ome::files::TileCoverage Class Reference

Tile coverage cache. More...

#include <ome/files/TileCoverage.h>

Classes
class	Impl
	Internal implementation details of TileCoverage. More...

Public Member Functions
	TileCoverage ()
	Constructor.
virtual	~TileCoverage ()
	Destructor.
bool	insert (const PlaneRegion &region, bool coalesce=true)
	Insert a region into the coverage cache. More...
bool	remove (const PlaneRegion &region)
	Remove a region from the coverage cache. More...
dimension_size_type	size () const
	Get the number of separate regions in the coverage cache. More...
void	clear ()
	Clear the coverage cache of all covered regions.
dimension_size_type	coverage (const PlaneRegion &region) const
	Covered area within the region. More...
bool	covered (const PlaneRegion &region) const
	Check if a region is completely covered. More...

Protected Attributes
std::shared_ptr< Impl >	impl
	Private implementation details.

Detailed Description

Tile coverage cache.

Cache and query covered 2D regions. Regions are stored in an R*Tree as half-open ranges of [x1,y1..x2,y2). This may be used, for example, to prevent writing out incomplete tiles and to output tiles in order when used with an accompanying tile cache.

Member Function Documentation

coverage()

dimension_size_type ome::files::TileCoverage::coverage

(

const PlaneRegion &

region

)

const

Covered area within the region.

This is the sum of all covered areas within the specified region. If the area is completely covered, this value will equal the area of the specified region.

Parameters

region

the region to check.

Returns

the covered area.

References ome::files::PlaneRegion::area(), impl, and ome::files::PlaneRegion::valid().

Referenced by covered(), and insert().

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covered()

bool ome::files::TileCoverage::covered

(

const PlaneRegion &

region

)

const

Check if a region is completely covered.

Parameters

region

the region to check.

Returns

true if completely covered, false otherwise.

References coverage(), ome::files::PlaneRegion::h, and ome::files::PlaneRegion::w.

insert()

bool ome::files::TileCoverage::insert	(	const PlaneRegion &	region,
		bool	coalesce = true
	)

Insert a region into the coverage cache.

The insert will only succeed if the region is completely uncovered. That is, it must not overlap with any currently covered region in the cache.

Region coalescing is enabled by default because the overhead of merging adjacent regions is much less than the cost of searching the cache with thousand of tiles. If filling the cache with aligned tiles of the same size in a consistent order, this should result in a very low region count (less than 5) and hence lookups will be very fast. It will be necessary to disable coalescing if the regions will subsequently be removed, since region splitting is not implemented.

Parameters

region	the region to insert.
coalesce	true to merge with adjacent tiles, or false to ensure the region is kept separated.

Returns

true if the region was inserted, or false if not inserted.

References coverage(), impl, and ome::files::PlaneRegion::valid().

remove()

bool ome::files::TileCoverage::remove

(

const PlaneRegion &

region

)

Remove a region from the coverage cache.

A separate region of the exact size of the specified region must exist in the coverage cache or else removal will fail. Disable coalescing if it is preventing removal due to merging adjacent tiles.

Parameters

region

the region to remove.

Returns

true if the region was removed, or false if not removed.

References impl.

size()

dimension_size_type ome::files::TileCoverage::size

(

)

const

Get the number of separate regions in the coverage cache.

Returns

the number of separate regions.

References impl.

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The documentation for this class was generated from the following files:

• ome/files/TileCoverage.h
• ome/files/TileCoverage.cpp