Design  | SFC  |  NOS  |  Code |  Diary  | WWW |  Essay |  Cisco | [Home]



WWW pages

Question: So it GIF the future?
No. It's unlikely. GIF, and the compression method that it uses (LZW) are proprietary. Uni-sys hold the patent on LZW, and many software and equipment makers pay a small royalty to use it; CompuServe developed GIF and widely pro-moted it. It has allowed free use in the past but may not do this in the future.
The future is likely to be the PNG (Portable Network Graphics), which are supported by most new WWW browsers. PNG is a good for-mat as it has strong compression for images, as there is no loss of graphic image data when an image is uncompressed. PNG also supports vari-able transparency of (alpha channels) and control of image brightness on different computers (gamma correction). It can be used for both small images and complex ones, such as photographs.
Dear Jargon Buster






WWW pages of the past (Nov 2000)

November 2000.
I need to make more use of colour in the tables on the pages. Thus I need to make the graphic images support alpha transparency. Unfortunately most of my images were saved with a white background, which means that I could not really change the colour of a cell in a table (as it would leave a large area of white around the graphic). If you want to see the effect that it does, look at the two School of Computing logos below.

You can see that the one with the transparent background takes on the background of the background colour, whereas the other one has a fixed white background. This, is of course, one of the great advantages of using GIF images rather than JPEG, as you cannot add transparancy to a JPEG image.

So I'm just covering all my old graphics so that the white background is covered into a transparent background. Once PNG format is fully supported, it will be much easier to define transparency, and also to use proper vector graphics. Until then, we're stuck with GIF. Oh BTW it looks as if there may be a licence fee charged for GIF compression in the future, thus the sooner we use PNG the better.

November 2000 [Expand]