Widgets and Hints

Hint Types

Strings and Numbers

Integer, float or string hint values should use the common literal representation of such values (e.g. 1, 2.3, foo).

Booleans

Boolean hint values can be specified using true or false. For historical reasons, the following strings are also accepted: yes, no, on, off, 1, 0.

Lists

List hint values can be specified either using a delimited string or a nested <hintlist> XML element. Strings are delimited using a pipe character (|). The following two forms are equivalent:

<param name="someParameter" widget="fileInput" fileTypes="exr|png"/>
<param name="anotherParameter" widget="fileInput">
  <hintlist name="fileTypes">
    <string value="exr"/>
    <string value="png"/>
  </hintlist>
</param>

Child elements of <hintlist> may be of type <int>, <float> or <string>, and may specify their value in either value or default properties.

Dictionaries

Dictionary hint values can be specified using a delimited string or a nested <hintdict> XML element. Items in strings are delimited using a pipe character (|); keys and values are separated by a colon character (:). The following two forms are equivalent:

<param name="someParameter" widget="mapper" options="a:1.0|b:2.0|c:3.0"/>
<param name="anotherParameter" widget="mapper">
  <hintdict name="options">
    <float name="a" value="1.0"/>
    <float name="b" value="2.0"/>
    <float name="c" value="3.0"/>
  </hintdict>
</param>

Child elements of <hintdict> may be of type <int>, <float> or <string>, and may specify their value in either value or default attributes. They must also specify a name attribute.

Common Hints

The following hints are applicable to most widget types.

Hint

Type

Description

label

String

Alters the display name of the widget. Please use this rarely as it can create confusion with regards to expressions and NodegraphAPI scripting.

labelPos

Integer

Sets the alignment of the label to either the left or right. Value should be either FormWidget.LABELPOS_LEFT (0) or FormWidget.LABELPOS_RIGHT (1).

New in Katana 6.0v1

readOnly

Boolean

If true, the value of the corresponding parameter is not editable via the Parameters tab. This does not affect scripting.

infoText

String

Displays a line of informational text below the editing widget for the parameter. Please use this sparingly as the same mechanism is used for displaying error messages on some widget contexts.

externalEditorSuffix

String

The file extension to use for the temporary file that is created when External editor… is chosen from the parameter’s context menu.

help

String

See Help Text.

mono

Boolean

If true, text in the editing widget is displayed using a monospace font.

Pages and Groups

group

<page> and <group> elements use the group widget type be default. It supports these hints:

Hint

Type

Description

open

Boolean

If true, the page/group is expanded in the UI to reveal its contents.

closed

Boolean

If false, the page/group is expanded in the UI. Use open in preference to this hint.

frameless

Boolean

If true, no frame or background will be displayed around the value.

New in Katana 6.0v1

presetsGroup

The presetsGroup widget type for pages allows you to define default values for specific parameters that are contained in/on the respective group/page. Defining a presetsGroup for a specific page results in a menu that displays in the Parameters tab for the parameters.

Widget type-specific hints:

Hint

Type

Description

policies

String

Specifies the parameter names for which to set default values, separated by commas.

presets

String

Specifies the default values for the different presets. Each preset is defined by a name and a list of values, one for each parameter specified in the policies attribute. The value and parameter types need to match. Presets are separated by a pipe character (|).

Note

Only floats, list of floats, and strings are allowed in the presets attribute.

In the example below, the <page> element’s widget is set to presetsGroup, and the element defines presets for four parameters: Kd, Kd_color, ColMap, and Ks. Each preset then contains four values: a float, a list of three floats (color), a string, and a float. For instance, the preset called Low contains the following values: 0.1,(0.1, 0.1, 0.1),"low_map",1.0.

<args format="1.0">
  <page name="Basics" open="True" widget='presetsGroup' policies='Kd,Kd_color,ColMap,Ks' presets='
      Low,0.1,(0.1, 0.1, 0.1),"low_map",1.0|
      Medium,0.4,(0.4, 0.4, 0.4),"mid_map",0.4|
      High,0.8,(0.8, 0.8, 0.8),"hi_map",0.5|
      MyPreset,1.0,(0.1, 0.2, 0.3),"Goofy",0.9'>

