ZX81 BMP converter

For those of you watching in black and white, the pink is next to the green...
User avatar
kolbeck
Microbot
Posts: 166
Joined: Mon Nov 13, 2017 9:04 pm

Re: ZX81 BMP converter

Post by kolbeck »

pavero wrote:
Thu Aug 13, 2020 8:03 pm
Maybe small improvement. It doesn't work for BMP files without a border - 256 x 192 pixels only. ;)
Hi @pavero - please try again, it should now support all sizes from EO

* No Border: 256x192 pixels
* Small Border: 264x200 pixels
* Standard Border: 320x240 pixels
* Large border: 400x300 pixels
* Full frame: 413x312 pixels

The PNG will of course have the same size as the input file. Also for large and full frame, the adjustment is not 100% correct - looks like the actual dump is not centered :-) Will be fixable when adjustment parameters are added.

/Thomas
0 x
https://zxinfo.dk - another ZXDB frontend
https://api.zxinfo.dk/ - ZXDB API for developers

User avatar
kolbeck
Microbot
Posts: 166
Joined: Mon Nov 13, 2017 9:04 pm

Re: ZX81 BMP converter

Post by kolbeck »

solaris104 wrote:
Thu Aug 13, 2020 8:19 pm
Some screenshot from EightyOne need correction.

Image

Image
@solaris104 - please try out the added correction parameters

/Thomas
0 x
https://zxinfo.dk - another ZXDB frontend
https://api.zxinfo.dk/ - ZXDB API for developers

4thRock
Microbot
Posts: 194
Joined: Thu Nov 09, 2017 9:35 am
Location: Portugal
Contact:

Re: ZX81 BMP converter

Post by 4thRock »

kolbeck wrote:
Fri Aug 14, 2020 12:01 pm
* Full frame: 413x312 pixels
Interesting. 312 lines seem to be the full extent of the generated TV signal, including non-visible sync lines:
Image
( http://blog.retroleum.co.uk/electronics ... -voltages/ )
0 x

User avatar
kolbeck
Microbot
Posts: 166
Joined: Mon Nov 13, 2017 9:04 pm

Re: ZX81 BMP converter

Post by kolbeck »

I have not seen any full frame programs yet, maybe a little challenge for our experts? :-)
0 x
https://zxinfo.dk - another ZXDB frontend
https://api.zxinfo.dk/ - ZXDB API for developers

solaris104
Berk
Posts: 13
Joined: Wed Jun 06, 2018 4:18 pm

Re: ZX81 BMP converter

Post by solaris104 »

kolbeck wrote:
Fri Aug 14, 2020 1:04 pm
@solaris104 - please try out the added correction parameters

/Thomas
Thank you, it's works :-)
0 x

pavero
Manic Miner
Posts: 403
Joined: Sat Dec 09, 2017 11:49 pm
Location: Czech Republic
Contact:

Re: ZX81 BMP converter

Post by pavero »

kolbeck wrote:
Fri Aug 14, 2020 12:01 pm
pavero wrote:
Thu Aug 13, 2020 8:03 pm
Maybe small improvement. It doesn't work for BMP files without a border - 256 x 192 pixels only. ;)
Hi @pavero - please try again, it should now support all sizes from EO

* No Border: 256x192 pixels
* Small Border: 264x200 pixels
* Standard Border: 320x240 pixels
* Large border: 400x300 pixels
* Full frame: 413x312 pixels

The PNG will of course have the same size as the input file. Also for large and full frame, the adjustment is not 100% correct - looks like the actual dump is not centered :-) Will be fixable when adjustment parameters are added.

/Thomas
Perfect! :-)
0 x

User avatar
kolbeck
Microbot
Posts: 166
Joined: Mon Nov 13, 2017 9:04 pm

Re: ZX81 BMP converter

Post by kolbeck »

@4thRock - look at this:
ZX81 Video Nonstandard Picture Size

The official picture size is 32x24 tiles (256x192 pixels) with huge borders. However, on a PAL screen, the ZX81 can display 40x34 tiles (320x272 pixels).
Info found on this page: https://problemkaputt.de/zxdocs.htm#zx8 ... esgraphics

/Thomas
1 x
https://zxinfo.dk - another ZXDB frontend
https://api.zxinfo.dk/ - ZXDB API for developers

User avatar
kolbeck
Microbot
Posts: 166
Joined: Mon Nov 13, 2017 9:04 pm

Re: ZX81 BMP converter

Post by kolbeck »

I have renamed the tool to ZX81 Screen Converter, as it how handles more than BMP files as input.

What is it?
ZX81 Screen Converter is an online tool target preserving ZX81 software for ZXDB, helping to create proper screen shots in formats like s81, scr and png. It take as input a screen dump file and converts to different formats. Allowed input formats:
* .bmp as produced by various emulators (e.g. EightyOne and SZ81)
* .png as produced by the ZX81 emulator for iOS (by Kevin Palser) and Retrospecs (Pixelate your pics!) also for iOS
* .s81 for standard non-hires ZX81 screens (a sequence of 768 character codes from the ZX81 charset)
* .scr widely used screen format used for ZX Spectrum screens, suitable for preserving ZX81 hi-res screens

It will always produce the following output:
* .s81 for standard non-hires ZX81 screens (a sequence of 768 character codes from the ZX81 charset) - if it is a hi-res screen, or the offset parameters is not correct - this will just be garbage.
* .scr for hires screens with regular size (in ZX Spectrum display format)
* .png for big screens, that goes beyond the 256x192 size (for example MaxDemo or QS Defenda)
* .txt for printing in console - mostly for fun (ANSI control codes to implement inverse print) - as with s81, it will be gargabe if hi-res or offset parameters are not aligned to 8x8 blocks. Use this to verify correct offset parameters.

For iOS ZX81 emulator, make sure to have at least v1.9.0 - as this version fixes some issues with the screen dump.

All border sizes from EightyOne with the following sizes are supported:
* No Border: 256x192 pixels
* Small Border: 264x200 pixels
* Standard Border: 320x240 pixels
* Large border: 400x300 pixels
* Full frame: 413x312 pixels

You can find the online converter here: https://zxinfo.dk/scr/ - and as always, leave a comment here :-)

/Thomas
1 x
https://zxinfo.dk - another ZXDB frontend
https://api.zxinfo.dk/ - ZXDB API for developers

User avatar
PeterJ
Site Admin
Posts: 2799
Joined: Thu Nov 09, 2017 7:19 pm
Location: Surrey, UK

Re: ZX81 BMP converter

Post by PeterJ »

I'm a bit late to the party with this one @kolbeck, but just to say Excellent!
0 x

Post Reply