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TIFFReadEncodedTile − read and decode a tile of data from an open TIFF file |
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#include <tiffio.h> int TIFFReadEncodedTile(TIFF *tif, u_long tile, u_char *buf, u_long size) |
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Read the specified tile of data and place up to size bytes of decompressed information in the (user supplied) data buffer. |
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The value of tile is a ‘‘raw tile number.’’ That is, the caller must take into account whether or not the data are organized in separate planes (PlanarConfiguration=2). TIFFComputeTile automatically does this when converting an (x,y,z,sample) coordinate quadruple to a tile number. To read a full tile of data the data buffer should be at least as large as the value returned by TIFFTileSize. The library attempts to hide bit- and byte-ordering differences between the image and the native machine by converting data to the native machine order. Bit reversal is done if the FillOrder tag is opposite to the native machine bit order. 16- and 32-bit samples are automatically byte-swapped if the file was written with a byte order opposite to the native machine byte order, |
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The actual number of bytes of data that were placed in buf is returned; TIFFReadEncodedTile returns −1 if an error was encountered. |
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All error messages are directed to the TIFFError(3TIFF) routine. |
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TIFFOpen(3TIFF), TIFFReadRawTile(3TIFF), TIFFReadTile(3TIFF), libtiff(3TIFF) Libtiff library home page: http://www.remotesensing.org/libtiff/ |