    <param name="Kd"/>
    <param name="Kd_color" widget="color"/>
    <param name="ColMap" widget="fileInput"/>
    <param name="Ks"/>
    <param name="Ks_color" widget="color"/>
    <param name="SpecularExponent"/>
    <param name="Ka"/>
    <param name="Ka_color" widget="color"/>
    <param name="opacity"/>
  </page>
  <page name="Textures" open="True" hide="False">
    <param name="SpecMap" widget="fileInput"/>
    <param name="RepeatS" widget="boolean"/>
    <param name="RepeatT" widget="boolean"/>
  </page>
  <page name="Bump Mapping" open="False">
    <param name="BumpMap" widget="fileInput"/>
    <param name="BumpVal"/>
  </page>
  <page name="Reflection">
    <param name="EnvMap" widget="fileInput"/>
    <param name="EnvVal"/>
    <param name="UseFresnel" widget="boolean"/>
  </page>
  <page name="Refraction">
    <param name="RefractMap" widget="fileInput"/>
    <param name="RefractVal"/>
    <param name="RefractEta"/>
  </page>
</args>

Basic Widgets

null

Parameters that are hinted with the null widget type are effectively hidden from the UI: no widgets are created for them. No other hints are evaluated for this type of widget.

number

Displays widgets for entering numeric values.

This is the default widget type used for number parameters.

Widget type-specific hints:

Hint

Type

Description

min

Float or integer

Specifies the minimum value when dragging on a parameter’s label. Values entered via the text field are not clamped.

max

Float or integer

Specifies the maximum value when dragging on a parameter’s label. Values entered via the text field are not clamped.

strictLimits

Boolean

If true, all values entered will be clamped to the min and max hints values, even if entered through the text field.

sensitivity

Float or integer

Specifies the label drag increment.

digits

Integer

Specifies the number of digits to display after the decimal point. The default value of -1 indicates full precision.

int

Boolean

If true, floating-point parameter types are displayed as integers. This affects display and also applies clamping on numeric entry.

constant

Boolean

If true, animation via curves is disabled.

slider

Boolean

If true, a slider is displayed to the right of the text entry field.

slidermin

Float or integer

Specifies the minimum value of the slider.

slidermax

Float or integer

Specifies the maximum value of the slider.

slidercenter

Float or integer

Specifies the origin value of the slider.

sliderexponent

Integer

Specifies a non-linear scaling of the slider.

slidersensitivity

Float or integer

Specifies the sensitivity of the slider.

string

Displays a widget for entering text.

This is the default widget type used for string parameters.

Widget type-specific hints:

Hint

Type

Description

replaceRegex

String

A regular expression whose matching values will be replaced upon text entry. These characters are replaced by _ unless specified by a matching replaceWith hint.

replaceWith

String

Used with replaceRegex to filter characters on text entry. For example:

<param name="someParameter" replaceRegex="[^A-Za-z0-9_ ]" replaceWith=" "/>

textColor

String

The color to display the text in. Supported formats can be found in the documentation for Qt’s color stylesheet property. See Color in https://doc.qt.io/qt-5/stylesheet-reference.html#color

New in Katana 6.0v1

Example:

<param name="redByName" textColor="red"/>
<param name="redByHexCode" textColor="#FF0000"/>
<param name="redByRGB" textColor="rgb(255, 0, 0)"/>

checkBox

Displays a check box widget. When applied to string parameters, either Yes or No are set as values. When applied to numeric parameters, either 0 or 1 are applied. It has no widget type-specific hints.

color

Displays a widget for picking color component values.

Can be used for number parameters.

Widget type-specific hints:

Hint

Type

Description

color_enableFilmlookVis

Boolean

Enable Filmlook visualization.

color_enableNoFilmlookColorSpace

Boolean

Enable No-Filmlook colorspace.

color_restrictComponents

Boolean

Restrict color components to the range 0 –> 1.

scenegraphLocation

Displays a widget for entering and jumping to a scene graph location path.

Can be used for string parameters.

Widget type-specific hints:

Hint

Type

Description

allowRelativePath

Boolean

If true, relative scene graph location paths are allowed.

adjustRelativeToPath

String

If defined, the Adjust Path Relative To <path> menu command is available from the widget. When chosen, the absolute path stored in the parameter is transformed to a relative path. The path is relative to the scene graph location stored in the parameter given in this hint.

allowAdoptScenegraphSelection

Boolean

If true, the Adopt Scene Graph Selection menu command is available from the widget.

omitEmptyWarning

Boolean

If true, a warning icon is not displayed in the widget when zero paths are present.

cel

Displays a CEL statement widget.

