = 0x8824,
            ISOSpeedRatings = 0x8827,
            OECF = 0x8828,
            ShutterSpeedValue = 0x9201,
            ApertureValue = 0x9202,
            BrightnessValue = 0x9203,
            ExposureBiasValue = 0x9204,
            MaxApertureValue = 0x9205,
            SubjectDistance = 0x9206,
            MeteringMode = 0x9207,
            LightSource = 0x9208,
            Flash = 0x9209,
            FocalLength = 0x920A,
            SubjectArea = 0x9214,
            FlashEnergy = 0xA20B,
            SpatialFrequencyResponse = 0xA20C,
            FocalPlaneXResolution = 0xA20E,
            FocalPlaneYResolution = 0xA20F,
            FocalPlaneResolutionUnit = 0xA210,
            SubjectLocation = 0xA214,
            ExposureIndex = 0xA215,
            SensingMethod = 0xA217,
            FileSource = 0xA300,
            SceneType = 0xA301,
            CFAPattern = 0xA302,
            CustomRendered = 0xA401,
            ExposureMode = 0xA402,
            WhiteBalance = 0xA403,
            DigitalZoomRatio = 0xA404,
            FocalLengthIn35mmFilm = 0xA405,
            SceneCaptureType = 0xA406,
            GainControl = 0xA407,
            Contrast = 0xA408,
            Saturation = 0xA409,
            Sharpness = 0xA40A,
            DeviceSettingDescription = 0xA40B,
            SubjectDistanceRange = 0xA40C
        }

        public enum Compression
        {
            NotSpecified = 0,
            Uncompressed = 1,
            JpegCompression = 6
        }

        public enum PhotometricInterpretation
        {
            RGB = 2,
            YCbCr = 6
        }

        public enum Orientation
        {
            TopLeft = 1,
            TopRight = 2,
            BottomRight = 3,
            BottomLeft = 4,
            LeftTop = 5,
            RightTop = 6,
            RightBottom = 7,
            LeftBottom = 8
        }

        public enum ExposureMode
        {
            AutoExposure = 0,
            ManualExposure = 1,
            AutoBracket = 2
        }

        public enum ExposureProgram
        {
            Undefined = 0,
            Manual = 1,
            Normal = 2,
            AperturePriority = 3,
            ShutterPriority = 4,
            CreativeProgram = 5,
            ActionProgram = 6,
            PortraitMode = 7,
            LandscapeMode = 8
        }

        public enum MeteringMode
        {
            Unknown = 0,
            Average = 1,
            CenterWeightedAverage = 2,
            Spot = 3,
            MultiSpot = 4,
            Pattern = 5,
            Partial = 6,
            Other = 255
        }

        public enum Flash
        {
            FlashDidNotFire = 0x0000,
            FlashFired = 0x0001,
            StrobeReturnNotDetected = 0x0005,
            StrobeReturnDetected = 0x0007,
            FlashFiredCompulsoryMode = 0x0009,
            FlashFiredCompulsoryModeStrobeReturnNotDetected = 0x000D,
            FlashFiredCompulsoryModeStrobeReturnDetected = 0x000F,
            FlashDidNotFireCompulsoryMode = 0x0010,
            FlashDidNotFireAutoMode = 0x0018,
            FlashFiredAutoMode = 0x00019,
            FlashFiredAutoModeStrobeReturnNotDetected = 0x001D,
            FlashFiredAutoModeStrobeReturnDetected = 0x001F,
            NoFlash = 0x0020,
            FlashFiredRedEyeReduction = 0x0041,
            FlashFiredRedEyeReductionStrobeReturnNotDetected = 0x0045,
            FlashFiredRedEyeReductionStrobeReturnDetected = 0x0047,
            FlashFiredCompulsoryModeRedEyeReduction = 0x0049,
            FlashFiredCompulsoryModeRedEyeReductionStrobeReturnNotDetected = 0x004D,
            FlashFiredCompulsoryModeRedEyeReductionStrobeReturnDetected = 0x004F,
            FlashFiredAutoModeRedEyeReduction = 0x0059,
            FlashFiredAutoModeRedEyeReductionStrobeReturnNotDetected = 0x005D,
            FlashFiredAutoModeRedEyeReductionStrobeReturnDetected = 0x005F
        }

        public enum WhiteBalance
        {
            Auto = 0,
            Manual = 1
        }

        public enum SceneCaptureType
        {
            Standard = 0,
            Landscape = 1,
            Portrait = 2,
            NightScene = 3
        }

