Provides access to members that control pixel reading and writing from a RasterBand.
Members
| Name | Description | |
|---|---|---|
 |
AcquireCache | Gets reference to edit cache. |
|
CreatePixelBlock | Allocates a PixelBlock of size requested and type of this band. |
 |
NumCacheRefs | Number of outstanding cache references |
|
Read | Read a block of pixels starting from tlc (top left corner). |
|
ReturnCache | Restores edit cache to previous state. |
|
Write | Write a block of pixels starting from tlc (top left corner). |
IRawPixels.AcquireCache Method
Gets reference to edit cache.
Public Function AcquireCache ( _
) As Object
public object AcquireCache (
);
IRawPixels.CreatePixelBlock Method
Allocates a PixelBlock of size requested and type of this band.
Public Function CreatePixelBlock ( _
ByVal Size As IPnt _
) As IPixelBlock
public IPixelBlock CreatePixelBlock (
IPnt Size
);
Remarks
CreatePixelBlock method only initializes the properties of a pixel block, such as dimension, pixel type etc. Read method of this interface should be used to read pixels into the pixel block.
IRawPixels.NumCacheRefs Property
Number of outstanding cache references.
Public ReadOnly Property NumCacheRefs As Integer
public int NumCacheRefs {get;}
IRawPixels.Read Method
Read a block of pixels starting from tlc (top left corner).
Public Sub Read ( _
ByVal tlc As IPnt, _
ByVal pxls As IPixelBlock _
)
public void Read (
IPnt tlc,
IPixelBlock pxls
);
IRawPixels.ReturnCache Method
Restores edit cache to previous state.
Public Function ReturnCache ( _
ByVal cache As Object _
) As Integer
public int ReturnCache (
object cache
);
IRawPixels.Write Method
Write a block of pixels starting from tlc (top left corner).
Public Sub Write ( _
ByVal tlc As IPnt, _
ByVal pxls As IPixelBlock _
)
public void Write (
IPnt tlc,
IPixelBlock pxls
);
Classes that implement IRawPixels
| Classes | Description |
|---|---|
| RasterBand | A representation of a single band of a raster dataset on disk. |
Remarks
When using a PixelBlock created by the RasterBand coclass, use only the first plane because the RasterBand is a single band. All formats can be read using this technique, but only GRID, TIFF, Imagine, BIL, BIP, and BSQ formats can be written. Reading the PixelBlock from the band completes the initialization of the PixelBlock and should be done before writing to the band.
The Read method reads a block of pixels into the input PixelBlock object. The data is read beginning at a specified pixel location. This pixel location is the offset from the top-left corner of the image, represented by (0,0), and increases down and to the right.
The Write method outputs the contents of a PixelBlock to the RasterBand. The PixelBlock is written to an area in the band specified by its top-left corner in the same pixel coordinate space used by the Read method. If transactioning is enabled, this write is persisted temporarily to a memory cache that allows undo support; otherwise, the data is persisted directly to disk at this time.
The AcquireCache and ReturnCache methods control a cache within the band object that allows the transactioning mechanism used by the RasterBand to be activated.