Added EllipticalArc link/licence.

NOTICE.md

@@ -204,3 +204,44 @@ AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
+
+# EllipticalArc.java
+
+http://www.spaceroots.org/documents/ellipse/EllipticalArc.java
+http://www.spaceroots.org/documents/ellipse/elliptical-arc.pdf
+
+Copyright (c) 2003-2004, Luc Maisonobe
+All rights reserved.
+
+Redistribution and use in source and binary forms, with
+or without modification, are permitted provided that
+the following conditions are met:
+
+   Redistributions of source code must retain the
+   above copyright notice, this list of conditions and
+   the following disclaimer. 
+   Redistributions in binary form must reproduce the
+   above copyright notice, this list of conditions and
+   the following disclaimer in the documentation
+   and/or other materials provided with the
+   distribution. 
+   Neither the names of spaceroots.org, spaceroots.com
+   nor the names of their contributors may be used to
+   endorse or promote products derived from this
+   software without specific prior written permission. 
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
+WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
+USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
+IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
+USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.

src/Shared/RenderHelpers/ArcToHelper.cs

@@ -45,6 +45,8 @@
 // Commented out some unused values calculations.
 // These are not supposed to be removed from the source code,
 // as these may be helpful for debugging.
+//
+// Adapted from http://www.spaceroots.org/documents/ellipse/EllipticalArc.java
 
 using System;
 using Avalonia.Media;