Can be used for string parameters.

Widget type-specific hints:

Hint

Type

Description

omitEmptyWarning

Boolean

See above.

text

Displays a multi-line text field.

Can be used for string parameters.

scriptEditor

Displays a multi-line text field for entering a script.

Can be used for string parameters.

Widget type-specific hints:

Hint

Type

Description

resistLabelResize

Boolean

If true, the size of the widget’s label is minimized. This gives the script editor more space at the expense of its left edge not lining up with nearby widgets.

supportsNonmodalExternalEditing

String

If true, a Edit in External Editor button is displayed above the text field.

highlighter

String

The syntax highlighter to use. Currently only “python” is supported.

scriptButton

Displays a button that executes a Python script when pressed. All submodules from the Katana module are available from within the script. Additionally, the following local variables are available:

parameter

The parameter object corresponding to the script button.

node

The node object that owns the parameter corresponding to the script button.

exit()

Exits the script button script.

Can be used for string parameters.

Widget type-specific hints:

Hint

Type

Description

buttonText

String

The text to display on the button.

scriptText

String

The Python script to execute when the button is pressed.

table

Displays a read-only table.

Widget type-specific hints:

Hint

Type

Description

tabularData

List of lists of strings/dicts

The values to display in the table, in row-major order. Each cell can be provided as a single value, or as a dict. In the former case, the value will be converted to a str and displayed with the default formatting. In the latter, the following keys are supported:

  • value: Value to be displayed in the table, will be converted into a str.

  • foreground_color: The color the text should be displayed in. Can be any value that a QColor can be constructed from.

horizontalHeaders

List of strings

The values of any horizontal headers. If not provided, no headers will be displayed.

verticalHeaders

List of strings

The values of any vertical headers. If not provided, no headers will be displayed.

Pull-down Widgets

boolean

Like checkBox, but displayed as a menu.

mapper

The mapper widget presents a pop-up menu with associative choices. Each value has an associated display value. For example:

<param name="opacity" widget="mapper">
  <hintdict name="options">
    <float value="0.0" name="A"/>
    <float value="0.5" name="B"/>
    <float value="1.0" name="C"/>
  </hintdict>
</param>

Can be used for string parameters.

Widget type-specific hints:

Hint

Type

Description

options

Dictionary

The dictionary keys are the ordered display values of the pop-up menu. Each is paired with a unique literal value for the parameter. This may be specified as either a string property of a <hintdict> child element. The following options are equivalent:

<param name="someParameter" widget="mapper" options="a:1.0|b:2.0|c:3.0"/>
<param name="anotherParameter" widget="mapper">
  <hintdict name="options">
    <float name="a" value="1.0"/>
    <float name="b" value="2.0"/>
    <float name="c" value="3.0"/>
  </hintdict>
</param>

options__order

List

When options is a dictionary, options__order defines the order of keys.

nonexclusiveCheckboxPopup

The nonexclusiveCheckboxPopup widget allows multiple options to be chosen from a pop-up menu.

Widget type-specific hints:

Hint

Type

Description

emptyLabel

String

The text to display when no option is chosen.

resolution

The resolution widget shows a list of pre-defined resolutions in addition to allowing a resolution to be entered manually.

Widget type-specific hints:

Hint

Type

Description

hideNumberFields

String

If true, widgets for entering a resolution numerically are hidden.

File Widgets

assetIdInput

The assetIdInput widget allows an asset to be chosen using the current asset plug-in’s browser or the built-in file browser.

Widget type-specific hints:

Hint

Type

Description

fileTypes

List of strings

Specifies the default file extensions to filter by in the dialog.

sequenceListing

Boolean

If true, file sequences can be chosen from the file browser.

acceptDir

Boolean

If true, directories can be chosen from the file browser.

dirsOnly

Boolean

If true, only directories can be chosen from the file browser.

assetIdOutput

Like assetIdInput, except that file paths that do not yet exist on disk can be chosen.

fileInput

Like assetIdInput, except that the default Katana file widget and browser are used, rather than the delegate and browser provided by the current asset plug-in.

Array Widgets

Katana determines whether a parameter should be declared as an array by inspecting its type and default value. For shaders, the renderer plug-in is responsible for supplying this information. In other cases, the default or value XML attribute is used and delimited by the comma character (,).

