EVT 2.0 (evt-viewer)

1 - Introduction

1.1 - About EVT

EVT (Edition Visualization Technology) is a light-weight, open source tool specifically designed to create digital editions from texts encoded according to the TEI XML schemas and Guidelines, freeing the scholars from the burden of web programming and enabling the final users to browse, explore and study digital editions by means of a user-friendly interface.

This tool was born in the context of the Digital Vercelli Book project, in order to allow the creation of a digital edition (which has been available in beta form for more than two years) of the Vercelli Book, a parchment codex of the late tenth century, now preserved in the Archivio e Biblioteca Capitolare of Vercelli and regarded as one of the four most important manuscripts of the Anglo-Saxon period as it regards the transmission of poetic texts in the Old English language. However it has evolved into a tool suitable to fit different texts and needs. For example, it is now being used to publish the digital edition of the Codice Pelavicino manuscript, a medieval codex preserving charters dating back to the XIII century. The continuous development and need to adapt it to different types of documents and TEI-encoded texts has shifted the development focus towards the creation of a more general tool for the web publication of TEI-based digital editions, able to cater for multiple use cases.

The entire structure of the software has been remodeled, in order to make it lighter, more usable and more adaptable; we decided to use the Model View Controller (MVC) approach, that is a very common architectural pattern in object-oriented programming, that allows to separate the logical presentation of the data, from the application logic and the processing core. Wanting to maintain the original feature of EVT, and therefore do not give up the client only approach, we decided to use AngularJS, a JavaScript framework inspired by the MVC programming logic, especially suitable for the development of client-side Web applications; among other things, this framework allows to define custom HTML components and use the data-binding mechanism to associate the model of the data to the UI elements, and manage the updates of the latter avoiding the direct DOM manipulation.

1.2 - How it works

Before the refactoring, EVT was composed of two main units: EVT Builder, for the transformation of the encoded text using special XSLT 2.0 templates, and EVT Viewer, for the visualization into a browser of the results of the transformations and the interaction with them. The idea under the new version of EVT is instead to leave to EVT Viewer the task of reading and parsing with JavaScript functions the encoded text, and “save” as much as possible within a data model, that persists in the client main memory, and is organized in a way that allows a very quick access to the data in case of need. This has obviously led to the elimination of the EVT Builder level, and therefore it allows to open a digital edition directly in the browser without any previous XSLT transformation.

Please note that starting from version 67 Firefox developers adopted the same security-conscious policy chosen by developers of Chrome and other Web browsers, that is forbidding loading local files (= documents available on the user’s computer drive) in the browser as a result of the execution of Javascript programs. The goal is to improve global security when browsing the Web, but the unpleasant collateral effect is that of preventing the loading of digital editions based on EVT, or similar software, from local folders. Fortunately there are several workarounds that can be used to test EVT editions that are located on your hard drive:

• option no. 1: launch Chrome from the command line with the --allow-file-access-from-files parameter, after that you can press CTRL+O to open the index.html file, or you can just drag and drop it on Chrome’s window; this is probably the most simple way to do it;
• option no. 2: download and install Firefox ESR v. 60: this version predates the new security policy adopted in FF v. 67 and, furthermore, it can be installed in parallel with any other version of Firefox;
• option no. 3: install an extension providing a local web server on Firefox or Chrome, f.i. there is [this one] (https://chrome.google.com/webstore/detail/web-server-for-chrome/ofhbbkphhbklhfoeikjpcbhemlocgigb) available for Chrome.

This problem, however, only affects local testing, after the edition has been uploaded on a server there are no problems in accessing it with any of the major browsers.

1.3 - Main features

At the present moment EVT can be used to create critical editions with multiple levels of apparatuses, encoded using [the TEI Parallel Segmentation Method] (http://www.tei-c.org/release/doc/tei-p5-doc/en/html/TC.html#TCAPPS). This means that a transcription encoded according to the Guidelines should already be compatible with EVT 2, or require only minor changes to be made compatible.

