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Author Topic: Rotate image  (Read 1582 times)

park

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Rotate image
« on: November 17, 2005, 07:49:22 pm »

I remember reading a thread a while back regarding image editing in MC changing or destroying some tag information. Is this still an issue? If I use MC's "Rotate" function, will the images lose resolution, as the windows images viewer warns when you try to rotate in the program. Will I lose tag info? Why cant MC read the orientation info in the tags and adjust appropriately?

Thanks,
Bri
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JimH

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Re: Rotate image
« Reply #1 on: November 17, 2005, 08:09:26 pm »

It never was an issue.

JPG rotation is lossless.
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Dutch Peter

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Re: Rotate image
« Reply #2 on: November 18, 2005, 12:42:28 am »

I am sorry to say this is not true.

I posted following 'feature' more than once:
Rotate an image with an empty 'name' tag.
The name tag will change into the name of the file.

This is not Lossless, is it?

Greetz.
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marko

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Re: Rotate image
« Reply #3 on: November 18, 2005, 01:54:06 am »

Rotating directly from within MC is indeed lossless, but there appears to be various means of reading the orientation.
What I mean is this: My camera has orientation sensitivity. Portrait pictures I take with it are shown with the correct orientation when viewed inside adobe photoshop elements, but are shown in landscape by MC. If I use MC to rotate the image to its correct orientation by, for the sake of example, "rotate 90 degrees clockwise" the image is then displayed incorrectly by elements, which needs a "90 degrees anti-clockwise" rotation to show the file correctly.
All very frustrating I'm sure you'll agree.

-marko.

glynor

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Re: Rotate image
« Reply #4 on: November 18, 2005, 03:55:15 pm »

I posted following 'feature' more than once:
Rotate an image with an empty 'name' tag.
The name tag will change into the name of the file.

This is not Lossless, is it?

Tag information and "lossless rotation" have little (or nothing) to do with one another in this case.  What Jim means is that when you rotate a JPEG image in MC it does not recompress the image with the JPEG algorithm again (which degrades the image quality).

It may or may not screw up empty "name" tags, I've never noticed, but that doesn't have anything to do with lossless or non-lossless.

As far as Marko's point, that drives me batty as well!!
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Yaobing

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Re: Rotate image
« Reply #5 on: November 21, 2005, 08:37:34 am »

MC Image Editor still does not have tagging support. Rotation in MC itself is lossless and does preserve tagging.
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Dutch Peter

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Re: Rotate image
« Reply #6 on: November 21, 2005, 11:27:00 am »

MC Image Editor still does not have tagging support. Rotation in MC itself is lossless and does preserve tagging.

Have you tried this:
Rotate an image with an empty 'name' tag.
The name tag will change into the name of the file.

I happen to use empty name tags .....
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park

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Re: Rotate image
« Reply #7 on: November 21, 2005, 06:40:50 pm »

Actually, my question was nothing to do with being lossless or not, though thanks for answering it. My question is that, in the windows pic and fax viewer utility,if you attempt to rotate an image it pops up a warning about changing the physical resolution of the image. I was just wondering if MC does the same thing.
It's discouraging to hear about the effects of rotating though (affecting how the photos can be seen in other apps).

Just a quick second question to those in the know:
Does adobe applications use some kind of industry wide standard for its rating tags etc. in images? Does such a standard exist?
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glynor

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Re: Rotate image
« Reply #8 on: November 22, 2005, 09:25:50 am »

If I use MC's "Rotate" function, will the images lose resolution

Actually, my question was nothing to do with being lossless or not, though thanks for answering it.

These two statements are contradictory.  Lossless means by definition that you don't lose anything (hence, loss-less or "without loss").

If you happen to lose the "name" tag (only when it's blank and I haven't verified this problem), that is a change in MC's database not in the image file itself (therefore still lossless as far as the image file is concerned).  The reason this is important is because once you make a lossy change to the actual image file, the data is gone and it can never come back.  (You can decrease resolution, but you can never accurately increase it.)

Just a quick second question to those in the know:
Does adobe applications use some kind of industry wide standard for its rating tags etc. in images? Does such a standard exist?

The state of metadata tagging in Images is kind-of a nightmare.  However, there are some standards including EXIF and some standard TIFF extensions which are somewhat similar to the ID3 tags in MP3 files.  Unfortunately, the image management and editing companies out there (Adobe I'm looking at you) have modified these "standards" so much that there really isn't a standard anymore.  The problem is that there is a standard way to add tags to images, but each manufacturer calls the tags different things (and some keep changing their minds).  There is supposed to be a tag naming standard (called Dublin Core) but no one seems to be comitted to following it quite yet.
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