The API should be considered unstable for now, subject to changes until a 1.0 release.
setSize
setZoom
setTitle
setGrid
originAtCenter
useDisplay
Set the size of the display and standard plane, in pixels.
Set the zoom level, in other words, the size of a single pixel as it appears on the physical viewing screen. Not supported by all environments.
If the display is in a window, sets the title of that window. Also used by discovery services to determine the name of a script without running it.
Show the grid on top of the display, spaced out the given number of units.
Move the x,y coordinate system's origin to the center of the plane, instead of the upper-left.
The display to use, instead of the default display. Either the name of a pre-existing display, or a display object.
Names of pre-existing displays:
ascii: When running in a terminal, output ascii art to stdout.
loadImage
makePolygon
rotatePolygon
oscil
on
Loads an image, by opening it and reading its contents. Can be passed to paste once reading has completed. If necessary, the image pixel data has its colors downsampled it to match the palette.
In some environments, such as node.js, loadImage is synchronous, so images are opened and read all at once. However, in order to keep scripts portable, it is recommended to also handle async environments, such as web browsers. To do this, call loadImage at the top-level of your script, and then only use paste inside of a call to then or a draw function that is passed to run. Raster.js guarantees that all images opened will be fully loaded once the draw function is invoked, assuming they exist.
filename: the name of the image to load. Either a local filesystem path or a web accessible URL.
returns an image, opened but not necessarily loaded
Converts a set of a points into a polygon.
shape: Either a list of points or a polygon.
returns a polygon
Rotates the given polygon by the given angle, returning a new polygon.
shape: Either a list of points or a polygon.
angle: Number of radians to rotate.
returns a polygon
Produce an oscillating wave value that varies between 0.0 and 1.0 in a sinusoidal motion. Parameters to oscil must be named parameters only, positional parameters are not allowed.
period: The period of the motion, in ticks. Larger means a slower motion. Default is 60
begin: How far into the motion to begin, as a fraction between 0.0 and 1.0. Default is 0.0
max: Maximum value to be returned, representing the distance from valley to peak. Default 1.0
tick: Parameter used as input. Default is ra.tick
Handle events caused by user interaction. Only eventName that is currently handled is keypress. Upon each keypress the callback will be invoked information about the event.
width
height
time
tick
TURN
Width and height of the scene, equivalent to the display size.
The number of seconds since the scene begin, as a floating point value.
The number of internal clock ticks, equal to 1 per frame, at 60 frames a second.
A mathematical constant representing the number of radians in the full rotation around a plane, equivalent to 2PI or TAU, approximately 6.2831853.
setColor
setTrueColor
Set the background color and clear the plane.
Set the foreground color to use for drawing.
For most of these methods, there are two versions, one starting with draw and another starting with fill. The former only renders the outside of a shape, the latter will fill it in.
drawLine -
drawDot -
drawSquare fillSquare
drawRect fillRect
drawCircle fillCircle
drawPolygon fillPolygon
- fillPattern
- fillFrame
- fillFlood
- fillPattern
Draw a line from the point x0,y0 to x1,y1.
If any of the values are non-integers, then the line is drawn between those points as though they are floating point values.
cc: "connect corners" flag. If all the values are integers, and cc is false, then the line is drawn from the center of one point to the center of the other, by off-setting each value by 0.5 to avoid sampling bias. However, if all values are integers and cc is a true value, then instead the line is drawn to connect corners between the opposite ends of those points.
Draw a dot at point x,y.
Draw a square with x,y as the upper-left point, and size being the width and height of the square. The number of pixels spanned, from the left edge of the left-most pixel, to the right edge of the right-most pixel, and from the top of the top-most pixel to the bottom of the bottom-most pixel, is equal to the value of size.
Fill a square with x,y as the upper-left point, and size being the width and height of the square. Same as drawSquare, except the shape's interior is also filled.
drawRect({x0, y0, x1, y1})
Draw a rectangle with x,y as the upper-left point, and w,h as the width and height.
fillRect({x0, y0, x1, y1})
Fill a rectangle with x,y as the upper-left point, and w,h as the width and height. Same as drawRect, except the shape's interior is also filled.
drawCircle({centerX, centerY, r, thick?})
Draw a circle with x,y as the upper-left point, and radius of r. The circle will be a ring 1 pixel wide, unless thick is specified. If it is, the thick is measured from the outside edge of the circle and goes inward. The radius is not changed by specifying thick.
r: radius of the circle. If this is an integer, then the number of pixels from the top or left edge of the top of left pixel to the other extreme will equal r * 2, an even number. If r is 0.5 more than some integer, the circle will instead span an odd number of pixels from one edge to the other. Other values will be rounded to the nearest half-integer.
fillCircle({centerX, centerY, r})
Fill a circle with x,y as the upper-left point, and radius of r. Same as drawCircle, except the shape's interior is also filled, and thick is not used.
Draws the outline of a polygon, offset by the optional x,y position.
shape: either a list of points (such as [[3,4],[5,6],[7,8]]) or a polygon object as returned by makePolygon or rotatePolygon.
Fills a polygon, offset by the optional x,y position. Same as drawPolygon, except the shape's interior is filled.
Draws the source onto the plane.
source: A source plane, such as an image that was created by loadImage.
x: X dimension (left) of the upper-left point where drawing starts.
y: Y dimension (top) of the upper-left point where drawing starts.
fillFrame iterates over each pixel of the plane, and invokes the callback with a mem representing the frame's data.
options: An optional object. Supported fields: previous if true, maintain an immutable copy of the previous frame.
callback: A callback to be invoked with the frame data. The parameters to this callback may take two forms:
function(x, y)
The callback will be invoked per each pixel in the plane. If the callback returns a number, that number will be assigned to that pixel. Otherwise the pixel's value is not modified.
Fill a region of contiguous color, by replacing it with the current set color. Starts at the given x,y coordinate and floods from there.
Fill the entire plane by tiling the pattern represented by the dots parameter. Dots must be a 2-d square array, with each element representing a color.
setScrollX
setScrollY
Scroll the plane x pixels horizontally. Rendering will wrap-around when it reaches the edge of the plane.
Scroll the plane y pixels vertically. Rendering will wrap-around when it reaches the edge of the plane.
Assigns the palette to use for displaying the scene. May either be the name of a pre-existing palette, or a list of rgb values.
If not invoked, the default palette is this:
Names of pre-existing palette:
quick: The default, shown above. 64 colors, a quick and simple rainbow palette.
dos: The DOS operating system.
nes: NES 8-bit video game console.
grey: Grey scale colors, from black to white.
gameboy: Gameboy handheld video game console.
zx-spectrum: ZX Spectrum 8-bit computer.
c64: Commodore 64 8-bit computer.
pico8: Pico-8 fantasy console.
Pick the color at position x,y and return it as a palette entry.
run
save
quit
nextFrame
Continually render to the display. The function drawFunc is called once per frame, before rendering begins.
Save the plane to the given filename. May only be run in an environment that supports creating files.
Quits the application.
Waits one frame.