Among the main features you will find:

• Critical edition support. Enlarged critical apparatus, sources apparatus and analogues apparatus, variant heat map, witnesses collation and variant filtering are some of the main features developed for the critical edition support.
• Bookmark. Direct reference to the current view of the web application, considering view mode, current document, page and edition level, eventual collated witnesses and selected apparatus entry.
• Named entities and lists of entities.
• Interactive bibliography. User can visualize the bibliography of the edition and reorder the entries by author, publisher or publishing date.
• High level of customization. The editor can customize both the user interface layout and the appearance of the graphical components.

2 - A short guide to EVT

EVT 2 can be used to prepare an edition right away, immediately after installing it on your hard drive: see the Installation and use section first, then Configuration, to understand how EVT works and how you can use it to publish your editions. A more detailed guide will be published separately, as a reference manual, and will also include instructions about customization.

If, on the other hand, you are interested in developing a specific functionality in EVT 2, or in modifying an existing one, we suggest that you download and install the Development framework. The README.md contained in it explains how to install and configure the development framework needed for this purpose. This step is only needed if you want to start working with EVT’s source code, so it is in no way necessary for basic users.

2.1 - Installation and use

Installation is quite simple, download the compressed archive from EVT’s home page, unzip it in a suitable location on your hard drive, and you are ready to use it:

• your encoded edition document must be copied in the data/text directory: EVT comes with a default directory structure, distinguishing between images, text and other types of data, but you can modify it as desired, provided that the appropriate paths are specified in the configuration file (config.json, see below);

• to have it parsed and loaded by EVT you have to point to it explicitly modifying the config.json file in the config directory: "dataUrl": "data/My edition.xml",; note that there are several other configuration options available in that file, so that you can customize the layout and appearance of your edition; also note that some configuration options may be necessary to make desired features available, for instance to add the required edition level, so make sure you read the following section and check the default configuration file.

• optionally, you can add your own CSS instructions to modify the appearance of specific TEI elements by editing the config-style.css file in the config directory. The customization of generic and linear TEI element is very simple, even if EVT does not yet consider them in the default visualization: in fact, the TEI elements which are not handled in any particular way by EVT are always transformed in HTML elements with the TEI tag name as class name. In this way, the customization is very easy: just add a rule that match the tag name of the TEI element to style. F.i., a deletion encoded with del element, can be displayed with a line through the text just by adding the rule .del { text-decoration: line-through; }.

2.2 - Configuration

There are several configuration options, ranging from the folders where edition data is stored to User Interface layout and available tools, that can be set by editing the config.json file in the config directory. Below you will find a detailed list of the available options: in the file you will see a list of options on the left, to configure EVT you will have to insert the appropriate values in the textual fields on the right. Sometimes those values will consist of boolean strings (“true” or “false”), sometimes they will be simple character strings (e.g. "Interpretative edition"), in other cases you will have to enter TEI XML elements (e.g. ", "); for colors it will be necessary to specify the correct RGB values (e.g. "rgb(108, 145, 207)").

If you find this file difficult to read and/or change you can try out the beta EVT2-Config-Generator: upload the current config.json, change the parameters you need to change and download the new config.json. Note that this is the first version of the EVT2 Config tool, so there may be glitches and/or problems, please report them to us.

Main edition data

Edition main information

• indexTitle. Choose a title for your edition. If you leave it blank the default 'EVT Viewer' title will be shown.
• webSite. If you specify an external web site there will be a link pointing to it.
• logoUrl. You can also add a custom logo that will appear before the edition title: just indicate the path to it; it can be a URL or a relative path: we suggest that you put it into data and point to it (f.i. data/icons/myLogo.jpg).

Source files

• dataUrl. Indicate the file name of the XML file of your encoded edition. It can point either to an internal folder or to an external online resource.
• sourcesUrl. Indicate the file name of the XML file encoding the list of all the bibliographic references for the sources apparatus. It can point either to an internal folder or to an external online resource.
• analoguesUrl. Indicate the file name of the XML file encoding the list of all the bibliographic references for the analogues apparatus. It can point either to an internal folder or to an external online resource.
• sourcesTextsUrl. Indicate the folder where you intend to put the XML containing the texts of external sources (if you have any).
• singleImagesUrl. Indicate the folder where you intend to save the edition images, default path is to data/images/single.
• enableXMLdownload. Decide if you want to enable the XML download (true) or not (false).

