Re: understanding _cairo_path_fixed_fill_extents()

Bill Spitzak <[email protected]>
Newsgroups gmane.comp.lib.cairo
Message-ID <CAL-8oAhkwPYtsUmD26_prhMZbgpSM+Gpi81NhTxHJ0d8R67Wzg@mail.gmail.com>
Usually when code figures out the extents, it also has a side effect of
making sure the points are in a particular order. This is due to it using
min() for one corner and max() for the opposite corner. So I think in this
case it is safe to say the points will be in this order.

Generally most code in Cairo and other places treat negative width/height
as empty rectangles, not inverted ones. In most cases this makes the code
simpler.

On Sat, Dec 19, 2015 at 10:13 AM, Enrico Weigelt, metux IT consult <
[email protected]> wrote:

> On 19.12.2015 11:11, Uli Schlachter wrote:
>
> > I don't really know, but I wonder: Why would the points be the other >
> way around? I guess path->extents.p1 is defined to be the north west
> > corner and it can only be south or east of p2 due to rounding issues
> > somewhere?
>
> It that really the case ? Can we be sure about that ?
> (honestly, I have no idea :()
>
> > So based on a definition of "p1 is the north-west corner", I think this
> function
> > does exactly the right thing. If this every is a problem, the code
> generating
> > this bogus extents should be fixed.
>
> Okay, do have that definition scribed in stone ? If not, should we do
> that ?
>
> I agree that such an definition might be helpful, but there *might* be
> cases where it's turned around. How can we detect those cases (and
> find the responsible code) w/o too much overhead ? Maybe some
> assert()'s.
>
> --mtx
>
> --
> Enrico Weigelt,
> metux IT consulting
> +49-151-27565287
> --
> cairo mailing list
> [email protected]
> http://lists.cairographics.org/mailman/listinfo/cairo
>

-- 
cairo mailing list
[email protected]
http://lists.cairographics.org/mailman/listinfo/cairo
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.