Font display size is incorrect

Font display size is incorrect

[Anand Tamariya]

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In the screenshot
(https://lifeofpenguin.blogspot.com/2021/06/basic-wysiwyg-printing-in-gnu-emacs.html),
<https://lifeofpenguin.blogspot.com/2021/06/basic-wysiwyg-printing-in-gnu-emacs.html>:height
property is set as the number in parentheses. The text display size is
incorrect in some cases. Following pairs are shown as same size: 120-130,
170-180, 210-220, 230-240.

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Re: Font display size is incorrect

[Eli Zaretskii]

> From: Anand Tamariya <atamariya@gmail.com>
> Date: Sun, 13 Jun 2021 11:17:44 +0530
> 
> In the screenshot (https://lifeofpenguin.blogspot.com/2021/06/basic-wysiwyg-printing-in-gnu-emacs.html), 
> :height property is set as the number in parentheses. The text display size is incorrect in some cases.
> Following pairs are shown as same size: 120-130, 170-180, 210-220, 230-240.

If you look closely at the produced display, you will see that the
heights of the above pairs of lines are indeed different; it's the
_width_ that is identical.  So it sounds like you expected the width
to change together with the height, but I'm not sure I understand why
such an assumption is justified.

Re: Font display size is incorrect

[Anand Tamariya]

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On Sun, Jun 13, 2021 at 1:47 PM Eli Zaretskii <eliz@gnu.org> wrote:

> > From: Anand Tamariya <atamariya@gmail.com>
> > Date: Sun, 13 Jun 2021 11:17:44 +0530
> >
> > In the screenshot (
> https://lifeofpenguin.blogspot.com/2021/06/basic-wysiwyg-printing-in-gnu-emacs.html),
>
> > :height property is set as the number in parentheses. The text display
> size is incorrect in some cases.
> > Following pairs are shown as same size: 120-130, 170-180, 210-220,
> 230-240.
>
> If you look closely at the produced display, you will see that the
> heights of the above pairs of lines are indeed different; it's the
> _width_ that is identical.  So it sounds like you expected the width
> to change together with the height, but I'm not sure I understand why
> such an assumption is justified.
>
If the fonts are only vertically stretched for their heights, all the lines
should be the same width. This is not the case. What's the algorithm here?
Is there a recommended way to draw 17pt and 18pt text so that they appear
distinct proportionally as they would in a hardcopy?

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Re: Font display size is incorrect

[Eli Zaretskii]

> From: Anand Tamariya <atamariya@gmail.com>
> Date: Sun, 13 Jun 2021 19:15:02 +0530
> Cc: emacs-devel@gnu.org
> 
>  If you look closely at the produced display, you will see that the
>  heights of the above pairs of lines are indeed different; it's the
>  _width_ that is identical.  So it sounds like you expected the width
>  to change together with the height, but I'm not sure I understand why
>  such an assumption is justified.
> 
> If the fonts are only vertically stretched for their heights, all the lines should be the same width. This is not the
> case. What's the algorithm here?

I don't think (but am not sure) the algorithm for choosing the width
for specific height is in Emacs.  I think it's in the font back-end,
like Fontconfig.

> Is there a recommended way to draw 17pt and 18pt text so that they appear distinct proportionally as they
> would in a hardcopy?

Sorry, I don't think I understand the question (and am not an expert
on font-related issues anyway).