VisColl files

• visCollTextUrl. Currently unused, please ignore.
• visCollStyleUrl. Currently unused, please ignore.
• visCollSvg. Indicate the folder where you intend to save the SVG images generated by the VisColl XSLT style-sheets, default path is to data/viscoll/SVG/. Note that you have to generate the images using an XSLT 2 processor, such as Saxon 9 (standalone product or within the Oxygen XML editor), and copy them in this folder before publishing the edition.
• visCollImageList. Indicate the path to the XML document holding the list of the manuscript images, default path is to data/viscoll/[name of document]. This document is not in TEI XML format, see VisColl documentation for more information.
• visCollDataModel. Indicate the path to the XML document holding the description of the manuscript quire structure, default path is to data/viscoll/[name of document]. This document is not in TEI XML format, see VisColl documentation for more information, the version required is the data model 2.

View modes

• defaultViewMode. Select which view mode you want to your edition to open on. Note that it must be an active mode!
• availableViewModes. Select which view modes you want to be available in your edition. You can deactivate a view mode either by deleting it or by setting the property visible to false (suggested method).

Edition levels

• defaultEdition. Select which edition level you want your edition to open on. Note that it must be an active edition level!
• showEditionLevelSelector. Decide if you want to display the edition level selector (true) or not false. This parameter is considered only if you select just one edition level: if there are two or more edition levels available, the edition selector will be always visible.
• availableEditionLevel. Select which edition levels you want to be available in your edition. You can deactivate a view mode both by deleting it and by setting to false the property visible (the latter being the suggested method). If you select just one edition level you can choose either to display the selector (with just one item) or not by setting showEditionLevelSelector respectively to true or false.

Edition navigation

• showDocumentSelector. Select if you want to activate (true) or not (false) the document selector, which allows the user to navigate an edition composed by different documents.
• enableNavBar. Select if you want to activate (true) or not (false) the navigation bar at the bottom of the screen.
• initNavBarOpened. If the navigation bar is active (see previous setting), sets its initial status: with true it will be shown when the edition is loaded, with false it will be hidden until the user decides to show it.

Generic tools

• toolPinAppEntries. Select if you want to activate (true) or not (false) the PIN tool, which allows the user to “save” apparatus entries or (named) entities in order to reach them more quickly when you need them.
• toolImageTextLinking. Select if you want to activate (true) or not (false) the Image-Text Linking tool, which allow the user to connect line by line the facsimile to the transcription. You will need to properly encode the zone and their coordinates and have Image-Text among the available view modes. Note that this is still a work-in-progress feature since we are still implementing the EVT 2 image viewer.

Named entities

• namedEntitiesSelector. Select if you want to activate (true) or not (false) the (named) entities selector, which allow the user to highlight on the text one or more specific (named) entitie(s).
• namedEntitiesToHandle. Customize the list of available named entities to be highlighted and to be shown among entities lists, by adding a new element in this list: for each element you should define a tagName, which is the XML tag that identify the entity and a label that will be shown in the selector. If you don’t need an entity that is already inserted in this list you can delete it or just use the property available set to false (suggested choice). Note that EVT can work properly only with persName, placeName and orgName; any other type of entity might cause problems (hopefully not!). If you need a new kind of named entity to be handled just notify the EVT Development Team.
• otherEntitiesToHandle. Customize the list of available entities to be highlighted by adding a new element in this list: for each element you should define a tagName, which is the XML tag that identify the entity, a label that will be shown in the selector and a color that will be used to highlight the entity within the text. If you don’t need an entity that is already inserted in this list you can delete it or just use the property available set to false (suggested choice).