Any widget assigned to an array parameter is used to display the entire array, rather than used once per element. Only certain widget types are equipped to work with arrays. In addition to those listed below, the string and number widget types can work with arrays of any size, and the color widget type works with 3- or 4-element arrays.

Dynamic arrays allow the addition, re-ordering and removal of array elements. All dynamic arrays should set the isDynamicArray hint to true.

The following hints are broadly applicable to arrays:

Hint

Type

Description

size

Integer

Specifies the size of the array. This is only needed when writing Args Files for Procedurals.

isDynamicArray

Boolean

Specifies whether the array can expand and contract.

tupleSize

Integer

Specifies the tuple size (column count). The following example displays two rows and three columns:

<float name="bbox" default="0,0,0,1,1,1" tupleSize="3"/>

sortableDelimitedString

The sortableDelimitedString widget shows a dynamic array of string widgets.

Widget type-specific hints:

Hint

Type

Description

size

Integer

Specifies the size of the array. This is only needed when writing Args Files for Procedurals.

isDynamicArray

Boolean

Must be true.

tupleSize

Integer

Specifies the tuple size (column count).

delimiter

String

Delimiter used to split the default value. Defaults to a pipe character (|).

childHints

Dictionary

Hints to pass to underlying string widget.

scenegraphLocationArray

The scenegraphLocationArray widget shows a dynamic array of scenegraphLocation widgets. It supports the size, isDynamicArray and tupleSize hints

dynamicArray

The dynamicArray widget shows a dynamic array of widgets of a particular type. All widget hints are passed through to the child widgets. Each child widget handles tupleSize*tupleGroupSize array elements.

For example, to display a dynamic array with 2 default colors:

<param
    name="colors"
    isDynamicArray="1"
    widget="dynamicArray"
    panelWidget="color"
    default="1,0,0,0,1,0"
    tupleSize="3"/>

To display a dynamic array of 2 4x4 matrices:

<param
    name="transforms"
    isDynamicArray="1"
    widget="dynamicArray"
    default="1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1,1,0,0,0,0,1,0,0,0,0,1,0,0,0,0,1"
    tupleSize="4"
    tupleGroupSize="4"/>

Widget type-specific hints:

Hint

Type

Description

size

Integer

Specifies the size of the array. This is only needed when writing Args Files for Procedurals.

isDynamicArray

Boolean

Must be true.

tupleSize

Integer

Specifies the tuple size (column count). This is passed to the child widgets.

tupleGroupSize

Integer

Specifies the number of tuples each child widget should handle.

panelWidget

String

Specifies the widget type to use for child widgets. If not given, string or number are used.

Ramp Widgets

colorRamp

floatRamp

../_images/myColorRamp.png ../_images/myFloatRamp.png

Color Ramp widgets allow users to define a 1D color gradient.

Float Ramp widgets allow users to define a curve.

Both types of widgets allow users to define ramps through a series of knots. Each knot is defined through its position on the ramp and its value at that position. The value of a knot is either a set of three floating-point numbers representing a color (Color Ramp) or a single floating-point number representing the Y coordinate of a point on a curve (Float Ramp).

A number of presets are available for users to choose from for individual Color Ramp and Float Ramp widgets.

Both types of widgets support two different structures for their underlying parameters:

  1. A set of sibling group parameters, each representing a GenericAssign-powered parameter, with enable, value, default, and type child parameters.

  • This structure is typically used for shader parameters, where grouping of parameters is only available via pages.

  • Here’s an example of the parameter structure of a Float Ramp parameter that is defined from an Args File, shown here in its XML representation as returned by calls of NodegraphAPI.Parameter.getXML() for each of four group parameters:

    <group_parameter name="myFloatRamp">
      <number_parameter name="enable" value="1"/>
      <number_parameter name="value" value="4"/>
      <number_parameter name="default" value="4"/>
      <string_parameter name="type" value="IntAttr"/>
    </group_parameter>
    
    <group_parameter name="myFloatRamp_Interpolation">
      <number_parameter name="enable" value="1"/>
      <string_parameter name="value" value="linear"/>
      <string_parameter name="default" value="linear"/>
      <string_parameter name="type" value="StringAttr"/>
    </group_parameter>
    
