Re: Import Python library into an Ada package?

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 2020-12-04 21:08, Roger Mc wrote:
> On Saturday, December 5, 2020 at 5:33:00 AM UTC+11, björn lundin wrote:
>> Den 2020-12-04 kl. 14:22, skrev Niklas Holsti:
>>> If you want to use Graphviz just to draw automatically laid-out graphs,
>>> there is another way, that I have used: make the Ada program write out
>>> the graph definition as a text file in the "dot" language, and then
>>> invoke the "dot" program from Graphviz to lay out and draw the graph
>>> into some graphical format.
>> And if you really just want to draw graphs - and can use another tool -
>> gnuplot can be controlled by spawning it and send commands on stdin via
>> pipes.
>>
>>
>> -- 
>> Björn
> Thanks for the many helpful comments regarding Graphviz.
> I shall certainly consider using these for my project.
> I'm not sure what is meant by "automatically laid-out graphs".


Graphviz and in particular its "dot" tool are used to draw nice views of 
"graphs" that consist of nodes and arcs, not the simple kind of x-y plot 
"graph" that we so often look at nowadays -- showing how the pandemic 
curve is growing or flattening -- and that, AIUI, gnuplot is mostly used 
for.

In the "dot" language, one defines a node-and-arc graph by listing and 
naming all the nodes and then listing all the arcs from one node to 
another. The "dot" tool performs an automatic lay-out that places the 
nodes on the two-dimensional plane (= drawing surface) so that few arcs 
cross other arcs, and most arcs connect nodes that are close together -- 
in other words, a a visually clear and neat node-arc graphic instead of 
an arbitrary spaghetti.

The "dot" language and tool provide many ways to control the lay-out and 
to annotate it. Very flexible.