Creating a 360 Degree Color Wheel
A color wheel sweeps a complete 360 degrees starting and ending with the same color. In the case of the RGB color wheel, the starting color is red and the Hue is 0.
When you create a simple Conical fill in Xara (select the Fill
Tool, then select Conical from the drop down list of Fill Types on the Infobar) Xara creates a symmetrical fill that sweeps 180 degrees and then 180 degrees in the opposite direction as
shown on the left. The fill is mirrored on either side. We can create a kind of color wheel by making the start and end color the same and selecting Alt Rainbow from the Fill Effects drop down list on the Infobar. But as
you can see from the example on the right, it is not a true color wheel because it is mirrored. So how did I create the color wheel on the previous page with only one conical fill?
First I changed the fill for the end color (on the bottom) to Hue
180 (1/2 of 360 for those of you who are math challenged) which is one half way around the color wheel as you see on the left. Selecting the Alt Rainbow option gives me the other half of the color wheel
as seen on the right. How do we get both halves then from the same fill?
By using the Rainbow option as shown on the right.
When you select Alt Rainbow, Xara creates a rainbow gradient using all the colors that appear on the color wheel going the long way around. If your start and end
color are the same, then Xara includes all the colors of the rainbow. The Rainbow option, on the other hand, creates a gradient using only
the colors that appear on the shortest way around the wheel. As both fills use Hue 180 which appears in the exact center of the color wheel, both create one half of a complete color wheel.
To make the complete color wheel we need the left half of the Alt Rainbow filled circle and the right half of the Rainbow filled circle. We will use a vertical
line to cut both circles in half.
Center a vertical line over each of the two color wheels and Combine Shapes... > Slice Shapes to cut each into half. Delete the opposite sides.
Move the two halves together and you have a complete 360 degree color wheel.
Now some of you might argue that it was really two conical fills, but both halves did use the same fill, it is just that one half used the Rainbow option while the
other half used the Alt Rainbow option.