#395 EXIF-"rotated" jpeg aren't resized properly

[Ildar Mulyukov]

if a jpeg photo has EXIF info saying that it's actually rotated by 90 degrees
then -size and -resize options do not work right: x dimension looks at physical x (which is y) and visa versa.
Example: a jpeg 200x100 with EXIF info saying "rotate 90 degrees clockwise" represents 100x200 image. If I -resize 50x then it makes 25x50, but it should produce 50x100.

[Bob Friesenhahn]

On Sun, 7 Aug 2016, Ildar Mulyukov wrote:

if a jpeg photo has EXIF info saying that it's actually rotated by
90 degrees then -size and -resize options do not work right: x
dimension looks at physical x (which is y) and visa versa.
Example: a jpeg 200x100 with EXIF info saying "rotate 90 degrees
clockwise" represents 100x200 image. If I -resize 50x then it makes
25x50, but it should produce 50x100.

Does adding the option '-auto-orient' prior to the -resize request
solve the problem?

Please note that -size does not resize images

Bob

[Bob Friesenhahn]

A fix for sometimes missing EXIF orientation has been applied as part of bug 400. Otherwise it is recommended to use -auto-orient before the resize request. GraphicsMagick expects that requests apply to the image pixels in their current raster form and it does not translate user requests to based on the orientation tag. We do not intend to change this.

[Ildar Mulyukov]

Hi, Bob,
Sorry for the delay.
Unfortunatelly '-auto-orient' doesn't work for me:

gm convert "$f" -auto-orient -resize $SIZE -background black -gravity center -extent $SIZE "$out.jpg"

still ignores EXIF info which is for one of my photos:

$ LANG=C exif IMG_0151.JPG | grep Orientation
Orientation |Right-top

GraphicsMagick 1.3.18

[Ildar Mulyukov]

Sorry, not true. Now the resize processes as expected.
But I found that:

1. the resulting image has still >>Orientation |Right-top<< while the picture already rotated.
2. man page still says "gm convert -size 800x600 input.jpg ... -resize" while you write: "Please note that -size does not resize images"

[Bob Friesenhahn]

On Sun, 9 Oct 2016, Ildar Mulyukov wrote:

Sorry, not true. Now the resize processes as expected.
But I found that:
1. the resulting image has still >>Orientation |Right-top<< while the picture already rotated.
2. man page still says "gm convert -size 800x600 input.jpg ... -resize" while you write: "Please note that -size does not resize images"

You are reading documentation for the -extent option, which does use
-size.

The -size option needs to be provided for formats where the size is
not already known.

The -resize (or -geometry) options resize the raster image.

The version of GraphicsMagick you are using is very old. Regardless,
GraphicsMagick's support for EXIF is still not very good yet in that
it does not support modifying the EXIF to take changes into account.

Bob

** [bugs:#395] EXIF-"rotated" jpeg aren't resized properly**

Status: closed-wont-fix
Group: v1.0_(example)
Created: Sun Aug 07, 2016 02:39 PM UTC by Ildar Mulyukov
Last Updated: Sun Oct 09, 2016 09:03 PM UTC
Owner: Bob Friesenhahn

if a jpeg photo has EXIF info saying that it's actually rotated by 90 degrees
then -size and -resize options do not work right: x dimension looks at physical x (which is y) and visa versa.
Example: a jpeg 200x100 with EXIF info saying "rotate 90 degrees clockwise" represents 100x200 image. If I -resize 50x then it makes 25x50, but it should produce 50x100.

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--
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer, http://www.GraphicsMagick.org/