png files do not appear. only on PocketBook

Espoir · 04-15-2020, 08:23 PM

Hello,

I am happy to have found your forum and I sincerely hope that you will be able to help me. Sorry for my English, I'm French.
Because of the Covid-19, I decided to write a book to help a grandparent's bereaved children because of the virus.
To try to give this book away for free as quickly as possible, I decided to make an ebook.
I am not a computer scientist and I apologize in advance for my low level.
Since I basically had a pdf, my book is 20 pages long, and I absolutely wanted to fix my layout,
Here's what I did:
I got each of my pages from my pdf in jpeg and png.
On Sigil: I started on the project to make a .epub3 where I put a photo (either in jpeg or in png depending on the weight / resolution) per page.

Here is my pb: .epub obtained works wonderfully on all e-readers and tablets tested EXCEPT on PocketBook.
On this brand, only my pages with jpeg images are displayed and not the png. While this brand accepts png normally. The pages with png image do not appear in the reader. There is a page but white.
I miss spending all my pages in jpeg because the resolution is better in png for an almost identical weight. Since my text is in these images, I will not want to affect the visual quality.

I do not understand. No matter how much I check again and again, I don't see why everyone else is reading my png and not this mark.

here are excerpts from my file content.opf
<meta name="cover" content="cover.jpg" />
</metadata>
<manifest>
<item id="Section0002.xhtml" href="Text/Section0002.xhtml" media-type="application/xhtml+xml"/>
<item id="Section0003.xhtml" href="Text/Section0003.xhtml" media-type="application/xhtml+xml"/>
<item id="Section0004.xhtml" href="Text/Section0004.xhtml" media-type="application/xhtml+xml"/>
<item id="Section0005.xhtml" href="Text/Section0005.xhtml" media-type="application/xhtml+xml"/>

(.....)
<item id="ncx" href="toc.ncx" media-type="application/x-dtbncx+xml"/>
<item id="cover.xhtml" href="Text/cover.xhtml" media-type="application/xhtml+xml"/>
<item id="x1.jpg" href="Images/1.jpg" media-type="image/jpeg"/>
<item id="x2.jpg" href="Images/2.jpg" media-type="image/jpeg"/>
<item id="x3.png" href="Images/3.png" media-type="image/png"/>
<item id="x4.png" href="Images/4.png" media-type="image/png"/>
<item id="x5.png" href="Images/5.png" media-type="image/png"/>

I only put the first pages for you. Do you see any errors? I put it well : media-type="image/png". Should we write it differently?

I also give you what I have in my "Section0003.xhtml" where there is a pgn image.

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="fr">
<head>
<title>Gramps</title>
</head>

<body>
<div style="text-align: center; padding: 0pt; margin: 0pt;">
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="100%" height="100%" viewBox="0 0 1410 2250" preserveAspectRatio="xMidYMid">
<image width="1410" height="2250" xlink:href="../Images/3.png"/>
</svg>

</div>
</body>
</html>

To compare, I also give you what I have in my "Section0002.xhtml" where there is a jpeg image. (this one works)

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="fr">
<head>
<title>Dedication</title>
</head>
<body>
<div style="text-align: center; padding: 0pt; margin: 0pt;">
<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="100%" height="100%" viewBox="0 0 1410 2250" preserveAspectRatio="xMidYMid">
<image width="1410" height="2250" xlink:href="../Images/2.jpg"/>
</svg>
</div>
</body>
</html>

Thank you so much.
Take care,
Marion.

KevinH · 04-15-2020, 08:36 PM

If it works on all readers except for the PocketBook perhaps the PocketBook has a limitations or bug with large png images.

Have you tried the same code but with a smaller .png image to see if it works on the PocketBook. Have you tried without wrapping it in an svg? I did not see any obvious issues with your code.

Espoir · 04-16-2020, 01:30 AM

Quote:

Originally Posted by KevinH

If it works on all readers except for the PocketBook perhaps the PocketBook has a limitations or bug with large png images.

Have you tried the same code but with a smaller .png image to see if it works on the PocketBook. Have you tried without wrapping it in an svg? I did not see any obvious issues with your code.

