Member

Description

nSize

Size of this structure.

bUseColorTransform

Flag that indicates whether to convert an RGB image to YUV space before compressing. (YUV space provides greater compression with higher image quality.) Possible values are:

Value

Meaning

TRUE

Convert to YUV space before compressing. (Default)

FALSE

Do not convert to YUV space before compressing.

bDerivedQuantization

Flag that indicates whether to use derived quantization or expounded quantization. Possible values are:

Value

Meaning

TRUE

Use derived quantization.

FALSE

Use expounded quantization.

uCompressionControl

Flag that indicates how to determine the resulting compression. The value of this members determines which structure member should be used for determining the compression. Possible values are:

Value

Meaning

J2K_COMPRESSION_LOSSLESS

Lossless compression.

J2K_COMPRESSION_RATIO

Compress the file based on the value of the fCompressionRatio member.

J2K_COMPRESSION_TARGETSIZE

Compress the file based on the target file size in the uTargetFileSize member.

J2K_COMPRESSION_QFACTOR

Compress the file based on the quality factor used by the SaveXXX function.

fCompressionRatio

Value that indicates the compression ratio to use. This value is used only if the uCompressionControl member is set to J2K_COMPRESSION_RATIO.

uTargetFileSize

Value that indicates the size of the target file, in bytes. This value is used only if the uCompressionControl member is set to J2K_COMPRESSION_TARGETSIZE.

uXOsiz

Horizontal offset from the origin of the reference grid to the left side of the image area.

uYOsiz

Vertical offset from the origin of the reference grid to the top of the image area.

uXTsiz

Width of one reference tile, with respect to the reference grid.

uYTsiz

Height of one reference tile, with respect to the reference grid.

uXTOsiz

Horizontal offset from the origin of the reference grid to the left side of the first tile.

uYTOsiz

Vertical offset from the origin of the reference grid to the top of the first tile.

uXRsiz

Reserved.

uYRsiz

Reserved.

uDecompLevel

Number of resolution levels in the compressed file. The maximum number of levels depends on the size of the image. Passing values that are too large will cause the save operation to fail. Each resolution level is one-half the size of the previous resolution, starting with the full image resolution. The default value is 5.

uProgressOrder

Indicates the order of progression. Possible values are:

Value

Description

J2K_LAYER_RESOLUTION_COMPONENT_POSITION

[0] Quality–axis order. Image starts out blurry and becomes clearer and more detailed as additional data is decoded.

J2K_RESOLUTION_LAYER_COMPONENT_POSITION

[1] Resolution-axis order. Image starts out small and becomes larger as additional data is decoded. Higher compression ratios achieved by leaving lower resolutions in the file.

J2K_RESOLUTION_POSITION_COMPONENT_LAYER

[2] Resolution-axis order. Image starts out small and becomes larger as additional data is decoded. Higher compression ratios achieved by leaving lower resolutions in the file.

J2K_POSITION_COMPONENT_RESOLUTION_LAYER

[3] Position–axis order. Image starts out as a series of blocks starting from the top left corner. Additional portions of the image become visible as more data is decoded. Image data stored by spatial location.

J2K_COMPONENT_POSITION_RESOLUTION_LAYER

[4] Color-axis order. Image starts out gray. Color is added as more data is decoded. Image data stored by color channel, starting with channel Y, then U, then V. If the transform to YUV option is used, the lowest decompressed image level for RGB is grayscale. Otherwise, the output is only the red channel.

nCodBlockWidth

Width of the code block, following wavelet transformation. The value must be a power of 2. It must be at least 4 and less than or equal to 1024.

nCodBlockHeight

Height of the code block, following wavelet transformation. The value must be a power of 2. It must be at least 4 and less than or equal to 1024.

CodBlockStyleFlags

Bit flags that indicate the behavior of the code block. For more information, refer to the CODBLOCKSTYLE structure.

uGuardBits

Number of extra bits to consider when encoding an image. This prevents coding overflow. Possible values are 0 - 7. The default is 2.

nDerived_Base_Mantissa

The base mantissa used for derived quantization.

nDerived_Base_Exponent

The base exponent used for derived quantization.

bUse_SOP_Marker

Flag that indicates whether to use the SOP marker. Possible values are:

Value

Meaning

TRUE

Use the SOP marker.

FALSE

Do not use the SOP marker. (Default)

bUse_EPH_Marker

Flag that indicates whether to use the EPH marker. Possible values are:

Value

Meaning

TRUE

Use the EPH marker.

FALSE

Do not use the EPH marker. (Default)

bUseROI

Flag that indicates whether to use a region of interest. Possible values are:

Value

Meaning

TRUE

Use a region of interest as specified in the uROIControl member.

FALSE

Do not use a region of interest. If you do not want to use a region of interest, set this to FALSE. Otherwise, there may be a significant compression and speed performance loss.

fROIWeight

Reserved for future use.

rcROI

RECT structure that contains the boundaries of the region of interest within the image.

uROIControl

Flag that indicates the region of interest to use. For a list of possible values refer to J2KREGIONOFINTEREST.

Value

Meaning

J2K_USE_OPTION_RECT

Use the rectangle specified in the rcROI member of the FILEJ2KOPTIONS structure to define the region of interest.

J2K_USE_LEAD_REGION

Use the LEAD bitmap region to define the region of interest. (Any region shape is acceptable; it will be converted internally by the filter to a rectangle.)