Hi Taco, On Tue, 17 May 2005, Taco Hoekwater wrote:

After some discussion with Karl Berry on math-font-discuss:

At Bachotek2005 there was a talk about the Latin Modern fonts, and there was a small math example included, of course. The presentation was shown using Adobe's PDF reader, and as you probably know, it displays the rules TeX draws for fractions and the radical bar horribly.

not to forget braces, so maybe also vertical lines are needed?

[...] Here is what I propose:

The creation of a new primitive called \mathrulechar, with the following semantics. Adding

\mathrulechar="0130

somewhere in the TeX source would make subsequent \radical commands use a suitable number of repetitions of the character "30 in math family 1 instead of the horizontal rule pdfTeX draws currently.

No additional macros are involved in the process.

(A suitable character has to be available, of course. It should be a dash, positioned flat on top of the baseline, no sidebearings)

Maybe instead of these repetitions you also could use the Tz operator together with font size scaling for stretching a single e.g. 1bp*1bp square pad to the wanted width/height? And what if this char. even came from an artificial one-character-only Type-1 font, produced (with proper hinting :-) inside pdftex? Regards, Hartmut

I've read through the follow-up messages to this, and looked at the original demo. in Acrobat V5.0.5 under Windows/XP at 1152 x 854 on a 19" monitor. With Acrobat options "Smooth Text" and "Smooth Line Art" both selected, the blend between the two is /almost/ invisible even at 1600% magnification. Before investing effort in a PdfTeX-level solution, I would ask if there are current versions/implementations of Acrobat that do /not/ yield an "almost perfect blend". If there are, then I would agree with other posters that we need to identify /all/ places in TeX where an on-screen glyph is composed of both font-based glyphs and rules, and then devise a solution which will accommodate all of these without the overhead of a full PicTeX-like approach. Philip Taylor -------- Taco Hoekwater wrote:

Hi,

After some discussion with Karl Berry on math-font-discuss:

At Bachotek2005 there was a talk about the Latin Modern fonts, and there was a small math example included, of course. The presentation was shown using Adobe's PDF reader, and as you probably know, it displays the rules TeX draws for fractions and the radical bar horribly.

The same is, in fact, true for xpdf and ghostview. The general problem is that rendering graphics and rendering text are not the same thing in PDF (nor PostScript), and that makes it hard for a viewer to align the two objects correctly. Our 'problem' is that people in general believe this is a bug in pdftex :-(

An example file is at http://tex.aanhet.net/temp/mathtest.pdf Especially look at the top left of the sqrt signs. The source code is trivial: $$\sqrt{\sqrt{\sqrt{\sqrt{\sqrt{\sqrt{x+1}}+1}+1}+1}+1}$$

I volunteered to write a patch for pdftex to try to remove the problem by making pdftex use a repeated character instead of a rule, but I am still a bit unsure about the best solution. Also, I vaguely remember that possibly somebody had done something with \radical a long time ago already, so I thought I'd ask feedback before doing any actual coding.

Here is what I propose:

The creation of a new primitive called \mathrulechar, with the following semantics. Adding

\mathrulechar="0130

somewhere in the TeX source would make subsequent \radical commands use a suitable number of repetitions of the character "30 in math family 1 instead of the horizontal rule pdfTeX draws currently.

No additional macros are involved in the process.

(A suitable character has to be available, of course. It should be a dash, positioned flat on top of the baseline, no sidebearings)

Greetings, Taco

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