Parameters

Reference ❯ Creating Parameters to Control Your Projects

Creating Parameters

parameter.number( name, min, max ) top ↑

Syntax

parameter.number( name )
parameter.number( name, min, max )
parameter.number( name, min, max, initial )
parameter.number( name, min, max, initial, callback )

This function creates a visual slider in the viewer that can be used to adjust a global variable in your code.

You generally call the parameter.number() function in the setup() function of your main file. The string you specify for name will be exposed as a global variable that can be used in your code. When you adjust the slider in the viewer, the variable will be set appropriately. The last three parameters, min, max and initial allow you to set the minimum, maximum and initial value of your parameter respectively. If an initial value is not specified, then the parameter takes on the minimum value initially. If no minimum or maximum values are specified, the parameter uses the range [0, 1].

The optional callback argument specifies a callback function to be called when the parameter slider changes. This callback function is provided the parameter's value as its single argument.

name

string, the parameter function will create a global variable with this name
min

int or float, specifies the minimum value that your parameter can take
max

int or float, specifies the maximum value that your parameter can take
initial

int or float, specifies the initial, or starting, value of the parameter
callback

function, this function will be called whenever the parameter is changed, it will be given the parameter value as an argument

Examples

function setup() --Creates a global variable called Radius parameter.number("Radius", 50.0, 300.0, 100.0) end function draw() background(128) ellipseMode(RADIUS) ellipse(WIDTH/2, HEIGHT/2, Radius) end

Related

parameter.integer( name, min, max ) top ↑

Syntax

parameter.integer( name )
parameter.integer( name, min, max )
parameter.integer( name, min, max, initial )
parameter.integer( name, min, max, initial, callback )

This function creates a visual slider in the viewer that can be used to adjust a global variable in your code.

The main difference between this function and the parameter.number() function is that this function always sets the variable declared in name to an integer value. Thus its min, max and initial values must also be integers.

You generally call the parameter.integer() function in the setup() function of your main file. The string you specify for name will be exposed as a global variable that can be used in your code. When you adjust the slider in the viewer, the variable will be set appropriately. The last three parameters, min, max and initial allow you to set the minimum, maximum and initial value of your parameter respectively. If an initial value is not specified, then the parameter takes on the minimum value initially. If no minimum or maximum values are specified, the parameter uses the range [0, 10].

The optional callback argument specifies a callback function to be called when the parameter slider changes. This callback function is provided the parameter's value as its single argument.

name

string, the parameter.integer function will create a global variable with this name
min

int, specifies the minimum value that your parameter can take
max

int, specifies the maximum value that your parameter can take
initial

int, specifies the initial, or starting, value of the parameter
callback

function, this function will be called whenever the parameter is changed, it will be given the parameter value as an argument

Examples

function setup() --Creates a global variable called Radius -- It also has a callback that prints the -- value when changed parameter("Radius", 50, 300, 100, function(x) print(x) end ) end function draw() background(128) ellipseMode(RADIUS) ellipse(WIDTH/2, HEIGHT/2, Radius) end

Related

parameter.color( name, color ) top ↑

Syntax

parameter.color( name )
parameter.color( name, color )
parameter.color( name, color, callback )

parameter.color( name )
parameter.color( name, red, green, blue )
parameter.color( name, red, green, blue, callback )

parameter.color( name )
parameter.color( name, red, green, blue, alpha )
parameter.color( name, red, green, blue, alpha, callback )

parameter.color( name )
parameter.color( name, gray )
parameter.color( name, gray, callback )

parameter.color( name )
parameter.color( name, gray, alpha )
parameter.color( name, gray, alpha, callback )

This function creates a visual color sample in the viewer that can be used to adjust a global color variable in your code.

You generally call the parameter.color() function in the setup() function of your main file. The string you specify for name will be exposed as a global variable of the color type.

This can be used in your code. When you tap the color sample in the viewer, an interactive color picker will be presented, allowing you to adjust the variable live, while your code is running.

You may also set the initial value of the color with either a color object, a gray scale value, or an rgb triplet (you may include an alpha value as well).

