kdu_image_in::get

Retrieves a new tile-line from the image component identified by comp_idx, or returns false if the input file is exhausted.

x_tnum must hold the horizontal tile index (starting from 0). This is used to determine how much of each line has already been read and so control internal line buffering. We leave line buffering to the image reading object itself, since it knows the smallest amount of memory which can actually be buffered; however, to simplify line buffering, we insist on the following rules which should not prove burdensome:

• For each line, tiles should be read from left to right;
• The number of tiles read from earlier lines should be at least as large as the number of tiles read from later lines; and
• When multiple components are managed by the same object, all components should be read for a given tile within a given line before moving to the next tile of that line and the components should be read in order.
• It can happen that some tiles have no samples whatsoever. For safety, these tiles should still be read from the get function.

Sample values in the line buffer are always signed quantities. For normalized (floating or fixed point) sample values, the nominal range is from -0.5 to 0.5, while for absolute integer values, the range is from -2^{B-1} to 2^{B-1}, where B is the bit-depth. The function takes care of renormalizing, and conversion between signed and unsigned data types.

comp_idx [int]

line [kdu_line_buf &]

x_tnum [int]