Some hints about the image loader.

VIPS_FOREIGN_PARTIAL means that the image can be read directly from the

file without needing to be unpacked to a temporary image first.

VIPS_FOREIGN_SEQUENTIAL means that the loader supports lazy reading, but

only top-to-bottom (sequential) access. Formats like PNG can read sets of scanlines, for example, but only in order.

If neither PARTIAL or SEQUENTIAL is set, the loader only supports whole image read. Setting both PARTIAL and SEQUENTIAL is an error.

VIPS_FOREIGN_BIGENDIAN means that image pixels are most-significant byte

first. Depending on the native byte order of the host machine, you may need to swap bytes. See vips_copy().