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Author Topic: rotating an image rotates it too much...  (Read 1828 times)

robydago

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rotating an image rotates it too much...
« on: December 04, 2007, 01:53:12 pm »

hi,
i have a lot of pictures with the rotation tag correctly set to 90 by the camera I use.
when I "rotate right" those images in MC, the tag is reset to 0 but the image is rotated right 180 degrees and not just the 90 needed... any reason?  To fix it, I then have to "rotate left" the just rotated image.

roby
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glynor

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Re: rotating an image rotates it too much...
« Reply #1 on: December 04, 2007, 02:11:41 pm »

This has happened to me before.  Sometimes it happens and sometimes it doesn't.

I suspect it has to do with MC showing the in-camera rotation, but applying the rotation you perform to the image itself (which then causes a double-rotation).

I don't know.  I've seen it too though!
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gappie

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Re: rotating an image rotates it too much...
« Reply #2 on: December 04, 2007, 02:17:26 pm »

This has happened to me before.  Sometimes it happens and sometimes it doesn't.

I suspect it has to do with MC showing the in-camera rotation, but applying the rotation you perform to the image itself (which then causes a double-rotation).

I don't know.  I've seen it too though!
yep, indeed. i had this a lot. with a camera that apparently put rotation changes in the rotation tag. mc rotates the image itself and put the rotation tag at 0 at the same time, which can give some interesting results. but after that the image rotation is clean.
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Matt

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Re: rotating an image rotates it too much...
« Reply #3 on: December 04, 2007, 02:38:18 pm »

hi,
i have a lot of pictures with the rotation tag correctly set to 90 by the camera I use.
when I "rotate right" those images in MC, the tag is reset to 0 but the image is rotated right 180 degrees and not just the 90 needed... any reason?  To fix it, I then have to "rotate left" the just rotated image.

roby


Internally, the image is already rotated right, so pick "Rotate Left" to flip it back. 

By picking "Rotate Right", you're adding another 90 degrees to the image, so it's correctly showing upside down.
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robydago

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Re: rotating an image rotates it too much...
« Reply #4 on: December 04, 2007, 02:47:11 pm »

Internally, the image is already rotated right, so pick "Rotate Left" to flip it back. 

By picking "Rotate Right", you're adding another 90 degrees to the image, so it's correctly showing upside down.

If you mean "rotate left" instead of "rotate right" I just tried and while the tag rotation is reset to 0 nothing happens to the image itself.
I tried also another strategy: I reset manually the rotation tag from 90 to 0 and the image was instantly rotated correctly by MC.

Maybe you should add an option "rotate according to exif information" or something like that...

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Matt

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Re: rotating an image rotates it too much...
« Reply #5 on: December 04, 2007, 02:50:34 pm »

Maybe you should add an option "rotate according to exif information" or something like that...

"Update Library (from Tags)" should do that.
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Matt Ashland, JRiver Media Center

robydago

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Re: rotating an image rotates it too much...
« Reply #6 on: December 04, 2007, 02:52:03 pm »

By picking "Rotate Right", you're adding another 90 degrees to the image, so it's correctly showing upside down.

FYI: all the images I'm having problems with are not shown 'correctly' by MC, 'cause even if the rotation tag contains the correct degrees ('90') indicating a portrait framing, MC still shows them as landscape
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Matt

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Re: rotating an image rotates it too much...
« Reply #7 on: December 04, 2007, 02:58:46 pm »

FYI: all the images I'm having problems with are not shown 'correctly' by MC, 'cause even if the rotation tag contains the correct degrees ('90') indicating a portrait framing, MC still shows them as landscape

If the JPEG was rotated but the EXIF not updated, you could get a case that appears incorrect.

If you see this, rotate (twice if necessary) with MC because it correctly updates the EXIF to no rotation.
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Matt Ashland, JRiver Media Center

robydago

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Re: rotating an image rotates it too much...
« Reply #8 on: December 04, 2007, 03:08:45 pm »

If the JPEG was rotated but the EXIF not updated, you could get a case that appears incorrect.

If you see this, rotate (twice if necessary) with MC because it correctly updates the EXIF to no rotation.

Matt,
you're right, those images are landscape oriented in MC only, while windows explorer shows them correctly.
I'm fixin them setting manually to 0 the rotation tag.

Thanks
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cosmicfx

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Re: rotating an image rotates it too much...
« Reply #9 on: December 06, 2007, 05:37:32 am »

Is it true that if rotating an image inside the MC Image Editor , then the rotation is NOT lossless rotation?

And if it is so, then can't MC make it that it is "lossless" in the future MC version?

Thanks
Cosmic
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Matt

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Re: rotating an image rotates it too much...
« Reply #10 on: December 06, 2007, 08:36:36 am »

Is it true that if rotating an image inside the MC Image Editor , then the rotation is NOT lossless rotation?

And if it is so, then can't MC make it that it is "lossless" in the future MC version?

Thanks
Cosmic

The commands on the right-click menu "Rotate Left" and "Rotate Right" are lossless JPEG rotations.

Using the editor would resave the file, so isn't as good for this task.
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Matt Ashland, JRiver Media Center
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