Class NativeImageRasterSource

Namespace

ThinkGeo.Core

Assembly

ThinkGeo.Core.dll

This class allows you to view standard .NET GDI+ image types such as BMP, TIF, JPG, and PNG.

public class NativeImageRasterSource : RasterSource

Inheritance

object

RasterSource

NativeImageRasterSource

Inherited Members

RasterSource.OnOpeningRasterSource(OpeningRasterSourceEventArgs)

RasterSource.OnOpenedRasterSource(OpenedRasterSourceEventArgs)

RasterSource.OnClosingRasterSource(ClosingRasterSourceEventArgs)

RasterSource.OnClosedRasterSource(ClosedRasterSourceEventArgs)

RasterSource.CloneDeep()

RasterSource.CloneDeepCore()

RasterSource.GetWorldFileText()

RasterSource.GenerateWorldFileText(RectangleShape, int, int)

RasterSource.GetImageWidth()

RasterSource.GetImageHeight()

RasterSource.GetHorizontalResolution()

RasterSource.GetVerticalResolution()

RasterSource.GetBoundingBox()

RasterSource.Open()

RasterSource.Close()

RasterSource.GetImage(RectangleShape, int, int)

RasterSource.ProjectionConverter

RasterSource.Projection

RasterSource.Transparency

RasterSource.BlueTranslation

RasterSource.RedTranslation

RasterSource.GreenTranslation

RasterSource.ScaleFactor

RasterSource.IsOpen

RasterSource.OpeningRasterSource

RasterSource.OpenedRasterSource

RasterSource.ClosingRasterSource

RasterSource.ClosedRasterSource

object.GetType()

object.MemberwiseClone()

object.ToString()

object.Equals(object)

object.Equals(object, object)

object.ReferenceEquals(object, object)

object.GetHashCode()

Remarks

This class handles all default supported image types of GDI+. As none of these types embed geographic information in them, you will need to ensure that the image file is always accompanied by a world file. The world file is text file that stores the associated geographic information we need to properly display the image along with your other feature data.

Constructors

NativeImageRasterSource()

This is the constructor the for the class.

public NativeImageRasterSource()

Remarks

None

NativeImageRasterSource(string)

This is the constructor the for the class.

public NativeImageRasterSource(string imagePathFilename)

Parameters

imagePathFilename string

This parameter represents the image you want to load.

Remarks

You can specify a path and filename that does not actually exist if you use the StreamLoading event. This event only uses the PathFilename parameter as a unique string that will be passed to you in the event, so that you can determine what stream you want to pass back.

NativeImageRasterSource(string, string)

This is the constructor the for the class.

public NativeImageRasterSource(string imagePathFilename, string worldfilePathFilename)

Parameters

imagePathFilename string

This parameter represents the image you want to load.

worldfilePathFilename string

This parameter represents the world file path and filename you want to load.

Remarks

You can specify a path and filename that does not actually exist if you use the StreamLoading event. This event only uses the PathFilename parameter as a unique string that will be passed to you in the event, so that you can determine what stream you want to pass back.

NativeImageRasterSource(string, RectangleShape)

This is the constructor the for the class.

public NativeImageRasterSource(string imagePathFilename, RectangleShape imageExtent)

Parameters

imagePathFilename string

This parameter represents the image you want to load.

imageExtent RectangleShape

This parameter represents the extnet of the image you want to load.

Remarks

You can specify a path and filename that does not actually exist if you use the StreamLoading event. This event only uses the PathFilename parameter as a unique string that will be passed to you in the event, so that you can determine what stream you want to pass back.

Properties

FileName

This property returns the filename part of the PathFilename.

public string FileName { get; }

Property Value

string

Remarks

None

FilePath

This property returns the path part of the PathFilename.

public string FilePath { get; }

Property Value

string

Remarks

None

ImagePathFilename

This property returns the path and filename of the image you want to represent.

public string ImagePathFilename { get; set; }

Property Value

string

Remarks

When you specify the path and filename, it should be in the correct format as such; however, the file does not need to actually exist on the file system. This is to allow us to accept streams supplied by the developer at runtime. If you choose to provide a file that exists, we will attempt to use it. If we cannot find it, then we will raise the SteamLoading event and allow you to supply the stream. For example, you can pass in "C:\NotARealPath\File1.jpg" which does not exist on the file system. When we raise the event for you to supply a stream, we will pass to you the path and filename so you can differentiate the files.

