[webkit-dev] Font layout features

Evan Martin evan at chromium.org
Thu Jan 21 09:17:20 PST 2010


On Wed, Jan 20, 2010 at 9:49 AM, Jason Rukman <JasonR at bsquare.com> wrote:
> As part of our port to windows CE we are using a Cairo configuration combined with freetype.  This is fairly similar to the Windows port but we are not using the native Windows GDI/cairo layer for fonts (instead we are using cairo-ft).  However, unlike the GTK port, we did not port Pango, and so are using Cairo font layout.  Can someone comment on what limitation we may have with Asian fonts/glyphs or other issues with this configuration?  We have ported the latest versions of freetype, fontconfig and cairo to CE.

It is difficult to answer your question, because it depends on what
you are doing.  Where is the code?

cairo_show_text() is the API to take pause at:
  http://www.cairographics.org/manual/cairo-text.html#cairo-show-text
"Note: The cairo_show_text() function call is part of what the cairo
designers call the "toy" text API. It is convenient for short demos
and simple programs, but it is not expected to be adequate for serious
text-using applications. See cairo_show_glyphs() for the "real" text
display API in cairo."

But I guess you must be doing some sort of interfacing with Freetype
because WebKit wants glyph extents, etc, which makes me guess you're
using a lower layer.

In general, you can gain or lose confidence in the quality of your
port by running the layout tests.  If there are any text rendering
problems that you see that aren't covered by the layout tests, we
should just create more tests.  (I have yet another bug in my queue to
add some more tricky Arabic ones that came up in doing font stuff for
Chrome...)


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