Images & tiles¶

iiisight’s tile-aware Image API support is one of its two capabilities that exist nowhere else in Python (async fetching is the other). Given a manifest’s image service, it loads info.json, builds spec-correct URLs, and computes the tile grid — handling the v2/v3 differences for you.

Loading an image service¶

A Canvas.image_service carries only what the manifest embedded (usually an id and profile). To get tiles and sizes, fetch its info.json with load_info() — an explicit network call:

Async

async with iiisight.AsyncClient() as client:
    manifest = await client.fetch_manifest(url)
    service = await client.load_info(manifest.canvases[0])   # or pass an ImageService
    print(service.width, service.height, service.compliance_level, service.loaded)

Sync

with iiisight.Client() as client:
    manifest = client.fetch_manifest(url)
    service = client.load_info(manifest.canvases[0])
    print(service.width, service.height, service.compliance_level, service.loaded)

Building URLs¶

url() assembles an Image API URL. size="max" is emitted as full for a v2 service and max for a v3 one — the most common v2/v3 footgun, handled automatically.

service.url()                                          # full / max region+size
service.url(region="0,0,100,100", size="100,")         # a specific region
service.url(rotation="90", quality="gray", fmt="png")
service.thumbnail_url(width=400)                        # prefers an advertised size

Computing tiles¶

tile_grid() enumerates the tile requests covering the whole image at a given scale factor, with correct edge-tile clamping. Each Tile has region, size, and a ready-to-fetch url.

for tile in service.tile_grid(scale_factor=4):
    print(tile.region, tile.size, tile.url)

all_tiles = service.tile_pyramid()   # every advertised scale factor

Requesting a scale factor the service does not advertise raises UnknownScaleFactor; calling tile_grid before load_info raises ImageServiceNotLoaded.

Fetching image bytes¶

data = await client.fetch_region(service, region="0,0,512,512", size="256,")
# sync: data = client.fetch_region(service, region="0,0,512,512", size="256,")

Parsing an info.json you already have¶

service = iiisight.parse_info(info_json_dict)   # pure, no I/O