KTurtle/C3/Special-Commands-in-KTurtle/English
| Visual Cue | Narration |
|---|---|
| Slide Number 1
Title slide |
Hello everybody. Welcome to this tutorial on Special Commands in KTurtle. |
| Slide Number 2
Learning Objectives |
In this tutorial, we will learn about
|
| Slide Number 3
System Requirement |
To record this tutorial I am using,
Ubuntu Linux OS version. 12.04. KTurtle version. 0.8.1 beta. |
| Slide Number 4
Pre-requisites |
We assume that you have basic working knowledge of KTurtle
If not, for relevant tutorials, please visit our website. |
| Switch to KTurtle Application
Dash home >>In the Search bar type KTurtle. Click on the KTurtle icon. |
Let's open a new KTurtle Application.
Click on Dash home. In the Search bar, type KTurtle. Click on the KTurtle icon. |
| Let's first look at “learn” command | |
| Slide Number 5
learn command |
learn is special command as it is used to create your own commands.
'learn' Command can takes input and returns output. |
| New command | Let's take a look at how a new command is created. |
| Zoom text | Let me zoom the program text to have a clear view. |
|
Switch to Kturtle Window repeat 4 { forward 10 turnleft 90 } |
Let's type a code in the editor to draw a square: repeat 4 within curly brackets { forward 10 turnleft 90 } Here the number 10 specfies the length of the side of the square. |
| Highlight learn and square commands | Now let's learn the commands involved to draw a square, using the learn command.
We will name of this set of commands to draw a square as square. The command 'learn' is followed by the name of the command to be learnt, in this case it is a square. |
| Type the code | Let's type the following code
learn space square space $x let's include the learn command within curly brackets { repeat 4 { let's repace 10 by $x forward $x turnleft 90 } } |
| Highlight square command | New command that we have defined is called square.
square takes one input argument, $x to set the size of the square. Note that when you run this code, square returns no output. The command learn is just 'learning' the other command square to be used later. square command can now be used like a normal command in the rest of the code. |
| Type the code | Let me add few more lines here.
Let's type learn square $x { repeat 4 { forward $x turnleft 90 } } go 200,200 square 100 Using the command square 100 Turtle draws a square of dimension 100. |
| Run the code | Let's click on Run code now
Turtle draws a square on the canvas. |
| Replace 100 by 50. | Let's now replace 100 by 50. |
| Run the code | Let's run again
Turtle draws an another square with dimension 50. Please note that this command can be used only within the scope of this program |
| Clear code | I will clear the current code from editor.
Type “clear” command and Run to clean the canvas. |
| Next we will learn about “random” command. | |
| Slide Number 6
"random" command |
|
| Let's put the “random” command to use in the application. | |
| Show code | I already have the code in a text editor.
Let me explain the code. |
| Highlight reset | “reset” command sets Turtle to default position |
| Highlight random 1,20 | Here, the command random 1,20 selects a random number which is equal or greater than 1 and equal or less than 20,
and assigns it to the variable x. |
| Highlight repeat 36
{ forward $x turnleft 10 } |
repeat command and the commands within curly brackets draw a circle |
| reset
$x=random 1,20 repeat 36 { forward $x turnleft 10 } |
I will copy the code from text editor and paste it into KTurtle's editor.
Pause the tutorial and type the program into your KTurtle editor. Resume the tutorial after typing the program |
| Run the code | When we run this code,
Turtle draws a circle with radius between 1 and 20 on the canvas. Let us execute this code a few times, You can see that a circle with a different size is generated each time. Every time you execute this code, a circle with a different radius is drawn on the canvas. |
|
Let us now use both the learn and random commands in an example. | |
| clear current code | I will clear the current code and type clear command and Run to clean the canvas. |
| I already have a program in the Text editor.
I will explain the code now. | |
|
Highlight reset |
“reset” command sets Turtle to its default position. |
| Highlight canvassize 300,300 | canvassize 300,300 sets the width and height of the canvas to 300 pixels each. |
| Highlight $R, $G, and $B | $R, $G, and $B are three variables to which I am assigning random values between 0 and 255. |
| Highlight canvascolor $R,$G,$B , | In the command canvascolor $R,$G, and $B ,
the Red-Green-Blue combination is replaced by the values assigned to the variables R, G, and B in the previous step. The canvas color is randomly set when this command is executed. |
| Highlight $red, $green and $blue | $red, $blue, $green are another set of variables
to which random values between 0 and 255 are assigned randomly. pencolor $red, $blue, $green the Red-Blue -Green combination values are replaced by the variables $red, $green and $blue to which random values were assigned in the previous step. |
| Highlight pencolor $red,$blue,$green | The color of the pen is also set randomly when the command is executed. |
| Highlight penwidth 2 | penwidth 2 sets the width of pen to 2 pixels. |
| code to a circle | Next I have entered the code to learn to draw a circle.
Here $x represents the size of the circle. repeat command followed by the code in curly brackets draws a circle. |
| Highlight go commands and circle commands |
The next set of commands that is go commands followed by circle commands draw circles with the specified sizes. |
| Example circle | For example:
circle with size 5 draws a circle with size 5 At the co-ordinates specified at X and Y positions in the go command. For each circle, I have specified different positions on the canvas. |
| reset
canvassize 300,300 $R= random 0,255 $G=random 0,255 $B=random 0,255 canvascolor $R,$G,$B $red=random 0,255 $blue=random 0,255 $green=random 0,255 pencolor $red,$blue,$green penwidth 2 learn circle $x{ repeat 36{ forward $x turnleft 10 } } go 85,85 circle 5 go 115,115 circle 5 go 145,145 circle 5 go 190,190 circle 5 go 220,220 circle 10 go 0,0 |
I will copy this code from text editor and paste it into KTurtle's editor. Pause the tutorial and type the program into your KTurtle editor. Resume the tutorial after typing the program. |
| Execute code | I will execute this code in Fullspeed.
You can execute this code at any of the speeds specified in the Run option. I will run this code a few times. You can see the difference in randomly set values of pen color and canvas color. Note the change in the color of the pen and the canvas on each execution. You can execute the code how many ever times you want and note the change in the randomly set values of the pen and canvas. |
| With this we come to the end of this tutorial.
Let's summarize | |
| Slide Number 7
Summary |
In this tutorial we have learnt about,
|
| Slide Number 8
Switch to KTurtle Window & Show Assignment |
As an assignment for you to solve,
|
| Slide number 9
Acknowledgement |
Watch the video available at this URL
http://spoken-tutorial.org/What is a Spoken Tutorial It summarises the Spoken Tutorial project If you do not have good bandwidth, you can download and watch it |
| Slide Number 10 | The Spoken Tutorial Project Team :
Conducts workshops using spoken tutorials Gives certificates to those who pass an online test For more details, please write to contact@spoken-tutorial.org |
| Slide number 11 | Spoken Tutorial Project is a part of the Talk to a Teacher project
It is supported by the National Mission on Education through ICT, MHRD, Government of India More information on this Mission is available at this link http://spoken-tutorial.org/NMEICT-Intro ] This script is contributed by IT for change, Bangaluru. This is Madhuri Ganpathi from IIT Bombay signing off. Thank you for joining. |
