Re: How much is one em (image size unit)?

[Fu Yuan]

> 在 2023年4月1日，上午5:35，Akib Azmain Turja <akib@disroot.org> 写道：
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
>>> From: Akib Azmain Turja <akib@disroot.org>
>>> Cc: Manuel Giraud <manuel@ledu-giraud.fr>
>>> Date: Fri, 31 Mar 2023 22:32:49 +0600
>>> 
>>>> Akib Azmain Turja <akib@disroot.org> writes:
>>>> 
>>>>> I'm trying to show an image such that it has same height as the text and
>>>>> resizes relatively with text scale.  I've achieved this with the 'em'
>>>>> unit as described in (elisp)Image Descriptors.  But 1 em seems to be
>>>>> pretty smaller than the font size.  How to figure out correct value in
>>>>> em unit such that image and the text has correct height?
>>>> 
>>>> Hi,
>>>> 
>>>> FWIW, your example works for me and scales accordingly when I zoom.
>>> 
>>> But 1 em is pretty smaller than the default font size.  I want to make
>>> the image height and the text height same.
>> 
>> Maybe this page will help you:
>> 
>>  https://learn.microsoft.com/en-us/typography/opentype/spec/ttch01
>> 
> 
> Thanks, but I couldn't understand much.  Say the line height is X em,
> then how can I figure out that X?

1 em equals to the text height. If your 1 em looks smaller than the text 
height, something might be wrong. Perhaps post a screenshot of what you get?

Yuan