LOADFILEOPTION

typedef struct _LOADFILEOPTION 
{ 
   L_UINT uStructSize; 
   L_INT XResolution; 
   L_INT YResolution; 
   L_UINT Flags; 
   L_INT Passes; 
   L_INT PageNumber; 
   L_UINT GlobalLoop; 
   L_IFDTYPE IFD; 
   L_UINT uRedScan; 
   L_UINT uGreenScan; 
   L_UINT uBlueScan; 
   L_UINT Flags2; 
   L_VOID *pFilterData; 
   L_SIZE_T uFilterDataSize; 
   L_INT nFilter; 
   L_INT nAttachment; 
} LOADFILEOPTION, * pLOADFILEOPTION; 

The LOADFILEOPTION structure specifies options for reading or writing an image file.

Members

uStructSize

Size of the LOADFILEOPTION structure. This should be sizeof(LOADFILEOPTION). You must fill this member.

XResolution

Horizontal dots per inch. (Used only with LBitmapBase::Initialize.)

YResolution

Vertical dots per inch. (Used only with LBitmapBase::Initialize.)

Flags

Any of the following flags. (You can use a bitwise OR to specify more than one value.)

Passes

The number of passes (scans through the image) when loading or saving a progressive JPEG or LEAD CMP file. (This value is also used when loading, but not when saving, interlaced PNG files.) (This value is also used when loading JBIG files to determine the number of resolutions to load to create a progressive load effect.)

Possible values when loading a progressive file:

PageNumber

The page number of a multipage file, which can contain more than one image. When loading a file, this is the exact page number. When saving a file, any value greater than 1 will cause the page to be appended to the end of the file. For more information on multipage files refer to Multipage File Formats.

GlobalLoop

Loop count when playing an animation. Use 0 for continuous looping. For no looping, turn off the EFO_GLOBALLOOP flag in the Flags field.

IFD

Offset within a TIFF file where a page starts. This serves as a reference page for loading pages to a large TIFF file.

uRedScan

(NITF only) Index of the scan to be loaded for the red component. Used only if ELO_MULTISPECTRALSCAN is set.

uGreenScan

(NITF only) Index of the scan to be loaded for the green component. Used only if ELO_MULTISPECTRALSCAN is set.

uBlueScan

(NITF only) Index of the scan to be loaded for the blue component. Used only if ELO_MULTISPECTRALSCAN is set.

Flags2

Any of the following flags. (You can use a bitwise OR to specify more than one value.)

nAttachment

1-based attachment number to load.

Comments

pLOADFILEOPTION is a pointer to an LOADFILEOPTION structure. Where the function parameter type is pLOADFILEOPTION, you can declare a LOADFILEOPTION variable, update the structure's fields, and pass the variable's address in the parameter. Declaring a pLOADFILEOPTION variable is necessary only if your program requires a pointer.

To load a stamp image, you must use the LFile::ReadStamp function.

If EFO_SIGNED is set, the bitmap can contain negative pixel values. This can cause the image to be incorrectly painted when it is loaded. In order to load correctly, you must call LBitmapBase::ClearNegativePixels before loading the image. If EFO_SIGNED is not set, any negative pixels in the image will be cleared internally.

NOTES:

• When loading JBIG files, the behavior is as follows:

  1) If only one resolution exists in the JBIG File, then the LFile::LoadFileCallBack function will be called with the image data for that resolution as it is decompressed.

  2) If the image contains more than one resolution and (Passes >= nResolutions, where nResolutions is the number of resolutions present in the file) then the LFile::LoadFileCallBack function will be called with the image data from the lowest resolution available in the file. The data that gets passed to the callback and/or inserted into the bitmap handle will be padded to the remaining width (that is, the size of the last resolution available in the file) with 0s. This will be repeated nResolution times, until the entire image (that is, the last resolution available) is loaded. Setting nPasses to CALLBACK_WHEN_MEANINGFUL or CALLBACK_ALWAYS has the same effect.

  3) If the image contains more than one resolution and (Passes is < nResolutions) then the process is the same as in case 2, except loading starts with the first resolution available, continues with the 2nd resolution, and so on, up to resolution Passes-1, and then loading is completed with the decompression of the last resolution available in the file.

• For information about loading and saving large TIFF files faster, refer to Loading and Saving Large Tiff/BigTIFF Files.

ELO_MULTISPECTRALSCAN is used internally by the NITF filter. You do not need to use this flag.

For an information on default load options, refer to LBaseFile::GetDefaultLoadFileOption

The structure is used by:

• LAnnContainer::Load
• LAnnContainer::LoadOffset
• LFile::ExtractAttachment
• LFile::ReadLoadResolutions
• LFile::FileConvert
• LFile::GetCommentSize
• LFile::GetInfo
• LFile::Load
• LFile::LoadBitmapList
• LFile::LoadFile
• LFile::LoadLayer
• LFile::LoadTile
• LFile::LoadOffset
• LFile::ReadComment
• LFile::ReadCommentExt
• LFile::ReadFileAttachments
• LFile::ReadFileTransforms
• LFile::ReadTag
• LFile::ReadStamp
• LFile::StartFeedLoad
• LFileSettings::GetLoadResolution
• LMemoryFile::GetInfo
• LMemoryFile::Load
• LMemoryFile::LoadMemory
• LMemoryFile::LoadMemoryTile
• LMemoryFile::ReadComment
• LMemoryFile::ReadTag