Picoterm support 2 types of Charset:
Non graphical Charset:
ASCII/VT100 mode where only 7 bits are used. The 8Th bit is used to invert the character to be displayed. This feature is used a lot under CP/M and retro boards. This font is based on Ubuntu Mono and defines only the chars from 0x20 to 0x7E.
At any moment, the \ESCG allows the terminal to returns this mode.
Graphical Charset:
ANSI mode where the 8th bit is used as part of charset encoding.
When Picoterm receives a \ESCF it switch to graphical font.
This charset is still based on Ubuntu Mono but includes lot additionnal chars. The font defines the chars from 0x20 to 0xFF.
Picoterm now support several graphical Charset (selected via the configuration screen).
| ID | Name | Description |
|---|---|---|
| 1 | NupetScii | Initial extended graphical charset combining lot of retro computer graphical chars This page also contains ressource to draw graphical ressources with NupetSCII. |
| 2 | CP437 | English IBM/MS-DOS Codepage used on a wide variety of computerized system |
The font8.c used in the original PicoTerm 80 column only defines the ASCII charset
(from 0 to 126. 127 is use for cursor display).
font8.c leaks of of nice graphical tile to create interface/forms/map/character/ (like Commodore 64 or Code Page 437 do have).
Extending ASCII charset would be a great idea to draw semi-graphical tables and rudimentary interfaces.
It is even possible to draw screen and maps by using the Playscii software (see further).
Here are the additionnal chars merged into the font8.c file.
font8.c + nupet.data ---( compile_font.py )---> mono8_nupetscii.c
font8.c + cp437.data ---( compile_font.py )---> mono8_cp437.c
If you are interested in Drawing & Rendering NuPetScii ressource in PicoTerm you can read:
- Mulitple Font-Face support
- Graphical Charset readme: explains how to create ressource and extract data
- Using NupetScii readme: some RC2014 assembly & codes related to NuPetScii usage on RC2014.
I discovered the NuPET font/charset designed by Tom Wilson on this Stefany Allaire article.
Tom did use its own Character-Editor to design the NuPET ASCII charset (and many other). Character-Editor is a ¢# opensource projet written available on GitHub.
Tom Wilson gracefuly authorise the usage of its NuPet font design in PicoTerm. Thanks to him for its sharing.
English IBM/MS-DOS Codepage used on a wide variety of computerized system in the world.
This character set remains the primary set in the core of any EGA and VGA-compatible graphics card. Many file formats developed at the time of the IBM PC are based on code page 437 as well (source: wikipedia.org).
Source: Code page 437n wikipedia.org
As NupetSCII, the cp437.c expand The font8.c (read details about NuPetScii to understand how it works).
font8.c + cp437.data ---( compile_font.py )---> cp437.c
If you want to draw screen or art with NuPetScii, you can use the Playscii from JP Lebreton, an open-source software written in Python3.
This software can be used on Windows, Mac and Linux. Linux version runs directly from source code.
Credit: Playscii by JP Lebreton
Some efforts have been made to create the NuPetSCII charset to create ressources with Playscii + NupetSCII.
The current folder contains the nupetscii-for-playscii.zip used to add NuPetScii font to PlayScii.
After installation of Playscii:
- open the nupetscii-for-playscii.zip archive.
- extract the
nupetscii.charandnupetscii.pngfiles from the archive. - copy the files in the
/charsetsfolder of Playscii software.
You can check that font is proprely installed by selecting the menu entry "char/color | Choose character set..." in the Playscii software.
Playscii is a great Python software to create ASCII based ressource/art.
Here is the docs/NupetSciiDemo.psci 49 x 15 art created with PlayScii.
The SPACEBAR is used to display/hide the toolbox.
In the toolbox, click on the "Set" to select the "nupetscii" character set.
Remark:
The "Palette" option stays on "c64_original".
The color data is currently not used as Picoterm display monochrom content.
When finished, select the menu "File | Save as".
And give a name to your file. It will be saved with the .psci extension.
Checking the psci file content reveal a storage format based on JSON. The format is quite simple and straightforward.
- The file contains frames
- Each frame contains layers
- Each layer contains tiles
- Each tile being a char (index in the charset) with additionnal properties.
So, accessing the characters/tiles of our 49 x 15 art is done with the following python expression (where data contains the loaded JSON).
screen = data['frames'][0]['layers'][0]['tiles']
The psci-extract.py python script can be used to convert the Playscii file to something more appropriate for the RC2014 computer (or SCM).
== PlayScii extractor 0.1 ==
Extract RC2014 data from art/screen drawed with playscii
by Meurisse D.
USAGE:
./psci-extract.py <filename.psci> -r -h
<filename> : the PlayScii saved file
-r : Create the .raw binary file (see description here below).
-hex <addr> : Create an Intel Hex file to store the raw data from
the given address (integer or hexadecimal like 0x8100).
-h : display this help.
=== .raw format ===
W : 1 byte, column Width
H : 1 byte, row Height
Data: column*row continuous bytes, Art/Screen data from row[1] to row[H].
Each row having W bytes (1 byte per column).
The following command creates the raw file with the data (see description here upper). This binary file can be very useful to store data onto the file system in a simple format (eg: CP/M).
python psci-extract.py ../docs/NupetSciiDemo.psci -r
You can check the NupetSciiDemo.raw file with an Hex Editor (the file is stored into the docs folder).
The following command create a HEX file (that can be uploaded to SCM) and store the data at a given address (0x8500 in the following example).
$ ./psci-extract.py ../docs/NupetSciiDemo.psci -hex 0x8500
NupetSciiDemo.psci to RC20214 SCM hex
source : ../docs/NupetSciiDemo.psci
charset : nupetscii
palette : c64_original
size : 49 x 15
layer name: Layer 1
data size : 737 bytes
target addr: 34048
file created @ ../docs/NupetSciiDemo.hex
You can check the NupetSciiDemo.hex file stored into the docs folder.
NuPetScii can be activated from PicoTerm menu and with ESC sequence (see README.md). So an application can request the terminal to switch to semi-graphical font (AKA NuPetScii) when needed.
See the examples described in the "using-nupetscii.md" document for more details.
The '.data' file is used to create the '.c' font compiled within Picoterm.
The file nupetscii.data contains the definition of the additional chars. This file will be compiled with the compile_font.py python script to generate the expanded font charset named nupetscii.c .
Remarks: the compile_font.py script will generates locally all the '.c' font for picoterm. Then '.c' file must be manually copied to the picoterm source code.
The nupetscii.c (and any other) file resulting from compile_font.py is the font file to be included within the PicoTerm sources.
Characters have the size of:
- 12px height * 8px wide (normal height)
- 15px height * 8px wide (extra height)
The char here below, sourced from nupetscii.data, is the biggest possible.
/* U+7F DEL=Frame (128) */
{.bitmap_index = @bitmap_index@, .adv_w = 128, .box_h = 15, .box_w = 8, .ofs_x = 0, .ofs_y = -3}
FFFFFFFF
F......F
F......F
F......F
F......F
F......F
F......F
F......F
F......F
F......F
F......F
F......F
F......F
F......F
FFFFFFFFY offet start at the bottom of char (the baseline). Descending chars like p,q use negative offset to properly align the char on the baseline.
The font can have 15 row height at the maximum with a descending offset of 3 pixels (-3). Normal characters (limited to the baseline) do makes 12 rows.
The original font is coded with 4 bit per pixel (4 bpp), so with values from 0 to F for each point.
The hexadecimal notation (0 to F) are used in the data file (one letter for each 4bpp entry)!
The dot is used inplace of "0" to improve the readability.