The optional callback argument specifies a callback function to be called when the color value changes. This callback function is provided a single argument, of the color type, containing the new value.

name

string, the parameter function will create a global color variable with this name
red

int, specifies the initial value of the red component of the color
green

int, specifies the initial value of the green component of the color
blue

int, specifies the initial value of the blue component of the color
gray

int, specifies the gray value of the color
alpha

int, specifies the initial value of the alpha component of the color
callback

function, this function will be called whenever the parameter is changed, it will be given the new color value as an argument

Examples

function setup() --Creates a global color variable called FillColor -- make it red by default parameter.color("FillColor", 255, 0, 0) --Creates a global color varialbe called StrokeColor -- make it white by default parameter.color("StrokeColor", color(255)) end function draw() background(128) strokeWidth(10) --Set our colors using the parameter values stroke(StrokeColor) fill(FillColor) ellipse(WIDTH/2, HEIGHT/2, 300) end

Related

parameter.boolean( name, initial ) top ↑

Syntax

parameter.boolean( name )
parameter.boolean( name, initial )
parameter.boolean( name, initial, callback )
parameter.boolean( name, callback )

This function creates a visual switch in the viewer that can be used to adjust a boolean variable in your code.

You generally call the parameter.boolean() function in the setup() function of your main file. The string you specify for name will be exposed as a global variable that can be used in your code.

When you adjust the switch in the viewer, the variable will be set appropriately. You may also specify an initial value for the switch. With true causing the switch to be set to the ON state, and false setting the switch to the OFF state.

The optional callback argument specifies a callback function to be called when the parameter switch changes. This callback function is provided the parameter's value as its single argument.

name

string, the parameter function will create a global variable with this name
initial

boolean, specifies the initial value of the boolean parameter
callback

function, this function will be called whenever the parameter is changed, it will be given the parameter value as an argument

Examples

function setup() -- Creates a simple switch that prints when changed parameter.boolean("MySwitch", true, switchChanged) end function switchChanged( value ) print( "MySwitch changed to " .. tostring(value) ) end

Related

parameter.text( name, initial ) top ↑

Syntax

parameter.text( name )
parameter.text( name, initial )
parameter.text( name, initial, callback )
parameter.text( name, callback )

This function creates a visual text box in the viewer. You can type in this control to adjust the contents of the corresponding string value defined by name.

You generally call the parameter.text() function in the setup() function of your main file. The string you specify for name will be exposed as a global variable that can be used in your code.

When you input text in the parameter.text control, the variable defined by name will be set appropriately. You may also specify the initial contents of the text variable by setting initial to a string.

The optional callback argument specifies a callback function to be called when the parameter text changes. This callback function is provided the parameter's value as its single argument.

name

string, the parameter function will create a global variable with this name
initial

string, specifies the initial value of the text parameter
callback

function, this function will be called whenever the parameter is changed, it will be given the parameter value as an argument

Examples

function setup() -- Creates a simple switch that prints when changed parameter.text("MyText", "Hello World!", textChanged) end -- Print our text parameter in upper-case function textChanged( value ) print( string.upper(value) ) end

Related

parameter.action( name, callback ) top ↑

Syntax

parameter.action( name, callback )

This function creates a visual button in the viewer sidebar. Pressing the button will call the function defined by callback. The name argument sets the label of the button.

You generally call the parameter.action() function in the setup() function of your main file. The string you specify for name will be used to label the button that appears in the viewer. It will not be exposed as a global variable.

The callback argument specifies a callback function to be called when the button is pressed. It is passed the name of the button as its only argument.

name

string, the parameter function will create a global variable with this name
callback

function, this function will be called whenever the parameter is changed, it will be given the parameter value as an argument

Examples

function setup() -- Creates a button to clear the output parameter.action("Clear Output", output.clear) end

Related

Watching Expressions

parameter.watch( expression ) top ↑

Syntax

parameter.watch( expression )

This function allows you to monitor the value of a Lua expression within the viewer. Generally you call the parameter.watch() function from the setup() function in your main file.

expression

string, the global variable or expression to watch

Examples

function setup() --Shows the elapsed time in the viewer parameter.watch("ElapsedTime") end

Related

Clearing the Parameter List

parameter.clear() top ↑

Syntax

parameter.clear()

This function clears the parameter list of all parameter widgets and watch values. You can then re-add parameters using the parameter group of functions.

Related

output.clear() top ↑

Syntax

output.clear()

This function clears the output buffer for the print() function.