How to specify and read image's orientation

I. I don't understand how to specify image's orientation.

Step 1: I specify the image's orientation using
```
magick 0.jpg -orient top-left 1.jpg
```
Step 2: I rotate the image using
```
magick 1.jpg -rotate 90 2.jpg
```
Step 3: I try to restore the orientation I have specified earlier using
```
magick 2.jpg -auto-orient 3.jpg
```

I expected that 3.jpg will be rotated -90 degrees, and so it will appear as 0.jpg and 1.jpg, but this doesn't happen, and it still appear as 2.jpg.

Am I doing something wrong?

II. Also, I don't understand how to find out the specified orientation. I tried

magick identify -format "%[orientation]" 3.jpg

but this returns Undefined.

Solution

You can set the orientation with exiftool like this:

exiftool -orientation#=6 image.jpg

Permissible numeric values are:

1 = Horizontal (normal)
2 = Mirror horizontal
3 = Rotate 180
4 = Mirror vertical
5 = Mirror horizontal and rotate 270 CW
6 = Rotate 90 CW
7 = Mirror horizontal and rotate 90 CW
8 = Rotate 270 CW

Or you can use verbiage like this:

exiftool -orientation="Rotate 90 CW" image.jpg

If you want to retrieve the orientation, you can get it like this:

exiftool -orientation image.jpg
Orientation                     : Rotate 90 CW

Or numerically with:

exiftool -orientation# image.jpg
Orientation                     : 6

Or unadorned, like this:

exiftool -s3 -orientation# image.jpg
6

You can equally retrieve it with ImageMagick, using escapes:

magick image.jpg -format "%[orientation]" info:
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Or with ImageMagick using a JSON parser such as jq:

magick image.jpg json: | jq -r '.[].image.orientation'
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Or with ImageMagick and awk:

magick identify -verbose image.jpg | awk '/Orientation/ {print $NF}'
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