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PositionStyle

Namespace: ThinkGeo.Core

This abstract class encapsulates the labeling position logic. It is inherited by other styles, such as the TextSytle.

public abstract class PositionStyle : Style

Inheritance Object → Style → PositionStyle

Remarks:

This abstract class is meant to be inherited by other classes and specialized to meet the needs of various labelers.

Properties

PolygonLabelingLocationMode

This property gets and sets the mode that determines how to locate polygon's labeling

public PolygonLabelingLocationMode PolygonLabelingLocationMode { get; set; }

Property Value

PolygonLabelingLocationMode

        This property gets the mode that determines how to locate polygon's labeling

Remarks:

There are two ways to handle polygon's labeling location. The first is to use polygon's centroid as the labeling location, the second way is to use polygon's boungdingbox center as the labeling location.

MaxNudgingInPixel

public int MaxNudgingInPixel { get; set; }

Property Value

Int32

NudgingIntervalInPixel

public float NudgingIntervalInPixel { get; set; }

Property Value

Single

BestPlacementSymbolWidth

public float BestPlacementSymbolWidth { get; set; }

Property Value

Single

BestPlacementSymbolHeight

public float BestPlacementSymbolHeight { get; set; }

Property Value

Single

AbbreviationDictionary

public Dictionary<string, string> AbbreviationDictionary { get; set; }

Property Value

Dictionary<String, String>

LeaderLineStyle

public LineStyle LeaderLineStyle { get; set; }

Property Value

LineStyle

LeaderLineRule

public LabelLeaderLinesRule LeaderLineRule { get; set; }

Property Value

LabelLeaderLinesRule

LeaderLineMinimumLengthInPixels

public float LeaderLineMinimumLengthInPixels { get; set; }

Property Value

Single

GridSize

This property gets and sets the grid size used for deterministic labeling.

public int GridSize { get; set; }

Property Value

Int32
This property gets the grid sized used for deterministic labeling.

Remarks:

The grid size determines how many labels will be considered as candidates for drawing. The smaller the grid size, the higher the density of candidates. Making the grid size too small may have a performance impact.

DuplicateRule

This property gets and sets the rule that determines how duplicate labels are handled.

public LabelDuplicateRule DuplicateRule { get; set; }

Property Value

LabelDuplicateRule

        This property gets the rule that determines how duplicate labels are
        handled.

Remarks:

There are three ways to handle duplicate label names. The first is to suppress all duplicates, which means if there are two street segments with the same name then only one will be drawn. The second way is to suppress duplicate labels only if they are in one quarter of the screen. In this way, the screen will be divided into four quadrants, and if the two duplicate labels are in different quadrants, then they will both draw. The last way is to draw all duplicates.

OverlappingRule

This property gets and sets the rule that determines how overlapping labels are handled.

public LabelOverlappingRule OverlappingRule { get; set; }

Property Value

LabelOverlappingRule
This property gets the rule that determines overlapping labels are handled.

Remarks:

This defines the rules for label overlapping. Currently, either we allow overlapping or we do not. In the future, we may extend this to allow some percentage of partial overlapping.

AllowLabelNudging

public bool AllowLabelNudging { get; set; }

Property Value

Boolean

AllowLineCarriage

This property gets and sets whether the labeler will allow carriage returns to be inserted.

public bool AllowLineCarriage { get; set; }

Property Value

Boolean

        This property gets whether the labeler will allow carriage returns to be
        inserted.

Remarks:

This property enables the labeler to split long labels into multiple lines if need be. For instance, if you have a lake whose name is "Southern Homestead Lake," then the labeler may try and break the name onto multiple lines in order to better label the feature.

SuppressPartialLabels

This property gets and sets whether a partial label in the current extent will be drawn or not.

public bool SuppressPartialLabels { get; set; }

Property Value

Boolean

Remarks:

This property provides a solution to the "cut off" label issue in Map Suite Web Edition and Desktop Edition, which occurs when multiple tiles exist. When you set this property to true, any labels outside of the current extent will not be drawn.

