Table of Contents

Class Layer

Namespace
ThinkGeo.Core
Assembly
ThinkGeo.Core.dll

This class is the base class for all types of Layers.

public abstract class Layer
Inheritance
Layer
Derived
Inherited Members

Remarks

The Layer class is where all other types of layers are inherited from. It provides the base set of functionality. Though all Layers inherit from this class, we strongly suggest if you decide to create your own layer type that you consider inheriting from the higher level RasterLayer for image-based layers and FeatureLayer for feature-based layers. They provide a rich set of default operations for the various types of layers and are simple to inherit from.

As it is abstract, there are a number of methods you need to implement. The first is DrawCore. In this method, you are responsible for drawing the layer's representation. The other two required methods are OpenCore and CloseCore. These open and close the Layer. In the Open, you are responsible for getting the layer ready for drawing. You should open any file references, etc. In the Close, you need to clean up all file handles, close other objects etc. It is important that the Close puts the class in a state where it can be re-opened in the future. It is different than Dispose, as closed Layers will still exist and can be re-opened later in the mapping life cycle. Many methods (in the layer and in higher level objects) will require that the Layer be open before these methods are called, otherwise they will throw an exception.

Constructors

Layer()

This is the default constructor for the Layer.

protected Layer()

Remarks

None

Properties

Attribution 

[Obsolete("Layer.Attribution (as well as Drawing Attribution) is deprecate and will be removed after v14.2. You can accomplish the similar feature by overriding layer.DrawCore/Layer.DrawAsyncCore method")]
public string Attribution { get; set; }

Property Value

string

Background

Gets and sets the background of the layer.

public GeoColor Background { get; set; }

Property Value

GeoColor

BlueTranslation

This property gets and sets the amount of blue to apply to the image.

public float BlueTranslation { get; set; }

Property Value

float

This property gets the amount of blue to apply to the image.

Remarks

None

ColorMappings

ColorMapping

public Dictionary<GeoColor, GeoColor> ColorMappings { get; }

Property Value

Dictionary<GeoColor, GeoColor>

DrawingExceptionMode

Gets or sets the DrawExceptionMode when exception happens.

public DrawingExceptionMode DrawingExceptionMode { get; set; }

Property Value

DrawingExceptionMode

DrawingTime

This property gets the last drawing time for the layer.

public TimeSpan DrawingTime { get; protected set; }

Property Value

TimeSpan

Remarks

We track the drawing time for the layer and report it back in this method. This is useful for determining the speed of various layers.

GreenTranslation

This property gets and sets the amount of green to apply to the image.

public float GreenTranslation { get; set; }

Property Value

float

This property gets the amount of green to apply to the image.

Remarks

None

HasBoundingBox

This property indicates whether a Layer has a BoundingBox or not. If it has no BoundingBox, it will throw an exception when you call the GetBoundingBox() and GetFullExtent() APIs.

public virtual bool HasBoundingBox { get; }

Property Value

bool

Remarks

The default value is false.

IsGrayscale

This property gets and sets if the image should be converted to grayscale.

public bool IsGrayscale { get; set; }

Property Value

bool

This property gets and sets if the image should be converted to grayscale.

Remarks

None

IsNegative

This property gets and sets whether the image should be converted to negative (inverse colors).

public bool IsNegative { get; set; }

Property Value

bool

This property gets and sets whether the image should be converted to negative (inverse colors).

Remarks

None

IsOpen

This property returns true if the Layer is open and false if it is not.

public bool IsOpen { get; }

Property Value

bool

Remarks

This method is the concrete wrapper for the abstract method IsOpenCore. Various methods on the Layer require that it be in an open state. If one of those methods is called when the state is not open, then the method will throw an exception. To enter the open state, you must call the Layer Open method. The method will raise an exception if the current Layer is already open.

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.

IsOpenCore

This property returns true if the Layer is open and false if it is not.

protected virtual bool IsOpenCore { get; set; }

Property Value

bool

Remarks

Various methods on the Layer require that it be in an open state. If one of those methods is called when the state is not open, then the method will throw an exception. To enter the open state, you must call the Layer Open method. The method will raise an exception if the current Layer is already open.

IsVisible

This property gets and set the visible state of the layer.

public virtual bool IsVisible { get; set; }

Property Value

bool

Remarks

If this property is set to false, the layer will not draw. We ensure this in the Draw method. This is useful for legends and other controls that control the visibility of layers.

KeyColors

Gets a value represents a collection of key colors. If SupportKeyColor property is false, it will throw exception when you use KeyColors.

public Collection<GeoColor> KeyColors { get; }

Property Value

Collection<GeoColor>

Remarks

It will make these colors transparent when draw image.

Name

This property gets and sets the name for the layer.

public string Name { get; set; }

Property Value

string

Remarks

The name is user defined. It is useful to set, as it may be used for higher level components such as legends, etc.

