The cache module

Cache logic.

class ImageEntry(image)

Bases: object

class ImageCache

Bases: object

Cache generated images.

Store and retrieve them under a key (see render.Renderer.key()).

maxsize = 209715200

currentsize = 0

clear()

Remove all cached images.

invalidate(page)

Clear cache contents for the specified page.

tileset(key)

Return a dictionary with tile-entry pairs for the key.

If no single tile is available, an empty dict is returned.

prepare(tiles)

Make room before rendering new tiles.

This ensures there is space for the new tiles by adjusting the cache size and/or purging older images as needed.

addtile(key, tile, image)

Add image for the specified key and tile.

purge(reservedsize=0)

Purge old images if needed.

At least reservedsize bytes will remain available.

closest(key)

Iterate over suitable image tilesets but with a different size.

Yields (width, height, tileset) tuples.

This can be used for interim display while the real image is being rendered.