This page contains descriptions of general purpose utility commands and functions available in Kojo.

Environment

Command/Function	Description
`size(w, h)`	sets the size of the canvas to the given width and height.
`cwidth`	returns the current width of the canvas.
`cheight`	returns the current height of the canvas.
`originBottomLeft()`	puts the origin at the bottom left of the canvas.
`setup { drawing code }`	calls the drawing code once at the beginning of your program.
`drawLoop { drawing code }`	calls the drawing code at the default refresh rate, which is 50 times a second.
`setRefreshRate(n)`	sets the refresh rate to `n` times per second. The next time a `clear()` is done, the refresh rate is reset to its default value of 50.
`erasePictures()`	erases all the pictures in the canvas.
`viewRotate(angle)`	rotates the contents of the drawing canvas by the given `angle`.
`viewTranslate(x, y)`	translates the contents of the drawing canvas by the given `(x, y)`).
`viewScale(factor)`	scales the contents of the drawing canvas by the given `factor`.

Random numbers

Command/Function	Description
`random(upperBound)`	Returns a random integer between `0` (inclusive) and `upperBound` (exclusive).
`random(lowerBound, upperBound)`	Returns a random integer between `lowerBound` (inclusive) and `upperBound` (exclusive).
`randomDouble(upperBound)`	Returns a random decimal fraction between `0` (inclusive) and `upperBound` (exclusive).
`randomDouble(lowerBound, upperBound)`	Returns a random decimal fraction between `lowerBound` (inclusive) and `upperBound` (exclusive).
`randomNormalDouble`	Returns a normally distributed number with mean `0` and standard deviation `1`.
`randomBoolean`	Returns a random boolean value. This is like a coin toss.
`randomFrom(seq)`	Returns a random value from the given sequence.
`randomFrom(seq, weights)`	Returns a random value from the given sequence as per the given distribution of weights.
`randomColor`	Returns a random color.
`initRandomGenerator()`	Initializes the Kojo random number generater with a random seed, and prints out the seed for future reference.
`initRandomGenerator(seed)`	Initializes the Kojo random number generater with the given seed (potentially obtained via the previous command) to enable the reproducing of random patterns.

Math

Function	Description
`mathx.map(value, start1, stop1, start2, stop2)`	Maps the given value from the range `(start1, stop1)` to the range `(start2, stop2)`.
`mathx.lerp(start, stop, amt)`	Returns the interpolation as per the given fraction `amt` in the range `(start, stop)`.
`mathx.constrain(value, min, max)`	Constrains the given `value` between `min` and `max`.
`mathx.distance(x1, y1, x2, y2)`	Calculates the distance between (x1, y1) and (x2, y2).
`mathx.distance(point1, point2)`	Calculates the distance between point1 and point2.
`mathx.angle(x1, y1, x2, y2)`	calculates the angle in degrees between the line from (x1, y1) to (x2, y2) and the horizontal.
`mathx.angle(point1, point2)`	calculates the angle in degrees between the line from point1 to point2 and the horizontal.
`rangeTill(from, untill, step)`	returns a range that starts from `from`, goes until (but excluding) `until`, and steps up by `step`. See example.

Colors

Function	Description
`cm.hsl(hueAngle, saturationFraction, lightnessFraction)`	Creates a color with the given hue, saturation, and lightness.
`cm.hsla(hueAngle, saturationFraction, lightnessFraction, opacityFraction)`	Creates a color with the given hue, saturation, lightness, and opacity.
`cm.linearGradient(x1, y1, c1, x2, y2, c2, cyclic)`	Creates a linear color gradient between color `c1` at position `(x1, y1)` and color `c2` at position `(x2, y2)`. The `cyclic` parameter specifies whether the gradient should be repeated or not.
`cm.radialGradient(cx, cy, c1, radius, c2, cyclic)`	Creates a radial color gradient between color `c1` at the center of a circle positioned at `(x1, y1)` and color `c2` at a distance `radius` from the center. The `cyclic` parameter specifies whether the gradient should be repeated or not.
`cm.linearMultipleGradient(x1, y1, x2, y2, distribution, colors, cyclic)`	Creates a linear color multi-gradient between position `(x1, y1)` and position `(x2, y2)`. The gardient is spread across this range as per the `distribution` and `colors`; `distribution` is a sequence of fractions, and `colors` is a sequence of colors. Both sequences should have the same number of elements. So, for example, if the `distribution` is `Seq(0, 0.4, 1)` and colors is `Seq(red, blue, green)`, then the multi-gradient will be made out of `red` at the beginning of the range, `blue` at 40% of the range, and `green` at the end of the range. The `cyclic` parameter specifies whether the gradient should be repeated or not.
`cm.radialMultipleGradient(x, y, r, distribution, colors, cyclic)`	Creates a radial color multi-gradient between position `(x, y)` as the center of a circle with radius `r` and the boundary of this circle. The gardient is spread across this range as per the `distribution` and `colors`; `distribution` is a sequence of fractions, and `colors` is a sequence of colors. Both sequences should have the same number of elements. So, for example, if the `distribution` is `Seq(0, 0.4, 1)` and colors is `Seq(red, blue, green)`, then the multi-gradient will be made out of `red` at the beginning of the range, `blue` at 40% of the range, and `green` at the end of the range. The `cyclic` parameter specifies whether the gradient should be repeated or not.

Misc

Function	Description
`isKeyPressed(keyCode)`	Returns true if the given key is currently pressed on the keyboard. Otherwise returns false.
`joystick(radius)`	Creates a joystick control with the given radius.
`js.currentVector`	Tells you the current vector for the joystick `js`. This vector is defined by two points - the center of the joystick control, and the center of the moveable joystick circle.
`js.movePlayer(pic, scaleFactor)`	For the joystick `js`, moves the player based on the movement of the joystick circle, as per the `currentVector` defined above. You can scale the currentVector by using `scaleFactor` to make the movement faster (`scaleFactor` > `1`) or slower (`scaleFactor` < `1`).

Examples

rangeTill

rangeTill(4, 10, 2).toArray //> res16: Array[Int] = Array(4, 6, 8)
rangeTill(4, 11.5, 2.5).toArray //> res17: Array[BigDecimal] = Array(4.0, 6.5, 9.0)

Kojo Wiki

docs for Kojo

Environment

Random numbers

Math

Colors

Misc

Examples

rangeTill