Discussion:
White background colour in GCOL is grey.
(too old to reply)
George Pearce
2021-05-11 14:03:34 UTC
Permalink
Could some kind soul help an ageing forgetful BASIC programmer.

I am simply trying to open a graphics window with a white background in 16 million colour mode in RIScOS 4.?. I am calling MODE MODE in 1900x1080p. GCOL seems to have been extended in v5.

Best I can do is GCOL 0, 191, which seem to give a light grey rather than full white. I can obviously correct this after the event, but am sure there must be a solution which I have yet to discover.

cheers

George Pearce
Richard Coleman
2021-05-12 13:44:45 UTC
Permalink
Post by George Pearce
Could some kind soul help an ageing forgetful BASIC programmer.
I am simply trying to open a graphics window with a white background in 16 million colour mode in RIScOS 4.?. I am calling MODE MODE in 1900x1080p. GCOL seems to have been extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey rather than full white. I can obviously correct this after the event, but am sure there must be a solution which I have yet to discover.
cheers
George Pearce
Hi George,
I think you might be needing the TINT part, so you would have GCOL 0,191 TINT 192 to get full white.
Details are at http://www.riscos.com/support/developers/bbcbasic/part3/keywords.html#gcol
Thanks,
Richard
Richard Ashbery
2021-05-12 13:53:42 UTC
Permalink
In article
Post by George Pearce
Could some kind soul help an ageing forgetful BASIC programmer.
I am simply trying to open a graphics window with a white
background in 16 million colour mode in RIScOS 4.?. I am calling
MODE MODE in 1900x1080p. GCOL seems to have been extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey
rather than full white. I can obviously correct this after the
event, but am sure there must be a solution which I have yet to
discover.
GCOL ON 255,255,255 : CLG

Hope that helps

Richard
Steve Fryatt
2021-05-12 17:23:19 UTC
Permalink
On 12 May, Richard Ashbery wrote in message
Post by Richard Ashbery
Post by George Pearce
I am simply trying to open a graphics window with a white background in
16 million colour mode in RIScOS 4.?. I am calling MODE MODE in
1900x1080p. GCOL seems to have been extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey rather
than full white. I can obviously correct this after the event, but am
sure there must be a solution which I have yet to discover.
GCOL ON 255,255,255 : CLG
That's RISC OS 5 only, so doesn't meet the OP's requirement of RISC OS 4
unless soft-loading BASIC is up for consideration.

GCOL 0, 255, 255, 255 : CLG might do what's required, though.
--
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/
George Pearce
2021-05-13 09:38:25 UTC
Permalink
Post by Steve Fryatt
On 12 May, Richard Ashbery wrote in message
Post by Richard Ashbery
Post by George Pearce
I am simply trying to open a graphics window with a white background in
16 million colour mode in RIScOS 4.?. I am calling MODE MODE in
1900x1080p. GCOL seems to have been extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey rather
than full white. I can obviously correct this after the event, but am
sure there must be a solution which I have yet to discover.
GCOL ON 255,255,255 : CLG
That's RISC OS 5 only, so doesn't meet the OP's requirement of RISC OS 4
unless soft-loading BASIC is up for consideration.
GCOL 0, 255, 255, 255 : CLG might do what's required, though.
--
Steve Fryatt - Leeds, England
http://www.stevefryatt.org.uk/
No, that does not work, screen colour is still black.
It seems to me there is an issue with COL, GCOL in 16 million mode, with no distinction between foreground and background colours, and no palette as such. In 16 and 256 colour modes , colours up to 128 are foreground, and above that are background.
I'm now very confused. I think the BASIC manual needs updating to deal with the larger monitor resolutions we now mostly have, and the entries for COL and GCOL need to address 16million mode.
I understand their application in 16 and 256 colour modes, though I do find the manual a bit confusing.

