some questions...

[gianni_1]

Hello,
first of all I want to say that the more I use it, the more I love this wonderful program!
In order to improve more and more, I would have some questions:
- how many books can Calibre hold?
- is it possible to make a modification that allows you to change the fonts of all the selected books?
- Is it possible to make a modification that allows you to change the images .png to .jpg in all the selected books, perhaps using an external, free and powerful program like Bulk Image Converter?
- Is it possible to make a modification that allows you to compress the images of all the selected books?
- why has Calibre E-book viewer become so slow that it can take even more than a minute to open a book for the first time?
Thank you so much,
Gianni

[theducks]

Originally Posted by gianni_1

Hello,
first of all I want to say that the more I use it, the more I love this wonderful program!
In order to improve more and more, I would have some questions:
- how many books can Calibre hold?
- is it possible to make a modification that allows you to change the fonts of all the selected books?
- Is it possible to make a modification that allows you to change the images .png to .jpg in all the selected books, perhaps using an external, free and powerful program like Bulk Image Converter?
- Is it possible to make a modification that allows you to compress the images of all the selected books?
- why has Calibre E-book viewer become so slow that it can take even more than a minute to open a book for the first time?
Thank you so much,
Gianni

1) Way more than you can deal with in a lifetime
2) No. way to many possible ways. You CAN remove embedded fonts in bulk, but no finesse. All or do it by the edit, one at a time
3) Converting the image is only 1 step. THEN the code needs to follow the change. Why? most readers can use either.
4)What system spec? How big and complex a book. FWIW a 4KB, 385 page opens in ~ 20 secs on a i7

[Quoth]

I think Calibre and any laptop/PC/Mac it can run on can hold more than 10 lifetimes even if you read one a day. Limit is more likely your disc if you have a 32 G SSD rather than 256 G or a 512 G HDD.

[gianni_1]

The first book I opened today is a regular 148-page textbook with no images, Calibre opened it in a minute and 17 seconds.
My PC has an X570 Phantom Gaming 4 motherboard, an AMD Ryzen 7 2700 CPU, 16GB of RAM, and the Calibre library is on a 1TB SSD.
No other processes were running.
It's normal?

[BetterRed]

Originally Posted by gianni_1

The first book I opened today is a regular 148-page textbook with no images, Calibre opened it in a minute and 17 seconds.
My PC has an X570 Phantom Gaming 4 motherboard, an AMD Ryzen 7 2700 CPU, 16GB of RAM, and the Calibre library is on a 1TB SSD.
No other processes were running.
It's normal?

What format did you open

A 'regular 148 page textbook' suggests a PDF or other fixed layout format. That would require mini-conversion.

BR

[retiredbiker]

- Is it possible to make a modification that allows you to change the images .png to .jpg in all the selected books, perhaps using an external, free and powerful program like Bulk Image Converter?
- Is it possible to make a modification that allows you to compress the images of all the selected books?

1. I use ImageMagick for this. Open a book in the editor, then select and export all the png images to a working directory. Then at the command line, change to that directory and run

mogrify -format jpg *.png

. then run

rm *.png

This leaves you with the jpg images. Go back into the editor and delete all the png images, and import the new jpg ones. Then, in the text files, search for .png and replace with .jpg. (You have to do that so the html knows to display the new files, otherwise you get nothing.) Then do the compression you need. This whole thing usually takes less than a minute, ImageMagick is really fast.

2. "All selected books" is not available either for the conversion or the compression, do it one at a time. I suspect it would be very complex for a plugin to safely do this sort of thing for many books...lots of edge cases, possible coding problems inside the books, and so on. And if a plugin depended on some tool (like ImageMagick or your Bulk thing), how many users' PCs might have that particular too installed? And sometimes I find books with a combination of png and gif (and maybe other) image formats that don't compress well. Or useless images I just want to delete.

I do sympathise with the desire for a bulk utility for this--I have many bloated books I collected before I learned how to do this, and started doing it on adding each such book. But I now look for a lot of things when I add a book, and I don't think I'd trust much mass processing...just my thinking.

[gianni_1]

Originally Posted by BetterRed

What format did you open

A 'regular 148 page textbook' suggests a PDF or other fixed layout format. That would require mini-conversion.

BR

no, it's a normal book in epub format.

[gianni_1]

Originally Posted by retiredbiker

1. I use ImageMagick for this. Open a book in the editor, then select and export all the png images to a working directory. Then at the command line, change to that directory and run

mogrify -format jpg *.png

. then run

rm *.png

This leaves you with the jpg images. Go back into the editor and delete all the png images, and import the new jpg ones. Then, in the text files, search for .png and replace with .jpg. (You have to do that so the html knows to display the new files, otherwise you get nothing.) Then do the compression you need. This whole thing usually takes less than a minute, ImageMagick is really fast.

2. "All selected books" is not available either for the conversion or the compression, do it one at a time. I suspect it would be very complex for a plugin to safely do this sort of thing for many books...lots of edge cases, possible coding problems inside the books, and so on. And if a plugin depended on some tool (like ImageMagick or your Bulk thing), how many users' PCs might have that particular too installed? And sometimes I find books with a combination of png and gif (and maybe other) image formats that don't compress well. Or useless images I just want to delete.

I do sympathise with the desire for a bulk utility for this--I have many bloated books I collected before I learned how to do this, and started doing it on adding each such book. But I now look for a lot of things when I add a book, and I don't think I'd trust much mass processing...just my thinking.

I already follow a similar procedure (but I think faster ...):
- I open the book with the editor
- I select all the images (jpeg, png, jpg, so as not to waste time selecting only the .png) and export them to a working folder.
- I use a powerful program (Bulk Image Converter) to convert only .png to .jpg.
- I delete in the book the exported images.
- I import in the book the exported (and edited) images.
- I compress the imported images.
- finally I change in the book from .png to .jpg.
It sounds like a long procedure, but it's actually the fastest one possible.