ForceLineCarriage

This property gets and sets whether the labeler will force carriage returns to be inserted.

public bool ForceLineCarriage { get; set; }

Property Value

Boolean

        This property gets whether the labeler will force carriage returns to be
        inserted.

Remarks:

This property forces the labeler to split long labels into multiple lines. For instance, if you have a lake whose name is "Southern Homestead Lake," then the labeler will break the name onto multiple lines in order to better label the feature.

FittingPolygon

This property gets and sets whether the labeler will try to fit the label as best as it can within the boundary of a polygon.

public bool FittingPolygon { get; set; }

Property Value

Boolean

        This property gets whether the labeler will try to fit the label as best as
        it can within the boundary of a polygon.

Remarks:

None

LabelAllPolygonParts

This property gets and sets whether the labeler will label every part of a multi-part polygon.

public bool LabelAllPolygonParts { get; set; }

Property Value

Boolean

        This property gets whether the labeler will label every part of a multi-part
        polygon.

Remarks:

In some cases, you may want to label all of the parts of a multi-part polygon, while in other cases you may not. For example, you may have a series of lakes where you do want to label each polygon. In another case, you may have a country with many small islands and in this case you only want to label the largest polygon.

LabelAllLineParts

This property gets and sets whether the labeler will label every part of a multi-part line.

public bool LabelAllLineParts { get; set; }

Property Value

Boolean

        This property gets whether the labeler will label every part of a multi-part
        line.

Remarks:

In some cases, you may want to label all of the parts of a multi-part line, while in other cases you may not.

FittingPolygonFactor

This property gets and sets the factor to which it will keep the label inside of the polygon.

public double FittingPolygonFactor { get; set; }

Property Value

Double

        This property gets the factor to which it will keep the label inside of the
        polygon.

Remarks:

None

TextLineSegmentRatio

This property gets and sets the ratio required for the label length to match the line length.

public double TextLineSegmentRatio { get; set; }

Property Value

Double

        This property gets the ratio required for the label length to match the line
        length.

Remarks:

This allows you to suppress labels where the label length would greatly exceed the line length. For example, if you set the ratio to 1, then the label will be suppressed if it is longer than the line. If the ratio is lower, then the label would need to be shorter than the line. If higher, then the label is allowed to run past the length of the line. This allows you to control the look of things like road labeling.

TextPlacement

This property gets and sets the location of the label for point features relative to the point.

public TextPlacement TextPlacement { get; set; }

Property Value

TextPlacement

        This property gets the location of the label for point features relative to the
        point.

Remarks:

This property allows you to choose where the labels are created relative to the point. For example, you can set the property to RightCenter, which would ensure that all labels are placed to the right of and vertically centered with the point. Different kinds of point layers can be positioned differently. If the point layer is dense and position is not a main concern, then you can try the BestPlacement property. That property overrides this property and tries to fit the label in the best location so that the minimum number of labels are suppressed due to overlapping issues.

MaskType

public MaskType MaskType { get; set; }

Property Value

MaskType

TextContent

This property gives you the option to customize the labeling by using one or more columns. For example supposing I have 2 columns "ColumnA" and "ColumnB" with the values of "ValueA" and "ValueB", by setting this property to "{ColumnA} - {ColumnB}", it will draw "ValueA - ValueB" for the corresponding feature. Do remember to add the columns you want to draw (ColumnA and ColumnB in the case above) to RequiredColumnNames collection;

public string TextContent { get; set; }

Property Value

String

MaxAdjacentCharDeltaAngle

public double MaxAdjacentCharDeltaAngle { get; set; }

Property Value

Double

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>

Methods

GetLabelingCandidateForOnePolygon(PolygonShape, String, GeoFont, Single, Single, GeoCanvas, Double)

internal LabelingCandidate GetLabelingCandidateForOnePolygon(PolygonShape polygon, string text, GeoFont font, float xOffsetInPixel, float yOffsetInPixel, GeoCanvas canvas, double rotationAngle)

