Calibre stretches images

Sangaku · 10-06-2013, 06:49 PM

When I convert kindle books with calibre, all of the images stretch. I'm talking math books, so there are quite a lot of images. Any ideas?

When I right click on the image and look at it outside of the epub, it looks perfectly normal. But in the epub viewer and on my nook, the images are super stretched out and often illegible.

Section8 · 10-06-2013, 07:08 PM

I think Calibre resizes images during conversion based upon the device configured in the output profile. This can be set in the Conversion dialog->Page Setup/Output profile. If you set the output profile to "Tablet", calibre shouldn't resize the images at all.

theducks · 10-06-2013, 07:17 PM

You want to consider ticking 'Maintain Aspect Ratio' to avoid distortion.
Choices: Fill the screen or Distort (if the geometry does not match)

DoctorOhh · 10-06-2013, 09:24 PM

Quote:

Originally Posted by Sangaku

When I convert kindle books with calibre, all of the images stretch. I'm talking math books, so there are quite a lot of images. Any ideas?

When I right click on the image and look at it outside of the epub, it looks perfectly normal. But in the epub viewer and on my nook, the images are super stretched out and often illegible.

The only image that calibre has this effect on is the cover image. Other images might be resized to fit the output device selected (if no resize is desired choose tablet for output device).

This means that either the book was designed with SVG wrappers on the images to fit the profile of Kindle devices which calibre is leaving as is but when viewed outside of the original aspect ratio of the Kindle look predictably distorted -or- there is a bug in calibre wrapping all converted images in a SVG wrapper just like it does the cover image.

The only way to know for sure is to follow the guidelines in the Sticky post at the top of this forum titled: How to ask a question about conversion problems and provide Kovid the files as outlined attached to a bug report.

Good Luck

dwig · 10-06-2013, 10:01 PM

Quote:

Originally Posted by Sangaku

...
When I right click on the image and look at it outside of the epub, it looks perfectly normal. But in the epub viewer and on my nook, the images are super stretched out and often illegible.

If true, then calibre is not stretching the images, at least the images themselves. The distortion is the result of the xHTML code causing the viewing software to distort the image display.

I couldn't say whether the "bogus" xHTML code is the result of some alteration during conversion by calibre or the result of some quirk in the original AZW/AZW3/MOBI/... code that displays "correctly" on the Kindle but fails when used in an ePub.

Sangaku · 10-08-2013, 01:56 AM

The input and output settings don’t seem to change the effect. Obviously images show up this way as soon as I drop the book into Calibre, so I don’t think Calibre “knows” how to view it correctly regardless of the format. Unfortunately no other programs do either after I use Calibre for the conversion.

I assumed the “Maintain Aspect Ratio” tick box would be in the conversion settings, but I didn’t see it there.

When I "explode" the book, it obviously has all the images in the correct size, but it’s making them huge and often stretched. Since the math in the book is images, there are quite a few of them.

I don’t know enough code to attempt anything in that arena. I guess I’ll try to submit the problem.

Thanks everyone for the replies, I appreciate the help.

theducks · 10-08-2013, 10:13 AM

The output option form uses the words 'Preserve Aspect Ratio'

sorry

I had a Sigil clip with 'Maintatains' as its name whhich I used to replace the 'none' in the SVG cover section of books under edit

The other pictures stretching is probably because their CSS selector says 100% for height or width. Sigil (or use Tweak EPUB and your TEXT editor) hand editing time

10-06-2013, 06:49 PM	#1
Sangaku Junior Member Posts: 2 Karma: 10 Join Date: Oct 2013 Device: nook	Calibre stretches images When I convert kindle books with calibre, all of the images stretch. I'm talking math books, so there are quite a lot of images. Any ideas? When I right click on the image and look at it outside of the epub, it looks perfectly normal. But in the epub viewer and on my nook, the images are super stretched out and often illegible.

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10-06-2013, 07:08 PM	#2
Section8 Addict Posts: 260 Karma: 2092424 Join Date: Oct 2011 Location: Arlington, TX Device: Kindle PW4, Moon+ Reader on a cheap Android tablet	I think Calibre resizes images during conversion based upon the device configured in the output profile. This can be set in the Conversion dialog->Page Setup/Output profile. If you set the output profile to "Tablet", calibre shouldn't resize the images at all.

10-06-2013, 07:17 PM	#3
theducks Well trained by Cats Posts: 30,912 Karma: 60358908 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	You want to consider ticking 'Maintain Aspect Ratio' to avoid distortion. Choices: Fill the screen or Distort (if the geometry does not match)

10-08-2013, 01:56 AM	#6
Sangaku Junior Member Posts: 2 Karma: 10 Join Date: Oct 2013 Device: nook	The input and output settings don’t seem to change the effect. Obviously images show up this way as soon as I drop the book into Calibre, so I don’t think Calibre “knows” how to view it correctly regardless of the format. Unfortunately no other programs do either after I use Calibre for the conversion. I assumed the “Maintain Aspect Ratio” tick box would be in the conversion settings, but I didn’t see it there. When I "explode" the book, it obviously has all the images in the correct size, but it’s making them huge and often stretched. Since the math in the book is images, there are quite a few of them. I don’t know enough code to attempt anything in that arena. I guess I’ll try to submit the problem. Thanks everyone for the replies, I appreciate the help.

10-08-2013, 10:13 AM	#7
theducks Well trained by Cats Posts: 30,912 Karma: 60358908 Join Date: Aug 2009 Location: The Central Coast of California Device: Kobo Libra2,Kobo Aura2v1, K4NT(Fixed: New Bat.), Galaxy Tab A	The output option form uses the words 'Preserve Aspect Ratio' sorry I had a Sigil clip with 'Maintatains' as its name whhich I used to replace the 'none' in the SVG cover section of books under edit The other pictures stretching is probably because their CSS selector says 100% for height or width. Sigil (or use Tweak EPUB and your TEXT editor) hand editing time