[Mac OS X TeX] small dots disappear in Quartz

[Dave McCollum]

<x-flowed>I thought I'd add a little (hopefully useful) info to this 
discussion. I use Matlab 5.2.1.x almost daily from either OS 9.2.1 or 
Classic.

It makes sense that, depending on the "viewer" application you use, 
certain types of graphics in EPS/PS/PDF files will appear differently 
when viewed on-screen. Further complicating this issue is that what 
looks good in a Matlab figure window is often ugly/too big in the 
printed version. Matlab either uses the Symbol font for this plot 
characters, or maybe PS primitives. In most cases, the Symbol font is 
used. Explanations may include, but may not be limited to, the 
following:

  - Sometimes, Matlab uses PS primitives for some graphics elements.
    In my experience, checking embedded fonts in Acrobat, or the EPS file
    itself, the Symbol font is often specified for these graphics elements.

  - Different viewer apps in OS X may use different rendering engines.
    Preview uses the Quartz built-in OS rendering engine, whereas Acrobat
    uses its own (?). Add in different types of anti-aliasing....

  - A very likely cause (in my mind, at least), is the use of the Symbol
    font for these graphics elements (the plot symbols in Matlab EPS
    files). It may be that the display/viewer differences could be due
    to whether or not the Symbol font is embedded into the PDF file. If
    not, then the font used to display the graphic elements may be different
    for different apps, compounding any issues associated with rendering
    engines and anti-aliasing.



-Dave


>Hi Troy,
>
>>  At 9:54 AM +1100 10/30/01, Ross Moore wrote:
>>  >Are the dots clean squares of pixels, or are they anti-aliased?
>>
>>  I'm not quite sure what you're getting at...  When I increase the
>>  scaling in Preview.app, I can eventually see that there are a bunch
>>  of small, overlapping circles; but definitely circles.
>
>Can you send me the image please, or a URL where I can download it.
>I'd like to tinker a bit.
>
>>  >If the former, then try using Ghostscript to render the image,
>>  >with anti-aliasing on for graphics primitives (not just for fonts)
>>  >  --- there is a setting   GRAPH_ALPHA_BITS ,  I think.
>>  >When you've got that working, use Ghostscript to write the image as
>>  >PDF (e.g. with a modification to the epstopdf Perl script) and try
>>  >viewing this in Acrobat.
>>
>>  We've just left my sphere of knowledge surrounding Ghostscript.  If
>>  you or someone else can tell me what to type into gs or some such, I
>>  can handle that.
>
>:-)  Let me try first.
>
>>  I have viewed this PDF with Acrobat Reader 5 in OS X and it
>>  _does_not_ exhibit this problem.  I can reduce the scale down to
>>  about 0.08 and I still see the blue blob.
>
>OK; this sounds like the problem is with Apple's viewer then.
>Perhaps a feature ?
>
>
>Cheers,
>
>	Ross
>
>
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