![]() ![]() The server component only requires the zoom area and the destination size to produce the visible image. ![]() ![]() The digilib scaling image server has used fractional relative coordinates from the beginning both for specifying the visible zoom area and the annotation marks. For example (0.3333, 0.5) specifies a point at (roughly) 1/3 of the width of the image and half the height of the image. Accuracy varies with the length of the decimal fraction. X and Y are decimal fractions between 0 and 1. Fractional relative coordinatesįractional relative coordinates are an image coordinate system where each axis is expressed as a fraction of the length respective side of the original image. The author proposes the use of fractional relative coordinates for scaleable resolution-independent images both as an extension of the Media Fragments syntax and in conjunction with the Well-Known-Text and GeoJSON formats for specifying more complex image regions. ![]() The Media Fragments syntax offers not enough freedom as in its original form it doesn't accomodate resolution-independent coordinats and it only specifies rectangles along coordinate axes while SVG offers too much freedom like polygon as well as path elements and the ability to use different coordinate systems for different elements together with an unwieldy XML-based format. In the section on the use of SVG it recommends the use of only a subset of SVG primitives and coordinate systems and the provision of the SVG as a separate resource or inline XML in the RDF graph. The Open Annotation Data Model proposes to use either Media Fragments or SVG. The status quo for the specification of image regions seems to be W3C Media Fragments that only allow rectangular regions specified in absolute pixels or (integer) percent or the use of SVG that is a full-fledged vector graphics language. The references should be resolution-independent to accomodate devices and user interfaces of different sizes and resolutions and also allow the specification of non-rectangular regions like polygons. The ability to reference image regions is an important part of scholarly electronic publications (HTML, PDF.) and annotation systems. Both projects have expressed strong interests in a common format for interoperable rich image annotations. The author is in close contact with the developers of the Annotorious image annotation tool and the HyperImage image annotation and linking environment. Since 2012 it has a plugin based on Annotator.js for point-like and rectangular server-side annotations. This function is used regularly by scholars in emails and documents. The author is also the main developer of the scaling image server digilib that is used at the MPIWG and by other research institutions and projects for presenting scanned historical documents, drawings, paintings, and other image material.ĭigilib had a simple client-side annotation function that encodes the state of the viewer and a point-like visual mark in a URL from the beginning in 2002. It has led efforts in the development of electronic online sources and research tools like Galileo Galileis Notes on Motion of 1998, ECHO Cultural Heritage Online of 2003 and many other projects on historical sources and cultural heritage. The MPIWG is an active proponent of digital methods in the humanities. Max Planck Institute for the History of Science Perspective on the topic of the workshop Position-paper.html Position paper for W3C Workshop on Annotations ApBetter image area annotations ![]()
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