George Pearce
Martin
2021-05-13 11:33:47 UTC
Permalink
Post by George Pearce
Post by Steve Fryatt
On 12 May, Richard Ashbery wrote in message
Post by Richard Ashbery
Post by George Pearce
I am simply trying to open a graphics window with a white
background in 16 million colour mode in RIScOS 4.?. I am
calling MODE MODE in 1900x1080p. GCOL seems to have been
extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey
rather than full white. I can obviously correct this after
the event, but am sure there must be a solution which I have
yet to discover.
GCOL ON 255,255,255 : CLG
That's RISC OS 5 only, so doesn't meet the OP's requirement of
RISC OS 4 unless soft-loading BASIC is up for consideration.
GCOL 0, 255, 255, 255 : CLG might do what's required, though.
No, that does not work, screen colour is still black.
It seems to me there is an issue with COL, GCOL in 16 million mode,
with no distinction between foreground and background colours, and
no palette as such. In 16 and 256 colour modes , colours up to
128 are foreground, and above that are background.
I'm now very confused. I think the BASIC manual needs updating to
deal with the larger monitor resolutions we now mostly have, and
the entries for COL and GCOL need to address 16million mode.
I understand their application in 16 and 256 colour modes, though I
do find the manual a bit confusing.
You do not say what version of RISC OS you are using, or which version
of BASIC, or what hardware you are running on. Any of those may be
your problem - the BASIC manual has been updated, but largely to
reflect changes made in the many years since RO4.

If the problem is the version of BASIC, then the most recent version
can be soft-loaded, as Steve said above.
--
Martin Avison
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received.
George Pearce
2021-05-13 13:40:19 UTC
Permalink
Post by Martin
Post by George Pearce
Post by Steve Fryatt
On 12 May, Richard Ashbery wrote in message
Post by Richard Ashbery
Post by George Pearce
I am simply trying to open a graphics window with a white
background in 16 million colour mode in RIScOS 4.?. I am
calling MODE MODE in 1900x1080p. GCOL seems to have been
extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey
rather than full white. I can obviously correct this after
the event, but am sure there must be a solution which I have
yet to discover.
GCOL ON 255,255,255 : CLG
That's RISC OS 5 only, so doesn't meet the OP's requirement of
RISC OS 4 unless soft-loading BASIC is up for consideration.
GCOL 0, 255, 255, 255 : CLG might do what's required, though.
No, that does not work, screen colour is still black.
It seems to me there is an issue with COL, GCOL in 16 million mode,
with no distinction between foreground and background colours, and
no palette as such. In 16 and 256 colour modes , colours up to
128 are foreground, and above that are background.
I'm now very confused. I think the BASIC manual needs updating to
deal with the larger monitor resolutions we now mostly have, and
the entries for COL and GCOL need to address 16million mode.
I understand their application in 16 and 256 colour modes, though I
do find the manual a bit confusing.
You do not say what version of RISC OS you are using, or which version
of BASIC, or what hardware you are running on. Any of those may be
your problem - the BASIC manual has been updated, but largely to
reflect changes made in the many years since RO4.
If the problem is the version of BASIC, then the most recent version
can be soft-loaded, as Steve said above.
--
Martin Avison
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received.
I did say at the start of my original question it is RISC OS 4.?, as Steve picked up.

4.02 on one machine and 4.39 Virtual Acorn RISC OS ADJUST

BASIC is BASIC 5 v 1.20 on the former and v1.29 on the latter.
I realise that there may be an issue with emulation, and the lack of physical Acorn hardware.

I have the BBC BASIC V manual, and it has nothing to say about 16 million colors but is concerned mainly with 16 and 256 colour modes, and old style low res screen modes.

Also I'm writing the program for someone who is using RISC OS 4, and would probably demur from soft loading a new OS!

That being said, 5 or 4, no one has addressed my query about the existence or not of Foreground and Background colours in 16M mode. I suspect not!

And no one has offered a solution to a white screen in said mode. Please someone!