Thank you for your reply. My png files are max 170ko.

I saw an old discussion with exactly the same problem as me but with Kobo.
https://www.mobileread.com/forums/sh...d.php?t=224526

They said : "Yes, this is a Kobo firmware issue.
The PNG will display fine if you force the reader to use the epub3
rendering engine.
The easiest way to do this is to obtain the Kobo Extended plugin
for Calibre which modifies the epub to look like the Kobo .kepub
format, which is rendered using the epub3 engine."

What you do think about this ?
Could I do something similar without altering the compatibility on other readers? If yes, how should I proceed?

Thank you.

Doitsu · 04-16-2020, 02:15 AM

@espoir:

It's hard to narrow down the problem without access to the files. Create a short demo file with one of the .png files that won't show on your Pocketbook and post it here.

You could also try to process your book with the Polish tool in Calibre (check Losslessly compress images). This might fix some problems created by tools that don't create standard-compliant .png files.

Espoir · 04-16-2020, 03:49 AM

Quote:

Originally Posted by Doitsu

@espoir:

It's hard to narrow down the problem without access to the files. Create a short demo file with one of the .png files that won't show on your Pocketbook and post it here.

You could also try to process your book with the Polish tool in Calibre (check Losslessly compress images). This might fix some problems created by tools that don't create standard-compliant .png files.

Thank you, I will try it. I put the epub in attachment. Thank you so much!

Doitsu · 04-16-2020, 11:57 AM

@Espoir

I've checked the .png files and they're all valid. Since your book displays fine both with ADE and Apple Books, this appears to be a PocketBook issue.

If device compatibility is important to you, you might want to replace the image files with HTML files because you can create the same look that your book now has by embedding fonts with Calibre or Sigil.

(You can also use my CSSFromFonts Sigil plugin to create the font framework.)

PeterT · 04-16-2020, 12:11 PM

Looking at the book it does seem relatively simple and I believe you'd easily be able to convert it to a textual Epub as opposed to one containing images.

There are some basic tutorials on creating epubs; for instance see https://wiki.mobileread.com/wiki/EPub_Tutorial

Another item to check (I'm on a phone right now so can't check); how are those images saved (not really sure of the technical term to use). RGB or CMYK?

j.p.s · 04-16-2020, 12:47 PM

Quote:

Originally Posted by Espoir

Thank you, I will try it. I put the epub in attachment. Thank you so much!

The PNGs are all RGBA instead of plain RGB. Could that be the problem?

DNSB · 04-16-2020, 01:57 PM

Quote:

Originally Posted by j.p.s

The PNGs are all RGBA instead of plain RGB. Could that be the problem?

Quite possibly. I remember quite a few years back that one company I did some work for had to convert their webpage png images to RGB with a colour indexed as transparent due to complaints from some users that the RGBA images showed as dark blobs.

Espoir · 04-16-2020, 03:15 PM

Quote:

Originally Posted by Doitsu

@Espoir

I've checked the .png files and they're all valid. Since your book displays fine both with ADE and Apple Books, this appears to be a PocketBook issue.

If device compatibility is important to you, you might want to replace the image files with HTML files because you can create the same look that your book now has by embedding fonts with Calibre or Sigil.

(You can also use my CSSFromFonts Sigil plugin to create the font framework.)

I had tried at the beginning to make my text normally in html but the readers did not respect my layout. My texts from the different pages were glued to each other. That's why I told myself that if I put an image like that I was quiet. It is essential that my text is divided into pages as always in the same way, even there is empty space. In addition, the text must always be the same size, whether there is very few text in all the page. Always centered, in the middle of the page. I had the impression that these criteria made it impossible to put into conventional text. I am wrong ? (I am ready to return to jpg if necessary but in no case my text must not respect my specific layout.)

Doitsu · 04-16-2020, 04:41 PM

Quote:

Originally Posted by Espoir

In addition, the text must always be the same size, whether there is very few text in all the page.

In that case, you might want to consider creating a .pdf file and publishing it as a print book via Kindle Direct Publishing.

