Tuesday, August 18, 2009

Metrics - good or bad?

Outside world example
When participating in software projects, people like to speak about metrics.
This is caused by the nature of the software projects. Program develipment oftenly turns to the research task.

You can easily track progress for the bridge construction. It's very easy. You can do 2 things:
  • Get financial documents and reports and see how it's going.
  • Go to the construction place and see how it works.
  • Ask constructors for report. Constructors would tell you, that 'Bridge is complete for 23.56%, first phase is done for 98%, seconds phase - for 33%'
  • Also - there are some numbers about quailty. For example, 4% of weldings need to be redone, 1.23% of surface paintings fails, etc...
Business people are happy. They have numbers. Using these numbers they can see progress, make plans and feel them pushing the thing.

Metrics in software projects - good or bad?
What about software projects?
You can not go to the construction place. You can ask programmers about 'How it's going?', and you'll get the answer 'Doing ok.'

You need numbers to show to business people. Business people will become upset very soon if you will tell them for a month that 'Progress is good!'

Also, having numbers stimulates programmers.
Here are several examples:
  • Code coverage. Percentage of code lines 'covered' with unit tests. Covered means here that when tests execute, this line is reached by execution.
  • Commit percentage. Mr. Alex is committing (putting code to repository) 3 more times than mr. Andrew. We need to punish Andrew!
  • Usually, work breakdown exists in form of tickets - bugs, feature requests, development tasks. People LOVE having metrics on these. For example - 299 work items done, 1020 left for work. Or - this milestone is completed for 50% - 144 of 288 tickets closed.
  • Easiest - count of the code lines produced by a developer.
The Main Thought
Metrics can do both things - indicat process, or hide it. As a business person, you can get positive reports during 2 months, showing that codebase grows speeds up and speeds up. But after those 2 month you'll face real f**ck-up.

Metric should be sane and wise.

You would not decide hospital to go to basing on the average temperature among all patients, would you?

Thursday, August 13, 2009

GWT Canvas widget - drawing in a browser


I believe many of you felt that some thing are hard to acquire with pure DOM objects and maniputllation. DOM puts you into hard fram. If you ever tried make something round-cornered, you know that count of the libraries doing this exceeds any reasonable task.

Methods used there are different: some use colored graphic corners, but don't allow you for selecting any color you want. Some of them need JavaScript runing on a page. Some need some weird markup, and tricks with the HyperText controls for IE. Some simply don't work well.

So, why not just to draw?

So, (how) can I draw in browser?
HTML 5 Canvas elements allows some drawings. But, making a web-application today, I'd not use this as a production decision. Simply because some old bad browsers don't know it.

And we don't want to make people feel lost because they are using IE6, do we? There's a solution, though. It's name is VML. It's Micro$oft answer to the SVG. (by the way, SVG is not that a good standard itself, too). Internet E$plorer does support VML, but the API is quite different from Canvas.

If we take 2 coverage areas - one of browsers already covered with Canvas tag (FireFox, all webkits, Opera) and VML (IE's) - we'll have plenty solid browser coverage.

The problems yet to be resolved is a cost of development. In order to get something working, you'll have spent more than twice more time than for single Canvas or for VML only.

So, (how) can I draw in browser? (GWT way)

When someone says about masking differences between the browsers, I always think of GWT. That's the best thing I love in it.

And, I used to search for vector graphics library for Google Web Toolkit.

I found one (just as a proof-of-concept) in the GWT-Widgets library. (There's also an interactive demo for the Canvas widget - you can draw different shapes over image just in a webpage without any flash, java or any other hard stuff).

Actually, I liked it.
Also, after incorporating the GWT-Widgets Canvas to a project, I found another one. This is demo for newer Canvas wrapper, and this is gwt-canvas project home page

The least I wanted to show you is the sample of Canvas working in the real world. The following is a way to see it (it's in Cyrillic, so I'll do verbose notes :) )
  1. The site is about calculation of the metal-plastic windows cost basing on different selections from user.
  2. Open up http://osnova.ks.ua
    It loads slowly, but wait until all the stuff is loaded.
  3. In the top navigation menu, select 'Посчитай!' item. This means 'Calculate' in english. It is the fourth item from the left, and it has vivid red background.
  4. You'll see a 'Выберите тип конструкции...' blue link underlined in the center of screen. Click on it.
  5. You'll see basic shape selector. The shapes themselves are drawn with canvas.
  6. Select one - and you'll get it big. Big shape with all sizes is also drawn with the help of canvas widget.
That's all for this site.

What I found good and bad in drawing on the webpage with GWT and Canvas

  • It works
  • It works in different browsers
  • It works fast enought
  • Instrument palette is enough for many basic features
  • As it is PoC, there are some issues. I've seen that sometimes wide lines disappeared in IE, leaving wireframe only.
  • You can NOT draw text. The text you see there - it is just images with letters. Actually, there's a solution for this - but it's weird. There's a pair of client and serverside script. Client sends request to the server with the phraze it wants to get. Serverside has the text with all the alphabet as an image, and then glues the phraze, thus creating image with the desired text, and then passes that by to client.
    That's too heavy for such a simple task
  • It can be done more easily with Flash, but this is a double-sided penny. You'll need your users to have Flash installed. From the statistics of people coming to this blog, 3 of 80 don't have flash installed. That's too bad for big amount of people. :)
Hope this stuff will be useful for you!