nuru image editor for the browser. Still a work-in-progress, but already fun! Why not try out the current state?
nuru is a file format for ASCII art and ANSI art. That is, images made up of characters. nuru-web allows to easily create and edit nuru files right in your browser. It is made with vanilla JavaScript, so there are no dependencies.
nuru "images" are really just characters (with optional color information). They can therefore - and are designed to - be displayed on a terminal, also known as a command line interface. There is a wide variety of such "text mode" images out there. The main differences are in the supported character set and the supported colors. This basically comes down to the underlying technology; whatever the terminal of a given time/ machine was capable of displaying would define the limitations of the possible ASCII/ ANSI art. nuru files support an array of different character and color modes.
The following glyph modes are available:
- None: only the space character is used (this requires a color mode)
- ASCII: the first 256 ASCII characters (as per Unicode) can be used
- Unicode: any character from Unicode Plane 0 can be used (U+0000 - U+FFFF, 65535 characters)
- Palette: a separate palette file is used to provide 256 available glyphs
The following color modes are available:
- None: no colors available (this requires a glyph mode other than 'None')
- 4 bit: 16 colors as per 4-bit ANSI escape codes can be used
- 8 bit: 256 colors as per 8-bit ANSI escape codes can be used
- Palette: a separate palette file is used to provide 256 available colors
If no colors are being used, the default background and foreground colors of the terminal will be used when displaying the image. What those are depends on the terminal and its settings and is not known at the time of image creation.
Also, in 4-bit mode, the actual colors used will depend on the terminal and its settings. You basically just define "red" or "bright green"; it is up to the terminal to decide which color value to use to display that color.
Images usually have a way of encoding the absence of pixel data; also known as transparency. In case of text mode images, the same can be achieved by printing a space character without a background color. This would mean that the terminal will simply display its native background color and nothing else.
In a nuru file, this is not necessarily encoded as the actual space character, although that's the most obvious choice. Instead, you can freely designate any available character as the one to mean "no character". This is done with the "glyph key". By default, this is set to 32 (which corresponds to the index of the space character both in ASCII as well as Unicode). Changing it to another number will make the character at that index of the current character palette the one that will be displayed as space.
Similarly, as terminals have their native background and foreground colors, the need to encode "no specific color" and "no specific background color" arises. This can be achieved via the "fg key" and "bg key" values. These are also just indices into the currently used colors/ color palette. Whenever you use the foreground color at position "fg key" to draw, then the terminal's default foreground color will be used to render that cell. The same goes for the background color. This means that at least one of the available colors has to be sacrificed to become the one to signify the absence of any particular color.
