new LegendHelper(tableColumn, tableStyleopt, regionProvideropt, nameopt)
Legends for table columns depend on both the table style and the selected column. This class brings the two together to generate a legend. Its key output is legendUrl.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
tableColumn |
TableColumn | The column whose values inform the legend. |
|
tableStyle |
TableStyle |
<optional> |
The styling for the table. |
regionProvider |
RegionProvider |
<optional> |
The region provider, if region mapped. Used if no table column set. |
name |
String |
<optional> |
A name used in the legend if no active column is selected. |
- Source:
Methods
getColorArrayFromValue(valueopt) → {Array.<Number>}
Maps an absolute value to a color array, based on the legend.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
value |
Number |
<optional> |
The absolute value. |
- Source:
Returns:
The color, as an array [r, g, b, a]. If there is no table column selected, use a random colour. If the value is null, use the nullColor. If no value is provided, or no color bins are defined, use the nullColor.
- Type
- Array.<Number>
getColorFromValue(valueopt) → {Color}
Maps an absolute value to a Color, based on the legend.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
value |
Number |
<optional> |
The absolute value. |
- Source:
Returns:
The color. If no value is provided, uses a default color.
- Type
- Color
getScaleFromValue(valueopt) → {Number}
Maps an absolute value to a scale, based on tableColumnStyle.
Parameters:
| Name | Type | Attributes | Description |
|---|---|---|---|
value |
Number |
<optional> |
The absolute value. |
- Source:
Returns:
The scale.
- Type
- Number
legendUrl() → {LegendUrl}
Returns the legendUrl for this legend. Can be called directly after instantiation.
- Source:
Returns:
The Legend URL object for the legend, with its url being a base64-encoded PNG.
- Type
- LegendUrl