In Valid Logic

Endlessly expanding technology

Late night CS hacking, few new things for Galleries

Didn't plan on it, but ended up having a bit of a late night hacking a few things into CS Galleries for v1.1.

Started out as going through some of the pictures users had emailed me that failed to be added.  Few of them were things I'd already fixed, caused by cameras that support adding the picture's date/time, but still add the tag with all zeros (which is below .NET's DateTime.MinValue).  That was already fixed early on post-1.0.

Then this other one was more tricky.  It was a picture that was failing the check to see if it was a valid image, even though Windows and everything else could still open it.  The code CS uses to check images without using System.Drawing is a class I ported from java (called ImageInfo).  In digging through it, I found the APP0 marker (typically has the identifier, version, DPIs, and embedded thumbnail size), which is normally 14 bytes, was only 8.  At first, I figured it was a cheaper camera that wasn't good with standards, but the EXIF info said it was a Canon PowerShot.  So I dug deeper.  Then in going through the JPEG spec, I found that 8 could be valid if it didn't have a DPI specified.

Then decided to dive into adding support reading the EXIF comments directly into the picture's description.  Then, I found that in Windows XP, when you add the title/subject/comments (by right clicking and going to Properties on the picture), that doesn't go into the jpeg comments, but the EXIF data.  So, I added support to the EXIF reader to get the Windows title/subject/keyword/author/comments tags.  Also, if you don't specify a title for the entry, it will first look for the Windows title, then the Windows subject, and then settle on the picture's filename.  For the description, if you didn't enter one, it'll first look for JPEG comments, and then settle on the Windows comments.

Have had a couple of users ask for reading comments from the picture, and now v1.1 will do that.

Now, it is 2am, and it is too late to watch Deadliest Catch.  It'll have to wait until tomorrow.

Wednesday, May 18, 2005

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