        public enum LightSource
        {
            Unkown = 0,
            Daylight = 1,
            Fluorescent = 2,
            Tungsten = 3,
            Flash = 4,
            FineWeather = 9,
            CloudyWeather = 10,
            Shade = 11,
            DaylightFluorescent = 12,
            DayWhiteFluorescent = 13,
            CoolWhiteFluorescent = 14,
            WhiteFluorescent = 15,
            StandardLightA = 17,
            StandardLightB = 18,
            StandardLightC = 19,
            D55 = 20,
            D65 = 21,
            D75 = 22,
            D50 = 23,
            ISOStudioTungsten = 24,
            OtherLightSource = 255
        }

        public enum GainControl
        {
            None = 0,
            LowGainUp = 1,
            HighGainUp = 2,
            LowGainDown = 3,
            HighGainDown = 4
        }

        public enum Contrast
        {
            Normal = 0,
            Soft = 1,
            Hard = 2
        }

        public enum Saturation
        {
            Normal = 0,
            LowSaturation = 1,
            HighSaturation = 2
        }

        public enum Sharpness
        {
            Normal = 0,
            Soft = 1,
            Hard = 2
        }

        public enum SubjectDistanceRange
        {
            Unknown = 0,
            Macro = 1,
            CloseView = 2,
            DistantView = 3
        }

        #pragma warning restore 1591
        #endregion

        #region Properties

        public static DateTime ExifDateTime(this Image image)
        {
            return GetPropertyDateTime(image, PropertyTag.DateTime);
        }

        public static DateTime ExifDateTimeDigitized(this Image image)
        {
            return GetPropertyDateTime(image, PropertyTag.DateTimeDigitized);
        }

        public static DateTime ExifDateTimeOriginal(this Image image)
        {
            return GetPropertyDateTime(image, PropertyTag.DateTimeOriginal);
        }

        public static string ExifMake(this Image image)
        {
            return GetPropertyString(image, PropertyTag.Make);
        }

        public static string ExifModel(this Image image)
        {
            return GetPropertyString(image, PropertyTag.Model);
        }

        public static string ExifImageDescription(this Image image)
        {
            return GetPropertyString(image, PropertyTag.ImageDescription);
        }

        public static string ExifSoftware(this Image image)
        {
            return GetPropertyString(image, PropertyTag.Software);
        }

        public static string ExifArtist(this Image image)
        {
            return GetPropertyString(image, PropertyTag.Artist);
        }

        public static Orientation ExifOrientation(this Image image)
        {
            return (Orientation)GetPropertyUInt16(image, PropertyTag.Orientation);
        }

        public static Flash ExifFlash(this Image image)
        {
            return (Flash)GetPropertyUInt16(image, PropertyTag.Flash);
        }

        public static SceneCaptureType ExifSceneCaptureType(this Image image)
        {
            return (SceneCaptureType)GetPropertyUInt16(image, PropertyTag.SceneCaptureType);
        }

        public static WhiteBalance ExifWhiteBalance(this Image image)
        {
            return (WhiteBalance)GetPropertyUInt16(image, PropertyTag.WhiteBalance);
        }

        public static MeteringMode ExifMeteringMode(this Image image)
        {
            return (MeteringMode)GetPropertyUInt16(image, PropertyTag.MeteringMode);
        }

        public static Compression ExifCompression(this Image image)
        {
            return (Compression)GetPropertyUInt16(image, PropertyTag.Compression);
        }

        public static ExposureMode ExifExposureMode(this Image image)
        {
            return (ExposureMode)GetPropertyUInt16(image, PropertyTag.ExposureMode);
        }

        public static ExposureProgram ExifExposureProgram(this Image image)
        {
            return (ExposureProgram)GetPropertyUInt16(image, PropertyTag.ExposureProgram);
        }

        public static PhotometricInterpretation ExifPhotometricInterpretation(this Image image)
        {
            return (PhotometricInterpretation)GetPropertyUInt16(image, PropertyTag.PhotometricInterpretation);
        }

        public static LightSource ExifLightSource(this Image image)
        {
            return (LightSource)GetPropertyUInt16(image, PropertyTag.LightSource);
        }

        public static GainControl ExifGainControl(this Image image)
        {
            return (GainControl)GetPropertyUInt16(image, PropertyTag.GainControl);
        }

        public static Contrast ExifLightContrast(this Image image)
        {
            return (Contrast)GetPropertyUInt16(image, PropertyTag.Contrast);
        }

