ROOL Forum: Recent Posts

Programming & Screen Sizes / Modes

Fri, 30 Sep 2022 15:58:10 -0000

You can use Wimp_ReadPixTrans to see how the Wimp would plot any given icon in the current screen mode.

As for adapting to the current mode, you’d need to look at the scaling factor you want to apply to your window in order to draw it as you want, and then in order to keep track of where everything is in the window, divide/multiply the offsets as necessary.

That way, you can plot the icons at 50%, 100%, and 200%.
Personally, I’d have a try with simple resized plotting first, before looking at swapping the actual sprite set used. Get the mechanics going, then add the embellishments. ;)

Hang on, you mean rectangular vs square? Ok, sure.

People on this forum are making reference to those still using Mesolithic hardware, so you know somebody is going to be rocking MODE 15 like it’s 1987!

Programming & Screen Sizes / Modes

Fri, 30 Sep 2022 15:27:23 -0000

Normally the templates stay the same and the sprites change.

Not sure I understand that. If the wimp scaled things automatically, yes. :) Unless I design a template for the smallest screen, how can they stay the same? Afterall, there are more OS units on a big mode than there are on a small one.

Hang on, you mean rectangular vs square? Ok, sure.

I was querying the issue of a large screen template, a large board (1600 units sq), large tiles and rack etc. Ideal for my eyes. If, for smaller screens, I scale down the board by 50% and leave any surrounding icons at the same size (44 units high for radio/option) it’ll look kinda odd!

I guess I’ll suck it and see.

Would you be interested in a monthly Zoom Meeting on everything coding on RISC OS?

Fri, 30 Sep 2022 14:40:27 -0000

@ Druck and Dave Higton

Sounds like you both would like to give us a talk on (or share) your experience on coding on RISC OS :)

That would be awesome, any favorite month? :)

Programming & Screen Sizes / Modes

Fri, 30 Sep 2022 13:51:15 -0000

Normally the templates stay the same and the sprites change.
34×17 rectangular (MODE 12) will be the same size as 34×34 square (MODE 27), for example.

Programming & Screen Sizes / Modes

Fri, 30 Sep 2022 12:31:40 -0000

Having got to the point of a working game, at least on my setup here, I’m tackling the issue of screen sizes and modes.

Currently, the game uses DrawFile to render Draw files and I can scale to fit my needs. I intend to use multiple Templates to best suit the situation met. Thinking large, medium, small plus one for rectangular pixel modes. I know I can’t cater for all scenarios.

Using WinED, it doesn’t scale down icons with underlying sprites very well, such as option and radio icons. Is this expected and therefore down to me to create smaller sprites for them? The same applies to text icons so is there anything to be aware of if I use the outline fonts option with those? Trinity should be available across the board but I seem to remember outline fonts not looking good on screen back in the day.

Finally, colours. Is it advisable to use as small a palette as possible, as in 16 colours rather than 256 for example with the older modes? Pink here looks grey in Virtual A5000 in a 16 colour mode with a 256 colour palette.

It’s suprising how much stuff you forget!

Any hints and tips welcome.

WROCC Meeting - Andrew Oyston - 5th Oct

Thu, 29 Sep 2022 22:17:25 -0000

Wakefield RISC OS Computer Club

Meeting on Wednesday 5th October at 7.45pm

Andrew Oyston

Andrew Oyston will be talking about his computer background and where RISC OS has featured in that. He will be walking through his computing hobby (retro hardware and games), contributions to several publications (especially where RISC OS comes in), and his future plans.

This ‘hybrid’ meeting is open to all: it will be taking place at the West Yorkshire Sports & Social Club — see for details — but will also be accessible using the Zoom conferencing service for those who can’t or don’t wish to attend in person. Zoom invitations will be sent out ahead of the meeting, but only to those who email to request one. If you would like to be part of the meeting (and don’t receive an invite in the next 24 hours as a member of WROCC), please RSVP — at the latest by the end of Tuesday 4th October.

If you haven’t used Zoom before, we suggest that before Wednesday you try to join the Zoom test meeting at on the device that you intend to use, in order to check that your system works OK. You will not require a Zoom account to take part.

