Setting colors within the model

Color as indicator

An important aspect of an end-user interface is the use of color. Color helps to visualize certain properties of the data contained in the interface. As an example, you might want to show in red all those numbers that are negative or exceed a certain threshold.

Setting colors in the model

AIMMS provides a flexible way to specify colors for individual data elements. The color of data in every graphical object in the graphical interface can be defined through an (indexed) “color” parameter. Inside your model you can make assignments to such color parameters based on any condition.

The set AllColors

In AIMMS, all named colors are contained in the predefined set AllColors. This set contains all colors predefined by AIMMS, as well as the set of logical color names defined by you for the project. Whenever you add a new logical color name to your project through the color dialog box, the contents of the set AllColors will be updated automatically.

Color parameters

Every (indexed) element parameter with the set AllColors as its range can be used as a color parameter. You can simply associate the appropriate colors with such a parameter through either its definition or through an assignment statement.


Assume that ColorOfTransport(i,j) is a color parameter defining the color of the variable Transport(i,j) in an object in the end-user interface. The following assignment to ColorOfTransport will cause all elements of Transport(i,j) that exceed the threshold LargeTransportThreshold to appear in red.

ColorOfTransport((i,j) | Transport(i,j) >= LargeTransportThreshold) := 'Red' ;

Creating Non-Persistent User Colors

Non-persistent user colors

During the start up of an AIMMS project, the set AllColors is filled initially with the collection of persistent user colors defined through the Tools-User Colors dialog box. Through the functions listed below, you can extend the set AllColors programmatically with a collection of non-persistent colors, whose lifespan is limited to a single session of a project.

The argument colorname must be a string or an element in the set AllColors. The arguments red, green and blue must be scalars between 0 and 255.

Adding non-persistent colors

You can use the function UserColorAdd to add a non-persistent color colorname to the set AllColors. The RGB-value associated with the newly added user color must be specified through the arguments red, green and blue. The function will fail if the color already exists, either as a persistent or non-persistent color.

Deleting and modifying colors

Through the functions UserColorDelete and UserColorModify you can delete or modify the RGB-value of an existing non-persistent color. The function will fail if the color does not exist, or if the specified color is a persistent color. Persistent colors can only be modified or deleted through the Tools- User Colors dialog box.

Retrieving RGB-values

You can obtain the RGB-values associated with both persistent and non-persistent user colors using the function UserColorGetRGB. The function will fail if the specified color does not exist.