George Pearce
News
2021-05-13 15:49:01 UTC
Permalink
Post by George Pearce
That being said, 5 or 4, no one has addressed my query about the
existence or not of Foreground and Background colours in 16M mode.
I suspect not!
And no one has offered a solution to a white screen in said mode. Please someone!
Have you tried using the colourtrans SWI calls? There are, for
example, ColourTrans_SetGCOL and ColourTrans_SetColour, which work in
all modes.
--
Chris Johnson
Martin
2021-05-13 16:09:32 UTC
Permalink
Post by George Pearce
Post by Martin
Post by Steve Fryatt
On 12 May, Richard Ashbery wrote in message
Post by George Pearce
I am simply trying to open a graphics window with a white
background in 16 million colour mode in RIScOS 4.?. I am
calling MODE MODE in 1900x1080p. GCOL seems to have been
extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light
grey rather than full white. I can obviously correct
this after the event, but am sure there must be a
solution which I have yet to discover.
[Snip]
Post by George Pearce
Post by Martin
You do not say what version of RISC OS you are using, or which
version of BASIC, or what hardware you are running on. Any of
those may be your problem - the BASIC manual has been updated,
but largely to reflect changes made in the many years since RO4.
If the problem is the version of BASIC, then the most recent
version can be soft-loaded, as Steve said above.
I did say at the start of my original question it is RISC OS 4.?, as Steve picked up.
Indeed ... which is why I referred to changes since RO4.
Post by George Pearce
4.02 on one machine and 4.39 Virtual Acorn RISC OS ADJUST
BASIC is BASIC 5 v 1.20 on the former and v1.29 on the latter. I
realise that there may be an issue with emulation, and the lack of
physical Acorn hardware.
OK thanks.
Post by George Pearce
I have the BBC BASIC V manual, and it has nothing to say about 16
million colors but is concerned mainly with 16 and 256 colour
modes, and old style low res screen modes.
Yes - I find that very confusing myself.
Post by George Pearce
Also I'm writing the program for someone who is using RISC OS 4,
and would probably demur from soft loading a new OS!
We are not suggesting softloading a new OS ... just the BASIC module.
Post by George Pearce
That being said, 5 or 4, no one has addressed my query about the
existence or not of Foreground and Background colours in 16M mode.
I suspect not!
And no one has offered a solution to a white screen in said mode. Please someone!
I wrote a little program...
MODE MODE
GCOL &8F :REM Yellow background
VDU 24,200;200;1000;900;
CLG
GCOL &FF :REM White background
VDU 24,300;300;1080;800;
CLG
PRINT "done"
and when running at X1920 Y1080 C16M I get a yellow rectangle on a
black screen, mostly covered by a white rectangle - which seems to be
what you want?

That is the same on...
Titanium with RO5.29 and BASIC v1.81
VRPC with RO4.39 and BASIC v1.80 (softloaded)
VRPC with RO4.39 and BASIC v1.29

Does that answer your question?
If not, then a misbehaving program might help.
--
Martin Avison
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received.
George Pearce
2021-05-13 16:22:08 UTC
Permalink
Post by Martin
Post by George Pearce
Post by Martin
Post by Steve Fryatt
On 12 May, Richard Ashbery wrote in message
Post by George Pearce
I am simply trying to open a graphics window with a white
background in 16 million colour mode in RIScOS 4.?. I am
calling MODE MODE in 1900x1080p. GCOL seems to have been
extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light
grey rather than full white. I can obviously correct
this after the event, but am sure there must be a
solution which I have yet to discover.
[Snip]
Post by George Pearce
Post by Martin
You do not say what version of RISC OS you are using, or which
version of BASIC, or what hardware you are running on. Any of
those may be your problem - the BASIC manual has been updated,
but largely to reflect changes made in the many years since RO4.
If the problem is the version of BASIC, then the most recent
version can be soft-loaded, as Steve said above.
I did say at the start of my original question it is RISC OS 4.?, as Steve picked up.
Indeed ... which is why I referred to changes since RO4.
Post by George Pearce
4.02 on one machine and 4.39 Virtual Acorn RISC OS ADJUST
BASIC is BASIC 5 v 1.20 on the former and v1.29 on the latter. I
realise that there may be an issue with emulation, and the lack of
physical Acorn hardware.
OK thanks.
Post by George Pearce
I have the BBC BASIC V manual, and it has nothing to say about 16
million colors but is concerned mainly with 16 and 256 colour
modes, and old style low res screen modes.
Yes - I find that very confusing myself.
Post by George Pearce
Also I'm writing the program for someone who is using RISC OS 4,
and would probably demur from soft loading a new OS!
We are not suggesting softloading a new OS ... just the BASIC module.
Post by George Pearce
That being said, 5 or 4, no one has addressed my query about the
existence or not of Foreground and Background colours in 16M mode.
I suspect not!
And no one has offered a solution to a white screen in said mode. Please someone!
I wrote a little program...
MODE MODE
GCOL &8F :REM Yellow background
VDU 24,200;200;1000;900;
CLG
GCOL &FF :REM White background
VDU 24,300;300;1080;800;
CLG
PRINT "done"
and when running at X1920 Y1080 C16M I get a yellow rectangle on a
black screen, mostly covered by a white rectangle - which seems to be
what you want?
That is the same on...
Titanium with RO5.29 and BASIC v1.81
VRPC with RO4.39 and BASIC v1.80 (softloaded)
VRPC with RO4.39 and BASIC v1.29
Does that answer your question?
If not, then a misbehaving program might help.
--
Martin Avison
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received.
Thanks to all for suggestions

To J Peach = GCOL 0,191 TINT 192 seems to work.
To Martin, thanks, I'll have a play with your prog.
To Chris - didn't know about ColourTrans_SetGCOL, and can't fathom at present how to use it to set a white background, but I'll persevere.

Again much thanks to a great community.
J Peachey
2021-05-13 14:04:20 UTC
Permalink
Post by George Pearce
Post by Steve Fryatt
On 12 May, Richard Ashbery wrote in message
Post by Richard Ashbery
Post by George Pearce
I am simply trying to open a graphics window with a white background in
16 million colour mode in RIScOS 4.?. I am calling MODE MODE in
1900x1080p. GCOL seems to have been extended in v5.
Best I can do is GCOL 0, 191, which seem to give a light grey rather
than full white. I can obviously correct this after the event, but am
sure there must be a solution which I have yet to discover.
GCOL ON 255,255,255 : CLG
That's RISC OS 5 only, so doesn't meet the OP's requirement of RISC OS 4
unless soft-loading BASIC is up for consideration.
GCOL 0, 255, 255, 255 : CLG might do what's required, though.
--
Steve Fryatt - Leeds, England
http://www.stevefryatt.org.uk/
No, that does not work, screen colour is still black.
It seems to me there is an issue with COL, GCOL in 16 million mode, with
no distinction between foreground and background colours, and no palette
as such. In 16 and 256 colour modes , colours up to 128 are foreground,
and above that are background.
I'm now very confused. I think the BASIC manual needs updating to deal
with the larger monitor resolutions we now mostly have, and the entries
for COL and GCOL need to address 16million mode.
I understand their application in 16 and 256 colour modes, though I do
find the manual a bit confusing.
George Pearce
What about GCOL 0,255 TINT 4. Although the manual implies tint is for
256/16 colour modes it does have an effect on my machine.

Have you tried the basic help - help GCOl which might give you a hint as
to what RO4 can offer?

John
--
_________________________________________
| University of Glos. Blighting Longlevens.
| mailto:***@jpeachey.co.uk
_______________________| http://www.jpeachey.co.uk
Steve Fryatt
2021-05-13 20:52:10 UTC
Permalink
On 13 May, George Pearce wrote in message
Post by George Pearce
It seems to me there is an issue with COL, GCOL in 16 million mode, with
no distinction between foreground and background colours,
That appears to be the case with the

GCOL mode, r, g, b

form that's in RISC OS 4's BASIC; it's foreground colour only if you want
the RGB option.

