[l2h] Black bars under integral signs when thelimitsof integration are -\infty and +\infty or analgebraicfraction for each of the upper and lower limits
Andres Lahe
alahe at staff.ttu.ee
Wed Aug 10 14:01:26 CEST 2011
Hello!
I have solved this problem with (latex2html.conf)
#$DVIPSOPT = ' -Ppdf -E';
$DVIPSOPT = ''; # -Pdf pulls in alt-rule.pro which causes black eqn
underlines
as in:
https://ccrma.stanford.edu/~jos/webpub/Eliminating_Black_Rules_Equation.html
My problem was in:
http://staff.ttu.ee/~alahe/ehitusmeh/opikHTML/Ehitusmehaanika.html
Andres Lahe
======================
Pat Somerville wrote:
> Thanks, Professor Ross Moore, for kindly writing to me on the
> mechanisms for the production and elimination of cropping bars. And
> thanks for mentioning the program MathJax to me. In an online form I
> wrote to someone involved with MathJax with some questions for him or
> her to see if MathJax can be used for the applications of printing
> mathematics onto paper and what amounts to sending an e-mail letter
> body with the .html file containing mathematics pasted onto it with
> the images in that letter as attachments to it.--Those two activities
> have been my primary end uses so far of the programs LaTeX for
> printing and LaTeX2HTML with the images as attachments to the e-mail
> letter. It is good that MathJax can handle LaTeX commands and uses
> open-source code; therefore I assume it would be provided free of
> charge. Also I think it is very honorable of you, since you have
> worked so much on the program LaTeX2HTML, to mention and suggest
> another program MathJax which performs the similar basic function,
> although in a somewhat different way, of making mathematical symbols
> capable of being displayed on Web pages. Some people might even
> consider that surprising. But I think it speaks well of you,
> Professor Moore. And thanks for your contributions to LaTeX2HTML,
> which has been a useful, free program for me! Thanks for your kindly
> provided help, Professor Moore!
>
> Pat
>
> --------------------------------------------------
> From: "Ross Moore" <ross.moore at mq.edu.au>
> Sent: Friday, April 15, 2011 2:24 AM
> To: "Pat Somerville" <l_pat_s at hotmail.com>
> Cc: "Latex2Hmtl list" <latex2html at tug.org>
> Subject: Re: [l2h] Black bars under integral signs when thelimitsof
> integration are -\infty and +\infty or analgebraicfraction for each of
> the upper and lower limits
>
>> Hello Pat,
>>
>> On 15/04/2011, at 2:42 PM, Pat Somerville wrote:
>>
>>
>>> In GIMP I could see that the right-hand portion of the upper limit
>>> of positive infinity was either right at the right-hand edge of the
>>> dash-lined box surrounding the image or perhaps was cut off there;
>>> I'm not sure.
>>
>>> Can you or someone explain to me the mechanisms in detail that cause
>>> the unwanted black line segments to be generated? So far I know
>>> from you, Dr. Takeno, that if a mathematical expression inside an
>>> image would otherwise extend beyond the right border of the image,
>>> somehow the black line segment was generated underneath the image.
>>> You explained something about the first step of the cropping
>>> procedure which was involved.
>>
>> The problem that needs to be solved is to align images inline,
>> so that they appear to sit nicely on the baseline when viewed
>> in a web-browser.
>>
>> However, HTML only allows vertical alignments of:
>> "top", "bottom" and "middle".
>>
>> Thus it is "middle" alignment which must be used.
>> But to do this, there often needs to be sufficiently much
>> white-space below the baseline, to balance what is above it.
>> That is, the baseline has to be seen to be exactly in the
>> middle of the image.
>>
>> The image is typeset on a smallish page, but not all of this
>> is actually needed, so first some excess white-space must be
>> cropped away. But you cannot crop all of it, else the middle
>> alignment will not do what is required.
