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Mathematical equations in OPF posts

Doug Kerr

Doug Kerr

Well-known member
However, this picture:
1785697674505.png


does not have much greater pixel resolution (404 px × 163 px), and that is probably how I would work for that equation.

This may all have to do with different antialising strategies, etc.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

I guess I would be interested to hear of a case in which you included a picture of an equation in an actual post on some other forum, and see how that "comes out".

Maybe you did that already.

I'm not on any other forums, so I can't try that.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

Now this:
1785698302072.png


has a substantially greater pixel resolution (884 px × 251 px). (Also a different typeface - sorry.)

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

I don't understand the entire scenario here, but MML libreoffice II.mml does not contain any picture of an equation.

I'm not sure how you made that file.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

Well, I seem to have a number of MML files that seem just like yours but by version control system is so bad I have no idea how I made them.

I somehow have the recollection that at one recent time I was able to save MathML files out of LibreOffice Writer, but now I can't do that.

I wonder whether the installation of Writer2LaTeX some how got rid of that.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi,Ted,

Aha! If I open an ODF file in LibreOffice Math, I can then save that equation as an MML file out of Math.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,
Ted Cousins said:
dprevived.com

Posting Real Equations here

Started by xpatUSA on July 27, 2026 in the Technical Discussions category. 26 replies, last one from Aug. 3, 2026.
dprevived.com dprevived.com
Click to expand...

Interesting. I did not have all that detail about sizing the display of equations described in MathML code in an HTML document, although I did know that the text size attribute would affect that. (I use that when putting equations in MathML in my Thunderbird email messages.)

But I don't really understand what is going on here. For example, I have never suggested that the way to put "pictures" of equations in forum posts is with MathML code (in a MML file).

I could imagine some situation where HTML coding was used and I had access to it and wanted to "patch" in a MathML description of an equation, which I could get from an MML file. But I have not in reality encountered such a situation

Best regards,

Doug
 
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Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

I write to correct a misconception in my earlier writing about putting pictures of equations in OPF posts.

I had always suggested that when I Paste a Saved picture of an equation into my OPF message composition screen that the picture was somehow embedded in the code for the message.

In reality, best I understand it, when I Paste a picture of an equation into my OPF composition window, the local OPF software encodes that picture into a PNG file (with an arbitrary filename) and sends that PNG file to the OPF server (I don't know when that actually happens).

The post itself then includes a link to that PNG file on the OPF server, along with instructions as to its display sizing, which causes it to be visible in the post as I compose it and as it is seen by others.

I think.

Best regards,

Doug
 
Ted Cousins

Ted Cousins

Member
Doug Kerr said:
Hi, Ted,


Interesting. I did not have all that detail about sizing the display of equations described in MathML code in an HTML document, although I did know that the text size attribute would affect that. (I use that when putting equations in MathML in my Thunderbird email messages.)

But I don't really understand what is going on here. For example, I have never suggested that the way to put "pictures" of equations in forum posts is with MathML code (in a MML file).

I could imagine some situation where HTML coding was used and I had access to it and wanted to "patch" in a MathML description of an equation, which I could get from an MML file. But I have not in reality encountered such a situation

Best regards,

Doug
Click to expand...
Hi Doug,

Over there, @Bryan is being most helpful:

dprevived.com

Posting Real Equations here

Started by xpatUSA on July 27, 2026 in the Technical Discussions category. 28 replies, last one from Aug. 3, 2026.
dprevived.com dprevived.com

this and his previous comment about CSS may lead to an understanding of all these different on-screen sizes of the same source image.

ArvoJ's post has a screen shot of how his system opens the .mml file from my site:

dprevived.com

Posting Real Equations here

Started by xpatUSA on July 27, 2026 in the Technical Discussions category. 28 replies, last one from Aug. 3, 2026.
dprevived.com dprevived.com

amazingly small equation on my screen ... yours?

Just to be clear I was not really suggesting the use of an MML file in a post here or over there, although it may seem like that; only opening it somehow to get an equation image. On my machine, LibreOffice Math has comprehensive font-sizing, alignment, etc. and a screenshot can be gotten with Windows and edited further if needed. But the on-screen size/appearance can still vary between Sites and/or Users.
 
Last edited:
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

I'm not sure I understand this discussion of the display of MML files. Does this fit in some way into schemes for including equations in forum posts, or is it just a collateral (and certainly intellectually-interesting) matter?

In any case, if I open the MML file you cited earlier, its onscreen-size will, among other things, depend on the "zoomage" I have invoked in the opening application (which can of course be any of many applications here).
If I put an equation into a Thunderbird email message as MathML code, without further qualification, the receiving application will display it at some default scale. But if I include display size information, then that will typically govern the display scale in the receiving application.

