DK11 for Delphi | GisLayerPixel.TGIS_LayerPixel.Loop | Overloads | Constructors | Fields | Methods | Properties | Events
Prepares enumerator to iterate the layer (pixels are treated as points).
// Delphi public function Loop( const _extent : TGIS_Extent; const _pixelsize : Double; const _band : Integer; const _writable : Boolean ) : TGIS_LayerPixelEnumeratorFactory; overload; virtual;
// C++ Builder public: virtual TGIS_LayerPixelEnumeratorFactory* Loop( TGIS_Extent* const _extent, const double _pixelsize, const int _band, const bool _writable ) /* overload */;
Name | Type | Description |
---|---|---|
_extent | TGIS_Extent | extent of items to be found; expected _extent units are in a Layer coordinate space |
_pixelsize | Double | minimum requested size of image pixel; by providing 0 a maximum possible resolution will be used, which is also a fastest method if a layer is full in-memory because in such situation a pointer to existing memory will be used |
_band | Integer | band specification
|
_writable | Boolean | if true than layer will post back any changes in locked area; if write is not possible then TGIS_PixelItem.Writable will be set accordingly |
Type | Description |
---|---|
TGIS_LayerPixelEnumeratorFactory | Pixel item returned row by row, column by column. |
_pixelsize
By providing _pixelsize=0, a native layer resolution is requested. This is also the fastest method if a layer is fully in-memory because, in such situation, a pointer to existing memory is used
General way to query for terrain profile:
foreach (TatukGIS.NDK.TGIS_PixelItem px in lp.Loop(0, line, false)) { Memo.AppendText( String.Format("Distance: {0}, Height:{1}\r\n", px.Distance, px.Value) ); }
General way to query for pixels within polygon and modifying value:
foreach (TGIS_PixelItem px in lp.Loop(polygon.Extent, 0, polygon, "T", true)) { px.Color = TGIS_Color.Red; }