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<p>Hi Juan,</p>
<p>In DrGeo, the user can define an arc passing though three points
(there is other way). With Vector Graphics primitive, there is
this largeFlag attribute, depending on its value and the position
of the three user defined points, the arc will do or not as
expected.</p>
<p>Bellow the arc does not do as expected, when largeFlag is false.
if I toggle largeFlag to true, then the arc goes through the three
points.</p>
<p><img moz-do-not-send="false"
src="cid:part1.6981408B.A03F5BCD@drgeo.eu" alt="The arc does not
pass by the third point" width="157" height="159"> <br>
</p>
<p>However it will not work the other way, when the second point is
moved close to the other points. I don't understand how should the
largeFlag attribute be set.</p>
<p>The DrGeo's arc model knows about its center, radius, starting
angle, and its oriented angle. Its polymoprhic pointAt: method
gives the coordinates of any point on its line, with curvilinear
abscissa between 0 and 1.<br>
</p>
<pre>drawOn: canvas
| start end r orientation |
start _ self drawable worldToMorph: (mathItem pointAt: 0).
end _ self drawable worldToMorph: (mathItem pointAt: 1).
r _ self drawable worldToPixel: mathItem radius.
orientation _ mathItem length negative.
canvas strokeWidth: borderWidth color: borderColor do: [
canvas moveToX: start x y: start y;
arcToX: end x y: end y rx: r ry: r angleOfXAxis: 0 largeFlag: false sweepFlag: orientation]
</pre>
<p><br>
</p>
<pre class="moz-signature" cols="72">--
GNU Dr. Geo
<a class="moz-txt-link-freetext" href="http://drgeo.eu">http://drgeo.eu</a>
<a class="moz-txt-link-freetext" href="http://blog.drgeo.eu">http://blog.drgeo.eu</a></pre>
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