Re: A Question

--===============2067848492==
Content-Type: multipart/alternative; boundary="00000000000099b9720582e2335c"

--00000000000099b9720582e2335c
Content-Type: text/plain; charset="UTF-8"

No that is incorrect. A line width less than one pixel will color in single
pixels with less than 100% opaqueness. It can actually color in 2 pixels,
if Cairo thinks the line width straddles the position between the pixels.
The line width NEVER "rounds to zero".


On Wed, Feb 27, 2019 at 2:05 AM Elmar Haneke <[email protected]> wrote:

>
> >    A question on Cairo: The X Y inputs to Cairo drawing functions are
> > type double.
> >
> > Dose this imply that pixel or line spacing could be less than 1.0?
> >
> > Could the spacing be say 0.5 or 0.25?
>
>
> On devices where an coordinate-distance of 1.0 does map to an single
> pixel this does make only limited sense as the space or line width might
> be rounded to 0.
>
>
> But for high resolution devices as printers or vector-graphics as PDF
> you can define coordinates to 72DPI or 300DPI or if you prefer to work
> metric even to millimeters.
>
> On such an setting an spacing of 0.25 does make an significant difference.
>
>
> Elmar
>
>
> --
> cairo mailing list
> [email protected]
> https://lists.cairographics.org/mailman/listinfo/cairo

--00000000000099b9720582e2335c
Content-Type: text/html; charset="UTF-8"
Content-Transfer-Encoding: quoted-printable

<div dir=3D"ltr">No that is incorrect. A line width less than one pixel wil=
l color in single pixels with less than 100% opaqueness. It can actually co=
lor in 2 pixels, if Cairo thinks the line width straddles the position betw=
een the pixels. The line width NEVER &quot;rounds to zero&quot;.<div><br></=
div></div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_at=
tr">On Wed, Feb 27, 2019 at 2:05 AM Elmar Haneke &lt;<a href=3D"mailto:elma=
[email protected]">[email protected]</a>&gt; wrote:<br></div><blockquote class=3D"g=
mail_quote" style=3D"margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204=
,204,204);padding-left:1ex"><br>
&gt; =C2=A0=C2=A0 A question on Cairo: The X Y inputs to Cairo drawing func=
tions are<br>
&gt; type double.<br>
&gt;<br>
&gt; Dose this imply that pixel or line spacing could be less than 1.0?<br>
&gt;<br>
&gt; Could the spacing be say 0.5 or 0.25?<br>
<br>
<br>
On devices where an coordinate-distance of 1.0 does map to an single<br>
pixel this does make only limited sense as the space or line width might<br=
>
be rounded to 0.<br>
<br>
<br>
But for high resolution devices as printers or vector-graphics as PDF<br>
you can define coordinates to 72DPI or 300DPI or if you prefer to work<br>
metric even to millimeters.<br>
<br>
On such an setting an spacing of 0.25 does make an significant difference.<=
br>
<br>
<br>
Elmar<br>
<br>
<br>
-- <br>
cairo mailing list<br>
<a href=3D"mailto:[email protected]" target=3D"_blank">cairo@cairogra=
phics.org</a><br>
<a href=3D"https://lists.cairographics.org/mailman/listinfo/cairo" rel=3D"n=
oreferrer" target=3D"_blank">https://lists.cairographics.org/mailman/listin=
fo/cairo</a></blockquote></div>

--00000000000099b9720582e2335c--

--===============2067848492==
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: base64
Content-Disposition: inline

LS0gCmNhaXJvIG1haWxpbmcgbGlzdApjYWlyb0BjYWlyb2dyYXBoaWNzLm9yZwpodHRwczovL2xp
c3RzLmNhaXJvZ3JhcGhpY3Mub3JnL21haWxtYW4vbGlzdGluZm8vY2Fpcm8=

--===============2067848492==--