Estimated 'support level' for a given file path, where support level is a summary of the likelihood that
pixel values and metadata will be returned correctly and in a way that achieves good performance.
The support level should be a value between 0 and 4. The following is a guide to its interpretation:
- 4 - 'ideal' support, e.g. the image was written by the library behind the ImageServer
- 3 - good support
- 2 - unknown support, i.e. worth a try
- 1 - partial/poor support, i.e. there are known limitations and all higher-scoring possibilities should be tried first
- 0 - no support
The use of floating point enables subclasses to make more subtle evaluations of performance, e.g. if an ImageServer
is particularly strong for RGB images, but falls short of guaranteeing ideal performance.
In practice, this is used by the ServiceLoader to rank potential ImageServerProviders so that the 'best' ones
are tried first for new image paths. The ServiceLoader will not attempt to create the ImageServer if the support level is 0.