GradientStyle¶

Namespace: ThinkGeo.Core

This gradient style is a new style with the concept of GradientBrush. By specifying the LowerValue and its color, as well as the UpperValue and its color, we can set the color of each feature based on a column value using linear interpolation.

public class GradientStyle : Style

Inheritance Object → Style → GradientStyle

Properties¶

ColumnName¶

This property gets and sets the column name used in the style.

public string ColumnName { get; set; }

Property Value¶

String
This property gets and sets the column name used in the style.

Remarks:

None.

LowerValue¶

This property gets and sets the lower value used in the style.

public double LowerValue { get; set; }

Property Value¶

Double
This property gets and sets the lower value used in the style.

Remarks:

None.

LowerColor¶

This property gets and sets the solid brush that is used for the style's lower value.

public GeoColor LowerColor { get; set; }

Property Value¶

GeoColor
This property gets and sets the solid brush that is used for the style's lower value.

Remarks:

None.

UpperValue¶

This property gets and sets the upper value used in the style.

public double UpperValue { get; set; }

Property Value¶

Double
This property gets and sets the upper value used in the style.

Remarks:

None.

UpperColor¶

This property gets and sets the solid brush that is used for the style's upper value.

public GeoColor UpperColor { get; set; }

Property Value¶

GeoColor
This property gets and sets the solid brush that is used for the style's upper value.

Remarks:

None.

NoDataValue¶

This property gets and sets the no data value used in the style.

public double NoDataValue { get; set; }

Property Value¶

Double
This property gets and sets the no data value used in the style.

Remarks:

None.

NoDataColor¶

This property gets and sets the solid brush that is used for the style's NoDataValue.

public GeoColor NoDataColor { get; set; }

Property Value¶

GeoColor
This property gets and sets the solid brush that is used for the style's NoDataValue.

Remarks:

None.

Name¶

This property gets and set the name of the style.

public string Name { get; set; }

Property Value¶

String
This property gets the name of the style.

Remarks:

This name is not used by the system; it is only for the developer. However, it can be used if you generate your own legend.

IsActive¶

This property gets and sets the active status of the style.

public bool IsActive { get; set; }

Property Value¶

Boolean
This property gets the active status of the style.

Remarks:

If the style is not active then it will not draw.

RequiredColumnNames¶

This property gets the collection of fields that are required for the style.

public Collection<string> RequiredColumnNames { get; }

Property Value¶

Collection<String>

        This property gets the collection of fields that are required for the
        style.

Remarks:

This property gets the collection of fields that are required for the style. These are in addition to any other columns you specify in styles that inherit from this one. For example, if you have use a ValueStyle and it requires a column name for the value comparison, then that column does not need to be in this collection. You only use the RequiredColumnNames for columns you need beyond those required by specific inherited styles.

Filters¶

public Collection<string> Filters { get; }

Property Value¶

Collection<String>

Constructors¶

GradientStyle(String, Double, GeoColor, Double, GeoColor)¶

This constructor creates a new instance by passing the ColumnName (which it will get the data from) as well as the lowerValue and its corresponding SolidBrush, and the upperValue and its corresponding SolidBrush.

public GradientStyle(string columnName, double lowerValue, GeoColor lowerColor, double upperValue, GeoColor upperColor)

Parameters¶

columnName String

lowerValue Double

lowerColor GeoColor

upperValue Double

upperColor GeoColor

Remarks:

In this constructor, the NoDataValue defaults to -9999 and the NoDataBrush color is transparent.

GradientStyle(String, Double, GeoColor, Double, GeoColor, Double, GeoColor)¶

This constructor creates a new instance by passing the ColumnName (which it will get the data from) as well as the lowerValue and its corresponding SolidBrush, the upperValue and its corresponding SolidBrush, and the NoDataValue and its corresponding SolidBrush.

public GradientStyle(string columnName, double lowerValue, GeoColor lowerColor, double upperValue, GeoColor upperColor, double noDataValue, GeoColor noDataColor)

Parameters¶

columnName String

lowerValue Double

lowerColor GeoColor

upperValue Double

upperColor GeoColor

noDataValue Double

noDataColor GeoColor

Methods¶

DrawCore(IEnumerable<Feature>, GeoCanvas, Collection<SimpleCandidate>, Collection<SimpleCandidate>)¶

This method draws the features on the view you provided.

protected void DrawCore(IEnumerable<Feature> features, GeoCanvas canvas, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters¶

features IEnumerable<Feature>
This parameter represents the features you want to draw on the view.

canvas GeoCanvas
This parameter represents the view you want to draw the features on.

labelsInThisLayer Collection<SimpleCandidate>
The labels will be drawn in the current layer only.

labelsInAllLayers Collection<SimpleCandidate>
The labels will be drawn in all layers.

Remarks:

This virtual method is called from the concrete public method Draw. In this method, we take the features you passed in and draw them on the view you provided. Each style (based on its properties) may draw each feature differently.


When implementing this virtual method, consider each feature and its column data values. You can use the full power of the GeoCanvas to do the drawing. If you need column data for a feature, be sure to override the GetRequiredColumnNamesCore and add the columns you need to the collection. In many of the styles, we add properties to allow the user to specify which field they need; then, in the GetRequiredColumnNamesCore, we read that property and add it to the collection.

GetRequiredColumnNamesCore()¶

This method returns the column data for each feature that is required for the style to properly draw.

protected Collection<string> GetRequiredColumnNamesCore()

Returns¶

Collection<String>
This method returns a collection of column names that the style needs.

Remarks:

This abstract method is called from the concrete public method GetRequiredFieldNames. In this method, we return the column names that are required for the style to draw the feature properly. For example, if you have a style that colors areas blue when a certain column value is over 100, then you need to be sure you include that column name. This will ensure that the column data is returned to you in the feature when it is ready to draw.

In many of the styles, we add properties to allow the user to specify which field they need; then, in the GetRequiredColumnNamesCore we read that property and add it to the collection.