Exceptions

ArgumentException

Setting an invalid FilePathName structure will throw an ArgumentException.

IsGrayscale

This property gets and sets whether the image shows in grayscale.

public bool IsGrayscale { get; set; }

Property Value

bool

Remarks

This property allows you to show the image in grayscale.

IsNegative

This property gets and sets whether the image shows as negative (inverted colors).

public bool IsNegative { get; set; }

Property Value

bool

Remarks

You can set this property to show the negative of the image.

Methods

CloseCore()

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

protected override void CloseCore()

Remarks

This protected virtual method is called from the concrete public method Close. The Close method plays an important role in the life cycle of the Image. 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 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 FeatureSource 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.

GetBoundingBoxCore()

This method returns the bounding box of the RasterSource.

protected override RectangleShape GetBoundingBoxCore()

Returns

RectangleShape

This method returns the bounding box of the RasterSource.

Remarks

This method returns the bounding box of the RasterSource.

Exceptions

InvalidOperationException

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

GetImageCore(RectangleShape, int, int)

This method returns an image based on the worldExtent, image width and image height.

protected override GeoImage GetImageCore(RectangleShape worldExtent, int canvasWidth, int canvasHeight)

Parameters

worldExtent RectangleShape

This parameter represents the worldExtent you want to draw.

canvasWidth int

This parameter represents the width of the image you want to draw.

canvasHeight int

This parameter represents the height of the image you want to draw.

Returns

GeoImage

This method returns an image based on the worldExtent, image width and image height.

Remarks

This method is responsible for returning the image based on the parameters passed in.

Exceptions

ArgumentNullException

If you pass in a worldExtent that is invalid, we will throw an ArgumentNullException.

ArgumentException

If you pass in a worldExtent that is invalid, we will throw an ArgumentException.

ArgumentOutOfRangeException

If you pass in a image width that is smaller than or equal to 0, we will throw an ArgumentOutOfRangeException.

ArgumentOutOfRangeException

If you pass in a image height that is smaller than or equal to 0, we will throw an ArgumentOutOfRangeException.

InvalidOperationException

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

GetImageHeightCore()

This method returns the height of the image in screen coordinates.

protected override int GetImageHeightCore()

Returns

int

This method returns the height of the image in screen coordinates.

Remarks

This method returns the height of the image in screen coordinates.

Exceptions

InvalidOperationException

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

GetImageWidthCore()

This method returns the width of the image in screen coordinates.

protected override int GetImageWidthCore()

Returns

int

This method returns the width of the image in screen coordinates.

Remarks

This method returns the width of the image in screen coordinates.

Exceptions

InvalidOperationException

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

OnStreamLoading(StreamLoadingEventArgs)

This method allows you to raise the StreamLoading event.

protected virtual void OnStreamLoading(StreamLoadingEventArgs e)

Parameters

e StreamLoadingEventArgs

This parameter represents the event arguments you want to raise the StreamLoading event with.

Remarks

This method allows you to raise the StreamLoading event. Normally events are not accessible to derived classes, so we exposed a way to raise the event as necessary through this protected method.

OpenCore()

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

protected override void OpenCore()

Remarks

This protected virtual method is called from the concrete public method Open. The Open method plays an important role, as it is responsible for initializing the Image. Most methods on the Image will throw an exception if the state of the Image is not opened. When the map draws each layer, it will open the Image 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 Image.

When implementing this abstract method, consider opening files for file-based sources, connecting to databases in the database-based sources and so on. You will get a chance to close these in the Close method of the Image.

Exceptions

InvalidOperationException

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

NotSupportedException

If the file format you passed is not one of these: .bmp, .gif, .exig, .jpg, .png, or .tiff, we will throw a NotSupportedException.

FileNotFoundException

If the world file cannot be found using the filename you passed, we will throw an FileNotFoundException when the source is not from a stream.

Events

StreamLoading

This event allows you to pass in your own stream to represent the image.

public event EventHandler<StreamLoadingEventArgs> StreamLoading

Event Type

EventHandler<StreamLoadingEventArgs>

Remarks

If you wish, you can pass in your own stream to represent the image. The stream can come from a variety of places, including isolated storage, a compressed file, or an encrypted stream. When the image is finished with the stream it will dispose of it, so be sure to keep this in mind when passing the stream in. If you do not pass in an alternate stream, the class will attempt to load the file from the file system using the PathFilename property.