Size Restrictions
This page provides additional information for the maxWidth and openFullMax properties of Asset.
Summary
Section titled “Summary”The following table summarises the effect of these two properties across all combinations. The numeric values in the example column are illustrative.
| # | Has roles | maxWidth | openFullMax | Open (anonymous) access | Authenticated access | Thumbnails |
|---|---|---|---|---|---|---|
| 1 | No | 0 | 0 | Any region, up to platform limit | N/A | Per policy / up to platform limit |
| 2 | No | 1000 | 0 | Any region, up to 1000px | N/A | Up to 1000px |
| 3 | No | any | >0 | Same as 1 or 2 (field ignored) | N/A | Same as 1 or 2 |
| 4 | Yes | 0 | 0 | None | Any region, up to platform limit | None |
| 5 | Yes | 1000 | 0 | None | Any region, up to 1000px | None |
| 6 | Yes | 0 | 400 | /full/ up to 400px | Any region, up to platform limit | Up to 400px |
| 7 | Yes | 1000 | 400 | /full/ up to 400px | Any region, up to 1000px | Up to 400px |
No roles
Section titled “No roles”When an image has no roles, openFullMax is ignored. Only maxWidth has any effect.
1. No roles, maxWidth=0, openFullMax=0
Section titled “1. No roles, maxWidth=0, openFullMax=0”Anyone can request any region up to the platform-imposed limit (platform-configured, 5000px by default). This includes upscaling.
The platform maxWidth is added to the info.json automatically.
Thumbnails are created according to the thumbnail policy, limited only by the image size itself (or the system limit if reached).
2. No roles, maxWidth=1000, openFullMax=0
Section titled “2. No roles, maxWidth=1000, openFullMax=0”Conforms to IIIF Image API behaviour for maxWidth. The size parameter of any request cannot produce an image exceeding the maxWidth bounding square. When the size parameter is max, the resulting image is confined to the maxWidth bounding box.
Thumbnails are created according to the thumbnail policy, up to the bounding square defined by maxWidth.
3. No roles, openFullMax != 0
Section titled “3. No roles, openFullMax != 0”openFullMax is only meaningful when the image has roles. If the image has no roles, the value is ignored and the behaviour is identical to scenarios 1 or 2, depending on maxWidth. Setting this field when an image has no roles is not an error, as you may vary roles separately.
Has roles
Section titled “Has roles”When an image has roles, the iiif-img delivery channel provides a probe service and related IIIF Auth services. The behaviour for open and authenticated access depends on the combination of maxWidth and openFullMax.
4. Has roles, maxWidth=0, openFullMax=0
Section titled “4. Has roles, maxWidth=0, openFullMax=0”The image service has a probe and related IIIF Auth services. Only users with one or more of the image’s roles can see any pixels.
An authorised user with a role can make requests up to the platform limit.
No thumbnails are produced, whatever the policy.
5. Has roles, maxWidth=1000, openFullMax=0
Section titled “5. Has roles, maxWidth=1000, openFullMax=0”The image service has a probe and related IIIF Auth services. Only users with one or more of the image’s roles can see any pixels.
An authorised user with a role can make requests up to the maxWidth limit (1000px).
No thumbnails are produced, whatever the policy.
6. Has roles, maxWidth=0, openFullMax=400
Section titled “6. Has roles, maxWidth=0, openFullMax=400”The image service has a probe and related IIIF Auth services.
Any user, including anonymous, can see /full/ region requests that fit within the bounding square defined by openFullMax (400px). Only users with one or more of the image’s roles can see non-full regions or sizes larger than openFullMax.
An authorised user with a role can make requests up to the platform limit (as maxWidth is 0).
Thumbnails are created according to the thumbnail policy, up to the bounding square defined by openFullMax (400px).
7. Has roles, maxWidth=1000, openFullMax=400
Section titled “7. Has roles, maxWidth=1000, openFullMax=400”The image service has a probe and related IIIF Auth services.
Any user, including anonymous, can see /full/ region requests that fit within the bounding square defined by openFullMax (400px). Only users with one or more of the image’s roles can see non-full regions or sizes larger than openFullMax.
An authorised user with a role can make requests up to maxWidth (1000px).
Thumbnails are created according to the thumbnail policy, up to the bounding square defined by openFullMax (400px), or maxWidth if lower (unlikely in practice, but not an error).