TGIS_Layer class

General layer class. Must be derived to provide file access.

Available also on: Delphi | Java | ActiveX | Python.

Syntax

// C#
public class TGIS_Layer : TGIS_LayerAbstract
{
}

' VisualBasic
Public Class TGIS_Layer
  Inherits TGIS_LayerAbstract
End Class

// Oxygene
type
  TGIS_Layer = public class( TGIS_LayerAbstract )
  end;

Inheritance

→ TGIS_BaseObjectDisposable → TGIS_LayerAbstract

Constructors

Inherited Overrides Protected

	Name	Visibility	Description
	TGIS_Layer()	public	Creates a layer with default parameters.
	TGIS_Layer(string)	public	Creates a layer and sets the Path property.

Fields

Inherited Protected

Name	Visibility	Description
FActive	protected	True if the layer is active.
FAddition	protected	Additional integer value.
FAge	protected	Layer age or last modification timestamp.
FBasemap	protected	True if the layer is interpreted as a basemap.
FBasemapDraw	protected	True if the layer is currently being drawn inside a basemap thread.
FCachedPaint	protected	False if layer must be painted directly (bypassing cache).
FCaption	protected	Layer caption.
FCodePage	protected	Code page in which text is stored.
FCodePageForced	protected	Code page forced by the project file or property setting.
FCollapsed	protected	True if the layer is collapsed in the legend hierarchy.
FComments	protected	Additional comments.
FConfigFile	protected	Configuration file handle.
FConfigFile2	protected	Configuration file handle.
FConfigName	protected	Configuration file name.
FCS	protected	Layer CRS (Coordinate Reference System) object.
FCustomData	protected	List of custom data.
FDormantMode	protected	Dormant mode for the layer.
FDriver	protected	Layer driver.
FExtent	protected	Layer extent.
FExtent3D	protected	Three-dimensional layer extent.
FFileCopyright	protected	Additional textual information about layer copyright.
FFileInfo	protected	Additional textual information about the layer, such as compression, pixel count, and copyright.
FGUID	protected	Unique layer identifier.
FHideFromLegend	protected	True if layer should not be visible in a legend.
FIcon	protected	Layer icon displayed in the legend.
FInPaint	protected	True while the layer is in the paint process.
FIsLocked	protected	True if the layer is in the locked state.
FIsModified	protected	True if the layer structure or geometry has been modified.
FIsOpened	protected	True if the layer has been opened.
FIsPrepared	protected	True if the layer has been prepared.
FIsReadOnly	protected	Read-only flag.
FMaxTileSize	protected	Maximum allowed tile size for the layer.
FMultiUserMode	protected	Multiuser mode.
FName	protected	Layer name.
FOnBusy	protected	Busy event fired regularly during long-running operations.
FOnPaintLayer	protected	PaintLayer event fired during Paint and related drawing operations.
FOnPassword	protected	Fired when opening a layer to resolve required user name or password values.
FOnRead	protected	Fired for each file read request.
FOnWrite	protected	Fired for each file write request.
forceCachedMode	protected	Set to True to force cached bitmap drawing.
FOverlappedExtentMargin	protected	Overlapped extent margin.
FParamsList	protected	List of parameter sets grouped by section.
FParentLayer	protected	Parent layer.
FPath	protected	Layer path.
FProjectedExtent	protected	Cached projected extent.
FProjectedExtentBase	protected	Cached projected extent base extent in unprojected layer coordinates.
FProjectedExtentEPSG	protected	Cached projected extent layer CRS (Coordinate Reference System) context.
FProjectedExtentRotationAngle	protected	Cached projected extent rotation angle context.
FProjectedExtentRotationPoint	protected	Cached projected extent rotation point context.
FProjectedExtentViewerEPSG	protected	Cached projected extent viewer CRS (Coordinate Reference System) context.
FRenderer	protected	Handle to a renderer used for drawing shapes.
FStatistics	protected	Statistics engine.
FStream	protected	Reference to a potential layer underlying stream.
FSubLayers	protected	Sublayer list.
FSubType	protected	Sublayer type flags for this layer.
FSupportsAsync	protected	Indicates whether the layer implements asynchronous operations.
FSupportsAutoStyle	protected	Indicates whether the layer supports auto styling.
FSupportsTiledPaint	protected	Indicates whether the layer supports tiled paint.
FTag	protected	Tag value.
FTagInternal	protected	Internal Tag value.
FTagPointer	protected	Pointer tag value.
FTileable	protected	True if the layer is currently printed or exported using tiles.
FTiledDrawMode	protected	Current tiled draw mode used while drawing in a basemap thread.
FTransform	protected	Custom transformation.
FTransparency	protected	Transparency value.
FUnSupportedOperations	protected	Set of operations not supported by the layer.
FUseConfig	protected	True if configuration file support is enabled.
FUserObject	protected	User object owned by the layer and destroyed when the layer is destroyed or when replaced.
FViewer	protected	Reference to viewer object.
inDraw	protected	True while layer drawing is still in progress to avoid circular drawing calls.
paramsCache	protected	List of prepared parameters.
paramsCacheUpdated	protected	True if cached parameters are ready for rendering.
View3D	public	3D representation settings for the layer.

