Use of Colour
You can assign a colour by using (1) one of 16 inbuilt strings, (2) one of 148 inbuilt TColors or (3) your own red, green and blue values.
You can look for an inbuilt TColor at the start of the W3Graphics unit (SmartCL.Graphics in Version 2.1 and System.Colors in Version 3.0). Examples include clAliceBlue, clAntiqueWhite, clAqua, clAquamarine, clAzure, clBeige and clBisque. Use one with code such as
Canvas.FillStyle := ColorToWebStr(clAliceBlue);
An example of the use of your own RGB values is
Canvas.FillStyle := 'rgb(189, 200, 179)'; // RobinEggBlue
An example with an alpha value is
Canvas.FillStyle := 'rgba(0, 255, 0, 0.5)';
The use of alpha values is vital in Alex Karet's BlendingEllipses.