Projection

Gets the projection of the layer.

public virtual Projection Projection { get; set; }

Property Value

Projection

RedTranslation

This property gets and sets the amount of red to apply to the image.

public float RedTranslation { get; set; }

Property Value

float

This property gets the amount of red to apply to the image.

Remarks

None

RequestDrawingInterval 

public TimeSpan RequestDrawingInterval { get; set; }

Property Value

TimeSpan

ThreadSafe 

public ThreadSafetyLevel ThreadSafe { get; set; }

Property Value

ThreadSafetyLevel

Transparency

This property gets and sets the amount of transparency to apply to the image.

public float Transparency { get; set; }

Property Value

float

This property gets the amount of transparency to apply to the image.

Remarks

None

WrappingExtent 

public RectangleShape WrappingExtent { get; set; }

Property Value

RectangleShape

WrappingMode 

public WrappingMode WrappingMode { get; set; }

Property Value

WrappingMode

Methods

CloneDeep()

Create a copy of Layer using the deep clone process.

public Layer CloneDeep()

Returns

Layer

A cloned Layer.

Remarks

The difference between deep clone and shallow clone is as follows: In shallow cloning, only the object is copied; the objects within it are not. By contrast, deep cloning copies the cloned object as well as all the objects within.

CloneDeepCore()

Create a copy of Layer using the deep clone process. The default implemenation uses serialization.

protected virtual Layer CloneDeepCore()

Returns

Layer

A cloned Layer.

Remarks

The difference between deep clone and shallow clone is as follows: In shallow cloning, only the object is copied; the objects within it are not. By contrast, deep cloning copies the cloned object as well as all the objects within.

Close()

This method closes the Layer and releases any resources it was using.

public void Close()

Remarks

This method is the concrete wrapper for the abstract method CloseCore. The close method plays an important role in the life cycle of the Layer. It may be called after drawing to release any memory and other resources that were allocated since the Open method was called.

If you override this method, it is recommended that you take the following things into account: This method may be called multiple times, so we suggest you write the method so that that a call to a closed Layer is ignored and does not generate an error. We also suggest that in the Close you free all resources that have been opened. Remember that the object will not be destroyed, but will be re-opened possibly in the near future.


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.

CloseCore()

This method closes the Layer and releases any resources it was using.

protected virtual void CloseCore()

Remarks

This abstract method is called from the concrete public method Close. The close method plays an important role in the life cycle of the Layer. It may be called after drawing to release any memory and other resources that were allocated since the Open method was called.

If you override this method, it is recommended that you take the following things into account: This method may be called multiple times, so we suggest you write the method so that that a call to a closed Layer is ignored and does not generate an error. We also suggest that in the Close you free all resources that have been opened. Remember that the object will not be destroyed, but will be re-opened possibly in the near future.

Draw(GeoCanvas, Collection<SimpleCandidate>)

This method draws the Layer.

public void Draw(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

canvas GeoCanvas

This parameter is the view object or a NativeImage to draw on.

labelsInAllLayers Collection<SimpleCandidate>

This parameter represents the labels used for collision detection and duplication checking.

Remarks

This method is the concrete wrapper for the abstract method DrawCore. This method draws the representation of the layer based on the extent you provided.

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.

Exceptions

ArgumentNullException

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

ArgumentNullException

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

ArgumentNullException

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

ArgumentOutOfRangeException

If you pass in a mapUnit that is not defined in the enumeration, it will throw a ArgumentOutOfRangeException.

DrawAttributionCore(GeoCanvas, string) 

[Obsolete("Layer.Attribution (as well as Drawing Attribution) is deprecate and will be removed after v14.2. You can accomplish the similar feature by overriding layer.DrawCore/Layer.DrawAsyncCore method")]
protected virtual void DrawAttributionCore(GeoCanvas canvas, string attribution)

Parameters

canvas GeoCanvas
attribution string

DrawCore(GeoCanvas, Collection<SimpleCandidate>)

This method draws the Layer.

protected abstract void DrawCore(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers)

Parameters

canvas GeoCanvas

This parameter is the view object or a NativeImage to draw on.

labelsInAllLayers Collection<SimpleCandidate>

This parameter represents the labels used for collision detection and duplication checking.

Remarks

This method is the concrete wrapper for the abstract method DrawCore. This method draws the representation of the layer based on the extent you provided.

When implementing this abstract 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 that allow the user to specify which field they need; then, in the GetRequiredColumnNamesCore, we read that property and add it to the collection.

DrawException(GeoCanvas, Exception)

This method will draw on the view when the layer.Draw throw exception and the DrawExceptionMode is set to DrawException instead of ThrowException.

protected void DrawException(GeoCanvas canvas, Exception e)

Parameters

canvas GeoCanvas

The target view to draw the layer.

e Exception

The exception thrown when layer.Draw().