Critical edition

Witnesses

• preferredWitness. Indicate the sigla of your preferred witness; this will be used everywhere if you forgot to encode the lemma for a particular variation of the text.
• skipWitnesses. Indicate the siglas (divided by commas) of witnesses you want to exclude from visualization.
• maxWitsLoadTogether. Maximum number of witnesses which are going to be shown at the same time.

Witnesses Group(s)

• witnessesGroups. If you want, you can divide the readings of all critical apparatus entries into groups. Each group should have a witnesses property (mandatory) that indicates the siglas of witnesses within the group and a groupName (optional) that indicates the name of group to be displayed (f.i. { “groupName”: “Group 1”, “witnesses”: “A, B, B1” }).

Apparatuses

EVT 2 is able to handle multiple levels of apparatuses: critical entries apparatus, sources apparatus and analogues apparatus. In "Reading view", all of them can be available both in inline mode (the apparatus will appear within the text, right after the portion of text to which it is connected) or in a separate box (there will be a container next to the main text where all the entries will be shown and aligned to the text, whenever the user clicks on an entry). By default, all the apparatuses will appear separately from the main text, but you can choose which mode you prefer by setting to true (inline) or false (separate box) the following parameters:

• showInlineCriticalApparatus, for critical apparatus entries;
• showInlineSources, for apparatus of sources;
• showInlineAnalogues, for apparatus of analogues.
• showReadingExponent. Indicate if you want to use alphabetic exponent for critical entries (true) or not (false).

Tools

• toolHeatMap. Indicate if you want to include the Heat Map tool within the Critical Edition box (true) or not (false). This tool gives the user an overview about text variance.

Multiple recensions

• versions. Here you can specify the @xml:id values used to distinguish between different recensions (or versions), the first value entered corresponds to the version used as critical text for the edition.

Advanced Settings

Tell the system how to recognize the data: indicate which XML tag you used for the encoding of the different objects.

XML Tag usage configuration

• listDef. List of Witnesses: element(s) you used to encode the lists of all the witnesses or changes referred to by the critical apparatus (f.i. <listWit> or <listChange>). Please divide values using commas.
• versionDef. Single witness: element(s) you used to encode a single witness or change referred to within the critical apparatus (f.i. <witness> or <change>). Please divide values using commas.
• fragmentMilestone. Fragment milestones: element(s) you used to indicate the beginning (or resumption) and the end (or suspension) of the text of a fragmentary witness (f.i. <witStart> or <witEnd>). Please divide values using commas.
• lacunaMilestone. Lacuna milestones: element(s) you used to indicate the beginning and the end of a lacuna in the text of a mostly complete textual witness (f.i. <lacunaStart> or <lacunaEnd>). Please divide values using commas.
• notSignificantVariant. Not significant variants: element(s) of attribute(s) you used to encode variants that are not significant and you do not want to appear in the main critical apparatus (f.i. <orig>, <sic> or @type=orthographic). Please divide values using commas.
• quoteDef. Quotes: element(s) used within the XML file to encode quotes for the sources apparatus (f.i. <quote>). Please divide values using commas.
• analogueDef. Analogues: element(s) used within the XML file to encode passages for the analogues apparatus. (f.i. <seg> or <ref[type=parallelPassage]>). Please divide values using commas.

Filters

• possibleLemmaFilters. Possible lemma filters: attribute(s), divided by commas, you want to consider as possible filters for lemmas (f.i. resp or cert). If you want, you can customize the color of each filter value in the tab "Colors" (otherwise random colors will be used).
• possibleVariantFilters. Possible variant filters: attribute(s), divided by commas, you want to consider as possible filters for variants (f.i. type, cause or hand). If you want, you can customize the color of each filter value in the tab "Colors" (otherwise random colors will be used).

Colors

• variantColorLight and variantColorDark. Generic variant Colors: customize the highlight colors (both dark and light for selected and unselected entries) for generic variants that do not have any specific metadata (or have metadata that are not considered as filters). Default colors are rgb(208, 220, 255) (light) and rgb(101, 138, 255) (dark).
• heatmapColor. Heat Map Color: customize the highlight color for variants when the heat map tool is activated (this will be the darkest color possible, that means the color of entries with the highest variance level). Default color is rgb(255, 108, 63).
• variantColors. Specific Variant Colors: customize the highlight color for each value of each lemma filter you defined in possibleLemmaFilters and each reading filter you defined in possibleVariantFilters. If you do not define a specific color, the system will use a random one.

