On Nov 19, 2008, at 17:33 , Carl Witthoft wrote:
Sorry if this is an old issue; it's certainly of very low priority.
I was playing around w/ font colors for, e.g. the main title in a
plot, and noticed that overwriting some text with the identical
text, but in white, leaves a small but noticeable 'border' outlining
each letter. I played around a bit with overwriting plotted lines
in the chart and didn't seem to see this effect. Is this a known
limitation on rendering fonts or some such?
It is the expected consequence of anti-aliasing. Since the edges of
the text are not fully opaque (more precisely the pixels that are not
entirely filled by the text glyph), they won't entirely mask what's
underneath and thus any previous content (including perviously drawn
text) will shine through (c.f. plotting text with alpha < 1). This is
an intended behavior for semi-opaque drawing although less intuitive
when the opacity is implicitly adjusted by anti-aliasing. You can
avoid this effect by disabling anti-aliasing (at the cost of inferior
visual quality).
Cheers,
Simon
_______________________________________________
R-SIG-Mac mailing list
[email protected]
https://stat.ethz.ch/mailman/listinfo/r-sig-mac
