Method

VipsImagelinecache

Declaration [src]

int
vips_linecache (
  VipsImage* in,
  VipsImage** out,
  ...
)

Description [src]

This operation behaves rather like vips_copy() between images in and out, except that it keeps a cache of computed scanlines.

The number of lines cached is enough for a small amount of non-local access.

Each cache tile is made with a single call to vips_region_prepare().

When the cache fills, a tile is chosen for reuse. If access is VipsAccess, then the least-recently-used tile is reused. If access is VipsAccess, then the top-most tile is reused. access defaults to VipsAccess.

tile_height can be used to set the size of the strips that vips_linecache() uses. The default is 1 (a single scanline).

Normally, only a single thread at once is allowed to calculate tiles. If you set threaded to TRUE, vips_linecache() will allow many threads to calculate tiles at once and share the cache between them.

::: tip “Optional arguments” * access: VipsAccess, hint expected access pattern * tile_height: gint, height of tiles in cache * threaded: gboolean, allow many threads

::: seealso vips_tilecache().

Parameters

`out`	`VipsImage`
	Output image.
	The argument will be set by the function.
	The instance takes ownership of the data, and is responsible for freeing it.
`...`	`none`
	`NULL`-terminated list of optional named arguments.

Return value

Returns:	`int`
	0 on success, -1 on error.