The Circles

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There are five different types of circles available in FX Draw.  Each of the circle figures has been created to solve a different drawing problem.  What makes them different is how the circle's control points are used to define the circle.



When you draw a circle it will be drawn with a default centre mark.  You have a choice of seven centre marks and these can be changed by right clicking on the circle.  These are the same marks that you can choose as points for the point tool.


Circles can be filled using the fill palette (see Setting Fill Type).


The centre mark for the circle can be set as a default.


When you are drawing diagrams including circles, your choice of circle tool can make a large difference to the ease with which you will draw your diagram.


Available Parameters for Circles








Centre Radius Circle




The centre & radius circle is defined by the centre of the circle and any point on the circumference.  This is the circle tool to use if you know the location of the centre of the circle.


To draw a centre & radius circle, you mark the centre of the circle with your initial click and the point on the circumference when you release the button.  Your Centre & Radius circle could extend beyond the bounds of the drawing area.  If this occurs, FX Draw will draw as much of the circle as possible.



Diameter Circle




When you are drawing a diameter circle, the two points you define will form a diameter of the circle


To draw a diameter circle, you click and hold the left mouse button – move the mouse to the other end of the diameter and release the mouse button.



Three Point Circle




Three-point circles are defined by ANY three points on their circumference.  They are ideal for drawing, for example, the circum-circle of a triangle.


To draw a three point circle, just click once on each of the three points.


Video - Three Point Circles


Circle in a Square




The four corner circle will draw a circle inscribed in a square region defined by four control points.


To draw a four corner circle, you click and hold the left mouse button – move the mouse to the diagonally opposite corner and release the mouse button.


Compass Circle




When you use a compass to draw a circle, you place the point on the centre, set the radius and draw - just like the centre/radius circle that is the first circle tool on our list.


The thing that IS different about using a compass is that with a compass you can keep the same radius to draw more circles.


That is what the Compass Circle tool does.  It is a Centre/Radius circle that remembers the radius.


The first time you use the compass circle tool it operates in exactly the same way as the centre/radius tool.


The second and subsequent times, you just click on the centre of the new circle.  The compass circle tool remembers the radius and marks the circle.




The compass circle tool will remember the radius for as long as it is selected.


You can force the compass circle tool to reset its radius by:


a)        Right clicking on a compass drawn circle.

b)        Right clicking on a blank part of the drawing canvas.

Video - The Compass Like Tools