Parameters

polygon PolygonShape

text String

font GeoFont

xOffsetInPixel Single

yOffsetInPixel Single

canvas GeoCanvas

rotationAngle Double

Returns

LabelingCandidate

Format(String, BaseShape)

protected string Format(string text, BaseShape labeledShape)

Parameters

text String

labeledShape BaseShape

Returns

String

FormatCore(String, BaseShape)

protected string FormatCore(string text, BaseShape labeledShape)

Parameters

text String

labeledShape BaseShape

Returns

String

OnFormatting(FormattingPositionStyleEventArgs)

protected void OnFormatting(FormattingPositionStyleEventArgs e)

Parameters

e FormattingPositionStyleEventArgs

OnFormatted(FormattedPositionStyleEventArgs)

protected void OnFormatted(FormattedPositionStyleEventArgs e)

Parameters

e FormattedPositionStyleEventArgs

DrawText(FeatureLabelingCandidate, GeoCanvas, Collection<SimpleCandidate>, Collection<SimpleCandidate>)

internal void DrawText(FeatureLabelingCandidate featureLabelingCandidate, GeoCanvas canvas, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

featureLabelingCandidate FeatureLabelingCandidate

canvas GeoCanvas

labelsInThisLayer Collection<SimpleCandidate>

labelsInAllLayers Collection<SimpleCandidate>

GetFeatureLabelingCandidates(IEnumerable<Feature>, GeoCanvas)

internal Collection<FeatureLabelingCandidate> GetFeatureLabelingCandidates(IEnumerable<Feature> features, GeoCanvas canvas)

Parameters

features IEnumerable<Feature>

canvas GeoCanvas

Returns

Collection<FeatureLabelingCandidate>

DrawMask(LabelingCandidate, GeoCanvas, Collection<SimpleCandidate>, Collection<SimpleCandidate>)

protected void DrawMask(LabelingCandidate labelingCandidate, GeoCanvas canvas, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

labelingCandidate LabelingCandidate

canvas GeoCanvas

labelsInThisLayer Collection<SimpleCandidate>

labelsInAllLayers Collection<SimpleCandidate>

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.

Exceptions

InvalidOperationException
In the event you attempt to call this method when the GeoCanvas's IsDrawing mode is false, it will throw an InvalidOperationException.

ArgumentNullException
If you pass a null as the view, we will throw an ArgumentNullException.

ArgumentNullException
If you pass a null as the features, we will throw an ArgumentNullException.

Remarks:

This overridden 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 overriding this 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 the column names that it needs.

Exceptions

ArgumentNullException
If columnName is null, we will throw an ArgumentNullException.

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.

FilterFeatures(IEnumerable<Feature>, GeoCanvas)

This method filters the features based on the grid size to facilitate deterministic labeling.

protected internal Collection<Feature> FilterFeatures(IEnumerable<Feature> features, GeoCanvas canvas)

Parameters

features IEnumerable<Feature>
This parameter represents the features that will be filtered.

canvas GeoCanvas
This parameter is the view that will be used for calculating font sizes.

Returns

Collection<Feature>
This method returns the features that will be considered for labeling.

Remarks:

This method is the concrete wrapper for the abstract method FilterFeaturesCore. In this method, we filter the features based on the grid size to facilitate deterministic labeling.

As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.

FilterFeaturesCore(IEnumerable<Feature>, GeoCanvas)

This method filters the features based on the grid size to facilitate deterministic labeling.

protected Collection<Feature> FilterFeaturesCore(IEnumerable<Feature> features, GeoCanvas canvas)

Parameters

features IEnumerable<Feature>
This parameter represents the features that will be filtered.

canvas GeoCanvas
This parameter is the view that will be used for calculating font sizes.

Returns

Collection<Feature>
This method returns the features that will be considered for labeling.

Remarks:

This overridden method is called from the concrete public method FilterFeatures. In this method, we filter the features based on the grid size to facilitate deterministic labeling.