Past Meetings

Videos of previous meetings can be found in our links to past meetings at

Club Membership

Annual membership of the Club is available for those living near and far at £10, but new members receive a 50% discount (ie. £5) in their first year.

Members receive:

For further information, please email or visit the Club’s website at

StrongED 4.69f12 released

Thu, 29 Sep 2022 22:09:10 -0000

Hi All,

The twelfth full release of StrongED 4.69 can found on the StrongED website

The download contains a copy of StrongED that has all modes installed to make sure that they are compatible with 4.69f12.

The main change in this version is that the calculations in the Undo code have been made unsigned so that StrongED runs okay on machines with more than 2GB of memory.

Changes in StrongED 4.69f12 (from 4.69f11)

A full list of changes starting from the initial release 4.69f1 through to 4.69f12 is included in the download.

As always, all feedback is welcome and appreciated!

Would you be interested in a monthly Zoom Meeting on everything coding on RISC OS?

Thu, 29 Sep 2022 20:25:33 -0000

There’s RISC_OSLib which is, well, anybody here care to say something nice about it?

Its all there was when I did the majority of my personal and professional RISC OS programs in the early 90s. It did the job, and what it lacked I was able to extend fairly easily. I found Toolbox more restrictive, even though it had a nicer structure.

BTW I would not recommend moving to plain C now, you are just swapping all the limitations of BASIC for a set of different memory allocation and pointer problems. C++ makes much more sense, even if you still write mainly C style non object orientated code, by using references, string classes and exceptions you can eliminate about 90% of the most common C bugs.

SDFS and eMMC-SD Devices

Thu, 29 Sep 2022 17:07:18 -0000

The eMMc on the cm4 uses an 8-bit bus for speed.

I have now set up my cm4 and I/O board – this has 1Gbyte of RAM and 32Gbyte of eMMc – so that it can dual boot into either Linux or RISC OS via a switch on the GPIO pins (between pins 29 and 30).

With the switch closed it boots into linux and it can see the 32Gbyte USB drive plus its 80Mbyte FAT partition (although this is not used as it boots from SD card) and can also see the 80Mbyte FAT partition on the SD card (which has the same contents plus the files ‘CMOS’ and ‘RISCOS.IMG’). Both have an amended CMDLINE.TXT and CONFIG.TXT to do the dual boot and to refer to the Linux partition via its UUID.

With the switch open it boots into Supervisor mode in RISC OS 5.28 and shows the eMMc as a hard disc icon (but cannot read it) and shows the FAT partition of the Linux 32Gbyte USB drive. If I run !Boot on another USB drive with HrdDisc4 on it, I have a full working desktop in RISC OS.

Now I am in a position to try out various roms to see whether eMMc under RISC OS is working yet. It is easy to copy a different RISC OS ROM image into place using Linux and if it hangs to go back one step.

See Archive 25:5 for how to set up a dual boot on a Pi4.

Would you be interested in a monthly Zoom Meeting on everything coding on RISC OS?

Thu, 29 Sep 2022 15:09:50 -0000

Everybody will tell you that necessary reading is the K&R book about C. If you like software archeology, I would recommend it, but if you want to learn to write programs in C, ignore it. There are some fundamental differences between K&R and the current ANSI/ISO standards

That’s certainly true of the first edition of K&R; I regret wasting my money on it. But the second edition is bang on, and I refer to it frequently.

Would you be interested in a monthly Zoom Meeting on everything coding on RISC OS?

Thu, 29 Sep 2022 15:07:22 -0000

Thinking about what Rick was saying earlier RE C, would it make more sense to look at learning C on another platform (assuming Mac etc. users would have ‘modern’ courses / reference materials) whilst learning RISC OS specifics alongside this? Or would I be making a rod for my own back?

Unless you’re writing a pure command-line app (which I think must be unusual these days), my opinion is that you should just do things the RISC OS way. Stuff you learn or practice on another platform that is specific to that platform, will not help you programming RISC OS, and will merely add to the amount of stuff you have to learn.