    <group_parameter name="myFloatRamp_Knots">
      <number_parameter name="enable" value="1"/>
      <numberarray_parameter name="value" size="4" tupleSize="1">
        <number_parameter name="i0" value="0"/>
        <number_parameter name="i1" value="0"/>
        <number_parameter name="i2" value="1"/>
        <number_parameter name="i3" value="1"/>
      </numberarray_parameter>
      <numberarray_parameter name="default" size="4" tupleSize="1">
        <number_parameter name="i0" value="0"/>
        <number_parameter name="i1" value="0"/>
        <number_parameter name="i2" value="1"/>
        <number_parameter name="i3" value="1"/>
      </numberarray_parameter>
      <string_parameter name="type" value="FloatAttr"/>
    </group_parameter>
    
    <group_parameter name="myFloatRamp_Floats">
      <number_parameter name="enable" value="1"/>
      <numberarray_parameter name="value" size="4" tupleSize="1">
        <number_parameter name="i0" value="0"/>
        <number_parameter name="i1" value="0"/>
        <number_parameter name="i2" value="1"/>
        <number_parameter name="i3" value="1"/>
      </numberarray_parameter>
      <numberarray_parameter name="default" size="4" tupleSize="1">
        <number_parameter name="i0" value="0"/>
        <number_parameter name="i1" value="0"/>
        <number_parameter name="i2" value="1"/>
        <number_parameter name="i3" value="1"/>
      </numberarray_parameter>
      <string_parameter name="type" value="FloatAttr"/>
    </group_parameter>
    
  1. A single group parameter with a set of child parameters.

  • This structure is used for user parameters that can be added to a node.

  • Here’s an example of the parameter structure of a Float Ramp user parameter that has been added from the Parameters tab, shown here in its XML representation as returned by a call of NodegraphAPI.Parameter.getXML():

    <group_parameter name="newParameter" hints="{&apos;rampInterp&apos;: &apos;interp&apos;, &apos;widget&apos;: &apos;floatRamp&apos;, &apos;rampFloats&apos;: &apos;values&apos;, &apos;rampKnots&apos;: &apos;positions&apos;}">
      <number_parameter name="rampSize" value="4" hints="{&apos;widget&apos;: &apos;null&apos;}"/>
      <numberarray_parameter name="positions" size="4" tupleSize="1" hints="{&apos;widget&apos;: &apos;null&apos;}">
        <number_parameter name="i0" value="0"/>
        <number_parameter name="i1" value="0"/>
        <number_parameter name="i2" value="1"/>
        <number_parameter name="i3" value="1"/>
      </numberarray_parameter>
      <numberarray_parameter name="values" size="4" tupleSize="4" hints="{&apos;widget&apos;: &apos;null&apos;}">
        <number_parameter name="i0" value="0"/>
        <number_parameter name="i1" value="0"/>
        <number_parameter name="i2" value="1"/>
        <number_parameter name="i3" value="1"/>
      </numberarray_parameter>
      <string_parameter name="interp" value="linear" hints="{&apos;widget&apos;: &apos;null&apos;}"/>
    </group_parameter>
    

In both cases, the widget type (either colorRamp or floatRamp) and widget-type specific hints are defined on the main parameter.

In both cases, ramps are defined by number array parameters that are considered companion parameters of the main parameter.

colorRamp

Color Ramp widgets allow users to define a 1D color gradient through a series of knots, each specified with a position value and 3 color component values (RGB).

../_images/myColorRamp.png

The following parameters are required in order to use a Color Ramp widget based on a set of sibling parameters:

  1. A number parameter that acts as the main parameter for the widget.

  • The parameter can have any name. In the examples below, we use 'myColorRamp' as the name.

  • The value of the parameter is interpreted as the number of knots that define the ramp.

  • The following widget type-specific hints can be set on the main parameter:

    Hint

    Type

    Description

    rampInterp

    String

    Defines the name of the interpolation parameter to use, if a name is used that does not follow the convention (see below).

    rampKnots

    String

    Defines the name of the number array parameter for knot positions to use, if a name is used that does not follow the convention (see below).

    rampColors

    String

    Defines the name of the number array parameter for knot values to use, if a name is used that does not follow the convention (see below).

    gradientHeight

    Integer

    The height of the gradient widget in pixels. Defaults to 10. Minimum is 5.

  1. A string parameter to define the interpolator to use for interpolating values in between two adjacent knots.

  • By convention, the parameter is expected to be named <name-of-main-parameter>_Interpolation, e.g. myColorRamp_Interpolation.

