New renderers - proposed fixes for known issues in latest scala renderer

["Fischer, Till" <tifischer AT itemis.de>]

Hi,

I just discovered the new renderers "gs-ui-swing" and "gs-ui-javafx" replacing the old Scala renderer. This looks good!

Git history tells me that Hicham Brahimi is responsible, but I couldn't find any contact information.

I wanted to contact him because I stumbled upon a few things:

First, "gs-ui-swing" must be build against the gs-core branch "uiScalaToJava", which cannot be found in the official repository at the moment (only in the fork of Hicham).

Second, I fixed a problem in the old Scala renderer that caused troubles when Graphstream was used inside a more complex UI (JetBrains IntelliJ in my case). In some situations the offset (x/y coordinate) of the viewport was not set correctly. This led to inconsitencies between the AWT AffineTransformation and Camera.metrics.viewport). This problem recurs with the new Swing renderer.

Furthermore, I reverted/fixed recent commmits for issues #199 and #217. Regarding issue #199: the fix removed the possibility to use the spherical coordinate system (radius+phi) for sprites (i.e. let them "orbit" around nodes). I just reverted the change. Regarding issue #217: the fix made nodes outrule sprites when the element at position (x,y) was searched. Neither nodes nor sprites should take precedence, instead the zIndex is relevant. This one I fixed properly.

If you want to have a look, all changes can be found in branch "1.3.1-awt-intellij-fix" of my fork at github, see here: https://github.com/till-f/gs-core, https://github.com/till-f/gs-ui.

Cheers,
Till