zooui.tilesystem.tileproviders.statictileprovider module

Class for loading tiles from the local tilestore.

class zooui.tilesystem.tileproviders.statictileprovider.StaticTileProvider(tilecache)

Bases: TileProvider

Constructor :

StaticTileProvider(tilecache)

Parameters :

tilecache : TileCache

StaticTileProvider(tilecache) –> StaticTileProvider

StaticTileProvider objects are used for loading tiles from the disk-cache into a TileCache.

This provider retrieves pre-generated tiles from the local filesystem tilestore. It checks the maximum tile level before attempting to load and returns None if the requested tile does not exist or cannot be loaded.

Implementation Notes:

• Inherits from TileProvider base class

• Uses PIL Image.open() to load tiles from disk

• Validates tilelevel against maxtilelevel metadata

• Returns None for invalid or missing tiles

Static Tile Provider Flow:

┌─────────────────────────┐               |       ┌──────────┐ ┌────────────┐
│ StaticTileProvider      │               |       │ Load     │ │ Try to     │
│ task queue receives     │               |       │ existing │ │ synthesize │
│ tile request            │               |       │ tile     │ │ from lower │
└────────────┬────────────┘               |       │ image    │ │ zoom tiles │
             │                            |       └────┬─────┘ └─────┬──────┘
             ▼                            |            │             │
┌─────────────────────────┐               |            │             ▼
│ Pop request from queue  │               |            │       ┌────────────┐
│ (LIFO - newest first)   │               |            │       │ If synth   │
└────────────┬────────────┘               |            │       │ fails,     │
             │                            |            │       │ load       │
             ▼                            |            │       │ source     │
┌─────────────────────────┐               |            │       │ image      │
│ Check TileStore         │               |            │       └─────┬──────┘
│ get_tile_path()         │               |            └─────┬───────┘
└────────────┬────────────┘               |                  │
             │                            |                  ▼
        ┌────┴────┐                       |    ┌─────────────────────────┐
        │         │                       |    │ Create Tile object      │
    EXISTS    DOESN'T EXIST               |    │ (PIL Image wrapper)     │
        │         │                       |    └────────────┬────────────┘
        ▼         ▼                       |                 │
                                          |                 ▼
                                          |    ┌─────────────────────────┐
                                          |    │ Store in TileCache      │
                                          |    └────────────┬────────────┘
                                          |                 │
                                          |                 ▼
                                          |    ┌─────────────────────────┐
                                          |    │ Save to TileStore       │
                                          |    │ (if not already there)  │
                                          |    └────────────┬────────────┘
                                          |                 │
                                          |                 ▼
                                          |    ┌─────────────────────────┐
                                          |    │ Notify completion       │
                                          |    │ (tile now available)    │
                                          |    └─────────────────────────┘

Constructor :

StaticTileProvider(tilecache)

Parameters :

tilecache : Any

StaticTileProvider(tilecache) –> None

Create a new StaticTileProvider with the given TileCache.

The tilecache parameter is the TileCache instance that this provider will use to store loaded tiles.

_load(tile_id)

Method :

StaticTileProvider._load(tile_id)

Parameters :

tile_id : Tuple[str, int, int, int]

StaticTileProvider._load(tile_id) –> Image or None

Load a tile from the local tilestore.

The tile_id tuple contains (media_id, tilelevel, row, col). This method first validates that the requested tilelevel does not exceed the maximum tilelevel for the media. It then attempts to load the tile from disk using the path provided by TileStore.get_tile_path().

Implementation Notes:

• Checks tilelevel against maxtilelevel metadata

• Returns None if tilelevel exceeds maxtilelevel

• Uses PIL Image.open() to load the tile

• Calls tile.load() to ensure pixel data is loaded

• Returns None on IOError (file not found or unreadable)