Reading EXIF without loading picture? (GflAX.dll)

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WatcherFF
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Joined: Wed May 06, 2009 6:38 pm

Reading EXIF without loading picture? (GflAX.dll)

Post by WatcherFF » Wed May 06, 2009 7:16 pm

Hello,

First I would like thank you for your work and really good library to manage the images. I mean GflAX DLL. Currently I'm using the version GflAX DLL 2.60- GFL 2.82 in a C# project.
In the feature list of library you wrote: "EXIF reading (with or without loading picture)". That's what I need - reading EXIF without loading picture. But I can't get it done. It seems like the picture will be loaded completely.

What is my goal:
I have a lot of photos in different formats: JPEG, TIFF, NEF, CR2, PNG etc. I need to scan them all very quick and read _only_ EXIF meta data (EXIFDateTaken, ExifDTDigitized and lastly DateTime) from each file, without to load the picture in the memory.

What I do now:

Code: Select all

GflAx.GflAxClass gl = new GflAx.GflAxClass(); 
...
gl.UseEmbeddedThumbnail = 1;
gl.LoadThumbnail(SrcFile, 0, 0);
String tmpDate = gl.EXIFDateTaken;
...
gl.FreeBitmap();
I'm almost happy with the solution. It is fast. When I understand it correctly, with this method the library access only embedded thumbnail of the picture. But I have nevertheless the problems with the pictures without embedded thumbnail. In that case it seems like library create the thumbnail by itself.
When I use the LoadBitmap() instead of LoadThumbnails() it takes much longer. I've been looking for a method like ReadExifTag( String Filename, int Tag ) or bytes[] ReadExifData(String Filename), but such methods doesn't exist in the dll.

Is it the right way to do "reading without loading picture"? How can I access only EXIF metadata?
Can you explain me, how can I to do it right using your library - reading EXIF without loading picture?

I looking forward to get your response.
Thank you in advance.

P.S. What the library really do, when I use LoadThumbnails(SrcFile, 0, 0)?

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xnview
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Re: Reading EXIF without loading picture? (GflAX.dll)

Post by xnview » Thu May 07, 2009 10:54 am

WatcherFF wrote: Is it the right way to do "reading without loading picture"? How can I access only EXIF metadata?
Can you explain me, how can I to do it right using your library - reading EXIF without loading picture?
It's not possible with GFLAx, only with GFL SDK
P.S. What the library really do, when I use LoadThumbnails(SrcFile, 0, 0)?
Try to load the embedded thumbnail without resize
Pierre.

WatcherFF
Posts: 5
Joined: Wed May 06, 2009 6:38 pm

Re: Reading EXIF without loading picture? (GflAX.dll)

Post by WatcherFF » Thu May 07, 2009 7:15 pm

xnview wrote:It's not possible with GFLAx, only with GFL SDK
Hello, Pierre!

Thank you very much for your quick reply.
How can I do read EXIF from a picture without loading using GFL SDK?

It is possible, that you take the feature also in the next release of GFLAx dll? I'll be really thankful for you, it you can do this. :D
Do you plan next release of your GFLAx dll?

P.S. Another question. I need to check, the current file type is supported by the GFLAx. Does the library provide such a method?

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xnview
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Re: Reading EXIF without loading picture? (GflAX.dll)

Post by xnview » Sun May 10, 2009 3:41 pm

WatcherFF wrote: How can I do read EXIF from a picture without loading using GFL SDK?
gflLoadEXIF :-)
It is possible, that you take the feature also in the next release of GFLAx dll? I'll be really thankful for you, it you can do this. :D
Do you plan next release of your GFLAx dll?
Currently i have no time to work on GFLAx :-(
P.S. Another question. I need to check, the current file type is supported by the GFLAx. Does the library provide such a method?
No, only GFL SDK
Pierre.

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