Jilm's Workshop

There are HP-UX workstations under my responsibility. Because I was never able to systematicaly check syslog.log for signs of future failure or disaster and because I think it could be usefull, I have created a simple perl script that should help me. Every one interested can download it here and use anyhow.

It may appear, you want to use SVG format in your application. What if you need to save an extra information that is usefull to your application, but still you want to keep the ability to use entire document in standard SVG viewer. In SVG specification, one can find short chapter, that is dedicated exactly to extensibility. In this blog post I am presenting results of my extensibility experiments.

It is not my first attempt to create this kind of SVG application. When I tried it for the last time I realized how to do it much more better. Thanks to flaxibility of JavaScript it would be possible to made it modular. Imagine something like graphic wrapper that would provide basic functionality through API. The funcionality would encompass user interface, loading and storing SVG document (drawing), application logic and modules administration. What about modules, what they should do? Right now I can see two kinds of them, drawing and editing ones.

It is obvious, that people working on SVG specification learned from HTML evolution, so they embeded the same CSS styling mechanism into SVG. I believe, that HTML + external CSS is pure good, because form and style is separated and one can be easily changed without affecting the other. Moreover, higher level semantics could be added to your documents. I think, many articles have been written about usefulness of HTML + CSS. I tried this concept on SVG + CSS and this post summarize results.

Imagine, you have JavaScript application, that allows user to create some sort of SVG picture (a graph created by user by entering values, for example). At the end of the session the user should be allowed to save created document of course. I tried to solve this task and here you can find some of my observations. The XMLHttpRequest object was used to send an SVG document to the server and only client side of the whole task is presented here. Moreover, no security issues are taken under account.

In my project of SVG Editor I needed to compute center point of an SVG path elliptical arc segment. First of all I found arithmetic process on the internet on the developers forum. I improved that procedure and implemented in JavaScript. Later I had to read an SVG specification for another thing and I found out, that there is the whole procedure stated in the Appendix F. For me, it is a lesson to read specification carefully before I start to think up something from scratch. In this post I offer work I have done.

One of the biggest usage of SVG that I can see, are user interaction components embedded into HTML pages. These components, such as buttons, menus, toolbars, etc. cannot be live alone. They must interact with the parent HTML page, or with another SVG component embedded into the same page. That is why I believe we need the ability to call JavaScript functions placed in HTML from within embedded SVG and vice versa.