Miscellaneous settings

Bibliography

• defaultBibliographicStyle. Select which bibliographic style you want to your edition to open on. Note that it must be an active bibliographic style!
• allowedBibliographicStyles. Select which bibliographic style you want to enable. Bibliographic styles will work properly if the system will find all needed information encoded in you XML file. You can deactivate a bibliographic style either by deleting it or by setting the property enabled to false (suggested method).

Search engine

• virtualKeyboardKeys. Here you can specify special characters that will appear as buttons in a virtual keyboard tied to the search engine. To add a special character to the virtual keyboard write here the @xml:id value in the corresponding <char> or <glyph> element between quotation marks (e.g. "amacr" for an a with macron), separate values using commas.

Image viewer options

• imageViewerOptions. Miscellaneous options for the image viewer, modify only if you know what you're doing!
• imageNormalizationCoefficient. The value of this parameter must be that of the width of the manuscript images (in pixels), leaving the default value or setting a wrong value may lead to text-image links malfunctioning (specifically, drawing the wrong areas for linking on the images).

3D viewer options

• tdhopViewerOptions. Miscellaneous options for the 3D viewer, modify only if you know what you're doing!
• Model_1. Indicate the 3D model that will be shown by default in the viewer.
• Model_2. Indicates the 3D model that will be shown as an alternative to the first one, choosing it from the selector in the menu.
• name. Indicates the 3D model's name that will be shown in in the menu selector.
• path. Indicate the folder where you intend to put 3D model.
• mesh. Indicates the 3D model's ID.

Languages

• languages. Customize the languages you want to set as available for the translation of the User Interface (just the UI!) by adding their codes in this list. At the moment we support just english ('en') and italian ('it'). If you want to add the support for a new language, just add a new *new_language_code*.json inside the i18n directory and a *new_language_code*.png image inside the images folder.

3 - Examples

There are several ready-to-use examples. The one used by default is n. 1.

If you want to explore the other two you will just have to open the corresponding settings file (f.i. config_marlowe.json) and save it as the main config.json file, overwriting the existing configuration. Then go to the index.html opened in your browser and reload the page!

• EXAMPLE 1: avicenna.xml - Short extract of Edizione Logica Avicennae, changed by CM for EVT testing purposes. It presents multiple levels of apparatuses (critical entries, sources and analogues), displayed in a separate dedicated frame. Configuration file for this edition: config_avicenna.json.

• EXAMPLE 2: pseudoEdition.xml - Pseudo edition for demonstration and testing purposes only, originally encoded by Marjorie Burghart for her TEI Critical Toolbox software, and modified in order to cover the highest number of possible use cases. It presents just the critical apparatus entry, displayed inline, within the main text. Configuration file for this edition: config_pseudoEdition.json.

• EXAMPLE 3: pelavicino.xml - Short extract of the Codice Pelavicino edition, which presents the encoding of named entities, in particular person, place and organization names. Configuration file for this edition: config_pelavicino.json.

• EXAMPLE 4 : marlowe.xml - Short extract of The Tragedie of Doctor Faustus (B text) by Christopher Marlowe. Text provided by Perseus Digital Library, with funding from Tufts University. Original version available for viewing and download at http://www.perseus.tufts.edu/hopper/. Configurations for this edition: config_marlowe.json.

• EXAMPLE 5: RC.xml - An experimental edition of the Ruthwell Cross to test the 3DHOP functionality recently added to EVT. Configuration file for this edition: config_visionaryCross.json.

4 - EVT Manual

Work in progress, a preliminary version is available in the doc folder.

5 - Feedback

User feedback is very much appreciated: please send all comments, suggestions, bug reports, etc. to evt.developers@gmail.com.