Distorted images on Paperwhite Signature Edition

[feklee]

Yesterday, I received a Kindle Paperwhite Signature Edition as a gift, model: M2L4EK

It’s a beautiful device with a big and easy to read screen, certainly a big upgrade from my Kindle Keyboard 3G. Only, it doesn’t support EPUB, which my Keyboard 3G does, by means of Duokan. So I just converted Marina Abramović’s Walk Through Walls to AZW3 using Calibre 6.13 on Windows 10 Pro. As input profile I tried Kindle and Default, and as output profile I select Kindle Oasis because - per description - this is intended also for the Paperwhite 2021.

Unfortunately, the images are vertically stretched. It looks like there are two types of images. Some are stretched to fill the entire page, some half the page, minus caption. This issue does not exist in the original EPUB, and I could read the book just fine using Duokan.

Is there an easy fix?

(I wish there was a jailbreak for the device with a decent EPUB and PDF reader, or a dual boot solution with Duokan like for the Keyboard 3G.)

[kovidgoyal]

https://www.mobileread.com/forums/sh...d.php?t=186697

[feklee]

Originally Posted by kovidgoyal

https://www.mobileread.com/forums/sh...d.php?t=186697

OK, so I extracted the first chapter. Then I lorem ipsumized the text using the Chrome plugin LoremIpsumReplacer, and I pixelated the images using ImageMagick, only to find out:

The issue happens with AZW3, but not with MOBI.

Find the modded file attached. Seems like I damaged the meta data or something. There is an error, but it doesn’t influence conversion. The pixels in the images should be squared. With the AZW3 in many images they are distorted.

I am happy to provide more info, but for me the issue seems to be solved. I simply convert from EPUB to MOBI instead of to AZW3.

[JSWolf]

Originally Posted by feklee

Yesterday, I received a Kindle Paperwhite Signature Edition as a gift, model: M2L4EK

It’s a beautiful device with a big and easy to read screen, certainly a big upgrade from my Kindle Keyboard 3G. Only, it doesn’t support EPUB, which my Keyboard 3G does, by means of Duokan. So I just converted Marina Abramović’s Walk Through Walls to AZW3 using Calibre 6.13 on Windows 10 Pro. As input profile I tried Kindle and Default, and as output profile I select Kindle Oasis because - per description - this is intended also for the Paperwhite 2021.

Unfortunately, the images are vertically stretched. It looks like there are two types of images. Some are stretched to fill the entire page, some half the page, minus caption. This issue does not exist in the original EPUB, and I could read the book just fine using Duokan.

Is there an easy fix?

(I wish there was a jailbreak for the device with a decent EPUB and PDF reader, or a dual boot solution with Duokan like for the Keyboard 3G.)

You actually want Input profile to be Default profile and Output profile to be Tablet. That way the images are not changed at all. With your current settings, images are modified.

[feklee]

Originally Posted by JSWolf

You actually want Input profile to be Default profile and Output profile to be Tablet. That way the images are not changed at all. With your current settings, images are modified.

I tried, and with input Default and output Tablet, I get the same issue in the AZW3 file. Note that the images are not uniformly stretched by a factor. Instead they seem to be stretched either to fill 50% of the height or 100%, minus caption.

[kovidgoyal]

The markup in that file is causing the distortion, since it hardocdes widths for the images. AZW3 supports such markup MOBI does not.

[feklee]

Originally Posted by kovidgoyal

The markup in that file is causing the distortion, since it hardocdes widths for the images. AZW3 supports such markup MOBI does not.

Thanks for looking into it. What fix do you recommend?

(MOBI looks fine to me, so maybe I don't even need a fix.)

[JSWolf]

Originally Posted by feklee

Thanks for looking into it. What fix do you recommend?

(MOBI looks fine to me, so maybe I don't even need a fix.)

Post a the section of the html code that displays the images and any relevent CSS code. We can take a look. It would be good to know what's going on if you want to fix a similar issue in the future.

[kovidgoyal]

You would need to remove the width attribute from all img tags which can be done via the Transform HTLM tab of the Look & feel section of the conversion dialog.

[feklee]

Originally Posted by kovidgoyal

You would need to remove the width attribute from all img tags which can be done via the Transform HTLM tab of the Look & feel section of the conversion dialog.

