old kids book images within epub too small on Libra

mgrimace · 06-28-2023, 08:34 AM

Hello,

I have a number of old kids ebooks that are basically comprised entirely of images wrapped inside an epub (e.g., comic-style kids books). The problem is that many of the older books have defined image sizes and each page shows up too small on my son's Kobo libra H20 (e.g., 800xsomething). Is there a plugin or way to automatically *grow* the images within the book to fit the screen (not the cover, the actual pages themselves)? The actual resolution doesn't matter if it's fuzzy or anything, they're fairly simple black and children's comic images.

I've tried setting the output style to tablet (no restrictions), Oasis (same resolution) but the images remain small.

Appreciate any advice

DNSB · 06-28-2023, 02:12 PM

You could try wrapping the images in an svg wrapper. Adjust the '1000' width and '1500' height to match the images you are using in both places where they are used. The last time I did something similar, 90% of the images were the same size so a simple copy/paste/edit image file name did most of the work.

Code:

<style type="text/css">
@page {padding: 0; margin:0;}
            body { text-align: center; padding:0; margin: 0; }
</style>
</head>

<body>
  <div>
    <svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1000 1500" width="100%" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="1500" width="1000" xlink:href="../Images/image001.jpeg"/></svg>
  </div>

JSWolf · 06-28-2023, 02:13 PM

Quote:

Originally Posted by DNSB

You could try wrapping the images in an svg wrapper. Adjust the 1000 width and 1500 height to match the images you are using in both places where they are used.

Code:

<style type="text/css">
@page {padding: 0; margin:0;}
            body { text-align: center; padding:0; margin: 0; }
</style>
</head>

<body>
  <div>
    <svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1000 1500" width="100%" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="1500" width="1000" xlink:href="../Images/image001.jpeg"/></svg>
  </div>

What that may do is making the images fuzzy as you increase the resolution of the low-res images.

DNSB · 06-28-2023, 02:15 PM

Quote:

Originally Posted by JSWolf

What that may do is making the images fuzzy as you increase the resolution of the low-res images.

To quote the OP:

Quote:

The actual resolution doesn't matter if it's fuzzy or anything, they're fairly simple black and children's comic images.

Please try to read and comprehend the messages you are responding to.

mgrimace · 06-28-2023, 04:04 PM

Quote:

Originally Posted by DNSB

You could try wrapping the images in an svg wrapper. Adjust the '1000' width and '1500' height to match the images you are using in both places where they are used. The last time I did something similar, 90% of the images were the same size so a simple copy/paste/edit image file name did most of the work.

Code:

<style type="text/css">
@page {padding: 0; margin:0;}
            body { text-align: center; padding:0; margin: 0; }
</style>
</head>

<body>
  <div>
    <svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1000 1500" width="100%" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="1500" width="1000" xlink:href="../Images/image001.jpeg"/></svg>
  </div>

Thanks for that info, makes sense! How do I go about doing that? My level of skills is mostly fetch metadata/convert :P

You're correct as well, every page is it's own unique image jpeg, and every image appears to be the same size/resolution!

Thanks again!
~M

Edit: I apologize in advance if this is something obvious or google-able. I'm having a hard time searching for answers to this particular question because most of my results bring me to cover images... it seems unique to have a 'book' composed of images, but most of my sons kids books are this way (new ones are fine just the older ones are challenging).

DNSB · 06-28-2023, 04:20 PM

I use Sigil for most epub editing tasks but the calibre editor will work much the same.

Basically, copy and paste everything from the "<style type="text/css">" to the "/div>" which are bolded in the code box. Locate the image size, modify the SVG wrapper with the image size and image file name. I've attached a sample of a page displaying a single image. The <h3 class="hidden">Chapter Title</h3> allows a title for the page in the ToC without having the text visible. You can leave it out if you are not using a ToC to jump between chapters.

Since you mention the images are the same size, you can modify one file and then use that as the source to copy/paste leaving only the image file name needing to be changed.