>>
>> Hence part of the image needs to be (at least part of) a frame,
>> that encompasses the full height, depth and width that is required.
>> This is the "black bars" that you see, when a step in the process
>> does not work as intended.
>>
>> The TeX coding in images.tex is designed to produce those black
>> bars at exactly the right place so that they enclose neatly the
>> full image plus the correct amount of white-space padding so that
>> the final image will align appropriately, after:
>>
>> 1. crop away excess whitespace
>> 2. crop away the "black bar" at the bottom
>> 3. crop away the "black bar" at the left side
>>
>> However, because colours can be used, both for the image content
>> and the background, and different scale factors can be chosen,
>> achieving the correct amount of cropping is not as easy as you
>> might think it should be.
>>
>> It is done by cropping away whole rows and columns that are all
>> of the same colour.
>>
>> Normally it will be "white" for step 1., leaving behind a rectangle
>> including the "black bars" --- "cropping bars" is a better term.
>>
>> Then for steps 2. & 3. the bottom and left-side cropping bars
>> are removed "provided" the whole row (or column) is indeed all
>> of the same colour --- usually black.
>>
>> Mostly this works pretty well, but it relies on the assumption
>> that the cropping bars do indeed enclose the full contents
>> that are to be shown. It is when this assumption is not actually
>> true that the black bars will remain.
>>
>> Your example failed presumably because the width when TeX typesets
>> an \hbox containing \int_{-\infty}^{\infty} has one of the
>> limits actually protruding outside the final box dimensions, by more
>> than the extra tolerance that LaTeX2HTML allows for the lengths
>> of the cropping bars.
>>
>>>
>>> I just guess from what you wrote, Dr. Takeno, that the script
>>> eqnfix.sh obtained from http://www.vyvy.org/main/en/node/102 on the
>>> Internet might not have been able to eliminate the black line
>>> segment under my integral sign due to a piece of the upper limit
>>> that otherwise would have extended beyond the right border of the
>>> .png image.
>>
>> Yes. Adding that extra \hspace{...} presumably expands the width
>> of the typeset \hbox (described above).
>>
>> You should be able to do it also using a TeX \phantom :
>> viz.
>> $\int_{-\infty}^{\infty} \phantom{dx}$
>>
>> But this might be too wide, so just adding a bit of extra space
>> would probably do:
>> $\int_{-\infty}^{\infty}\;$
>>
>> Similarly forcing extra space, either vertically or horizontally,
>> can be the best solution in other circumstances too;
>> e.g. when using fancy fonts with twirls and swashes, such as
>> with Zapf Chancery, or calligraphic styles.
>>
>>>
>>> Thanks, Professor Ross Moore, for suggesting I use the -debug option
>>> in a latex2html command.
>>>
>>
>>
>> While LaTeX2HTML is quite good for producing websites based on LaTeX
>> content --- I spent many man-hours working on it, along with others,
>> back in the 1990s and early this century --- it is now rather dated.
>>
>> The software that you should be looking at for 21st century websites
>> is called MathJAX.
>> http://www.mathjax.org/
>>
>> By Googling around, you should be able to find lots of articles
>> that decry the use of images of bit of mathematics.
>> It is better to get the browser to do proper TeX-based typesetting
>> using JavaScript, or other sophisticated scripting language.
>> However not all web browser software can support this. :-(
>>
>> This has always been the case, since the mid-1990s.
>> MathJAX is the best supported solution so far.
>>
>>
>> Hope this helps,
>>
>> Ross
>>
>> ------------------------------------------------------------------------
>> Ross Moore ross.moore at mq.edu.au
>> Mathematics Department office: E7A-419
>> Macquarie University tel: +61 (0)2 9850 8955
>> Sydney, Australia 2109 fax: +61 (0)2 9850 8114
>> ------------------------------------------------------------------------
>>
>>
>>
>>
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--
Toredat päeva!
Andres Lahe
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