        public static Saturation ExifSaturation(this Image image)
        {
            return (Saturation)GetPropertyUInt16(image, PropertyTag.Saturation);
        }

        public static Sharpness ExifSharpness(this Image image)
        {
            return (Sharpness)GetPropertyUInt16(image, PropertyTag.Sharpness);
        }

        public static SubjectDistanceRange ExifSubjectDistanceRange(this Image image)
        {
            return (SubjectDistanceRange)GetPropertyUInt16(image, PropertyTag.SubjectDistanceRange);
        }

        public static Rational ExifExposureTime(this Image image)
        {
            return GetPropertyRational(image, PropertyTag.ExposureTime);
        }

        public static double ExifFNumber(this Image image)
        {
            return GetPropertyRational(image, PropertyTag.FNumber).ToDouble();
        }

        public static double ExifAperture(this Image image)
        {
            return GetPropertyRational(image, PropertyTag.ApertureValue).ToDouble();
        }

        public static Rational ExifSubjectDistance(this Image image)
        {
            return GetPropertyRational(image, PropertyTag.SubjectDistance);
        }

        public static double ExifFocalLength(this Image image)
        {
            return GetPropertyRational(image, PropertyTag.FocalLength).ToDouble();
        }

        public static UInt16 ExifISOSpeedRating(this Image image)
        {
            return GetPropertyUInt16(image, PropertyTag.ISOSpeedRatings);
        }

        public static Rational ExifDigitalZoomRatio(this Image image)
        {
            return GetPropertyRational(image, PropertyTag.DigitalZoomRatio);
        }

        #endregion

        public static bool HasProperty(this Image image, PropertyTag property)
        {
            return Array.IndexOf(image.PropertyIdList, (Int32)property) > -1;
        }

        public static DateTime GetPropertyDateTime(this Image image, PropertyTag property)
        {
            if (!image.HasProperty(property))
                return DateTime.MinValue;

            string value = GetPropertyString(image, property);

            // If first char is blank or string is empty no DateTime is present
            if (value == string.Empty || value[0] == ' ')
                return DateTime.MinValue;

            // DateTime is written as YYYY:MM:DD HH:MM:SS
            // and needs to be converted to YYYY-MM-DD HH:MM:SS
            // to be convertable to a .Net DateTime
            string datePart = value.Substring(0, 10).Replace(':', '-');
            string timePart = value.Substring(11);
            return Convert.ToDateTime(datePart + ' ' + timePart);
        }

        public static string GetPropertyString(this Image image, PropertyTag property)
        {
            if (!image.HasProperty(property))
                return string.Empty;

            PropertyItem item = image.GetPropertyItem((Int32)property);
            if (item.Type != (short)PropertyType.AsciiString)
                return string.Empty;

            byte[] buffer = item.Value;
            return Encoding.ASCII.GetString(buffer).Trim('\0');
        }

        public static UInt32 GetPropertyUInt32(this Image image, PropertyTag property)
        {
            if (!image.HasProperty(property))
                return 0;

            PropertyItem item = image.GetPropertyItem((Int32)property);
            if (item.Type != (short)PropertyType.UnsignedLong)
                return 0;

            byte[] buffer = item.Value;
            return BitConverter.ToUInt32(buffer, 0);
        }

        public static UInt16 GetPropertyUInt16(this Image image, PropertyTag property)
        {
            if (!image.HasProperty(property))
                return 0;

            PropertyItem item = image.GetPropertyItem((Int32)property);
            if (item.Type != (short)PropertyType.UnsignedShort)
                return 0;

            byte[] buffer = item.Value;
            return BitConverter.ToUInt16(buffer, 0);
        }

        public static Rational GetPropertyRational(this Image image, PropertyTag property)
        {
            if (!image.HasProperty(property))
                return Rational.Zero;

            PropertyItem item = image.GetPropertyItem((Int32)property);
            if (item.Type != (short)PropertyType.UnsignedLongPair)
                return Rational.Zero;

            byte[] buffer = item.Value;
            Int32 numerator = BitConverter.ToInt32(buffer, 0);
            Int32 denominator = BitConverter.ToInt32(buffer, 4);

            Rational rational = new Rational(numerator, denominator);
            return rational;
        }
    }

    public struct Rational
    {
        private Int32 _numerator;
        public Int32 Numerator
        {
            get
            {
                return _numerator;
            }
            set
            {
                _numerator = value;
            }
        }

        private Int32 _denominator;
        public Int32 Denominator
        {
            get
            {
                return _denominator;
            }
            set
            {
                if (value == 0)
                    throw new ArgumentOutOfRangeException("Denominator", 0, "Denominator can't be zero.");

