Using the Turtle to Draw Simple Pictures

Basic Commands | Buttons | Save the Project | Conclusion | Assignments | Download the Project

Task

• To create simple pictures using turtle geometry

• basic commands of turtle geometry forward, left, right, back, repeat, clean

• how to paste buttons on a page and how to use them with the commands

The same turtle commands in SuperLogo work also in the Imagine Logo environment. Try typing several commands in the command line e.g. draw a simple letter T ? fd 100 rt 90 FD 50 bk 100

The effect of this command is different to SuperLogo - the screen will be cleaned, but the turtle stays in the same place (it does not go to its home position and will not turn to its initial heading). To return the turtle to its home position and initial heading use the command clean. Try

? clean ; the turtle stays in the position where it has finished the letter T
? clearscreen ; the turtle returned into the home position (0,0) and initial heading to the North

Pen colour, width and pattern

Use the command setPenColour or setPC to draw with a coloured pen. To find the right colour press <Enter> and the Colours chooser will open. You can select or mix the colours. Several colours are named e.g. "white, "blue, "red, etc. Similarly, you can use the command setPenWidth or setPW to set the turtle's pen width.

Type in these commands to draw a blue flag - the pole and the flag have a length of 100 and pen width of 5

? clear
? setPC "blue
? setPW 5
? FD 100
? repeat 4 [FD 100 rt 90]

Buttons

Pasting a button, and defining an event

To save time you can put turtle commands on buttons. In Superlogo you have the Button window, in Imagine Logo you can use the buttons directly on the page, you can move them, resize them, put images on them... The icon for inserting a new button is situated in the Main Bar - select it and put the button on the page. Click with the right mouse button on the selected button and in its context menu select Change b1. Change the button's Caption and event onPush to the command clearscreen. Click on OK.
 

Changing a button's size and position
 

You can see the new button, but the word 'clearscreen' is not wholly visible - you need to resize it: in the lower right-hand corner of the button press the <Ctrl> key and the right mouse button simultaneously - the cursor will change into aand you can resize the button by dragging it to the right. If you want to move any button, select Move b1 from its context menu and drag the button into a new position. You can now make buttons for moving forward 50, turning right 90, turning left 90, etc. in exactly the same way.

Save the Project

Select Save Project As... from the File menu and give it a name in the Save project dialogue box.

Conclusion

You have created a simple project that allows you to draw pictures by controlling the turtle using buttons. You do not have to write all the commands, you can just press the buttons.

Assignments

1. Draw the following simple pictures using your buttons: a flag, a pair of glasses, and a windmill. 2. Add more buttons to control the turtle's pen colour. 3. Make up other commands, create a button on the page, and then draw your own picture.

Download the Project

You can download an example of the finished project by clicking here.