Methods

Inherited Overrides Protected

Name	Visibility	Description
Alive	public	Makes a layer non-dormant.
ApplyAutoStyle	public	Applies auto-styling to the layer.
ApplyAutoStyle(bool)	public	Applies auto-styling to the layer.
applyConfigOptions	protected	Applies layer option settings from a configuration file.
applyConfigProjection(TGIS_ConfigAbstract)	protected	Applies projection settings from a configuration file.
applyConfigProjection(TGIS_ConfigAbstract, TGIS_Layer)	protected	Applies projection settings from a configuration file.
ApplyCuttingPolygon	public	Sets a clipping polygon for the layer.
ChangeHash	public	Changes the hash used to verify layer modifications.
ClearModified	public	Sets IsModified flag to false for a layer and its sublayers.
doApplyAutoStyle	protected	Applies layer-specific auto-styling implementation.
Dormant	public	Makes a layer dormant.
DormantGain	public	Calculates the approximate memory gain in megabytes that can be achieved by calling Dormant.
Draw	public	Draws a layer.
DrawEx	public	Draws a layer within a defined extent.
drawExtent	protected	Calculates the device drawing and clipping area.
drawExtentEx	protected	Calculates the device drawing and clipping area.
DrawFlash	public	Draws a flash.
DrawSelected	public	Draws only the selected item(s) on layer.
DrawSelectedEx	public	Draws only the selected item(s) on layer that are within a defined extent.
DrawSpecial	public	Draws a layer using the passed renderer.
ForEachSubLayer	public	Calls the callback for the layer and all of its sublayers.
GetAvailableLayers	public	Gets a list of layers available in storage.
GetSubLayer	public	Retrieves the layer identified by name.
HourglassShake	public	Notifies about a busy state using an hourglass.
IsGrid	public	Checks if the layer type is grid.
IsPixel	public	Checks if the layer type is pixel.
isSectionInVisibilityRange	protected	Checks whether the section is visible by testing layer properties: Level with MinLevel/MaxLevel, ScaleAsFloat with MinScale/MaxScale, and Zoom with MinZoom/MaxZoom.
isSublayer	protected	Checks if the layer is a sublayer.
IsSupported	public	Checks if the operation is supported by the layer.
IsTopology	public	Checks if the layer type is topology.
IsVector	public	Checks if the layer type is vector.
IsVector3D	public	Checks if the layer type is vector 3D.
IsVisible	public	Checks if the layer is visible in a defined extent and current params.
Lock	public	Locks the layer for burst-mode operation.
lockThread	protected	Locks the layer thread.
MarkAsProxy	public	Marks the layer to be used as a proxy layer.
MarkModified	public	Sets IsModified flag to true for a layer and its sublayers.
Move	public	Moves a layer up or down in the viewer zorder list.
MoveEx	public	Moves a layer up or down in the viewer zorder list (only visible layers).
MustCalculateStatistics	public	Verifies whether all statistics required to render the layer are available.
MustReproject	public	Checks whether the layer must be reprojected.
MustSave	public	Checks whether the layer was modified by editing.
Open	public	Opens the layer.
OpenAsync	public	Opens the layer asynchronously.
optimizeParamsCache(int)	protected	Moves the specified section to the top of the cached list.
