THE INTERACTIVE GUI

In order to make Galapagos more fun to learn with, an interactive GUI (Graphical User Interface) is provided. Users can make changes on the board while a computation is in progress and effect its execution. Drawing tools enable the user to draw on the board while a program is being executed. If a line is drawn in front of a turtle which has a relevant interrupt, the interrupt will be invoked if needed.

The user has a special user pen that can draw line, rectangles or free hand. These modes are available from the toolbar. The User's pen width and color can be modified using the User Pen menu or the toolbar.

Color buttons are provided on the toolbar to give a known RGB color to the user pen. It is useful when the user draw an object on the board and wants a turtle to see this object. The colors are:

White - (255 255 255)

Black - (0 0 0)

Blue - (0 0 255)

Red - (255 0 0)

Green - (0 255 0)

Yellow - (255 255 0)

Another option available is changing a turtle's heading and position, using the Move Turtle button:

If this button is pressed then a turtle can be dragged to a new location simply by dragging it with the mouse. In order to change the turtle's heading, hold down a control key and move the move towards the desired location, the turtle will follow the movement of the mouse.