[cairo] Cairo & mono libgdiplus

[Carl Worth]

On Wed, 12 Oct 2005 21:54:46 -0400, "Jonathan S. Chambers" wrote:
> basic Hobby pens for testing. (The author explicitly lists the pens
> for small diameters.) I did a little bit of testing and the pens
> didn't resolve the issues we're coming across, especially the issue
> of pens of width 1.

Hmm... I'd definitely be interested in seeing some of the results
you're getting. Do you have a minimal code sample along with the bad
result?

There are at least three things that will have to be right if you want
to get nice-looking non-antialiased lines:

1) The lines will have to be positioned properly with respect to the
   device pixel grid, (that is, likely centered on half-integer
   coordinates for width 1 lines). So that's a matter of the
   application code getting things right.

2) A correct implementation of Hobby's pen polygons. If you're just
   dropping in his explicit pens, that should be working fine.

3) Appropriately careful rasterization. There are some edge conditions
   that need to be just right here. I don't know that the depth 1
   rasterization implementation has ever been carefully examined to
   provide the result you'll want here.

A test case should provide some quick guidance on what might be wrong
here. Items 1 and 3 not being correct could result in lines looking
consistently the wrong width, (such as 2 pixels wide instead of 1).
While not properly implementing item 2 will result in lines appearing
with inconsistent width.

> If you'd prefer to discuss this via some other means (AIM, ICQ,
> mailing list) or not at all, please let me know.

Thanks for moving the conversation here to the list. That will be
perfect I think.

-Carl
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