dpb587 / go-iiif-image-api-v3

Data types and behaviors for the IIIF Image API 3.0 specification.

A package focused on low-level data types and behaviors for the IIIF Image API (v3) specification.

• parsing {region}/{size}/{rotation}/{quality}.{format} parameter values;
• validating parameters against advertised compliance levels, maximums, and extra features;
• resolving relative parameter values against an image profile for absolute pixels;
• converting parameter values to canonical form;
• enumerating region+size based on static size or tile configuration; and
• constructing basic info.json contents.

This package does not perform image processing. Resolved parameters should typically be used for performing upstream or RPC requests to dedicated image servers.

Learn more from code documentation, examples, or *_test.go files.

Example

The following example is based on examples/parse/main.go. Import the packages...

import (
	iiifimageapi "github.com/dpb587/go-iiif-image-api-v3"
	"github.com/dpb587/go-iiif-image-api-v3/imagerequest"
)

And then use any of the functions necessary to process the request...

// Params are the raw values, typically received as paths of an HTTP request.
var params = imagerequest.RawParams{"pct:25,25,50,50", "max", "90", "color.png"}

// ParseParams extracts typed values from the raw parameters of an image
// request and ensure they are valid values per the specification.
parsedParams, err := imagerequest.ParseRawParams(params)
if err != nil {
  log.Fatalf("parsing params: %v", err)
}

// Resolve validates parameters according to a specific image (e.g. profile/
// feature support, region/size bounds), and converts any relative values into
// an absolute form (e.g. pct:* to pixels, size upscaling, and quality).
resolvedParams, err := parsedParams.Resolve(imagerequest.ResolveOptions{
  ImageInformation: iiifimageapi.ImageInformation{
    Profile: iiifimageapi.ComplianceLevel2Name,
    Width:   3024,
    Height:  4032,
  },
  DefaultQuality: "color",
})
if err != nil {
  log.Fatalf("resolving params: %v", err)
}

// Optionally refer to the canonical form of parameters (per specification).
canonicalParams := resolvedParams.Canonical()

License

MIT License