DaDither image converter

[DecAns]

Hi.

I'm developing a converter of full-color images to various retro platform formats. The BBC Micro platform is also supported. You can convert images to modes 0, 1, 2, 4, 5. 2+NuLA mode is also supported (BBC file format is used).

I have a couple of questions:
1) I'm using PAR 13:12. Is this the correct PAR? Does NuLA use the same PAR?
2) Are there standards for overscan images?

Screenshots:





Hope it will be useful to someone.

[brianmartin_2001]

Major congrats , that looks superb.

Sorry for my ignorance , but is Nula essential ( I assume for best results)
or can a regular Beeb produce similar?

[DecAns]

is Nula essential?

The first screenshot is a picture for a regular BBC, the second screenshot is a picture for NuLA.

[fizgog]

It's nice to see some development tools being created for the beeb, well done.

Looking forward to a release build

[DecAns]

Looking forward to a release build

I forgot to give the download link

Windows x86 and x64 versions.

[james]

This seems to be the website, run through Google and translated into English

[tricky]

There is the dithertron web site too.
Are you planning on supporting the pictures where you can change the palette entries each scan line?
The elk can swap 4 palette entries, but the beeb can only easily do 2 with a full width image.
This is mostly for mode 1 without nula, but you could probably change 3 nula palette entries per scan line iirc h how you spec them. You could also arrange to have colours 8..15 used and swap them for their alternate flash colours pretty much for free.
There are a couple of threads around somewhere along with my code and possibly another image converter with the palette entry code.

[DecAns]

Are you planning on supporting the pictures where you can change the palette entries each scan line?

I am not a BBC Micro user and have no knowledge of the internals of the BBC Micro. So I can only do this if you provide me with more details.

The elk can swap 4 palette entries, but the beeb can only easily do 2 with a full width image.

What is "elk"?

This is mostly for mode 1 without nula

Does BBC allow me to change the palette in mode 1? Can I use any 4 of the 8 colors to create an image in mode 1?

you could probably change 3 nula palette entries per scan line

Is there a file format specification for such files? Are there any examples of such files?

[tricky]

You can change part of the the palette at any time, so yes, mode 0 and 1 allow you to choose from the 8 basic colours and with appropriate code, this can be done per scan line, or even mid line with more complicated code.
The flaming colours can be stopped from flashing and there is a single register that controls which set of colours are visible, so if you had two non-flashing colours (0-7) and two flashing, the flashing ones could be swapped for their opposites very cheaply (my viewer didn't support this).
The Elk is there affectionate name for the Electron, like three beeb is for the BBC micro and then Arc or Archie for the Archimedes.
I'll try and find the thread, but from memory the file format was the screen data with two sets of 256 byes prepended where the byte encoded the palette entry to swap and the colour to swap it to. Sometimes it would swap to itself to keep the coffee simple.

[geraldholdsworth]

I forgot to give the download link

Windows x86 and x64 versions.

Any chance of macOS version?

[Cybershark]

Sometimes it would swap to itself to keep the coffee simple.

Am definitely a simple coffee man, myself. Black, one sugar

[tricky]

Code

[tricky]

One of the enhanced mode 1 threads viewtopic.php?t=10147

[DecAns]

Any chance of macOS version?

No. I am Windows developer and know nothing about Mac.

beeb can only easily do 2 with a full width image. This is mostly for mode 1 without nula

So, my very first trying to play around with Mode 1 and changing the palette:









For the final version, I need specifications for the format in which such files should be saved. And a couple of samples of such files.

[tricky]

I'll see if I can put something together this weekend as I understand that not being a beeb coder the stuff in viewtopic.php?p=122381#p122381 isn't any good to you.
It basically needs the four stating colours and the two to change on each line, encoded for the beeb.
I'll include the explanation for the encoding.

[DecAns]

I'll include the explanation for the encoding.

I hope one day you will find the time to make documentation.