HeaderDecoder Class Members
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The following tables list the members exposed by HeaderDecoder.
Public Constructors
| Name | Description |
| HeaderDecoder Constructor | Creates a HeaderDecoder instance and read in two passes the main header of the codestream. The first and last marker segments shall be respectively SOC and SOT. |
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Public Fields
| Name | Description |
| CRG_FOUND | Flag bit for CRG marker segment found |
| mainHeadOff | The offset of the main header in the input stream |
| nTileParts | The number of tile parts in each tile |
| OPT_PREFIX | The prefix for header decoder options: 'H' |
| PPM_FOUND | Flag bit for SOD marker segment found |
| PPT_FOUND | Flag bit for SOD marker segment found |
| SOD_FOUND | Flag bit for SOD marker segment found |
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Public Properties
| Name | Description |
| CbULX | Returns the horizontal code-block partition origin.Allowable values are 0 and 1, nothing else. |
| CbULY | Returns the vertical code-block partition origin. Allowable values are 0 and 1, nothing else. |
| DecoderSpecs | Return the DecoderSpecs instance filled when reading the headers |
| ImgHeight | Returns the image height in the reference grid. |
| ImgULX | Return the horizontal upper-left coordinate of the image in the reference grid. |
| ImgULY | Return the vertical upper-left coordinate of the image in the reference grid. |
| ImgWidth | Returns the image width in the reference grid. |
| MaxCompImgHeight | Return the maximum height among all components |
| MaxCompImgWidth | Return the maximum width among all components |
| NomTileHeight | Returns the nominal width of the tiles in the reference grid. |
| NomTileWidth | Returns the nominal width of the tiles in the reference grid. |
| NumComps | Returns the number of components in the image. |
| NumFoundMarkSeg | Returns the number of found marker segments in the current header. |
| NumTiles | Return the number of tiles in the image |
| ParameterInfo | Returns the parameters that are used in this class. It returns a 2D String array. Each of the 1D arrays is for a different option, and they have 3 elements. The first element is the option name, the second one is the synopsis and the third one is a long description of what the parameter is. The synopsis or description may be 'null', in which case it is assumed that there is no synopsis or description of the option, respectively. |
| TileOfTileParts | Sets the tile of each tile part in order. This information is needed for identifying which packet header belongs to which tile when using the PPM marker. |
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Public Methods
| Name | Description |
| checkMarkerLength | Checks that the marker segment length is correct. |
| createChannelDefinitionMapper | Creates and returns the ChannelDefinitonMapper which maps the input channels to the channel definition for the appropriate colorspace. |
| createColorSpaceMapper | Creates and returns the EnumeratedColorSpaceMapper corresponding to the information read from the JP2 image file via the ColorSpace parameter. |
| createDequantizer | Returns the dequantizer parameters. Dequantizer parameters normally are the quantization step sizes, see DequantizerParams. |
| createEntropyDecoder | Creates and returns the entropy decoder corresponding to the information read from the codestream header and with the special additional parameters from the parameter list. |
| createPalettizedColorSpaceMapper | Creates and returns the PalettizedColorSpaceMapper which uses the input samples as indicies into a sample palette to construct the output. |
| createResampler | Creates and returns the Resampler which converts the input source to one in which all channels have the same number of samples. This is required for colorspace conversions. |
| createROIDeScaler | Creates and returns the ROIDeScaler corresponding to the information read from the codestream header and with the special additional parameters from the parameter list. |
| extractTilePartMarkSeg | This method extracts a marker segment in a tile-part header and stores it into a byte buffer for the second pass. The marker is first recognized, then its flag is activated and, finally, its content is buffered in an element of byte arrays accessible thanks to a hashTable. If a marker segment is not recognized, it prints a warning and skip it according to its length. |
| getCompSubsX | Returns the component sub-sampling factor, with respect to the reference grid, along the horizontal direction for the specified component. |
| getCompSubsY | Returns the component sub-sampling factor, with respect to the reference grid, along the vertical direction for the specified component. |
| getOriginalBitDepth | Returns the original bitdepth of the specified component. |
| getPackedPktHead | Return the packed packet headers for a given tile. |
| getPPX | Returns the precinct partition width for the specified tile-component and resolution level. |
| getPPY | Returns the precinct partition height for the specified tile-component and resolution level. |
| getTilingOrigin | Returns the tiling origin, referred to as '(Px,Py)' in the 'ImgData' interface. |
| isOriginalSigned | Returns true if the original data of the specified component was signed. If the data was not signed a level shift has to be applied at the end of the decompression chain. |
| precinctPartitionUsed | Returns the boolean used to know if the precinct partition is used |
| readFoundTilePartMarkSeg | Retrieves and reads all marker segments previously found in the tile-part header. |
| resetHeaderMarkers | Method that resets members indicating which markers have already been found |
| ToString | Print information about the current header. |
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See Also