  • A different name can be used, in which case that name needs to be specified in the rampInterp hint on the main parameter.

  • Valid options for interpolator types are 'linear' and 'constant'.

  1. A number array parameter for knot positions.

  • By convention, the parameter is expected to be named <name-of-main-parameter>_Knots, e.g. myColorRamp_Knots.

  • A different name can be used, in which case that name needs to be specified in the rampKnots hint on the main parameter.

  1. A number array parameter for knot values.

  • By convention, the parameter is expected to be named <name-of-main-parameter>_Colors, e.g. myColorRamp_Colors.

  • A different name can be used, in which case that name needs to be specified in the rampColors hint on the main parameter.

  • Each value in myColorRamp_Knots corresponds to three values in myColorRamp_Colors.

Example:

<!-- A Color Ramp compound parameter, consisting of 4 sibling parameters -->
<int name='myColorRamp' default='5' widget='colorRamp' gradientHeight='15'/>
<string name='myColorRamp_Interpolation' default='linear' options='linear|constant' widget='null'/>
<float name='myColorRamp_Knots' default='0,0,0.5,1,1' size='5' widget='null'/>
<float name='myColorRamp_Colors' default='1,0,0,1,0,0,0,1,0,0,0,1,0,0,1' size='15' tupleSize='3' widget='null'/>

Note

By convention, the positions and values of the first and last knots appear twice. That means that in order to define 3 knots, 3 + 2 = 5 positions and 5 * 3 = 15 values need to be specified, as shown in the example above.

floatRamp

Float Ramp widgets allow users to define a curve through a series of knots, each specified with a position (X) value and a Y value.

../_images/myFloatRamp.png

The following parameters are required in order to use a Float Ramp widget based on a set of sibling parameters:

  1. A number parameter that acts as the main parameter for the widget.

  • The parameter can have any name. In the examples below, we use 'myFloatRamp' as the name.

  • The value of the parameter is interpreted as the number of knots that define the ramp.

  • The following widget type-specific hints can be set on the main parameter:

    Hint

    Type

    Description

    rampInterp

    String

    Defines the name of the interpolation parameter to use, if a name is used that does not follow the convention (see below).

    rampKnots

    String

    Defines the name of the number array parameter for knot positions to use, if a name is used that does not follow the convention (see below).

    rampFloats

    String

    Defines the name of the number array parameter for knot values to use, if a name is used that does not follow the convention (see below).

    minPosition

    Float or integer

    The smallest value to which the X coordinate of a knot on the curve can be set. Defaults to 0.

    maxPosition

    Float or integer

    The largest value to which the X coordinate of a knot on the curve can be set. Defaults to 1.

    minValue

    Float or integer

    The smallest value to which the Y coordinate of a knot on the curve can be set. Defaults to 0.

    maxValue

    Float or integer

    The largest value to which the Y coordinate of a knot on the curve can be set. Defaults to 1.

    panZoomEnabled

    Boolean

    Controls whether panning and zooming of the curve is allowed. Defaults to true.

  1. A string parameter to define the interpolator to use for interpolating values in between two adjacent knots.

  • By convention, the parameter is expected to be named <name-of-main-parameter>_Interpolation, e.g. myFloatRamp_Interpolation.

  • A different name can be used, in which case that name needs to be specified in the rampInterp hint on the main parameter.

  • Valid options for interpolator types are:

    • 'linear'

    • 'constant'

    • 'bspline' (currently drawn as a Catmull-Rom-like spline)

    • 'catmull-rom' (currently drawn as a Catmull-Rom-like spline)

    • 'hermite' (currently drawn as a Catmull-Rom-like spline)

    • 'bezier'

  1. A number array parameter for knot positions.

  • By convention, the parameter is expected to be named <name-of-main-parameter>_Knots, e.g. myFloatRamp_Knots.

  • A different name can be used, in which case that name needs to be specified in the rampKnots hint on the main parameter.

  1. A number array parameter for knot values.

  • By convention, the parameter is expected to be named <name-of-main-parameter>_Floats, e.g. myFloatRamp_Floats.

  • A different name can be used, in which case that name needs to be specified in the rampFloats hint on the main parameter.

  • Each value in myFloatRamp_Knots corresponds to a value in myFloatRamp_Floats.