                _denominator = value;
            }
        }

        public static Rational Zero
        {
            get
            {
                return new Rational(0, 1);
            }
        }

        public Rational(Int32 numerator, Int32 denominator)
        {
            _numerator = 0;
            _denominator = 1;
            Numerator = numerator;
            Denominator = denominator;
        }

        public override string ToString()
        {
            return string.Format("{0}/{1}", Numerator, Denominator);
        }

        public double ToDouble()
        {
            return (double)Numerator / Denominator;
        }
    }
}

This introduces several new methods to the Image class starting with “Exif” such as ExifDateTime, ExifMake and ExifExposureTime. The Rational class was inserted into the same code block in this sample, in the main project it has it’s own file under CrazyBeavers.Math. Hope you enjoy this piece of code!

Just updated jQuery Tag Editor to version 1.3. Added another demo as well.

Something I really like with WordPress is the really nice tag editor. It works so smooth and looks way better then just having a textbox with comma-separated list of tags so for ImagerGallery.Net I decided to write one of my own. I’ve put up a demo of it for now for those interested, it’s available at the following url:

http://blog.crazybeavers.se/wp-content/demos/jquery.tag.editor/

I’m currently doing quite a lot of work on my ny MVC-version of Imager Gallery. I still have a lot to do before I have anything to release (or even use myself) though but I thought I could release a few snippets that I’ve found useful.

First out is a HttpHandler that will process .css-files and remove any unused whitespace from the file before sending it to the client. I’ve been meaning to write this for a long time but never really had the time until someone posted a link about it over at ASPSidan.se showing their own implementation. Reading up on his post about it I found that it was based on a solution by Sam Collett. Both implementations lacked a few things that I wanted to have so I sat down with Sams code and started improving it, mainly making it a work as a handler for .css-files instead of a Generic Handler wanting a querystring but also adding caching and compiling the regular expression as a static member.

To use this, just pop it in a .cs-file in your your App_Code folder and add it to your web.config (as described in the comments for the class). You also need to configure your IIS to route .css-files through the asp.net process to make it run (not needed under IIS7 or IIS6 configured for MVC). Hope you find it useful!

using System;
using System.IO;
using System.Text.RegularExpressions;
using System.Web;
using System.Web.Caching;

namespace HttpHandlers
{
    /// <summary>
    /// Handler for compacting css-files on the fly
    /// Based on solution by Sam Collett found at
    /// http://webdevel.blogspot.com/2007/09/csscompact-webhandler-for-shrinking-css.html
    ///
    /// Needs to be added to web.config under System.Web/httpHandlers like this
    /// <add verb="GET,HEAD" path="*.css" type="HttpHandlers.CssCompactHandler"/>
    ///
    /// For debuing purposes you can append a querystring whenbrowsing to your .css-file
    /// to skip the compacting. It would look like this:
    /// http://mySite/Content/Site.css?noCompact=1
    /// </summary>
    public class CssCompactHandler : IHttpHandler
    {
        // Staticly compiled regex to avoid compiling it each request
        private static Regex RegexRemoval = new Regex(@"^\s+|/\*([^*\\\\]|\*(?!/))+\*/|\r|\n|\t", RegexOptions.Multiline | RegexOptions.Compiled);

        public void ProcessRequest(HttpContext context)
        {
            HttpResponse Response = context.Response;
            HttpRequest Request = context.Request;
            Cache Cache = context.Cache;

            FileInfo fileInfo = new FileInfo(Request.PhysicalPath);
            if (!fileInfo.Exists)
            {
                Response.StatusDescription = "The server has not found anything that matches the requested URI.";
                Response.StatusCode = 404;
                Response.End();
            }

            Response.ContentType = "text/css";
            Response.Cache.SetLastModified(fileInfo.LastWriteTime);

            // If we are in debugmode (set in web.config) then
            // we dont want to cache the css since we are probably
            // still in development
            if (context.IsDebuggingEnabled)
            {
                Response.Cache.SetCacheability(HttpCacheability.NoCache);
            }
            else
            {
                Response.Cache.SetCacheability(HttpCacheability.Public);
                Response.Cache.SetExpires(DateTime.Now.AddDays(1));
            }

