[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

I have solved this problem with (latex2html.conf)
#$DVIPSOPT = ' -Ppdf  -E';
$DVIPSOPT = ''; # -Pdf pulls in alt-rule.pro which causes black eqn 
as in:  
My problem was in: 

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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