[Mono-dev] Reading Exif Data with System.Drawing or Gtk#
sebastien.pouliot at gmail.com
Mon Sep 27 08:16:39 EDT 2010
On Sun, 2010-09-26 at 17:38 +0200, Patrick Kowalzick wrote:
> Dear List,
> I am reading exif-data from jpegs (mainly thumb and orientation) using
> System.Drawing. Something like:
> string orientation = null;
> using (FileStream fs = new FileStream(path,FileMode.Open))
> using (Image img = Image.FromStream(fs,true,false))
> foreach (PropertyItem pi in img.PropertyItems)
> if (pi.Id == 274)
> orientation =
> Important here is the third parameter from Image.FromStream
> (validateImageData), which should supress loading the complete
> image-file, if you access exif data only.
> This works fine for MS.net, but mono (2.6 on Ubuntu) reads the complete
> image. See as well:
> "# Status: TODO
> # Comment: useEmbeddedColorManagement and validateImageData aren't
> As a result, there are massive performance differences between MS.net
> and mono :(.
> So I am looking for alternatives to just read exif data from images, if
> possible without including third party libraries (maybe taglib# with
> picture support). I am already using GTK#, so this would be the best
> solution for me.
Well you can consider contributing the missing code to mono :-)
> What I found so far:
> -System.Windows.Media.Imaging.BitmapSource is not yet included in mono,
> and will not in mono 2.8(?).
> -Gdk.Pixbuf Solution, but just for reading orientation:
> Gdk.Pixbuf icon = new Gdk.Pixbuf(path);
> string orientation = icon.GetOption("orientation");
> Same behaviour: needs to load image first, and I do not find any
> information, which options I could retrieve via "GetOption".
> Does anyone has a pointer for me, where to search for more information,
> or how to read Exif Data using Gtk?
Mono (well libgdiplus) use libexif. A quick googling returned the
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