api:dk11:delphi:gislayerpixel.tgis_layerpixel.lockpixels_tgis_extent_tgis_cscoordinatesystem_double_boolean
Table of Contents
TGIS_LayerPixel.LockPixels(TGIS_Extent; TGIS_CSCoordinateSystem; Double; Boolean) method
DK11 for Delphi | GisLayerPixel.TGIS_LayerPixel.LockPixels | Overloads | Constructors | Fields | Methods | Properties | Events
Locks a fragment of the pixel layer for updating.
Syntax
// Delphi public function LockPixels( const _ext : TGIS_Extent; const _cs : TGIS_CSCoordinateSystem; const _pixelsize : Double; const _writable : Boolean ) : TGIS_LayerPixelLock; overload; virtual;
// C++ Builder public: virtual TGIS_LayerPixelLock* LockPixels( TGIS_Extent* const _ext, TGIS_CSCoordinateSystem* const _cs, const double _pixelsize, const bool _writable ) /* overload */;
Parameters
| Name | Type | Description |
|---|---|---|
| _ext | TGIS_Extent | area to be locked; if bigger then layer extent then will be truncated to layer extent |
| _cs | TGIS_CSCoordinateSystem | coordinate system of _cs; if nil then same as layer CS |
| _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 |
| _writable | Boolean | if true than layer will post back any changes in locked area; if write is not possible then TGIS_LayerPixelLock.Writable will be set accordingly |
Result
| Type | Description |
|---|---|
| TGIS_LayerPixelLock | locked area |
Remarks
Must be paired with UnlockPixels.
To speed-up operation, the function can return a larger area than requested. Use Bounds property of result value to obtain actual scope.
References
2023/02/22 01:15