LiTeX is a lightweight mathematical equation renderer for low-resolution LCDs built in Python or c++ with Arduino (developed for Teensy 4.0). It is similar to CASIO or Texas Instrument's "V.P.A.M" or "MathPrint".
It contains a customizable rendering engine using a LALR (look-ahead, left-to-right, rightmost derivation) parser. The parser accepts a string formatted similarly to LaTeX. There is also an optional 4-wire SPI library if you want to display LiTeX on a monochrome LCD. Currently, it is set up for an ST-7567 display.
There is also a customizable, in-place equation evaluator that evaluates any LiTeX equation into a complex number. The evaluator supports all of the functions included in LiTeX, and also supports implicit multiplication. It can solve single variable equations with x using newton's method. (Solver is currently Python-only)
- Self-resizing parenthesis
- Self-resizing radicals (nth root)
- Self-aligning fraction bars
- Exponents with smaller font
- Variable base log (using subscript)
- All 6 basic trigonometric functions: sin cos tan sec, etc..
- Inverse trig function of sin, cos, and tan
- Algebreic constants: e, pi, i, x
- Expression Evaluator with implicit multiplication support
- Complex number support with all functions
Expression syntax differs slightly from regular LaTeX when it comes to a few functions. To make the expression less ambiguous, easier for the parser to understand, and to make the code more lightweight, extra braces are required around a few functions. Functions that are not in this list are the same as in LaTeX.
Negative sign, which is shorter than the minus operator, can be specified by using the tilde (~). e.g. "~4+3" Using the minus operator in that example ("-4+3") does not yield an error, but it may cause unexpected errors if placed in other parts of the expression. It is best to use the tilde when specifying a negative number.
After realizing that the python implementation of negative sign is really bad, the ~ character is only recognized by the rendering engine. It is immediately replaced with - in the evaluator.
Exponents should look like this when they are inputted into both the renderer and the evaluator. e.g. "a^{b}" Braces are required even if there is only 1 digit in the exponent.
Like with exponents, braces are required around the contents of the subexpression. e.g. "a_{b}"
Radicals require the index of the root to be specified in braces before the radicand. e.g. "\sqrt{2}{3}" Renders and evaluates as the square root of 3.
To specify a trigonometric function, just type it out in the expression, followed by a set of parenthesis to indicate the contents. e.g. "sin(3)"
Inverse trig functions can be specified by adding "^{~1}" after specifying a trig function. e.g "sin^{~1} Default units for trig functions are radians.
Complex numbers are not specified with the letter i: "4+3i", but rather with the escape sequence "\im". Using "i" will print the letter i, as used in sine, not the imaginary number. e.g. "4+3\im"
All special constants: pi, e, etc.. require an escape sequence to render and evaluate properly. eg: "\e^{2\im\pi}"
r"1 + \e^{2\pi\im} - (3\sqrt{2}{\frac{sin(4)}{5}log_{6^{2}}(7) * 8} / 9)^{10}"
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--PRERENDER--