optimizeParamsCache(int, bool)	protected	Moves the specified section to the top of the cached list.
Paint	public	Draws the layer or fires PaintLayer event (if defined).
Prepare	public	Opens the layer for non-drawing operations.
PrepareForExport	public	Prepares layer for export.
PrepareParams	public	Prepares cached rendering parameters for internal use.
prepareParamsCache	protected	Prepares the cached section list for rendering.
prepareParamsCache(string)	protected	Prepares the cached section list for the specified style.
PreRecognize	public	Checks if the layer can read the file.
Project	public	Applies a projection on the single point.
Project3D	public	Applies a projection on the single point in 3D.
Project3D_Ref	public	Applies projection to a single 3D point.
ProjectExtent	public	Applies a projection on the extent.
Project_Ref	public	Applies projection to a single point.
RaiseBusyEvent	public	Fires Busy event of the layer.
RaiseBusyPrepare	public	Fires BusyPrepare method of the assigned viewer.
RaiseBusyRelease	public	Fires BusyRelease method of the assigned viewer.
RaiseBusyShake	public	Fires BusyShake method of the assigned viewer.
ReadConfig	public	Reads the layer configuration files.
ReadConfigParam	public	Reads a layer configuration parameter.
RecalcExtent	public	Recalculates the layer extent.
RecalcProjectedExtent	public	Recalculates the projected extent.
ReOpen	public	Reopens the layer.
RereadConfig	public	Rereads the layer configuration files.
resetMustReproject	protected	Resets the MustReproject state.
RevertAll	public	Reverts layer to its original content.
RootLayer	public	Returns the absolute parent layer.
SaveAll	public	Saves the layer and destroys mirrored items.
SaveData	public	Saves layer and destroys mirrored items.
SetCSByEPSG	public	Sets the coordinate system using an EPSG code.
SetCSByWKT	public	Sets the coordinate system from a WKT (Well-Known Text) string containing a GEOGCS or PROJCS definition.
SetCSByWKTFile	public	Sets the coordinate system from a file containing a WKT (Well-Known Text) string, such as a Shapefile .PRJ file.
setUp	protected	Performs the first general layer setup step.
setUp2	protected	Performs the second general layer setup step.
setUp3	protected	Performs the third general layer setup step.
setUpAsync	protected	Performs the first general layer setup step asynchronously.
storeConfigOptions	protected	Stores layer option settings in a configuration file.
transformExtent	protected	Transforms an extent using the custom transformation.
Unlock	public	Unlocks the layer from burst-mode operation.
unlockThread	protected	Unlocks the layer thread.
UnprepareForExport	public	Finalizes export initialized with PrepareForExport.
Unproject	public	Applies reverse projection (recovers from the projection) on the single point.
Unproject3D	public	Applies reverse projection to a single 3D point.
Unproject3D_Ref	public	Applies reverse projection to a single 3D point.
UnprojectExtent	public	Applies reverse projection (recovers from the projection) on the extent.
Unproject_Ref	public	Applies reverse projection to a single point.
ViewerReParent	public	Sets the viewer for the layer and its sublayers.
WriteConfig	public	Writes the layer configuration files.

