Class: RadialGradient

OM.style. RadialGradient


new RadialGradient(config)

This class defines a radial color gradient.

Parameters:
Name Type Description
config Object

An object which defines the radial gradient. It can have the following
attributes.


  • styleName {String} The style name

  • cx {float} The X offset of the gradient's center point. Must be a number between
    0 and 1, where 0 indicates the left border of the gradient coordinate system.

  • cy {float} The Y offset of the gradient's center point. Must be a number between
    0 and 1, where 0 indicates the top border of the gradient coordinate system.

  • radius {float} The radius of the gradient. The radius must be a number between 0 and 1.

  • stops {Array} The color stops of the gradient. The color stops are specified by
    an array of color stop objects. Each color stop object has two properties, offset and color,
    which specify the stop offset and color respectively. The stop offset is a number between 0
    and 1. It specifies the location of the color stop relative to the start point of the gradient.
    0 indicates the gradient start point and 1 indicates the gradient end point. The color is expressed as "#rrggbbaa".
    Example of a stops array:
    [{offset:0, color:"#ffffffff"}, {offset:1, color:"#ff0000ff"}]

  • useFeatureBoundingBox {Boolean} Default value is true. If false, the layer's bounding box
    will be used as gradient boundary

  • stroke {String} The stroke color. The string format is "#RRGGBB".

  • strokeThickness {float} The stroke width. Default value is 1.

  • strokeOpacity {float} The stroke opacity. A number between 0 (transparent) and 1 (opaque).
    Default value is 1.

  • fillOpacity {float} The fill opacity. A number between 0 (transparent) and 1 (opaque). Default value is 1.

   </UL>

Extends

Methods


bindData(attribute, column, formatter)

Binds a Column data set to a specified aspect of this style. This creates
a single binding on this style instance. Check individual sub-styles to
see how many bindings they support.
Each binding is comprised of three key pieces: the style attribute being
bound, the Column data set that drives the style attribute, and a resolver
function that computes and returns an effective style attribute for any
given data value from the Column.

Parameters:
Name Type Description
attribute string

the name of the style attribute to be bound to a data Column. An
attribute is a visual aspect of the style, such as "Fill",
"Size" etc.

column object

A data column (typically an instance of OM.Column) that will
format the specified visual attribute of the style. If a String type
value is passed in, then it is assumed to be the name of
an property in the target VectorLayer's features.

formatter object

an instance of OM.style.Formatter; it
maps an individual item's value (such as sales volume) to a
particular visual style attribute value (such as a color).

Inherited From:

draw(feature, mapContext, options)

The actual logic for drawing a feature using a style is implemented in this method.
Must be overidden by sub-classes.

Parameters:
Name Type Description
feature OM.Feature

the feature to be applied with this style

mapContext OM.MapContext

the current map context

options Object

the rendering options, typically the graphics group

Inherited From:
Returns:
Type
undefined

getBindables()

Returns a list of bindable style attributes. A bindable attribute is
a certain aspect of a style (such as its fill color, stroke width or
overall size) that can be changed based on some business data value
associated with each feature. It is typically bound to a Column data
set.

Inherited From:
Returns:

an array containing names of bindable attributes; if
no bindable attribute exists then an empty array is
returned.

Type
Array

getConfig()

Gets the config of style.

Inherited From:
Returns:

the config object


getStyleName()

Return the style name

Inherited From:
Returns:

the style name


hasBinding()

Checks if this style has associated data bindings.

Inherited From:
Returns:

true if there is one or more data bindings; false otherwise

Type
Boolean

isBindable(attr)

Checks whether a specified style attribute is bindable.

Parameters:
Name Type Description
attr String

the name of the attribute to be checked

Inherited From:
Returns:

true if the argument is bindable; false otherwise

Type
Boolean

isBound()

Checks whether a specified (bindable) attribute is already bound to some
Column data set.

Inherited From:

isFeatureBound(feature)

Checks whether the given feature is bound to any of the bindings in
this style.

Parameters:
Name Type Description
feature OM.Feature

the feature instance to be checked

Inherited From:
Returns:

returns true if the feature has associated values from
any of the style bindings' Column instances. Returns false if there
is no values associated with this feature, or there is no bindings
at all in this style.

Type
Boolean

resolveBinding(b, feature)

Resolves a specified binding for a given feature.
When a Style object has one or more of its visual attributes (such as Size
for a Marker style or Fill for a Color style) bound to an external data
column, then such visual attributes must be resolved for each and every feature
using the feature's associated data column value. The resolved visual
attribute values are then used to apply the style to that feature.

In other words, each time this method is called against a specific feature,
the following process always takes place:


  • the feature's unique id is obtained
  • the id is then used by the binding to find the corresponding data
    value from the associated Column instance
  • the data value is used to determine or resolve the visual attribute
    of this style such as Size or Fill color.
  • the visual attribute value is set on this Style instance for the
    duration of rendering the feature.

Parameters:
Name Type Description
b Object

the binding object

feature Object

the feature to be resolved with

Inherited From:
Returns:

the resolved style attribute

Type
Object

unbindAllData(attribute)

Un-binds all Column data sets currently bound to the specified style attribute.

Parameters:
Name Type Description
attribute String

the name of the style attribute

Inherited From:

unbindData(attribute)

Un-binds all Column data set for the given attribute.

Parameters:
Name Type Description
attribute String

name of the style attribute (such as 'Fill', 'Size'

Inherited From: