Re: Graphic to visualize data flow between processes, buffers and files

On 05.01.2016 20:33, Alvaro Herrera wrote:

As in the original discussion, this is probably too fiddly and the resulting SVG files are going to be really ugly anyway. I think the consensus was that we should use some toolchain that uses a source format that looks like actual source code, such as the dot or xfig formats, of stuff like that -- which is "compiled" into the target graphic format. As I recall, what we lacked was somebody with time and knowledge to actually produce a useful image starting from such a source, produce Makefile rules to run the transformation from the Makefiles, and to inject the image into the SGML so that it works in the HTML and PDF outputs. With such a proof of concept we're much more likely to take this idea seriously.

I don't want to be intrusive, but obviously I didn't get the point at the first attempt. I hope that I now have understood the needs and concerns of the community: you are looking for tools and a source code format for SVN files which is easy to handle, diff-able and convertible into different graphic formats.

To achieve these objectives I composed a suite of tools and templates:

• The SVN file is edited with a text editor. This sounds a little crazy, as SVN editors are trendy and easy to handle. But in conjunction with a set of templates this job gets relative easy. Of course the developer needs some knowledge about SVN, but it is intended that only few and simple elements of SVN are used to keep the source clear. After a short period of familiarization and with a look at existing files everyone can work this way. Also the range of lines keeps small as there are predefined complex objects which can be included with one line of code.
• Actually there are three files with predefined SVN objects and CSS definitions. This facilitates the work and leads to consistent use of graphic elements like fonts, colors, sizes. One file contains simple objects like text or ellipses with predefined attributes, the next one contains complex pictures like PCs, and the last one contains all CSS stuff.
• As fare as I have seen, the SVN files are rendered consistently by browsers and image viewers. Using Inkscape in batch-mode they can be converted to pdf, png and other formats without loss of elements or significant image sharpness.
• Using xmlling the SVN files can be validated against the SVN DTD.
• In the readme file there are examples of converting and XML validation.
• There is the problem, that Inscape does not consider external CSS files. I described a workaround in the CSS file.
  

Please study the attached three example files: simple.svn, simple_with_external_file.svn and pg_processes.svn. The last two make use of pg_lib_basic_objects.svn, pg_lib_external_objects.svn and pg_lib_css.svn.


Regards, Jürgen Purtz