Remarks

This method can be overriden its logic by rewrite the DrawExceptionCore.

DrawExceptionCore(GeoCanvas, Exception)

This method will draw on the view when the layer.Draw throw exception and the DrawExceptionMode is set to DrawException instead of ThrowException.

protected virtual void DrawExceptionCore(GeoCanvas canvas, Exception e)

Parameters

canvas GeoCanvas

The target view to draw the layer.

e Exception

The exception thrown when layer.Draw().

DrawWithColorTransformation(GeoCanvas, Collection<SimpleCandidate>, RectangleShape, float, float) 

protected virtual void DrawWithColorTransformation(GeoCanvas canvas, Collection<SimpleCandidate> labelsInAllLayers, RectangleShape extent, float width, float height)

Parameters

canvas GeoCanvas
labelsInAllLayers Collection<SimpleCandidate>
extent RectangleShape
width float
height float

GetBoundingBox()

This method returns the bounding box of the Layer.

public RectangleShape GetBoundingBox()

Returns

RectangleShape

This method returns the bounding box of the Layer.

Remarks

This method is the concrete wrapper for the abstract method GetBoundingBoxCore. This method returns the bounding box of the RasterLayer.

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.

GetBoundingBoxCore()

This method returns the bounding box of the Layer.

protected virtual RectangleShape GetBoundingBoxCore()

Returns

RectangleShape

This method returns the bounding box of the Layer.

Remarks

This method returns the bounding box of the Layer.

Exceptions

InvalidOperationException

In the event you attempt to call this method on a layer which has not been opened, it will throw an InvalidOperationException.

IsDrawingNeeded(double) 

public bool IsDrawingNeeded(double currentScale)

Parameters

currentScale double

Returns

bool

IsDrawingNeededCore(double) 

protected virtual bool IsDrawingNeededCore(double currentScale)

Parameters

currentScale double

Returns

bool

LoadLayer(Stream) 

public static Layer LoadLayer(Stream layerStream)

Parameters

layerStream Stream

Returns

Layer

LoadLayer(Uri) 

public static Layer LoadLayer(Uri layerUri)

Parameters

layerUri Uri

Returns

Layer

OnDrawingAttribution(DrawingAttributionLayerEventArgs) 

[Obsolete("Layer.Attribution (as well as Drawing Attribution) is deprecate and will be removed after v14.2. You can accomplish the similar feature by overriding layer.DrawCore/Layer.DrawAsyncCore method")]
protected virtual void OnDrawingAttribution(DrawingAttributionLayerEventArgs args)

Parameters

args DrawingAttributionLayerEventArgs

OnDrawingException(DrawingExceptionLayerEventArgs) 

protected virtual void OnDrawingException(DrawingExceptionLayerEventArgs e)

Parameters

e DrawingExceptionLayerEventArgs

OnDrawingProgressChanged(DrawingProgressChangedEventArgs) 

protected virtual void OnDrawingProgressChanged(DrawingProgressChangedEventArgs e)

Parameters

e DrawingProgressChangedEventArgs

OnDrawnAttribution(DrawnAttributionLayerEventArgs) 

[Obsolete("Layer.Attribution (as well as Drawing Attribution) is deprecate and will be removed after v14.2. You can accomplish the similar feature by overriding layer.DrawCore/Layer.DrawAsyncCore method")]
protected virtual void OnDrawnAttribution(DrawnAttributionLayerEventArgs args)

Parameters

args DrawnAttributionLayerEventArgs

OnDrawnException(DrawnExceptionLayerEventArgs) 

protected virtual void OnDrawnException(DrawnExceptionLayerEventArgs e)

Parameters

e DrawnExceptionLayerEventArgs

OnRequestedDrawing(RequestedDrawingLayerEventArgs) 

protected virtual void OnRequestedDrawing(RequestedDrawingLayerEventArgs eventArgs)

Parameters

eventArgs RequestedDrawingLayerEventArgs

OnRequestingDrawing(RequestingDrawingLayerEventArgs) 

protected virtual void OnRequestingDrawing(RequestingDrawingLayerEventArgs eventArgs)

Parameters

eventArgs RequestingDrawingLayerEventArgs

Open()

This method opens the Layer so that it is initialized and ready to use.

public void Open()

Remarks

This method is the concrete wrapper for the abstract method OpenCore. The open method plays an important role, as it is responsible for initializing the Layer. Most methods on the Layer will throw an exception if the state of the Layer is not opened. When the map draws each layer, the layer will be opened as one of its first steps; then, after it is finished drawing with that layer, it will close it. In this way, we are sure to release all resources used by the Layer.