The RISC OS 5 version of BASIC (which as I've noted already can be
soft-loaded on to RISC OS 4 systems and is an improvement in a number of
ways) has the

GCOL ON mode, r, g, b

to set the background colour (plus

GCOL OF mode, r, g, b

to explicitly set the foreground).
Post by George Pearce
and no palette as such.
Correct: the 32k and 16M modes don't have a pallette.
Post by George Pearce
I think the BASIC manual needs updating to deal with the larger monitor
resolutions we now mostly have, and the entries for COL and GCOL need to
address 16million mode.
This has already been done. You can download a PDF from the bottom of

https://www.riscosopen.org/content/downloads/common

but the printed version (which is what I referred to for my comments above
and in my previous post) is well worth the money.

https://www.riscosopen.org/content/sales/bbc-basic-reference
--
Steve Fryatt - Leeds, England

http://www.stevefryatt.org.uk/
George Pearce
2021-05-14 09:54:10 UTC
Permalink
Post by Steve Fryatt
On 13 May, George Pearce wrote in message
Post by George Pearce
It seems to me there is an issue with COL, GCOL in 16 million mode, with
no distinction between foreground and background colours,
That appears to be the case with the
GCOL mode, r, g, b
form that's in RISC OS 4's BASIC; it's foreground colour only if you want
the RGB option.
The RISC OS 5 version of BASIC (which as I've noted already can be
soft-loaded on to RISC OS 4 systems and is an improvement in a number of
ways) has the
GCOL ON mode, r, g, b
to set the background colour (plus
GCOL OF mode, r, g, b
to explicitly set the foreground).
Post by George Pearce
and no palette as such.
Correct: the 32k and 16M modes don't have a pallette.
Post by George Pearce
I think the BASIC manual needs updating to deal with the larger monitor
resolutions we now mostly have, and the entries for COL and GCOL need to
address 16million mode.
This has already been done. You can download a PDF from the bottom of
https://www.riscosopen.org/content/downloads/common
but the printed version (which is what I referred to for my comments above
and in my previous post) is well worth the money.
https://www.riscosopen.org/content/sales/bbc-basic-reference
--
Steve Fryatt - Leeds, England
http://www.stevefryatt.org.uk/
I have already bought the excellent new BASIC manual.
I would like to try soft loading the new BASIC into RISC OS 4.39, but can't seem to find it (only complete OS or Harddisc4) or instructions about softloading when found.
I presume it is a module. Will it replace the existing BASIC, or be an addition, and if the latter how is it invoked.

Many thanks for your patience with a doddering 85 year old - I used to know lots of stuff!!

George Pearce
Martin
2021-05-14 10:05:25 UTC
Permalink
Post by George Pearce
I would like to try soft loading the new BASIC into RISC OS 4.39,
but can't seem to find it (only complete OS or Harddisc4) or
instructions about softloading when found. I presume it is a
module. Will it replace the existing BASIC, or be an addition, and
if the latter how is it invoked.
I have emailed you a zip file which should help.

Martin
--
Martin Avison
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received.
George Pearce
2021-05-14 14:50:08 UTC
Permalink
Post by Martin
Post by George Pearce
I would like to try soft loading the new BASIC into RISC OS 4.39,
but can't seem to find it (only complete OS or Harddisc4) or
instructions about softloading when found. I presume it is a
module. Will it replace the existing BASIC, or be an addition, and
if the latter how is it invoked.
I have emailed you a zip file which should help.
Martin
--
Martin Avison
Note that unfortunately this email address will become invalid
without notice if (when) any spam is received.
Thanks Martin
Absolutely brilliant. All seems well on first installation into Virtual Acorn

George

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