Drawing with the Pen Barb Ericson Georgia Tech June 2011

Project Description We will create a spider sprite and have it draw with the Pen blocks –We will teach it to draw a square –And make a flower out of many squares

Big Picture Delete the cat sprite Paint the sprite that you will draw with –A spider Program the sprite –To draw a square when it receives a square message –And a flower out of many squares

Delete cat sprite To delete the cat –Click the scissors –Click the cat Or right click on the cat and select delete

Draw the sprite Click on the star with a paintbrush –Under the stage view

Using the paint program Click on the ellipse tool –Click the filled circle –Pick the color –Click and drag to draw a circle

Draw legs for the spider Use the line tool to draw legs –Click on the line tool icon –Pick the color for the legs –Click and drag to draw

Draw a head and eyes Use the ellipse tool to draw a head and eyes –Click "undo" if you make a mistake –Click "OK" when done

Grow or shrink sprite You can change the size of the sprite –Click on the arrows pointing out icon to grow it and arrows pointing in to shrink –Then click on sprite

Programming Steps When the green flag is clicked do all set-up –Clear the drawing area –Draw a square How do you draw a square? –Repeat 4 times Move 50 steps Turn 90 degrees

Set-up When the green flag is clicked - Control –Clear the drawing area – in Pen –Put the pen down – also in Pen

Draw a Square Repeat 4 times – Control –Move 10 steps – Motion Change to 50 –Turn – Motion Change to 90

Drawing many squares We can draw a flower by drawing many squares –And turning between them

Breaking this into pieces Use broadcast and receive to make reusable parts –drawSquare –drawSquareFlower

Challenge Add other shapes –Triangle Add a way to clear the drawing –When you press a key Add a variable to control the width of the square –You can even make this a slider

Connection to Art Piet Mondrian made modern art with just black lines and solid colors –Can you do something like this? –Try setting the pen width and color