When implementing the abstract method, consider opening the FeatureSource or RasterSource. You will get a chance to close these in the Close method of the Layer.

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.

OpenCore()

This method opens the Layer so that it is initialized and ready to use.

protected virtual void OpenCore()

Remarks

This abstract method is called from the concrete public method Open. The open method plays an important role, as it is responsible for initializing the Layer. Most methods on the Layer will throw an exception if the state of the Layer is not opened. When the map draws each layer, the layer will be opened as one of its first steps; then, after it is finished drawing with that layer, it will close it. In this way, we are sure to release all resources used by the Layer.

When implementing the abstract method, consider opening the FeatureSource or RasterSource. You will get a chance to close these in the Close method of the Layer.

Exceptions

InvalidOperationException

In the event you attempt to call this method on a Layer which has already been opened, it will throw an InvalidOperationException.

RequestDrawing() 

public void RequestDrawing()

RequestDrawing(IEnumerable<RectangleShape>) 

public void RequestDrawing(IEnumerable<RectangleShape> extentsToRefresh)

Parameters

extentsToRefresh IEnumerable<RectangleShape>

RequestDrawing(IEnumerable<RectangleShape>, TimeSpan) 

public void RequestDrawing(IEnumerable<RectangleShape> extentsToRefresh, TimeSpan bufferTime)

Parameters

extentsToRefresh IEnumerable<RectangleShape>
bufferTime TimeSpan

RequestDrawing(IEnumerable<RectangleShape>, TimeSpan, RequestDrawingBufferTimeType) 

public void RequestDrawing(IEnumerable<RectangleShape> extentsToRefresh, TimeSpan bufferTime, RequestDrawingBufferTimeType bufferTimeType)

Parameters

extentsToRefresh IEnumerable<RectangleShape>
bufferTime TimeSpan
bufferTimeType RequestDrawingBufferTimeType

RequestDrawing(TimeSpan) 

public void RequestDrawing(TimeSpan bufferTime)

Parameters

bufferTime TimeSpan

RequestDrawing(TimeSpan, RequestDrawingBufferTimeType) 

public void RequestDrawing(TimeSpan bufferTime, RequestDrawingBufferTimeType bufferTimeType)

Parameters

bufferTime TimeSpan
bufferTimeType RequestDrawingBufferTimeType

RequestDrawing(RectangleShape) 

public void RequestDrawing(RectangleShape extentToRefresh)

Parameters

extentToRefresh RectangleShape

RequestDrawing(RectangleShape, TimeSpan) 

public void RequestDrawing(RectangleShape extentToRefresh, TimeSpan bufferTime)

Parameters

extentToRefresh RectangleShape
bufferTime TimeSpan

RequestDrawing(RectangleShape, TimeSpan, RequestDrawingBufferTimeType) 

public void RequestDrawing(RectangleShape extentToRefresh, TimeSpan bufferTime, RequestDrawingBufferTimeType bufferTimeType)

Parameters

extentToRefresh RectangleShape
bufferTime TimeSpan
bufferTimeType RequestDrawingBufferTimeType

StartRequestDrawing() 

protected void StartRequestDrawing()

Events

DrawingAttribution 

[Obsolete("Layer.Attribution (as well as Drawing Attribution) is deprecate and will be removed after v14.2. You can accomplish the similar feature by overriding layer.DrawCore/Layer.DrawAsyncCore method")]
public event EventHandler<DrawingAttributionLayerEventArgs> DrawingAttribution

Event Type

EventHandler<DrawingAttributionLayerEventArgs>

DrawingException 

public event EventHandler<DrawingExceptionLayerEventArgs> DrawingException

Event Type

EventHandler<DrawingExceptionLayerEventArgs>

DrawingProgressChanged 

public event EventHandler<DrawingProgressChangedEventArgs> DrawingProgressChanged

Event Type

EventHandler<DrawingProgressChangedEventArgs>

DrawnAttribution 

[Obsolete("Layer.Attribution (as well as Drawing Attribution) is deprecate and will be removed after v14.2. You can accomplish the similar feature by overriding layer.DrawCore/Layer.DrawAsyncCore method")]
public event EventHandler<DrawnAttributionLayerEventArgs> DrawnAttribution

Event Type

EventHandler<DrawnAttributionLayerEventArgs>

DrawnException 

public event EventHandler<DrawnExceptionLayerEventArgs> DrawnException

Event Type

EventHandler<DrawnExceptionLayerEventArgs>

RequestedDrawing 

public event EventHandler<RequestedDrawingLayerEventArgs> RequestedDrawing

Event Type

EventHandler<RequestedDrawingLayerEventArgs>

RequestingDrawing 

public event EventHandler<RequestingDrawingLayerEventArgs> RequestingDrawing

Event Type

EventHandler<RequestingDrawingLayerEventArgs>