Theoretically, you could also create a fixed layout epub, but only a handful epub3 readers and apps actually support this format.

If you want to give CSS a try, post a sample file that contains 2 typical chapters both as images and as HTML files. I'm sure that someone with better CSS skills than me will come up with a stylesheet that closely matches your layout, if you give us the name and the size of the font that you used for the images.

You also might want to remove the other attachment, since it appears to be your complete book.

Espoir · 04-16-2020, 05:23 PM

Quote:

Originally Posted by DNSB

Quite possibly. I remember quite a few years back that one company I did some work for had to convert their webpage png images to RGB with a colour indexed as transparent due to complaints from some users that the RGBA images showed as dark blobs.

my png are srgb. Can be the problem ?

Tex2002ans · 04-16-2020, 05:31 PM

I tested the Post #5 EPUB on my Android phone, PocketBook app, and it works fine.

Is your device much older, maybe doesn't have enough RAM?

Espoir · 04-16-2020, 06:12 PM

Quote:

Originally Posted by Doitsu

In that case, you might want to consider creating a .pdf file and publishing it as a print book via Kindle Direct Publishing.

Theoretically, you could also create a fixed layout epub, but only a handful epub3 readers and apps actually support this format.

If you want to give CSS a try, post a sample file that contains 2 typical chapters both as images and as HTML files. I'm sure that someone with better CSS skills than me will come up with a stylesheet that closely matches your layout, if you give us the name and the size of the font that you used for the images.

You also might want to remove the other attachment, since it appears to be your complete book.

I have a pdf. But on the platforms I can't put it. They convert it automatically. On Amazon, I was able to put the ebook because their conversion to them from my epub posed no bp. But I want to put it on other sites and there I need an ePub. I'll try to convert the png... Cross fingers!

Espoir · 04-16-2020, 06:27 PM

Quote:

Originally Posted by Tex2002ans

I tested the Post #5 EPUB on my Android phone, PocketBook app, and it works fine.

Is your device much older, maybe doesn't have enough RAM?

It was two friends of mine who tested. One with a reader from 2014 but another with a reader from 2018 (with RAM =1GB). Do you think that the reader for 2018 is just too old? How do I do then? I stop bothering myself and tell them that they need the latest updates and that they can always reach me if they want a pdf?