Code:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html>

<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops">
<head>
  <meta charset="utf-8"/>
  <title>Cardinal PNG</title>
  <link href="../Styles/stylesheet.css" rel="stylesheet" type="text/css"/>
  <style type="text/css">
@page {padding: 0; margin:0}
            body { text-align: center; padding:0; margin: 0; }
</style>
</head>

<body>
  <h3 class="hidden">Cardinal PNG</h3>

  <div>
    <svg height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1500 2000" width="100%" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="2000" width="1500" xlink:href="../Images/cardinal.png"/></svg>
  </div>
</body>
</html>

CSS stylesheet:

Code:

body {
  display: block;
  font-size: 1em;
  margin: 0 0 0 0;
  padding: 0 0 0 0;
  widows: 1;
  orphans: 1;
}

.hidden {
  display: none;
}

JSWolf · 06-28-2023, 07:42 PM

Are these images supposed to be full screen? Would they be OK say 1/2 screen?

mgrimace · 06-28-2023, 10:23 PM

Quote:

Originally Posted by JSWolf

Are these images supposed to be full screen? Would they be OK say 1/2 screen?

hmm, it'd probably fine half screen, right now they're roughly a quarter of the screen. They're basically comic strips. Each panel, which is then even smaller since there's a few panels per page, is difficult to read at that size for him as a relatively new reader.

I'm trying to make it as fun and painless as possible for him to encourage reading as much as I can

mgrimace · 06-28-2023, 10:24 PM

Quote:

Originally Posted by DNSB

I use Sigil for most epub editing tasks but the calibre editor will work much the same.

Basically, copy and paste everything from the "<style type="text/css">" to the "/div>" which are bolded in the code box. Locate the image size, modify the SVG wrapper with the image size and image file name. I've attached a sample of a page displaying a single image. The <h3 class="hidden">Chapter Title</h3> allows a title for the page in the ToC without having the text visible. You can leave it out if you are not using a ToC to jump between chapters.

Since you mention the images are the same size, you can modify one file and then use that as the source to copy/paste leaving only the image file name needing to be changed.

Code:

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html>

<html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops">
<head>
  <meta charset="utf-8"/>
  <title>Cardinal PNG</title>
  <link href="../Styles/stylesheet.css" rel="stylesheet" type="text/css"/>
  <style type="text/css">
@page {padding: 0; margin:0}
            body { text-align: center; padding:0; margin: 0; }
</style>
</head>

<body>
  <h3 class="hidden">Cardinal PNG</h3>

  <div>
    <svg height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1500 2000" width="100%" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="2000" width="1500" xlink:href="../Images/cardinal.png"/></svg>
  </div>
</body>
</html>

CSS stylesheet:

Code:

body {
  display: block;
  font-size: 1em;
  margin: 0 0 0 0;
  padding: 0 0 0 0;
  widows: 1;
  orphans: 1;
}

.hidden {
  display: none;
}

Thanks so much for the detailed info and clear steps, I appreciate it!

Comfy.n · 06-28-2023, 11:55 PM

I had this case a while ago: a magazine in AZW3 format that, when converted to PDF, would result in images compressed and reduced, no matter what I would change in the HTML or the conversion settings. I just wanted uncompressed and full-size images.

HTML looked like this for each image:

<body><div class="class-0-7" id="id-0-7"><div class="class-0-8" id="id-0-8"><img class="class-0-9" id="id-0-9" src="../images/00003.jpeg" width="2386" height="3142"/></div></div>

What eventually worked was extracting all images to a folder, creating a ZIP archive with them - I had luck that their filenames were numerically ordered. Then I renamed it to CBZ and was able to convert this file to PDF without any compression or image resizing.

In this case, I had to disable comic processing in Calibre CBZ input conversion dialog.

edit: I don't know if CBZ or PDF are available on the Libra but... just a random idea.

06-28-2023, 08:34 AM	#1
mgrimace Connoisseur Posts: 93 Karma: 1255124 Join Date: Feb 2013 Location: Ontario, Canada Device: Kobo Libra Colour, Kobo Libra 2, Kobo Libra H2O, Kindle Oasis 9	old kids book images within epub too small on Libra Hello, I have a number of old kids ebooks that are basically comprised entirely of images wrapped inside an epub (e.g., comic-style kids books). The problem is that many of the older books have defined image sizes and each page shows up too small on my son's Kobo libra H20 (e.g., 800xsomething). Is there a plugin or way to automatically grow the images within the book to fit the screen (not the cover, the actual pages themselves)? The actual resolution doesn't matter if it's fuzzy or anything, they're fairly simple black and children's comic images. I've tried setting the output style to tablet (no restrictions), Oasis (same resolution) but the images remain small. Appreciate any advice

