Table of Contents
Complex plane: polylines
CGRAPH offers a description using a polyline to represent more complicated borders. This also allows extensive images to be displayed. The line can also be a closed border, in which case it is referred to as a polygon.
The function is defined uniformly here above the default values for all types of area images, because common images only make sense if the same function is used. The variable names z and param (as complex numbers) as well as x and y (as the real and imaginary parts of the variable z) are permitted.
CGRAPH provides several input options:
Input via default values
Straight line segments can be defined in the area on the left-hand side.
Complex numbers can be entered in the Next point field. After clicking on Add to list, they appear in the List of lines.
If you want to enter a closed polygon, simply tick the corresponding checkbox. It is not necessary to re-enter the starting point.
Graphical input
By switching the tab in the area on the right to Graphical input, it is possible to create polylines graphically. A graphics window is displayed on the right-hand side for this purpose. The first click in the graphics window defines the starting point. A blue line then appears, which you can use to define the second point with the next click, and so on. Double-clicking transfers the entry to the list of lines.
If you press the Shift key while selecting the next point, the angle will jump in increments of 15 degrees. This makes it easier to enter ‘round’ values.
Editing polylines
Once an entry in the List of lines is selected, it can be edited.
The value of the clicked entry in the list is displayed on the left-hand side and can now be changed. Once the change has been made, click on Change values. If you want to leave the list entry unchanged, click on Cancel change.
An entry selected in the list can be removed by clicking on the Delete entry button.
The Export… and Load from file buttons can be used to create and reload semicolon-separated CSV files. The format of each line is simply Point.
After clicking on the Create graph button, CGRAPH switches to the Graphics tab and shows the graph – the original image on the left and the image above the function on the right.
The default values can be viewed in the tree on the left. If the function contains a parameter, it is displayed as a red square in the original image. Double-clicking on this square allows you to change the parameter graphically by simply moving the mouse. Clicking on the original image deactivates the parameter change. If the Shift key is pressed at the same time, the original parameter is restored. A more detailed explanation of this function can be found in the notes on changing a complex parameter in the graphic display.
The specified points can be changed retrospectively – clicking on one of the values switches CGRAPH back to the tab with the default values. The graphic is adjusted as soon as the Create graphic button is clicked.