<glossdef><para>Degrees are units to measure angles or turns. A full turn is 360 degrees, a half turn 180 degrees and a quarter turn 90 degrees. The commands <userinput>turnleft</userinput>, <userinput>turnright</userinput> and <userinput>direction</userinput> need an input in degrees.</para></glossdef>
<glossterm>input and output of commands</glossterm>
<glossdef><para>Some commands take input, some commands give output, some commands take input <emphasis>and</emphasis> give output and some commands neither take input nor give output.</para>
<para>Some examples of commands that only take input are: <screen>
</screen> The <userinput>forward</userinput> command takes <userinput>50</userinput> as input. <userinput>forward</userinput> needs this input to know how many <glossterm linkend="pixels">pixels</glossterm> it should go forward. <userinput>pencolor</userinput> takes a colour as input and <userinput>print</userinput> takes a string (a piece of text) as input. Please note that the input can also be a container. The next example illustrates this: <screen>x = 50
</screen> The <userinput>inputwindow</userinput> command takes a string as input, and outputs the number or string that is entered. As you can see, the output of <userinput>inputwindow</userinput> is stored in the container <userinput>x</userinput>. The <userinput>random</userinput> command also gives output. In this case it outputs a number between 1 and 100. The output of the random is again stored in a container, named <userinput>r</userinput>. Note that the containers <userinput>x</userinput> and <userinput>r</userinput> are not used in the example code above.</para>
<glossdef><para>This is a feature of &kturtle; that makes coding even easier. With intuitive highlighting the code that you write gets a colour that indicates what type of code it is. In the next list you will find the different types of code and the colour they get in <link linkend="the-code-editor">the code editor</link>. <table>
<title>Different types of code and their highlight colour</title>
<entry>Lines that are commented start with a comment characters (#). These lines are ignored when the code is executed. Comments allow the programmer to explain a bit about his code or can be used to temporarily prevent a certain piece of code from executing.</entry>
<entry>Brackets are used to group portions of code. Brackets are often used together with <link linkend="controlling-execution">execution controllers</link>.</entry>
<glossdef><para>A pixel is a dot on the screen. If you look very close you will see that the screen of your monitor uses pixels. All images on the screen are built with these pixels. A pixel is the smallest thing that can be drawn on the screen.</para>
<para>A lot of commands need a number of pixels as input. These commands are: <userinput>forward</userinput>, <userinput>backward</userinput>, <userinput>go</userinput>, <userinput>gox</userinput>, <userinput>goy</userinput>, <userinput>canvassize</userinput> and <userinput>penwidth</userinput>.</para></glossdef>
<glossdef><para>RGB combinations are used to describe colours. The <quote>R</quote> stand for <quote>red</quote>, the <quote>G</quote> stands for <quote>green</quote> and the <quote>B</quote> stands for <quote>blue</quote>. An example of an RGB combination is <userinput>255,0,0</userinput>: the first value (<quote>red</quote>) is 255 and the others are 0, so this represents a bright shade of red. Each value of an RGB combination has to be in the range 0 to 255. Here a small list of some often used colours: <table frame="none">
<para>To easily find the RGB combinations of a colour you should try the colour picker! You can open the colour picker using <link linkend="tools-color-picker"><menuchoice><guimenu>Tools</guimenu><guimenuitem>Colour Picker</guimenuitem></menuchoice></link>.</para>
<para>Two commands need an RGB combination as input: these commands are <userinput>canvascolour</userinput> and <userinput>pencolour</userinput>.</para></glossdef>
<glossdef><para>A sprite is a small picture that can be moved around the screen. Our beloved turtle, for instance, is a sprite.</para>
<para>Note: with this version of &kturtle; the sprite cannot be changed from a turtle into something else. Future versions of &kturtle; will be able to do this.</para></glossdef>
<glossdef><para>Wrapping is what happens when the turtle draws something that is to big to fix in on the canvas and wrapping is set <quote>on</quote>. <screenshot> <screeninfo>This is what happens when wrapping is <quote>on</quote></screeninfo> <mediaobject> <imageobject> <imagedata fileref="wrapping.png" format="PNG"/> </imageobject> <textobject> <phrase>An example of wrapping</phrase> </textobject> </mediaobject> </screenshot> When the turtle moves off a border of the canvas it is instantly taken to the opposite border so it can continue its move. This way the turtle will always stay on the screen while it moves. This happens when wrapping is on.</para>
<para>Wrapping can be turned on and off with the <userinput>wrapon</userinput> and <userinput>wrapoff</userinput> commands. When &kturtle; starts wrapping is turned on by default.</para></glossdef>
