VisB is a plugin for ProB2-UI, the new user interface of ProB based on JavaFX and the ProB2-Java-API . It is included in the latest Snapshot builds of ProB2-UI, but can be downloaded at https://www3.hhu.de/stups/downloads/prob2/plugins/ for older version of ProB2-UI.
An article about VisB has been published in the ABZ'2020 proceedings.
To start VisB choose the "Open VisB" command in the Visualisation menu.
You can now choose a JSON file which builds on top of a SVG graphics file. The JSON file contains a reference to a SVG file, along with entries to modify attributes based on the current state of a B model and entries which specify how VisB should react to clicks on the SVG. The SVG file should contain object ids which are referenced in the JSON file.
Here is a sample file:
{
"svg":"Train2.svg",
"items":[
{
"id":"Train1_rect",
"attr":"visibility",
"value":"IF 1:TRAIN THEN \"visible\" ELSE \"hidden\" END"
},
{
"id":"Train1_rect",
"attr":"fill",
"value":"IF train_speed(1)>0 THEN \"blue\" ELSE \"orange\" END"
},
{
"id":"Train1_rect",
"attr":"x",
"value":"train_back_loc(1)*10+20"
},
{
"id":"Train1_rect",
"attr":"width",
"value":"train_length(1)*10"
}
],
"events":[
{
"id":"Train1_rect",
"event":"Train_Move1",
"predicates":[
"1=1"
]
}
]
}
The main VisB Json file should contain an svg attribute with a relative or absolute path to the SVG file to be shown. One can also include subsidiary VisB Json files using the include attribute with again a relative or absolut path to another Json file:
{
"svg":"my_svg_file.svg",
"include":"subsidiary_visb_file.json",
"items":[
...
}
The svg attribute in subsidiary files will be ignored. You can override the VisB items in the included file (i.e., a VisB item for an id and attribute in the top-level file will override items for the same id and attribute in the included files).
For VisB items every entry needs
For VisB event every entry needs
Additionally VisB now recognises for both items and events:
Other attributes will be ignored. E.g, one can use a comment attribute to add comments to the VisB items.
When executing an event, VisB now performs the following replacements within the predicates of the event:
Finally, events can now be associated with various hovers. For this you just need to add an attribute hovers which contains a list of JSON objects with the following attributes:
Note that the enter and leave values have to be static at the moment; in future we plan to allow B formulas here and also apply the repetition/replacement mechanism specified above. If you just wish to attach a hover to an SVG object (and no B operation/event) you can set the event field of the VisB event to the empty string ("event":""). You should not use attributes for the hover which are set by VisB items.
Here is an example VisB event with hovers:
{
"id": "button",
"event": "toggle_button",
"hovers": [{ "attr":"stroke-width", "enter":"6", "leave":"1"},
{ "attr":"opacity", "enter":"0.8", "leave":"1.0"}]
}
You can use the repeat and for attributes to replicate a VisB item or event. Replication consists in duplicating the item or event, and replacing %0 within the identifier and value attributes of the time with the repeated string or integer.
For example, the repeat instruction below will result in the creation of three VisB items, one for id txt_ttd1, for txt_ttd2, and one for txt_ttd3. The value formula for txt_ttd1 is "IF 1: dom(TTD) THEN visb_ttd_back(%0) ELSE -1000 END".
{
"repeat": ["1","2","3"],
"id":"txt_ttd%0",
"attr":"x",
"value":"IF %0: dom(TTD) THEN visb_ttd_back(%0) ELSE -1000 END"
},
A for loop can be used instead for the above example as follows:
{
"for": {"from":1, "to":3},
"id":"txt_ttd%0",
"attr":"x",
"value":"IF %0: dom(TTD) THEN visb_ttd_back(%0) ELSE -1000 END"
},
It is possible to apply both repeat and for attributes at the same time, as this example shows. (The exact details of multiple iterations for a VisB item might change in future.)
{
"repeat": [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20],
"for": {"from":1, "to":20},
"id": "tile%1x%0",
"event": "TryQueen",
"hovers": [{ "attr":"opacity", "enter":"0.5", "leave":"1"}],
"predicates" : ["i=%1","j=%0"]
}
Some examples can be found here. More details and examples will be added later.
It is sometimes useful to use simple coordinates for your VisB items and B expressions, e.g. x coordinates of 0..100. You can quite often do this and use the SVG transform attribute to scale and move the SVG object to the right place. The simple train VisB example shows how to do this. In essence your SVG file can contain this:
<polygon id = "ttd_polyline"
points="0,0 100,0"
stroke="gray" fill="none"
transform="translate(10,22.5)" />
and the VisB JSON file contains this, making use of LibrarySVG.def (automatically available) external function svg_axis:
{
"id":"ttd_polyline",
"attr":"points",
"value":"svg_axis({0} \\/ ran(%tt.(tt:TTDS|1+max(TTD_TrackElements(tt)))),100.0/real(TrackElementNumber+1),100.0,2.0)",
"comment":"show ticks for TTD Limits"
},
This is the Bibtex entry for an article about VisB in the ABZ'2020 proceedings:
@inproceedings{WerthLeuschel:abz2020,
author = {Michelle Werth and Michael Leuschel},
title = {{VisB}: A Lightweight Tool to Visualize Formal Models with {SVG} Graphics},
booktitle = {Proceedings ABZ 2020},
editor="Raschke, Alexander and M{\'e}ry, Dominique and Houdek, Frank",
year = {2020},
series = {LNCS 12071},
pages = "260--265",
isbn="978-3-030-48077-6"
}
To install VisB in the JavaFX-based ProB2-UI you need to:
1. Choose "Plugin Menu" in the Advanced menu 2. Click on the "Add Plugin..." button. 3. Select the VisB JAR file you have downloaded from https://www3.hhu.de/stups/downloads/prob2/plugins/ 4. Choose the "Open VisB" command in the Advanced menu to start VisB