understanding font size

arslonga · 05-02-2019, 11:40 PM

Just out of curiosity, what is the unit for font size? koreader only displays a numerical value. Thank you for your attention.

NiLuJe · 05-03-2019, 12:36 AM

It's just that: a numerical value ;p. Probably not even close to a point, given how it's affected by potentially-user-configured DPI scaling.

It gets thrown through the usual blender of DPI scaling according to user-preference, which leads to a value in pixels, and, for reflowable content, that is run through a sieve to round it to the nearest integer value in a scale of supported values (a scale recently updated to basically offer full granularity in steps of 1px).
In the end, CRe honors a px value (you never get to actually see that value, but you could, with a simple well-placed print statement).

warface9991 · 05-06-2019, 06:16 AM

Quote:

Originally Posted by NiLuJe

It's just that: a numerical value ;p. Probably not even close to a point, given how it's affected by potentially-user-configured DPI scaling.

It gets thrown through the usual blender of DPI scaling according to user-preference, which leads to a value in pixels, and, for reflowable content, that is run through a sieve to round it to the nearest integer value in a scale of supported values (a scale recently updated to basically offer full granularity in steps of 1px).
In the end, CRe honors a px value (you never get to actually see that value, but you could, with a simple well-placed print statement).

Hi

What does DPI do? The default is 96 but when I increase the DPI I don't see much change. Does increasing it make it better to look at text?

Frenzie · 05-06-2019, 09:07 AM

For reasons that aren't completely clear to me the program's DPI and the crengine DPI aren't completely linked. Generally speaking you'll see more of a difference by playing around with Settings → Screen.

NiLuJe · 05-06-2019, 12:36 PM

Oh, right, yeah, what @Frenzie said. The DPI button in the bottom menu is indeed... weirder

.

warface9991 · 05-06-2019, 03:37 PM

Thanks for your answers!

Frenzie · 05-07-2019, 05:54 AM

I think it's preferable to increase the crengine DPI (in the bottom menu) btw. You definitely see it with certain CSS units as well as image size.

maraskan_user · 04-10-2021, 07:27 AM

This is very interesting! Maybe we could use this thread to collate thoughts, theories and data on the functioning of the present scaling in KOReader. A couple of months ago I did some experiments and took a few notes on the different settings available:

"Screen DPI"

+ Affects UI size.
+ Affects EM fonts.
- Doesn't affect PX, PT, IN, imageSize.

src>> Device:setScreenDPI(_dpi)

"Font Size"

- Doesn't affects UI size.
+ Affects EM fonts.
- Doesn't affect PX, PT, IN, imageSize.

src>> SetFontSize()

"Zoom (dpi)"

- Doesn't affects UI size.
- Doesn't affects EM fonts.
+ Affects PX, PT, IN, imageSize.

src>> SetRenderDPI()
src>> self._document:setIntProperty("crengine.render.dpi ", value or 96)

This weird separation is more historically grown than intentional, I assume? I still remember how confusing it was when I started using koreader...

05-02-2019, 11:40 PM	#1
arslonga Connoisseur Posts: 59 Karma: 10 Join Date: Jul 2011 Device: none	understanding font size Just out of curiosity, what is the unit for font size? koreader only displays a numerical value. Thank you for your attention.

05-03-2019, 12:36 AM	#2
NiLuJe BLAM! Posts: 13,477 Karma: 26012492 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	It's just that: a numerical value ;p. Probably not even close to a point, given how it's affected by potentially-user-configured DPI scaling. It gets thrown through the usual blender of DPI scaling according to user-preference, which leads to a value in pixels, and, for reflowable content, that is run through a sieve to round it to the nearest integer value in a scale of supported values (a scale recently updated to basically offer full granularity in steps of 1px). In the end, CRe honors a px value (you never get to actually see that value, but you could, with a simple well-placed print statement). Last edited by NiLuJe; 05-03-2019 at 12:40 AM.

04-10-2021, 07:27 AM	#8
maraskan_user Member Posts: 12 Karma: 10 Join Date: Dec 2020 Location: Germany Device: Boox Nova 3, Galaxy Tab S6, Samsung M21	This is very interesting! Maybe we could use this thread to collate thoughts, theories and data on the functioning of the present scaling in KOReader. A couple of months ago I did some experiments and took a few notes on the different settings available: "Screen DPI" + Affects UI size. + Affects EM fonts. - Doesn't affect PX, PT, IN, imageSize. src>> Device:setScreenDPI(_dpi) "Font Size" - Doesn't affects UI size. + Affects EM fonts. - Doesn't affect PX, PT, IN, imageSize. src>> SetFontSize() "Zoom (dpi)" - Doesn't affects UI size. - Doesn't affects EM fonts. + Affects PX, PT, IN, imageSize. src>> SetRenderDPI() src>> self._document:setIntProperty("crengine.render.dpi ", value or 96) This weird separation is more historically grown than intentional, I assume? I still remember how confusing it was when I started using koreader...

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
iPad understanding kindle publisher font	arslonga	Apple Devices	6	04-25-2014 11:12 AM
Problem changing font size using font size key	Waylander	Conversion	0	10-02-2013 03:30 PM
Determine font and font size on incoming epub?	peaceridge	Calibre	4	01-30-2012 03:35 PM
PRS-300 Med font size too big, but small font size too small	eli2k	Sony Reader	4	05-28-2010 09:47 AM

05-06-2019, 09:07 AM	#4
Frenzie Wizard Posts: 1,613 Karma: 724945 Join Date: Oct 2014 Location: Antwerp Device: Kobo Aura H2O	For reasons that aren't completely clear to me the program's DPI and the crengine DPI aren't completely linked. Generally speaking you'll see more of a difference by playing around with Settings → Screen.

05-06-2019, 12:36 PM	#5
NiLuJe BLAM! Posts: 13,477 Karma: 26012492 Join Date: Jun 2010 Location: Paris, France Device: Kindle 2i, 3g, 4, 5w, PW, PW2, PW5; Kobo H2O, Forma, Elipsa, Sage, C2E	Oh, right, yeah, what @Frenzie said. The DPI button in the bottom menu is indeed... weirder .

05-06-2019, 03:37 PM	#6
warface9991 Connoisseur Posts: 58 Karma: 10 Join Date: Apr 2019 Device: Kobo GLO HD	Thanks for your answers!

05-07-2019, 05:54 AM	#7
Frenzie Wizard Posts: 1,613 Karma: 724945 Join Date: Oct 2014 Location: Antwerp Device: Kobo Aura H2O	I think it's preferable to increase the crengine DPI (in the bottom menu) btw. You definitely see it with certain CSS units as well as image size.