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ThinkGeo Cloud
ThinkGeo UI Controls
ThinkGeo Open Source
Help and Support
External Resources
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This abstract class is the basis for all image-based layers in the system.
This is a constructor for the class. If you use this constructor, you should set the properties you need manually.
If you use this constructor, you should set the properties you need manually.
This method returns the projection parameters of the current layer.
This method returns the horizontal resolution of the image.
This method returns the vertical resolution of the image.
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RequestDrawing(IEnumerable<RectangleShape>,TimeSpan)
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This method returns the bounding box of the RasterLayer.
The open method plays an important rol,e as it is responsible for initializing the RasterLayer. Most methods on the RasterLayer will throw an exception if the state of the RasterLayer is not opened. When the map draws each layer, it will open the RasterLayer 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 RasterLayer.
The close method plays an important role in the life cycle of the RasterLayer. 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 RasterLayer 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.
DrawCore(GeoCanvas,Collection<SimpleCandidate>)
This method will draw the image from the GeoImage source based on the parameters provided.
The DrawCore method will be called when the layer is being drawn. It will determine if the image is within the extent and the threshold defined. If these parameters are met, it will query the RasterSource for an image and then apply the other various properties (such as transparency, etc.) on the image. Lastly, it will draw the image on the GeoImage or native image passed into the method.
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DrawExceptionCore(GeoCanvas,Exception)
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OnDrawingException(DrawingExceptionLayerEventArgs)
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OnDrawingAttribution(DrawingAttributionLayerEventArgs)
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IsExtentWithinThreshold(RectangleShape,Double,Double,Int32,GeographyUnit)
This method returns whether the current extent is within the upper and lower threshold properties.
This method is used to determine whether the RasterLayer needs to draw based on the current extent and the the threshold parameters provided.
IsExtentWithinThreshold(RectangleShape,Double,Double,Int32,GeographyUnit,Single)
This method returns whether the current extent is within the upper and lower threshold properties.
This method is used to determine whether the RasterLayer needs to draw based on the current extent and the the threshold parameters provided.
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This property gets and sets whether the image should be converted to negative (inverse colors).
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The set for this property is protected and only intended to be used by developers who are creating their own ImageSources. This is the main property to set for developers who are creating their own RasterLayer derivatives.
This property gets and sets the upper threshold in the scale at which to display the image.
Above the upper threshold in scale, the image will not be displayed. This, in conjunction with the LowerThreshold property, allows you to create a band in which it is suitable to display the image source. By default, the upper threshold is double.max and lower threshold is double.min. This means the image should always display.
This property gets and sets the lower threshold in the scale at which to display the image.
Below the lower threshold in scale, the image will not be displayed. This, in conjunction with the UpperThreshold property, allows you to create a band in which it is suitable to display the image source. By default, the upper threshold is double.max and lower threshold is double.min. This means the image should always display.
This property returns true if the RasterLayer contains projection parameters and false if it does not contain any projection parameters.
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Gets a value represents a collection of key colors. If HasKeyColor property is false, it will throw exception when you use KeyColors.
It will make these colors transparent when draw image.
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Various methods on the RasterLayer 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 RasterLayer's Open method. The method will raise an exception if the current RasterLayer is already open.
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Event Arguments:RequestingDrawingLayerEventArgs