Welcome to Pencil Code

Drawing In Place

• dot - draw a colored circle.
• box - draw a colored square.
• label - write a text label.

Moving the Turtle

• fd - go forward.
• rt - right turn.
• lt - left turn.
• bk - go backward.
• speed - pick a speed.

Using Color

• pen - trace with a pen color.
• colors - 140 named colors.
• fill - fill a traced shape.
• css - styling objects.

Two Dimensional Motion

• home - jump to the origin.
• moveto - move to an absolute location.
• movexy - move by an x y offset.
• slide - move relative to the turtle direction.
• jumpto - jump to a location without drawing.
• jumpxy - jump by an offset without drawing.

Angles and Arcs

• angles - rotation and direction.
• turnto - set the turtle direction.
• drawing arcs - how to do curves with lt and rt.

Responding to Events

• button - make a button control.
• keydown - respond to a keyboard key.
• click - respond to a mouse click.
• dblclick - respond to a double-click.

Sprites, Images, and Pixels

• new Turtle - create another turtle.
• new Sprite - create a blank sprite.
• new Audio - load a sound.
• wear - change the turtle image.
• img - about image urls.
• clip - reshape a sprite.
• twist - changing the forward direction.
• mirror - reversing a sprite.
• drawon - draw on a sprite.
• canvas - access the raw canvas.

Animation Queues and Timing

• about animation - overview of animation in Pencil Code.
• frame-based animation - like frames of a movie.
• queue-based animation - animation with to-do lists.
• animation queues - understanding how animation queues work.
• mixing queue- and frame-based animation - the ultimate form of animation.
• pause - pause the turtle.
• sync - synchronize turtles.
• await - wait for a return value.

Interactivity with Framerate Animation

• about framerates - understaing frame rate animation.
• lastmousemove - checking the mouse.
• getxy - read turtle coordinates.
• direction - read turtle direction.
• distance - read distance between turtles.

Turtle Math

• round, floor, ceil, trunc - rounding functions.
• max ,min - find the smallest or largest number.
• abs, sign - remove or read the sign of a number.
• sin, cos, tan - basic trig functions.
• atan, asin, acos, atan2 - inverse trig functions.
• sqrt, pow - compute powers and roots.
• ln, log10 - logarithms.
• PI, E, etc - some numeric constants.

• urls - overview of special urls on Pencil Code.
• img - creative commons images by search.
• home - running files fullscreen.
• load - loading files as JSON.
• save - saving files with JSON.
• proxy - proxy HTTP requests.
• socket.io - socket.io reflector.