One way to define a circle is by specifying its size and location on the command line. The parameters cr and and cc define the center row and column respectively. The rad parameter can be used to specify its radius.
The int switch allows you to define a circle interactively on the image of a previous tv command. Move the cursor to an image and, if necessary, wait for the cursor to become the special "circle center" shape: a small dot inside a square. Press and hold down the Left button to define the center of the circle. Then, while still holding down the Left button, move the cursor to one corner of the desired circle position; a rubber circle will show the shape and size of the circle being defined as you move the cursor. When it looks correct, release the Left button. The circle center coordinates and number of rows and columns will be printed to the screen, and the circle inserted into the circle list. of the corners. After you have finished making a circle interactively, it is displayed on all windows into which it will fit. If no circle number is specified, an new circle will be assigned.
The show switch presents the specified circle on all displayed windows into which it can fit. If no circle is specified all circles are shown.
The del switch deletes the given circle from the list of circles. However, it will not undraw the circle from any windows in which it is currently being shown.
If no arguments are specified the defined circles are listed.
circle 1 cr=10 cc=10 rad=10- defined circle 1 at (10,10) with a 10 pixel radius.
circle 1 show -displays circle 1 on the tv images.
circle 10 del