If I just double-click on that file were I have it stored, my OS opens it in Firefox (my browser). With the default zoomage, the equation displayed there looks like this (I have tried to portray its actual size, which I really can't do):

1785769635040.png

But if I change the zoomage on Firefox to the greatest available value, then it looks like this:

1785769745564.png

But I am still unclear as to what the issue is here.

Indeed a MathML representative of an equation, absent any associated HTML code about display size, does not represent the equation as displayed at any specific physical scale. In that regard, the MathML code is just like this in HTML:

Boatyard​

At what size should that be rendered in some yet-unspecified receiving application? That is not defined.

There is of course much about this I don't know.

Best regards,

Doug
 
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Ted Cousins

Ted Cousins

Member
Doug Kerr said:
Hi, Ted,

I'm not sure I understand this discussion of the display of MML files. Does this fit in some way into schemes for including equations in forum posts, or is it just a collateral (and certainly intellectually-interesting) matter?

In any case, if I open the MML file you cited earlier, its onscreen-size will, among other things, depend on the "zoomage" I have invoked in the opening application (which can of course be any of many applications here).
If I put an equation into a Thunderbird email message as MathML code, without further qualification, the receiving application will display it at some default scale. But if I include display size information, then that will typically govern the display scale in the receiving application.

If I just double-click on that file were I have it stored, my OS opens it in Firefox (my browser). With the default zoomage, the equation displayed there looks like this (I have tried to portray its actual size, which I really can't do):

View attachment 14335
But if I change the zoomage on Firefox to the greatest available value, then it looks like this:

View attachment 14336
But I am still unclear as to what the issue is here.

Indeed a MathML representative of an equation, absent any associated HTML code about display size, does not represent the equation as displayed at any specific physical scale. In that regard, the MathML code is just like this in HTML:

Boatyard​

At what size should that be rendered in some yet-unspecified receiving application? That is not defined.

There is of course much about this I don't know.

Best regards,

Doug
Click to expand...

I just said earlier

Just to be clear I was not really suggesting the use of an MML file in a post here or over there, although it may seem like that; only opening it somehow to get an equation image. On my machine, LibreOffice Math has comprehensive font-sizing, alignment, etc. and a screenshot can be gotten with Windows and edited further if needed. But the on-screen size/appearance can still vary between Sites and/or Users.
Click to expand...

Let's regard MathML or a .mml file simply as a means of obtaining an equation image while that image's screen-size can vary between sites/users from tiny to huge.
 
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Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,
Ted Cousins said:
I just said earlier
Click to expand...
Ah, sure.

In any case, here I can open that MML file in several applications, and see the equation, and do various things with it.

Here it is in MathMagic Lite )here at an arbitrary scale):

1785771458181.png


It has a physical size on screen, but that depends on the zoomage set in MathMagic Lite.

And of course I can open it in LibreOffice Math. But is physical appearance there is at an arbitrary scale.

This is no different from a JPG file, which carries an image with certain pixel dimensions but not having any actual physical size (although it may appear to have such owing to the "DPI" tag).

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Hi, Ted,

if I had an MML file describing an equation (perhaps sent by a colleague), and I wanted that equation included in a technical paper I was composing in LibreOffice Write, how would I do that?

I have a very roundabout way that involves two instances of LibreOffice Math (and an intermediate representation in Star Math), but I would hope there would be a more direct way.

Thanks.

Best regards,

Doug
 
Ted Cousins

Ted Cousins

Member
Doug Kerr said:
Hi, Ted,

Ah, sure.

In any case, here I can open that MML file in several applications, and see the equation, and do various things with it.

Here it is in MathMagic Lite )here at an arbitrary scale):

View attachment 14337

It has a physical size on screen, but that depends on the zoomage set in MathMagic Lite.

And of course I can open it in LibreOffice Math. But is physical appearance there is at an arbitrary scale.

This is no different from a JPG file, which carries an image with certain pixel dimensions but not having any actual physical size (although it may appear to have such owing to the "DPI" tag).

Best regards,

Doug
Click to expand...
Understood.

best,

Ted.
 
Ted Cousins

Ted Cousins

Member
Doug Kerr said:
Hi, Ted,

if I had an MML file describing an equation (perhaps sent by a colleague), and I wanted that equation included in a technical paper I was composing in LibreOffice Write, how would I do that?
Click to expand...
Sorry, I have yet to use LibreOffice Write and never used Open Office other than to read MS Word documents, so can't help with that.
I have a very roundabout way that involves two instances of LibreOffice Math (and an intermediate representation in Star Math), but I would hope there would be a more direct way.
Click to expand...
Hopefully so ...

best,

Ted.
 
Doug Kerr

Doug Kerr

Well-known member
I think an issue being considered here is this:

Suppose that in an OPF post, we include an equation as a "picture" of the equation.

Now, to another member looking at the post in the usual way., is the "scale" of that equation appropriate?