AbbreviateText(Feature, GeoCanvas)

protected void AbbreviateText(Feature feature, GeoCanvas canvas)

Parameters

feature Feature

canvas GeoCanvas

AbbreviateTextCore(Feature, GeoCanvas)

protected void AbbreviateTextCore(Feature feature, GeoCanvas canvas)

Parameters

feature Feature

canvas GeoCanvas

GetLabelingCandidates(Feature, GeoCanvas, GeoFont, Single, Single, Double)

This method determines whether the specified feature is a good candidate to be labeled, based on the labeling properties set.

protected Collection<LabelingCandidate> GetLabelingCandidates(Feature feature, GeoCanvas canvas, GeoFont font, float xOffsetInPixel, float yOffsetInPixel, double rotationAngle)

Parameters

feature Feature

        This parameter is the feature that will be considered as a labeling
        candidate.

canvas GeoCanvas

        This parameter is the view that will be used to draw the feature. This method will not
        draw on this view, but rather will use it to determine font size, etc.

font GeoFont

xOffsetInPixel Single

yOffsetInPixel Single

rotationAngle Double

Returns

Collection<LabelingCandidate>
A collection of labeling candidates.

Remarks:

This method is the concrete wrapper for the abstract method GetLabelingCanidatesCore. This method determines if the feature passed in is a good candidate to be labeled based on the labeling properties set.

As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.

GetLabelingCandidateCore(Feature, GeoCanvas, GeoFont, Single, Single, Double)

This method determines whether the specified feature is a good candidate to be labeled, based on the labeling properties set.

protected Collection<LabelingCandidate> GetLabelingCandidateCore(Feature feature, GeoCanvas canvas, GeoFont font, float xOffsetInPixel, float yOffsetInPixel, double rotationAngle)

Parameters

feature Feature

        This parameter is the feature that will be considered as a labeling
        candidate.

canvas GeoCanvas

        This parameter is the view that will be used to draw the feature. This method will not
        draw on this view, but rather will use it to determine font size, etc.

font GeoFont

xOffsetInPixel Single

yOffsetInPixel Single

rotationAngle Double

Returns

Collection<LabelingCandidate>
A collection of labeling candidates.

Remarks:

This overridden method is called from the concrete public method GetLabelingCanidate. In this method, we take the feature you passed in and determine if it is a candidate for labeling. If it is, then we will add it to the return collection. The algorithm to determine whether the label will draw is complex and determined by a number of properties and factors.

MeasureText(GeoCanvas, String, GeoFont)

internal DrawingRectangleF MeasureText(GeoCanvas canvas, string text, GeoFont font)

Parameters

canvas GeoCanvas

text String

font GeoFont

Returns

DrawingRectangleF

WrapText(String, GeoFont, GeoCanvas)

public string WrapText(string text, GeoFont font, GeoCanvas canvas)

Parameters

text String

font GeoFont

canvas GeoCanvas

Returns

String

CheckDuplicate(LabelingCandidate, GeoCanvas, Collection<SimpleCandidate>, Collection<SimpleCandidate>)

This method will determine whether the label will be suppressed because it is a duplicate.

protected bool CheckDuplicate(LabelingCandidate labelingCandidate, GeoCanvas canvas, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

labelingCandidate LabelingCandidate

        This parameter is the labeling candidate that will be checked to determine if it is a
        duplicate.

canvas GeoCanvas
This parameter is the view used for calculations.

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

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

Returns

Boolean
This method returns whether the label will be suppressed as a duplicate.

Remarks:

This method is the concrete wrapper for the abstract method CheckDuplicateCore. This method will determine if the label will be suppressed because it is a duplicate. It also takes into consideration the duplicate rules for the class. So, for example, if we set to allow duplicates, then the method will always return false. If the class is set to not allow duplicates and this label is a duplicate, then it will return true and be suppressed.

As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.

