home *** CD-ROM | disk | FTP | other *** search
- Hints and Tips
- 8.10
- Debugging via the Serial Port − (Unfortunately, we had problems
- importing the text into Impression when we put this hint in last month’s
- magazine. Sorry for any confusion that we caused − it was our fault and
- not John West’s! The correct version is as follows...)
- 8.10
- The os_cli line makes use of the system redirection to send the text to
- the serial port, and so it should have read:
- 8.10
- os_cli(“echo Start of initialise()
- 8.10
- {serial: }”);
- 8.10
- More details of redirection can be found on page 419 of the RISC OS 3
- User Guide. The new Acorn C/C++ does not support os_cli, so you should
- use _kernel_oscli instead.
- 8.10
- From Basic, the OSCLI command is the direct equivalent.
- 8.10
- OSCLI “echo Start of PROC_init
- 8.10
- {serial: }”
- 8.10
- John West, Surrey
- 8.10
- Disc protection − Of the 100+ readers’ floppy discs I’ve processed over
- the last few months, there was a fair smattering of broken cases,
- mangled sliders and disc errors. In every case, the defective discs had
- been sent in paper envelopes without further protection from the rough
- and tumble of Her Majesty’s mails. This prompts me to repeat Ed’s
- recommendation of many moons ago that it is well worthwhile giving your
- discs adequate protection in the post. Jiffy bags or board-backed
- envelopes cost only a few pence from stationers and, provided any
- covering documentation is limited to a couple of pages, you are unlikely
- to exceed the 60g limit for 19p/25p postage.
- 8.10
- Jim Nottingham, Pocklington
- 8.10
- Impression borders − The built-in borders in Impression provide ¼ point,
- 1 point and 4 point thick black borders (numbers 1, 2 & 3), but how do
- you get a 5 point border? There is no way for the user to specify the
- thickness and, also, the lines don’t join properly at the corners, as
- you can see...
- 8.10
- Here is a simple way to make your own line borders using Draw:
- 8.10
- Create a new Draw document and set the zoom to 8:1. Show the grid and
- lock to it. Set the grid spacing to 0.125 inches with 9 subdivisions −
- since one point equals 1/72 inch, each subdivision is one point. For a 5
- point line make a rectangle 5 squares wide and about 30 squares deep. To
- make the corners square, you need to make a 5 by 5 square immediately
- above the rectangle.
- 8.10
- Finally, set the fill colour of both to black and the line colour to
- none and save the file in your border directory.
- 8.10
- You can also make curved or bevelled joins by changing the corner square
- into a sector or a triangle.
- 8.10
- To get half point thicknesses, you need to set the number of
- subdivisions to 18.
- 8.10
- Unfortunately, the 8:1 maximum zoom in Draw is too small to do quarter
- point lines directly, so you need to construct them double size and then
- “magnify” them by 0.5, or else use Artworks with a 4000% magnification.
- On the monthly disc is a selection of plain rectangular borders from ¼
- point to 6 point thickness.
- 8.10
- The only remaining problem is that Impression puts the borders around
- the outside of the frame so, with thick borders, you can’t use the “snap
- to frames” feature to get your alignment right when the frames have
- different borders, as you can see from the frame opposite.
- 8.10
- Cain Hunt, Cambridge
- 8.10
- Mouseballs − Logitech mice sometimes begin to slip when a glassy film of
- material builds up around the periphery of the rollers which contact the
- mouse ball. This can be as little as 0.5mm wide but is very tenacious.
- Using a piece of metal or wood to dislodge the material can easily
- damage the rollers. With a bit of patience it can be softened using
- isopropyl alcohol on a cotton bud. Lint free cloth is even better. This
- takes a few minutes of gentle rubbing to do the trick. One of the
- rollers is spring loaded and is a little more difficult. A clean cotton
- bud holding a little IPA can be used to rub around the mouse ball to
- remove the stickiness. If an Archive type mat is used, a gentle wash
- with warm water and detergent will delay the problem recurring.
- Everything has to be completely dry before reassembly.
- 8.10
- Les May, Rochdale u
-