Screenshots

Broken link? Feature request? Anything related to the Spectrum Computing website here.
4thRock
Microbot
Posts: 178
Joined: Thu Nov 09, 2017 9:35 am
Location: Portugal
Contact:

Re: Screenshots

Post by 4thRock »

kolbeck wrote:
Fri Jul 31, 2020 8:29 am
Not completely true - take a look at https://spectrumcomputing.co.uk/entry/32034 - it generates a 320x240 display on ZX81 - also there a few other demos that goes beyond the 256pixels width. I know it's really edge cases, just to get the facts correct :-)
Thanks for the info it's important. On this case the .scr is just cropping the image, another format would be better (as Einar mentioned).
All these titles are marked as ZX81 Hi-res: WRX , right ?

Meanwhile, you might have noticed that ZX80 and ZX81 titles now display a white border by default.
There's also progress on displaying different border colours (using the existing .SCR and .GIFs), yet more work is needed.
This so that you guys know that this discussion is helpful and things are progressing in the background. ;)
1 x

User avatar
Einar Saukas
Dynamite Dan
Posts: 1311
Joined: Wed Nov 15, 2017 2:48 pm

Re: Screenshots

Post by Einar Saukas »

4thRock wrote:
Fri Jul 31, 2020 12:57 pm
There's also progress on displaying different border colours (using the existing .SCR and .GIFs), yet more work is needed.
Currently all screenshots have black border by default, except ZX80/ZX81 screenshots that have white border by default.

However this information is configurable. For instance, the running screen for 10 OTHELLO has blue border, the running screens for Ad Lunam Plus have white border.

If anyone notices anything else that needs fixing, please help to fill this spreadsheet!
1 x

4thRock
Microbot
Posts: 178
Joined: Thu Nov 09, 2017 9:35 am
Location: Portugal
Contact:

Re: Screenshots

Post by 4thRock »

Added a few more games to the spreadsheet! :D
0 x

User avatar
Einar Saukas
Dynamite Dan
Posts: 1311
Joined: Wed Nov 15, 2017 2:48 pm

Re: Screenshots

Post by Einar Saukas »

4thRock wrote:
Sat Aug 01, 2020 4:56 pm
Added a few more games to the spreadsheet! :D
Thank you!
0 x

User avatar
kolbeck
Microbot
Posts: 144
Joined: Mon Nov 13, 2017 9:04 pm

Re: Screenshots

Post by kolbeck »

First attempt at converting ZX81 screen dump in BMP to ASCII / ZX81 Character set.

Left is the ASCII (Unicode) Rendering, and Right is the BMP as produced by EightyOne. There are only a few characters not easily available for printing, but that's not important. The program also produces a 768 bytes file, containing values from 0-192 representing the ZX81 characters found.

Image

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

4thRock
Microbot
Posts: 178
Joined: Thu Nov 09, 2017 9:35 am
Location: Portugal
Contact:

Re: Screenshots

Post by 4thRock »

Found an interesting reference to timings of non-interlaced PAL:
http://blog.retroleum.co.uk/electronics ... -voltages/

Image
0 x

User avatar
Einar Saukas
Dynamite Dan
Posts: 1311
Joined: Wed Nov 15, 2017 2:48 pm

Re: Screenshots

Post by Einar Saukas »

moroz1999 wrote:
Sun Jul 26, 2020 11:04 pm
Einar Saukas wrote:
Sat Jul 25, 2020 12:30 am
The ZX81 screen only contains 256x192 pixels without attributes, so nothing can be lost in a conversion to SCR (using black INK/white PAPER). Although it would be even better to store ZX81 screens as a simple sequence of 24x32=768 bytes (one byte for each character on screen). Perhaps we can convince @moroz1999 to support this new format? :)
No problem! I just need a short description and one sample to test it with.
Each S81 file should have exactly 24 rows x 32 columns = 768 bytes (one byte for each character on screen), stored from left to right, top to bottom. The bit 6 of each byte should always be zero (otherwise the file is considered invalid), therefore valid values for each byte are 0..63 or 128..191. Each byte value corresponds to a character image from the ZX81 charset. The pixel images for the first 64 characters are stored in the standard ZX81 ROM starting at address $1E00. The other 64 characters are exactly the same characters, but inverted.

The color is always black INK on white PAPER. The resulting image size should be 256 pixels wide by 192 pixels high, without border.

Here's a sample S81 file and the corresponding SCR file. Also I already added a S81 screenshot to this page so it can be used for testing.

Thank you!
0 x

User avatar
Einar Saukas
Dynamite Dan
Posts: 1311
Joined: Wed Nov 15, 2017 2:48 pm

Re: Screenshots

Post by Einar Saukas »

The S80 format is identical to S81, except using the ZX80 charset. The pixel images for the first 64 characters are stored in the standard ZX80 ROM starting at address $0E00.
0 x

Post Reply