Thanks for the suggestion. Here is an example of an image that gets heavily stretched vertically across an entire page, minus caption (code reformatted by me):

<div class="img_wrap" id="div12">
  <div class="block_51" id="c01-fig7">
    <div class="squeeze squeeze51_0">
      <img
        alt=""
        class="squeeze-epub"
        src="images/Abra_9781101905050_epub3_010_r1.jpg"
        style="width:100%;"
      ><img
         alt=""
         class="squeeze-amzn"
         height="373"
         src="images/Abra_9781101905050_epub3_010_r1.jpg"
         width="284">
    </div>
  </div>
  <p class="caption" id="p60"> eirmod tempor invidunt ut labore et dolore </p>
</div>

What I tried as transformation rule:


However, all that this does is create two equally stretched images. First, I tried just removing width, and when that didn't work, I just remove pretty much everything.

(note that I'm fine exporting to mobi, but I'm also happy to continue testing Calibre in case that helps)

[Quoth]

if width or height is a percent (like 75% or 100%), the other property must be auto, because that percent is enclosing thing size, not image size, so
width: 50%;
height: 50%;
doesn't give a half size image, it will stretch to half height and width of the screen by default.

If the image is really 800 x 600 pixels (w x h) then these work

Absolute sizing
height: 300px;
width: 400px;

Set based on width and 2.5% of screen margin
height: auto;
width: 95%;

Or if it's a portrait image 1080 wide and 1920 high and you want it a 1/3rd of page
height: 33.3%;
width: auto;


If you want it centred put it in a p or div
<p class="centred"><img class="size2" src="images/image.png" alt="descriptive text"/> </p>
<p class="centred">Some caption</p>

.size2 {
height: auto;
width: 50%
}

.centred {
display: block;
font-family: "Droid Sans", sans-serif;
font-weight: bold;
margin-bottom: 0.5em;
margin-left: 0;
margin-right: 0;
margin-top: 0;
padding-bottom: 0;
padding-left: 0;
padding-right: 0;
padding-top: 0;
text-align: center;
text-indent: 0
}

This class will do for a caption too.
Never use "auto" with any margin or padding property.

[feklee]

Thanks, but I'm not the one who writes that code. I just try to convert, and I realize that the file displays fine as EPUB, and it also displays fine on my Kindle when converted to MOBI. It does not, however, display fine on my Kindle when converted to AZW3.

In the snipped that I posted, I'd say things look OK. The image is included twice. Apparently the software used for viewing just hides the instance that is not applicable.

For the first instance, the width is specified, so that the height can be selected proportionally by the viewer. There should be no stretching:

<img
  alt=""
  class="squeeze-epub"
  src="images/Abra_9781101905050_epub3_010_r1.jpg"
  style="width:100%;">

In the second instance, the dimensions are hardcoded in about the aspect ration of the image, again no excuse for extensive stretching:

<img
  alt=""
  class="squeeze-amzn"
  height="373"
  src="images/Abra_9781101905050_epub3_010_r1.jpg"
  width="284">

The size of Abra_9781101905050_epub3_010_r1.jpg is 1200×1600 pixels.

[Quoth]

This should never be done in an img tag in ebooks, though OK on a web page:
style="width:100%;"
or
height="373"
src="images/Abra_9781101905050_epub3_010_r1.jpg"
width="284"

1) style="width: etc" in an img tag is a different thing to width="pixels" in an img tag

2) width & height should only be set in CSS, never in the the img tag because some ereader renderers will ignore it.

3) Never set width or height without setting both.

Inline attributes are a poor idea in epub2, epub3 and azw3/KF8

What is the CSS of class="squeeze-epub" ? That could be messing up the images.

Each image that't differently styled should have a class in CSS file.

Some eReader renderers work differently to web pages. The PC viewers are usually using a web browser so will work when epub, kepub, azw3/KFX, mobi/KF7 or KFX on eink fails.

[Quoth]

Here is classic difference:

<img src="workplace.jpg" alt="Workplace" usemap="#workmap" width="400" height="379">

<map name="workmap">
<area shape="rect" coords="34,44,270,350" alt="Computer" href="computer.htm">
<area shape="rect" coords="290,172,333,250" alt="Phone" href="phone.htm">
<area shape="circle" coords="337,300,44" alt="Cup of coffee" href="coffee.htm">
</map>

This is trivial client side image map code that needs no javascript and allows an interactive image. You could make a click & point plot your own adventure with images rather than text.

It won't work on most ereaders, in ebooks, sadly.

This also often won't work (fine for web sites)

img {
display: block;
margin-left: auto;
margin-right: auto;
width: 50%;
}

For ereaders it needs to be an image inside p or div tags using class="centred"
Example makes ALL images 50%, so you'd have a class for each size.

img {
height: auto;
width: 50%
}

.centred {
display: block;
margin-left: 0;
margin-right: 0;
text-align: center;
}

[feklee]

I'll stick to MOBI. That works, no need for AZW3.