forked from Lephenixnoir/TeX
88 lines
3.2 KiB
Markdown
88 lines
3.2 KiB
Markdown
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# Natural display engine with TeX syntax for fx-9860G and fx-CG 50
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This library is a customizable 2D math rendering tool for calculators. It can be used to render 2D formulae, either from an existing structure or TeX syntax.
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```latex
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\frac{x_7}{\left\{\frac{\frac{2}{3}}{27}\right\}^2}
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```
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![Sample on a Graph 35+E II](https://framapic.org/CkFr4ab3FjcZ/bXQg9LyozGqg.jpg)
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## Features
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* Build formulae from TeX syntax
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* Highly-customizable graphical and layout parameters
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* Drawing is based on a few user-provided primitives (point, line, text size,
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text)
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* Compatible with fxlib and gint
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List of currently supported elements:
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* Fractions (`\frac`)
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* Subscripts and superscripts (`_` and `^`)
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* Grouping parentheses, brackets and braces (`\left` and `\right`)
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Features that are partially implemented (and what is left to finish them):
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* Support for inline style and display style (compute display-style subscript
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and superscript layout, and expose a parameter)
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* API functions to build TeX objects without a TeX formula (expose functions
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which are currently in the parser)
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* Full fx-CG 50 support (suitable parenthesis styles)
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See the `TODO.md` file for more features to come.
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## Building
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First specify the platform you want to use :
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* `cli` is for command-line tests, with no visualization (PC)
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* `sdl2` is an SDL interface with visualization (font support coming) (PC)
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* `fx9860g` builds the library for fx-9860G targets (calculator)
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* `fxcg50` builds the library for fx-CG 50 targets (calculator)
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For calculator platforms, you can use `--toolchain` to specify a different toolchain than the default `sh3eb` and `sh4eb`. The install directory of the library is guessed by asking the compiler, you can override it with `--prefix`.
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Example for an SDL setup:
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```sh
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% ./configure --platform=sdl2
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```
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Then you can make the program, and if it's a calculator library, install it. You can later delete `Makefile.cfg` to reset the configuration, or just reconfigure as needed.
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```sh
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% make
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% make install # fx9860g and fxcg50 only
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```
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## Using in a program
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Before using the library in a program, a configuration step is needed. The library does not have drawing functions and instead requires that you provide some, namely:
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* Draw a pixel (`TeX_intf_pixel`)
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* Draw a line (`TeX_intf_line`)
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* Compute the size occupied by a string (`TeX_intf_size`)
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* Render a string (`TeX_intf_text`)
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The three rendering functions are available in fxlib; for monospaced fonts the fourth can be implemented trivially. In gint, the four can be defined as wrappers for `dpixel()`, `dline()`, `dsize()` and `dtext()`.
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The type of formulae is `TeX_Flow`. To parse and compute the size of a formula, use the `TeX_parse()` functions, which returns a new formula object (or `NULL` if a critical error occurs).
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```c
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char *code = "\\frac{x_7}{\\left\\{\\frac{\\frac{2}{3}}{27}\\right\\}^2}";
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struct TeX_Flow *formula = TeX_parse(code);
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```
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The size of the formula can be queried through `formula->width` and `formula->height`. To render, specify the location of the top-left corner and the drawing color (which will be passed to all primitives):
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```c
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TeX_draw(formula, 0, 0, BLACK);
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```
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The same formula can be drawn several times. When it is no longer needed, free it with `TeX_free()`:
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```c
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TeX_free(formula);
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```
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