            // HEAD requests only need the headers so we skip the
            // content here
            if (Request.HttpMethod != "HEAD")
            {
                string cacheName = string.Format("CssCompactHandlerCache_{0}", fileInfo.FullName);
                string cacheValue = Cache[cacheName] as string;
                if (cacheValue != null && Request.QueryString["noCompact"] == null)
                {
                    Response.Write(cacheValue);
                    Response.End();
                }

                using (StreamReader cssStream = fileInfo.OpenText())
                {
                    string cssContent = cssStream.ReadToEnd();
                    if (Request.QueryString["noCompact"] == null)
                    {
                        cssContent = RegexRemoval.Replace(cssContent, "");

                        // Set up a CacheDependency on the css-file,
                        // this way the cache will be invalidated if
                        // we change the file
                        CacheDependency dependency = new CacheDependency(fileInfo.FullName);
                        Cache.Add(string.Format("CssCompactHandlerCache_{0}", fileInfo.FullName), cssContent, dependency, DateTime.Now.AddYears(1), Cache.NoSlidingExpiration, CacheItemPriority.AboveNormal, null);
                    }
                    Response.Write(cssContent);
                }
            }
        }

        public bool IsReusable
        {
            get
            {
                return true;
            }
        }
    }
}

Just spent the evening writing a class to decode RFC2047 strings in C#. It was requested by a user on ASPSidan, a Swedish site dedicated to ASP, ASP.Net and other Microsoft technologies but before I was done someone had already found another implementation on the net. Anyway, the code shouldn’t go to waste so I’m posting it here if anyone needs it.

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Globalization;

namespace CrazyBeavers.Net.Mail
{
    public static class RFC2047Decoder
    {
        public static string Parse(string input)
        {
            StringBuilder sb = new StringBuilder();
            StringBuilder currentWord = new StringBuilder();
            bool readingWord = false;

            Int32 i = 0;
            while (i < input.Length)
            {
                char currentChar = input[i];
                char peekAhead;
                switch (currentChar)
                {
                    case '=':
                        peekAhead = (i == input.Length - 1) ? ' ' : input[i + 1];

                        if (peekAhead == '?')
                            readingWord = true;
                        break;

                    case '?':
                        peekAhead = (i == input.Length - 1) ? ' ' : input[i + 1];

                        if (peekAhead == '=')
                        {
                            readingWord = false;

                            currentWord.Append(currentChar);
                            currentWord.Append(peekAhead);

                            sb.Append(ParseEncodedWord(currentWord.ToString()));
                            currentWord = new StringBuilder();

                            i += 2;
                            continue;
                        }
                        break;
                }

                if (readingWord)
                {
                    currentWord.Append(currentChar);
                    i++;
                }
                else
                {
                    sb.Append(currentChar);
                    i++;
                }
            }

            return sb.ToString();
        }

        private static string ParseEncodedWord(string input)
        {
            StringBuilder sb = new StringBuilder();

            if (!input.StartsWith("=?"))
                return input;

            if (!input.EndsWith("?="))
                return input;

            // Get the name of the encoding but skip the leading =?
            string encodingName = input.Substring(2, input.IndexOf("?", 2) - 2);
            Encoding enc = Encoding.GetEncoding(encodingName);

            // Get the type of the encoding
            char type = input[encodingName.Length + 3];

            // Start after the name of the encoding and the other required parts
            Int32 i = encodingName.Length + 5;

            switch (char.ToLowerInvariant(type))
            {
                case 'q':
                    while (i < input.Length)
                    {
                        char currentChar = input[i];
                        char[] peekAhead = new char[2];
                        switch (currentChar)
                        {
                            case '=':
                                peekAhead = (i >= input.Length - 2) ? null : new char[] { input[i + 1], input[i + 2] };

                                if (peekAhead == null)
                                {
                                    sb.Append(currentChar);
                                    i++;
                                    break;
                                }

                                string decodedChar = enc.GetString(new byte[] { Convert.ToByte(new string(peekAhead, 0, 2), 16) });
                                sb.Append(decodedChar);
                                i += 3;
                                break;
                            case '?':
                                if (input[i + 1] == '=')
                                    i += 2;
                                break;
                            default:
                                sb.Append(currentChar);
                                i++;
                                break;
                        }
                    }
                    break;
                case 'b':
                    string baseString = input.Substring(i, input.Length - i - 2);
                    byte[] baseDecoded = Convert.FromBase64String(baseString);
                    sb.Append(enc.GetString(baseDecoded));
                    break;
            }
            return sb.ToString();
        }
    }
}

Just thought I would post this lovely picture I took during my travel down to Sölvesborg and Sweden Rock Festival 2009. It was taken a few miles north of Jönköping and is composed of six or seven pictues that was merged using Photoshop to get a full panoramic picture.