Properties

Inherited Protected

Name	Visibility	Description
Active	public	True if the layer is visible and can be localized.
Addition	public	Additional blending value.
Age	public	Time elapsed since the layer was created.
Basemap	public	True if the layer must be treated as a basemap for background painting.
BasemapDraw	public	True if the layer is currently being drawn in a basemap thread.
CachedPaint	public	False if the layer must be painted directly, bypassing the cache.
Caption	public	Layer caption; if not assigned directly, it will be filled with Name when the layer is added to the viewer.
CodePage	public	Code page used to store text.
Collapsed	public	True if the layer is collapsed in the legend, meaning only the layer title is visible.
Comments	public	Additional user comments.
ConfigFile	public	Configuration file handle.
ConfigName	public	Configuration file name.
CS	public	Coordinate Reference System (CRS) assigned to the layer.
CustomData	public	List of custom, user-defined data saved to and restored from config and project files.
DirectMode	public	True if the layer is direct-mode (bypassing cache).
DormantMode	public	Memory-management mode for the layer.
Driver	public	The layer's driver name.
Extent	public	Extent of the layer.
Extent3D	public	Three-dimensional extent of the layer.
FileCopyrights	public	Copyright information about the layer.
FileInfo	public	Additional textual information about the layer such as compression, number of pixels, copyright, etc.
GUID	public	Unique layer identifier.
HideFromLegend	public	False if the layer should not be visible in the legend.
Icon	public	Layer icon presented in the legend.
InPaint	public	True while the layer is being painted.
IsExportable	public	True if the layer is exportable.
IsLocked	public	True if the layer is in locked state.
IsModified	public	True if structure (field, geometry etc) was modified.
IsOpened	public	True if the layer is opened and is ready for operations.
IsPersistent	public	True if the layer is persistent.
IsReadOnly	public	True if the layer is read-only.
IsTopmost	public	True if the layer can be interpreted as the topmost (trackable) layer.
Layer3D	public	Mode of 3D layer operations.
MaxTileSize	public	Maximum allowed tile size for the layer.
MultiUserMode	public	Multiuser access mode for the layer.
Name	public	Layer name.
OverlappedExtentMargin	public	Overlap margin applied to the layer extent.
Params	public	Parameters (colors, fills, etc.) object.
ParamsList	public	List of all parameter sections attached to the current layer.
ParentLayer	public	Parent layer of a sublayer.
Path	public	Path to file holding the layer's data.
PathWithDriver	public	Path to file with the layer's data extended with driver name.
ProjectedExtent	public	Extent of the layer in projected units.
Renderer	public	Handle to a renderer used for drawing shapes.
Statistics	public	Layer statistics engine.
Stream	public	Stream providing layer data as an alternative to reading from the file specified by Path.
SubLayers	public	List of sublayers belonging to the layer.
SubType	public	Subtype flags describing the layer role within a layer hierarchy.
SupportsAsync	public	Indicates whether the layer implements asynchronous operations.
SupportsAutoStyle	public	Indicates whether the layer supports auto styling.
SupportsTiledPaint	public	Indicates whether the layer supports tiled paint.
Tag	public	Tag has no predefined meaning.
TagInternal	public	TagInternal has no predefined meaning.
TagPointer	public	TagPointer has no predefined meaning.
Tileable	public	True if the layer is currently being printed or exported using tiles.
TiledDrawMode	public	Indicates whether the layer is currently being drawn by the tiler.
Transform	public	Custom coordinate transformation applied to the layer.
Transparency	public	Transparency value for the layer (0..100).
UnSupportedOperations	public	Set of operations not supported by the layer.
UseConfig	public	True if the configuration file is active.
UserObject	public	Associates a user-defined object with the layer.
Viewer	public	Reference to the viewer that owns or displays this layer.
ZOrder	public	Layer position relative to all other layers.
ZOrderEx	public	Layer position relative to other visible layers.

Events

Inherited Protected

Name	Visibility	Description
BusyEvent	public	Fired regularly during long-running operations.
PaintLayerEvent	public	Fired during layer painting.
PasswordEvent	public	Fired when opening a layer to resolve username/password values as key/value pairs.
ReadEvent	public	Fired on each file read request.
WriteEvent	public	Fired on each file write request.

Remarks

PURPOSE: Provides the abstract base implementation for GIS layers, including lifecycle management, rendering support, coordinate-system handling, configuration, and sublayer hierarchy.

BEHAVIOR: The class manages common layer state such as path, viewer association, extents, styling parameters, locking, dormant mode, and modification tracking. Descendants implement the actual data access and format-specific behavior.

CONSTRAINTS: This class is abstract and cannot provide file access on its own. Use a supported descendant class for a concrete layer implementation.

TatukGIS Developer Kernel

Table of Contents

TGIS_Layer class

Syntax

Inheritance

Constructors

Fields

Methods

Properties

Events

Remarks

References

TatukGIS Developer Kernel

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Table of Contents

TGIS_Layer class

Syntax

Inheritance

Constructors

Fields

Methods

Properties

Events

Remarks

References

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