Compo returns
David Pilling (8394) 77 posts |
Second attempt… Implosion has not been removed from SparkFS. The Compo ReadMe for example in C120demo/zip extracts with no problem on my working copy of the open source version, but not on 1.56. It seems the problem is the Zip module supplied with 1.56. The last version of SparkFS I produced is available from my website (for free), just for this sort of eventuality, but it would be better if everyone went with the latest open version, in the long run it will be better and have more features. ROOL have put a lot of effort into it. When working on the open source version of SparkFS, I used Spark and thought what a nice little program it is – one thing it can do is show the compression format of files in archives at a glance. |
Sprow (202) 1129 posts |
I’ve sometimes thought it’d be handy if the Filer had an extra column when in ‘Full info’ display mode, allowing a string of meta data of some sort (this would need the underlying OS_GBPB to request it of the filing system, and perhaps offer it around to other interested modules). In SparkFS’ case that would allow the compression type to be shown, and things like the dimensions of JPEGs and videos and similar. Windows has this already – the columns available seem to depend on the context, so when inside a ZIP you get more options than for a normal display. |
David Pilling (8394) 77 posts |
Here I go, throwing rocks, the implode/explode problem appears to be compiler related. 2002 compiler OK, modern ones not.
Yes could be a some fun there for not much extra complexity. Going back it was said that it should be possible to use the RISC OS filer to display your own data, so that writing something like Spark one would not have to clone the filer. I think that is what can be done on Windows – “shell extension” (?) But it is not as easy to write file systems on Windows. |
Clive Semmens (2335) 3140 posts |
Not that I could write a filer*, but my experience is that it’s not as easy to write anything on Windows (or Mac for that matter). * – Well, I suppose I probably could, but I’d have to learn a lot of stuff first… |
jim lesurf (2082) 1399 posts |
Back on Compo… I’ve now succeeded in the attempts to get my brain to tell my fingers to write a composcript that can plot a series of different antenna patterns onto the compo canvas so the usr can see the results of different antenna arrays. Quite nice to see antenna field patterns pop up one after another. :-) At some point I’ll see if I can add the far field patterns that are related and indicate the ‘gain’, etc. Potentially a handy toy for RF use. |
jim lesurf (2082) 1399 posts |
OK, I’ve now written a version of the Compo ‘antenna patterns’ script, etc, that seems OK here. Useful as a test/demo. All being well, I plan to write about this in detail for ‘Archive’ magazine as a first show of what using scripting can do! However since I need to provide the magazine with the files needed I decided to put them up at http://jcgl.orpheusweb.co.uk/Compo/CompoRevived/Plotblank.zip now so that people can have a look and: 1) Check I’ve not fscked it up. :-) 2) Gives some idea of the scope/potential. To generate, just DND the ‘call_’ file on the Compo canvas.. As normal for !Compo the helper apps need to have been seen by the filer. The far-field antenna plot is a drawfile you then add to the canvas. When considering (2) take into account the possibility that the field patterns could be animations, showing the field propagating outwards! Realy nice as a visual for explaining the mysteries of how those funny rooftop antennas behave… I’d probably add labels, but you can work out which near field pattern is for which antenna arrangement by comparing it with the DrawFile’s graph of the far-field pattern. As usual, the code by me is rubbish, it just staggers to doing what I wanted. I then quit whilst ahead. :-) |
Jean-Michel BRUCK (3009) 282 posts |
It’s good to see this demonstration on wave propagation and the potential of !Compo. I looked at your code, but the equations are not explicit enough at my level. I will try to draw a radiation pattern with Pari/GP For your code, it must remain readable which is the case, perhaps a little more documentation on the subject to be illustrated… |
jim lesurf (2082) 1399 posts |
It would be easier to explain in terms of complex numbers/values. The ‘C’ I wrote just tries to hack/duck past that. What I’ve done thus far is really aimed at a demo to show what !compo can do given the ability to ‘plot onto an object on the canvas! I’m doing an “Archive” article that also does this. Probably need another diagram for it. (The article also shows some example antennas which should help.) But I’m also wanting to avoid too much ‘antenna theory’ for Archive! May also do a webpage that deals with that and uses the images as illustrations. But one step at a time… I have trouble reading my own code. I just shuffle the statements until it works. The only lessons I ever had on programming were for an ICL1900 back in the 1970s. FORTRAN, punched cards and tapes… Different world. |
jim lesurf (2082) 1399 posts |
I’ve been experimenting with using Compo / CompoScript and quite impressed with what it can do for a task that is otherwise quite difficult. This is to generate illustrative ‘snapshot’ plots of the near-field patterns around array antennas. In my case so I can explain ‘how they work’ etc on webpages on the basis that a diagram can do more than lots of words or eqiations. Compo can now plot out examples like this http://jcgl.orpheusweb.co.uk/Compo/CompoRevived/DRDpattern.jpeg The small ‘object’ in the middle of the field pattern represents the antenna. In this case a simple 3-element ‘Yagi’ array of the kind used to get good VHF/FM radio reception. Fuller explanations would be in the text. But this shows neatly some aspects of their behavior which even antenna engineers tend to overlook! More detailed explanation will be on the webpage once I’ve managed to write it. |