It seems that Zoomify decreases the quality of the images quite severely but I’m afraid it will have to do with that. I’ll see if I can upload the original picture later on when I get on a faster connection (it took me half an hour to upload the Zoomify images).

Adding descriptive comments to your code is something that everyone will always tell you to do though in reality many people simply don’t do it. Some are just lazy, some doesn’t see the need of it, some are to stressed out to do it and some things that the c# compiler will warn you about just doesn’t need commenting. Looking at the last category, things that just doesn’t need commenting, we many times find enums. Look at this as a sample.

/// <summary>
///  Datatypes used by the EXIF specification
/// </summary>
public enum ExifDataTypes
{
	UnsignedByte = 1,
	AsciiString = 2,
	UnsignedShort = 3,
	UnsignedLong = 4,
	UnsignedRational = 5,
	SignedByte = 6,
	Undefined = 7,
	SignedShort = 8,
	SignedLong = 9,
	SignedRational = 10,
	SingleFloat = 11,
	DoubleFloat = 12
}

What useful comments could added to this? When compiling I’m getting twelve warnings about this code not being documented though I do have a hard time finding out what I should write about each option since I feel that the names are quite self explanatory. Just adding a dummy comment to each line would get rid of the warnings but also clutter up my code which isn’t really helping me. I could also tell the compiler to ignore all warnings of this type (“/nowarn 1591″ when compiling) though there might be other places in my code where I want to know that I missed a comment.

So no luck just yet. There is however a third method to use. Going back to C there has been a way to communicate with the compiler from your code using directives called “pragmas”. C# have it as well though the standard compiler (csc.exe) only understands two commands, warning and checksum. For my problem, warning was the one I could use.

The code below has a pragma added that tells the compiler not to raise warnings with id 1591 (missing comments) from line 6 to line 19.

/// <summary>
///  Datatypes used by the EXIF specification
/// </summary>
public enum ExifDataTypes
{
#pragma warning disable 1591
	UnsignedByte = 1,
	AsciiString = 2,
	UnsignedShort = 3,
	UnsignedLong = 4,
	UnsignedRational = 5,
	SignedByte = 6,
	Undefined = 7,
	SignedShort = 8,
	SignedLong = 9,
	SignedRational = 10,
	SingleFloat = 11,
	DoubleFloat = 12
#pragma warning restore 1591
}

It still gives me lots of warnings (still have some huge enums for the EXIF class that needs this) but now I have a chance of finding the real warnings and still document the parts of my code that really needs documenting.

I’m a huge fan of batchfiles (.bat) in Windows. They are usually so simple to write and can help you out with automating tasks that otherwise would be a pain in your ass. As an example, here is a little file I’ve set up at work for my coworkers to be able to convert movieclips to .wmv.

@echo off
"J:\PathToOurMovieArchive\ffmpeg.exe" -i %1 -b 1024k -vcodec wmv2 -acodec wmav2 -ar 44100 -ab 48000 -ac 1 -y %1-convertedHQ.wmv
pause

It’s simple enough. Don’t output anything and then execute ffmpeg,exe with the specified parameters taking the first of the dropped files as input. Works great and produces a wmv-movieclip in the same folder as the original file. The problem with this file is that it if you drop two files on this batch it will only convert the first one, which forces you to drag them one by one and then have them run simultaneously which might not be desirable on a slow computer.

To solve this problem I went to the all mighty Google and found the FOR IN command. My problem was that it I couldn’t find any samples with it working with dropped files and I couldn’t get it working by just doing FOR %i in (%*). The problem (according to the help for the FOR-command availabile in FOR /?) was that if used in a batchfile I need to designate my variable as %%i instead of %i. After changing that it all worked like charm. So this is how my batchfile ended up, it supports any number of dropped files (well I guess it has a built in limit such as 65335 or something though I’m pretty sure my coworkers won’t drop more then 10 files) and then executes each file in order and not all at once.

@echo off
for %%i in (%*) do "J:\PathToOurMovieArchive\ffmpeg.exe" -i %%i -b 1024k -vcodec wmv2 -acodec wmav2 -ar 44100 -ab 48000 -ac 1 -y %%i-convertedHQ.wmv
pause

I hope that this was to some help for somebody. If you have any other good tips on scripting with batchfiles then please add a comment about it as I’m always eager to learn new things with this great technique.