I say "appropriate" rather then "correct" as there is no "correct" result. A forum post is not intended to be a laid-out page (as if we were to send somebody a PDF file of a report with equations in it). One simple demonstration of this is the fact that text lines may wrap at different places depending on various properties of the installation through which the post is being observed. And the text may be rendered in different typefaces, depending on what is available in the system at the "observing" end.

I have not heard any reports from other members that various posts (including in the thread) in which I have included equations as their "pictures" end up to other members with the equations not at what they consider to be an "appropriate" scale.

To play with that a little, I will use an "equation" that is really just a text phrase (but composed in an equation editor, MathMagic Lite).

What will follow is, first, that phrase just as regular text in this post, followed with a "picture" of the same text (as is it were an equation) with its display size in the post set to make it, as I see it here, essentially match the text just above it.

The quick brown fox
1785781159663.png


Now to you, dear reader, the second may display at he same size as the first, or not. (And the typefaces may not even be the same.)

And in this situation, there is no "correct" result. But some results may be more "appropriate" than others (to the individual observer)

I think.

I would be pleased to hear from other members whether, as you see this, those two text phrases seem to essentially be the "same size".

Best regards,

Doug
 
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Doug Kerr

Doug Kerr

Well-known member
Now, as a further exercise, suppose in an OPF post I was discussing a photometric matter, and said:

******
The luminous flux from the point source “captured” by the lens, ΦpL, is given by:

1785782509697.png

******

Now, is that equation displayed in a size that seems "sensible" in allowing you to follow the discussion? (That is after all my objective.)

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Oh, I just remembered that I can in fact see the HTML code of a page open in my browser.

I will do some more poking around.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
Mu guess at this point is that if I put a picture of an equation in an OPF post, and make it have a certain display size as seen here on my post composition screen, the HTML code for the link to that image defines its display size in terms of pixels (presumably as on the observer's screen).

But I think that would be modulated by the zoomage setting of the browser on which the OPF site was being seen. (And probably impacted by the available screen space on the device used by the observer)

Maybe.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
It seems that in the HTML code for the OPF page as seen by a user, in the code block that emplaces a picture, the value "width" in the attribute "style" in the tag <img>dictates the width at which the image should be displayed, seemingly applicable to some zoomage setting in the browser.

Here is an example:

Code: 
style="width: 441px"

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
I note that if I Paste a picture of an equation into my post in the composition window and do not resize it, the "style" attribute is empty. I don't know what this dictates as to display size to an observer.

My guess is that it is displayed at the size indicated by the image dimensions in the HTML block (again presumably as they would be at some reference browser zoomage level.

Maybe.

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
I note that, at any zoomage setting of the browser, the size at which a picture is displayed when it has not been resized (and thus for which there is no "width" value in the code) is the same as if there was a "width" value that was the same as the width of the source image (the source image pixel dimensions are included in the code block).

Best regards,

Doug
 
Doug Kerr

Doug Kerr

Well-known member
So still unresolved (largely out of lack of reports from the field) are:

• As to posts on OPF, if equations are included via their "pictures", is the result "appropriate" at various observing stations?

• As to posts on various other forums, if equations are included via their "pictures", is the result "appropriate" at various observing stations?

Best regards,

Doug
 
Ted Cousins

Ted Cousins

Member
Doug Kerr said:
Hi, Ted,

Now this:
View attachment 14333

has a substantially greater pixel resolution (884 px × 251 px). (Also a different typeface - sorry.)

Best regards,

Doug
Click to expand...
Here's the HTML source for the above:

Code: 
							<article class="message-body js-selectToQuote">
								
								<div class="bbWrapper">Hi, Ted,<br />
<br />
Now this:<br />
<div class="bbImageWrapper  js-lbImage" title="1785698302072.png"
		data-src="https://openphotographyforums.com/forums/attachments/1785698302072-png.14333/" data-lb-sidebar-href="" data-lb-caption-extra-html="" data-single-image="1">
		<img src="https://openphotographyforums.com/forums/attachments/1785698302072-png.14333/"
			data-url=""
			class="bbImage"
			data-zoom-target="1"
			style="width: 257px"
			alt="1785698302072.png"
			title="1785698302072.png"
			width="854" height="251" loading="lazy" />
	</div><br />
<br />
has a substantially greater pixel resolution (884 px × 251 px). (Also a different typeface - sorry.)<br />
<br />
Best regards,<br />
<br />
Doug</div>
								<div class="js-selectToQuoteEnd">&nbsp;</div>
								
							</article>
The image has three widths, but your 884 is a typo.

LOTS of things in the <img ... /> that could affect the display appearance ??

The <img source link opened in a separate FireFox tab comes out full size 854x251 px on my hard drive but huge in this post!:

1785698302072-png.14333


FWIW,

Ted[/img]
 
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