06-28-2023, 02:12 PM	#2
DNSB Bibliophagist Posts: 46,168 Karma: 168983734 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	You could try wrapping the images in an svg wrapper. Adjust the '1000' width and '1500' height to match the images you are using in both places where they are used. The last time I did something similar, 90% of the images were the same size so a simple copy/paste/edit image file name did most of the work. Code: <style type="text/css"> @page {padding: 0; margin:0;} body { text-align: center; padding:0; margin: 0; } </style> </head> <body> <div> <svg xmlns="http://www.w3.org/2000/svg" height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1000 1500" width="100%" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="1500" width="1000" xlink:href="../Images/image001.jpeg"/></svg> </div>

06-28-2023, 04:20 PM	#6
DNSB Bibliophagist Posts: 46,168 Karma: 168983734 Join Date: Jul 2010 Location: Vancouver Device: Kobo Sage, Libra Colour, Lenovo M8 FHD, Paperwhite 4, Tolino epos	I use Sigil for most epub editing tasks but the calibre editor will work much the same. Basically, copy and paste everything from the "<style type="text/css">" to the "/div>" which are bolded in the code box. Locate the image size, modify the SVG wrapper with the image size and image file name. I've attached a sample of a page displaying a single image. The <h3 class="hidden">Chapter Title</h3> allows a title for the page in the ToC without having the text visible. You can leave it out if you are not using a ToC to jump between chapters. Since you mention the images are the same size, you can modify one file and then use that as the source to copy/paste leaving only the image file name needing to be changed. Code: <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html> <html lang="en" xml:lang="en" xmlns="http://www.w3.org/1999/xhtml" xmlns:epub="http://www.idpf.org/2007/ops"> <head> <meta charset="utf-8"/> <title>Cardinal PNG</title> <link href="../Styles/stylesheet.css" rel="stylesheet" type="text/css"/> <style type="text/css"> @page {padding: 0; margin:0} body { text-align: center; padding:0; margin: 0; } </style> </head> <body> <h3 class="hidden">Cardinal PNG</h3> <div> <svg height="100%" preserveAspectRatio="xMidYMid meet" version="1.1" viewBox="0 0 1500 2000" width="100%" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink"><image height="2000" width="1500" xlink:href="../Images/cardinal.png"/></svg> </div> </body> </html> CSS stylesheet: Code: body { display: block; font-size: 1em; margin: 0 0 0 0; padding: 0 0 0 0; widows: 1; orphans: 1; } .hidden { display: none; } Last edited by DNSB; 06-28-2023 at 04:23 PM.

06-28-2023, 11:55 PM	#10
Comfy.n want to learn what I want Posts: 1,611 Karma: 7891011 Join Date: Sep 2020 Device: none	I had this case a while ago: a magazine in AZW3 format that, when converted to PDF, would result in images compressed and reduced, no matter what I would change in the HTML or the conversion settings. I just wanted uncompressed and full-size images. HTML looked like this for each image: <body><div class="class-0-7" id="id-0-7"><div class="class-0-8" id="id-0-8"><img class="class-0-9" id="id-0-9" src="../images/00003.jpeg" width="2386" height="3142"/></div></div> What eventually worked was extracting all images to a folder, creating a ZIP archive with them - I had luck that their filenames were numerically ordered. Then I renamed it to CBZ and was able to convert this file to PDF without any compression or image resizing. In this case, I had to disable comic processing in Calibre CBZ input conversion dialog. edit: I don't know if CBZ or PDF are available on the Libra but... just a random idea. Last edited by Comfy.n; 06-29-2023 at 12:06 AM.

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06-28-2023, 07:42 PM	#7
JSWolf Resident Curmudgeon Posts: 79,743 Karma: 145864619 Join Date: Nov 2006 Location: Roslindale, Massachusetts Device: Kobo Libra 2, Kobo Aura H2O, PRS-650, PRS-T1, nook STR, PW3	Are these images supposed to be full screen? Would they be OK say 1/2 screen?