[ENHANCEMENT] Reducing book size through image scaling

xdgc · 08-06-2019, 03:55 PM

Space is at premium on my 4GB Paperwhite. A number of my books have glorious big full color photos that I can't make use of on a 1448x1072 B&W screen, so I wrote a program to resample these to fit on screen in grayscale. I save as much as 80%-85% of book size this way.

I wanted to integrate this into Calibre. At first I tried making a separate plugin, but in the end I felt it fit much better as an addition to Polish. I have a patch that implements this "kindlify" mode as an alternative to Polish's stock image recompression.

What is the correct procedure to submit this for review upstream? The various web pages and posts here are unclear on the subject of how to submit ready-for-review updates to core Calibre, and the launchpad tracker doesn't seem like the right place to send git branches. Github PR?

kovidgoyal · 08-06-2019, 08:48 PM

github PR is fine, however, Polish is supposed to only have non-destructive tools. A separate grayscaling/downsampling tool would be better.

xdgc · 08-06-2019, 09:23 PM

Thanks. I guess I see this as little different from the existing image recompression. I do not want to destroy the original, which is why I leaned toward Polish: it keeps the ORIGINAL_FOO format. Creating another plugin that creates ORIGINAL_ formats seems redundant.

But let's say I redo it as a standalone plugin. What's your advice on naming my original so that it does not conflict with Polish?

kovidgoyal · 08-06-2019, 10:21 PM

Feel free to name it ORIGINAL_ that is used by many things in calibre, including the conversion system.

xdgc · 08-06-2019, 10:42 PM

Alright. I don't know whether I will get around to this (plugin architecture super confuses me) but I appreciate the guidance.

kovidgoyal · 08-06-2019, 11:46 PM

Feel free to ask if you need guidance, lots of plugin developers hang out here.

08-06-2019, 03:55 PM	#1
xdgc Junior Member Posts: 3 Karma: 10 Join Date: Aug 2019 Device: none	[ENHANCEMENT] Reducing book size through image scaling Space is at premium on my 4GB Paperwhite. A number of my books have glorious big full color photos that I can't make use of on a 1448x1072 B&W screen, so I wrote a program to resample these to fit on screen in grayscale. I save as much as 80%-85% of book size this way. I wanted to integrate this into Calibre. At first I tried making a separate plugin, but in the end I felt it fit much better as an addition to Polish. I have a patch that implements this "kindlify" mode as an alternative to Polish's stock image recompression. What is the correct procedure to submit this for review upstream? The various web pages and posts here are unclear on the subject of how to submit ready-for-review updates to core Calibre, and the launchpad tracker doesn't seem like the right place to send git branches. Github PR?

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Shrinking pdf in calibre / different folders reducing size	godlich	PDF	5	08-27-2014 02:31 AM
Tutorial on reducing font size on a per book basis	howyoudoin	Amazon Kindle	0	11-09-2013 06:47 AM
Reducing file size for straight-text epub?	Christi H	ePub	5	01-10-2013 10:09 PM
Reducing the size of epub files?	Corpsegoddess	ePub	8	01-09-2013 08:14 PM
Calibre reducing image sizes?	HarryT	Conversion	2	04-21-2011 08:18 AM

08-06-2019, 08:48 PM	#2
kovidgoyal creator of calibre Posts: 43,835 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	github PR is fine, however, Polish is supposed to only have non-destructive tools. A separate grayscaling/downsampling tool would be better.

08-06-2019, 09:23 PM	#3
xdgc Junior Member Posts: 3 Karma: 10 Join Date: Aug 2019 Device: none	Thanks. I guess I see this as little different from the existing image recompression. I do not want to destroy the original, which is why I leaned toward Polish: it keeps the ORIGINAL_FOO format. Creating another plugin that creates ORIGINAL_ formats seems redundant. But let's say I redo it as a standalone plugin. What's your advice on naming my original so that it does not conflict with Polish?

08-06-2019, 10:21 PM	#4
kovidgoyal creator of calibre Posts: 43,835 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Feel free to name it ORIGINAL_ that is used by many things in calibre, including the conversion system.

08-06-2019, 10:42 PM	#5
xdgc Junior Member Posts: 3 Karma: 10 Join Date: Aug 2019 Device: none	Alright. I don't know whether I will get around to this (plugin architecture super confuses me) but I appreciate the guidance.

08-06-2019, 11:46 PM	#6
kovidgoyal creator of calibre Posts: 43,835 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Feel free to ask if you need guidance, lots of plugin developers hang out here.