Layer "views" enhancment

[Simon Kagstrom <simon kagstrom bth se>]

Hello Dia list!

I've been thinking a bit about a possible Dia extension and thought I'd hear
what the list has to say about it. I have not implemented it yet.

My idea is to add a concept of Views to the layers. A view defines a set of
visible layers. For example, the "Overview" view could include layers 0-3
while the "Detailed" view could include layers 0-7 and so on. There can be
many views in each diagram and views can be added, deleted and modified in the
Layer dialogue.

The reason I personally would like this is that I often create animations for
presentations with Dia, where each "frame" consists of a number of
layers. However, it can be fairly tedious to manage the layers when exporting
to other formats (which I do on the command line), e.g.,

dia --show-layers=0-3,8,11 ...
dia --show-layers=4,6-8 ...
...

It would be much easier to instead do

dia --show-views=Overview ... (or --show-views=1)
dia --show-views=Detailed


So, on to the questions.

1. Would the rest of you like to see something like this implemented?

2. I'm worried that the implementation might be intrusive. Although the "View"
   datastructure is basically just a vector of layers, the views would have to
   be saved with the diagram. I'm not very familiar with how this is done, but
   would the views break the compability with older versions?


I'm hoping I should be able to add this functionality to Dia, unless someone
else beats me to it ;-)

// Simon