Mod: make links in preview clickable

[moormaster]

Solves issue #516

The <img/> tag in the preview.html template was extended with an image map to enable links in plantuml diagram to become clickable with click in the preview panel.

[qjebbs]

Image map mismatch after zoomed, any idea how to fix it?

[moormaster]

Image maps are not responsive - thats why you need to recalculate them when the image changes its zoom. This should be done by the "image-map-resizer" library which I have added.

Did you do another "npm install" when trying to build this branch?

[qjebbs]

map areas good after zoom with latest commits.

but found another problem, please consider following:

@startuml
Bob -> Alice : [[http://a.com]] hello
newpage
Bob <- Alice : [[http://b.com]] hello
@enduml

the first page had no map areas, and not clickable.

[qjebbs]

And one more error (cmd+p => open webview developper tools)

Uncaught TypeError: Failed to execute 'observe' on 'MutationObserver': parameter 1 is not of type 'Node'.

imageMapResize('#image-map');
    new MutationObserver(() => {
            imageMapResize('#image-map');
    })
    .observe(
        document.getElementById('image'),
        {'attributes': true}
    );

[moormaster]

fixed the way image maps are transported to and processed by the preview-webview. This should fixe multi-page umls. fixed error: created MutationObserver only if the #image element already exists

[qjebbs]

Thanks! There is a map render issue on the plantuml server side, request to the following url get empty response.

https://www.plantuml.com/plantuml/map/1/SoWkIImgAStDuN9KqBLJS5AmKeYEpYWfAR3Irq_KIyxFZOtboaijBqXCJmMgiD55LP44LU6GcfS2D0C0

which is the 2nd map of diagram:

@startuml
A -> B : [[http://a.com]]
newpage
A <- B : [[http://b.com]]
@enduml

[moormaster]

Thanks! There is a map render issue on the plantuml server side, request to the following url get empty response.

The issue seems to only be present on plantuml.com. If one sets up an own plantuml server using the most recent docker container at https://github.com/plantuml/plantuml-server retreiving the map of a multipage uml works fine.