04-15-2020, 08:23 PM	#1
Espoir Member Posts: 11 Karma: 10 Join Date: Apr 2020 Device: epub3	png files do not appear. only on PocketBook Hello, I am happy to have found your forum and I sincerely hope that you will be able to help me. Sorry for my English, I'm French. Because of the Covid-19, I decided to write a book to help a grandparent's bereaved children because of the virus. To try to give this book away for free as quickly as possible, I decided to make an ebook. I am not a computer scientist and I apologize in advance for my low level. Since I basically had a pdf, my book is 20 pages long, and I absolutely wanted to fix my layout, Here's what I did: I got each of my pages from my pdf in jpeg and png. On Sigil: I started on the project to make a .epub3 where I put a photo (either in jpeg or in png depending on the weight / resolution) per page. Here is my pb: .epub obtained works wonderfully on all e-readers and tablets tested EXCEPT on PocketBook. On this brand, only my pages with jpeg images are displayed and not the png. While this brand accepts png normally. The pages with png image do not appear in the reader. There is a page but white. I miss spending all my pages in jpeg because the resolution is better in png for an almost identical weight. Since my text is in these images, I will not want to affect the visual quality. I do not understand. No matter how much I check again and again, I don't see why everyone else is reading my png and not this mark. here are excerpts from my file content.opf <meta name="cover" content="cover.jpg" /> </metadata> <manifest> <item id="Section0002.xhtml" href="Text/Section0002.xhtml" media-type="application/xhtml+xml"/> <item id="Section0003.xhtml" href="Text/Section0003.xhtml" media-type="application/xhtml+xml"/> <item id="Section0004.xhtml" href="Text/Section0004.xhtml" media-type="application/xhtml+xml"/> <item id="Section0005.xhtml" href="Text/Section0005.xhtml" media-type="application/xhtml+xml"/> (.....) <item id="ncx" href="toc.ncx" media-type="application/x-dtbncx+xml"/> <item id="cover.xhtml" href="Text/cover.xhtml" media-type="application/xhtml+xml"/> <item id="x1.jpg" href="Images/1.jpg" media-type="image/jpeg"/> <item id="x2.jpg" href="Images/2.jpg" media-type="image/jpeg"/> <item id="x3.png" href="Images/3.png" media-type="image/png"/> <item id="x4.png" href="Images/4.png" media-type="image/png"/> <item id="x5.png" href="Images/5.png" media-type="image/png"/> I only put the first pages for you. Do you see any errors? I put it well : media-type="image/png". Should we write it differently? I also give you what I have in my "Section0003.xhtml" where there is a pgn image. <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="fr"> <head> <title>Gramps</title> </head> <body> <div style="text-align: center; padding: 0pt; margin: 0pt;"> <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="100%" height="100%" viewBox="0 0 1410 2250" preserveAspectRatio="xMidYMid"> <image width="1410" height="2250" xlink:href="../Images/3.png"/> </svg> </div> </body> </html> To compare, I also give you what I have in my "Section0002.xhtml" where there is a jpeg image. (this one works) <?xml version="1.0" encoding="utf-8"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="fr"> <head> <title>Dedication</title> </head> <body> <div style="text-align: center; padding: 0pt; margin: 0pt;"> <svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" width="100%" height="100%" viewBox="0 0 1410 2250" preserveAspectRatio="xMidYMid"> <image width="1410" height="2250" xlink:href="../Images/2.jpg"/> </svg> </div> </body> </html> Thank you so much. Take care, Marion.

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04-15-2020, 08:36 PM	#2
KevinH Sigil Developer Posts: 8,759 Karma: 5706256 Join Date: Nov 2009 Device: many	If it works on all readers except for the PocketBook perhaps the PocketBook has a limitations or bug with large png images. Have you tried the same code but with a smaller .png image to see if it works on the PocketBook. Have you tried without wrapping it in an svg? I did not see any obvious issues with your code.

04-16-2020, 02:15 AM	#4
Doitsu Grand Sorcerer Posts: 5,727 Karma: 24031401 Join Date: Dec 2010 Device: Kindle PW2	@espoir: It's hard to narrow down the problem without access to the files. Create a short demo file with one of the .png files that won't show on your Pocketbook and post it here. You could also try to process your book with the Polish tool in Calibre (check Losslessly compress images). This might fix some problems created by tools that don't create standard-compliant .png files.

04-16-2020, 11:57 AM	#6
Doitsu Grand Sorcerer Posts: 5,727 Karma: 24031401 Join Date: Dec 2010 Device: Kindle PW2	@Espoir I've checked the .png files and they're all valid. Since your book displays fine both with ADE and Apple Books, this appears to be a PocketBook issue. If device compatibility is important to you, you might want to replace the image files with HTML files because you can create the same look that your book now has by embedding fonts with Calibre or Sigil. (You can also use my CSSFromFonts Sigil plugin to create the font framework.)

04-16-2020, 12:11 PM	#7
PeterT Grand Sorcerer Posts: 13,507 Karma: 78910112 Join Date: Nov 2007 Location: Toronto Device: Libra H2O, Libra Colour	Looking at the book it does seem relatively simple and I believe you'd easily be able to convert it to a textual Epub as opposed to one containing images. There are some basic tutorials on creating epubs; for instance see https://wiki.mobileread.com/wiki/EPub_Tutorial Another item to check (I'm on a phone right now so can't check); how are those images saved (not really sure of the technical term to use). RGB or CMYK?

04-16-2020, 05:31 PM	#13
Tex2002ans Wizard Posts: 2,306 Karma: 13057279 Join Date: Jul 2012 Device: Kobo Forma, Nook	I tested the Post #5 EPUB on my Android phone, PocketBook app, and it works fine. Is your device much older, maybe doesn't have enough RAM?

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