CheckDuplicateCore(LabelingCandidate, GeoCanvas, Collection<SimpleCandidate>, Collection<SimpleCandidate>)

This method will determine if the label will be suppressed because it is a duplicate.

protected bool CheckDuplicateCore(LabelingCandidate labelingCandidate, GeoCanvas canvas, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

labelingCandidate LabelingCandidate

        This parameter is the labeling candidate that will be checked to determine if it is a
        duplicate.

canvas GeoCanvas
This parameter is the view that will be used for calculations.

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

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

Returns

Boolean
This method returns whether the label will be suppressed as a duplicate.

Remarks:

This overridden method is called from the concrete public method CheckDuplicate. This method will determine if the label will be suppressed because it is a duplicate. It also takes into consideration the duplicate rules for the class. So, for example, if we set to allow duplicates, then the method will always return false. If the class is set to not allow duplicates and this label is a duplicate, then it will return true and be suppressed.

CheckOverlapping(LabelingCandidate, GeoCanvas, GeoFont, Single, Single, Double, Collection<SimpleCandidate>, Collection<SimpleCandidate>)

This method will determine if the label will be suppressed because of overlapping.

protected bool CheckOverlapping(LabelingCandidate labelingCandidate, GeoCanvas canvas, GeoFont font, float xOffsetInPixel, float yOffsetInPixel, double rotationAngle, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

labelingCandidate LabelingCandidate

        This parameter is the labeling candidate that will be checked to determine if it is
        overlapping.

canvas GeoCanvas
This parameter is the view that will be used for calculations.

font GeoFont

xOffsetInPixel Single

yOffsetInPixel Single

rotationAngle Double

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

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

Returns

Boolean
This method returns whether the label will be suppressed because of overlapping.

Remarks:

This method is the concrete wrapper for the abstract method CheckOverlappingCore. This method will determine if the label will be suppressed because it is overlapping another label. It also takes into consideration the overlapping rules for the class. So, for example, if we set to allow overlap, then the method will always return false. If the class is set to not allow overlap and this label is overlapping, then it will return true and be suppressed.

As this is a concrete public method that wraps a Core method, we reserve the right to add events and other logic to pre- or post-process data returned by the Core version of the method. In this way, we leave our framework open on our end, but also allow you the developer to extend our logic to suit your needs. If you have questions about this, please contact our support team as we would be happy to work with you on extending our framework.

CheckOverlappingCore(LabelingCandidate, GeoCanvas, Collection<SimpleCandidate>, Collection<SimpleCandidate>)

This method will determine whether the label will be suppressed because of overlapping.

protected bool CheckOverlappingCore(LabelingCandidate labelingCandidate, GeoCanvas canvas, Collection<SimpleCandidate> labelsInThisLayer, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

labelingCandidate LabelingCandidate
This parameter is the labeling candidate that will be checked to determine if it is overlapping.

canvas GeoCanvas
This parameter is the view that will be used for calculations.

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

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

Returns

Boolean
This method returns whether the label will be suppressed because of overlapping.

Remarks:

This overridden method is called from the concrete public method CheckOverlapping. This method will determine if the label will be suppressed because it is overlapping another label. It also takes into consideration the overlapping rules for the class. So, for example, if we set to allow overlap, then the method will always return false. If the class is set to not allow overlap and this label is overlapping, then it will return true and be suppressed.

ConvertToScreenShape(Feature, GeoCanvas)

This method converts a feature in world coordinates to screen coordinates.

protected static BaseShape ConvertToScreenShape(Feature feature, GeoCanvas canvas)

Parameters

feature Feature

        This parameter is the feature to be converted from world coordinates.

canvas GeoCanvas

        This parameter is the view that will be used to convert the world coordinate feature to a screen coorindate feature.

Returns

BaseShape
A screen coordinate shape.

Remarks:

This overridden method can be called by this class and its sub concrete classes. In this method, we take the view and the feature in world coordinates and convert it to screen coordinates.

Events

Formatting

public event EventHandler<FormattingPositionStyleEventArgs> Formatting;

Formatted

public event EventHandler<FormattedPositionStyleEventArgs> Formatted;