Example:

<!-- A Float Ramp compound parameter, consisting of 4 sibling parameters -->
<int name='myFloatRamp' default='5' widget='floatRamp' panZoomEnabled='false'/>
<string name='myFloatRamp_Interpolation' default='linear' options='linear|catmull-rom|bspline' widget='null'/>
<float name='myFloatRamp_Knots' default='0,0,0.4,1,1' size='5' widget='null'/>
<float name='myFloatRamp_Floats' default='0,0,0.7,0.4,0.4' size='5' widget='null'/>

Note

By convention, the positions and values of the first and last knots appear twice. That means that in order to define 3 knots, 3 + 2 = 5 positions and 5 values need to be specified, as shown in the example above.

Conditional Visibility and Locking

Conditional Visibility and Conditional Locking allow for parameters and pages to be conditionally visible or locked (against edits) based on value comparisons of referenced other parameters. Hints representing the parse tree of a conditional statement are supported as string hints or string entries within a dictionary hint.

When specifying hints for visibility, the root hint is named conditionalVisOp. For locking, it’s conditionalLockOp. When using a <hintdict> element to store the hints, that <hintdict> itself is named conditionalVisOps and conditionalLockOps respectively. All examples will be displayed in the <hintdict> form and describe conditional visibility.

Each conditional is specified with a prefix name suffixed with Op. The prefix for the root-level condition is always conditionalVis. Operators which compare values address the referenced parameters via POSIX-style paths relative to the parameter or page on which the hint is defined. Page names are included in the parameter path. A conditional expression which evaluates to false results in the hinted widget being hidden. Comparison values are always specified as strings and converted to the type of the parameter against which they’re compared. The available operators and their operands are:

Operator

Operand 1

Operand 2

Description

isEqualTo

prefixPath

prefixValue

Does an equality test with the value specified by prefixPath of the specified parameter against the provided prefixValue.

isNotEqualTo

prefixPath

prefixValue

See above.

isGreaterThan

prefixPath

prefixValue

Does an comparison test with the value specified by prefixPath of the specified parameter against the provided prefixValue.

isLessThan

prefixPath

prefixValue

See above.

isGreaterThanOrEqualTo

prefixPath

prefixValue

See above.

isLessThanOrEqualTo

prefixPath

prefixValue

See above.

and

prefixLeft

prefixRight

The values of the prefixLeft and prefixRight operands are the prefixes of additional conditional operators. If both evaluate to true, this operator also evaluates to true.

or

prefixLeft

prefixRight

The values of the prefixLeft and prefixRight operands are the prefixes of additional conditional operators. If either evaluate to true, this operator also evaluates to true.

Here is a simple example in which we’ll hint a subpage to be visible only if the parameter value of its peer is non-zero:

<page name="Lighting">
  <param name="someParameter"/>
  <param name="showAdvancedOptions" widget="checkBox"/>
  <page name="Advanced">
    <hintdict name="conditionalVisOps">
      <string name="conditionalVisOp" value="notEqualTo"/>
      <string name="conditionalVisPath" value="../showAdvancedOptions"/>
      <string name="conditionalVisValue" value="0"/>
    </hintdict>
    <param name="anotherParameter"/>
  </page>
</page>

Another example demonstrating the or operator and the relationship of prefix in the operand values. This will display the “Advanced” page if either the showAdvancedOptions parameter is non-zero or the someParameter value is greater than 1.0:

<page name="Lighting">
  <param name="someParameter"/>
  <param name="showAdvancedOptions" widget="checkBox"/>
  <page name="Advanced">
    <hintdict name="conditionalVisOps">
      <string name="conditionalVisOp" value="or"/>
      <string name="conditionalVisLeft" value="conditionalVis1"/>
      <string name="conditionalVisRight" value="conditionalVis2"/>
      <string name="conditionalVis1Op" value="notEqualTo"/>
      <string name="conditionalVis1Path" value="../showAdvancedOptions"/>
      <string name="conditionalVis1Value" value="0"/>
      <string name="conditionalVis2Op" value="isGreaterThan"/>
      <string name="conditionalVis2Path" value="../someParameter"/>
      <string name="conditionalVis2Value" value="1.0"/>
    </hintdict>
    <param name="anotherParameter"/>
  </page>
</page>

Please note that only the root operation is required to have a prefix starting with conditionalVis. The prefixes of the second and third operations are defined here by the values of conditionalVisLeft and conditionalVisRight - and could be anything.