ref: 9b93e2f3b8bfb3010e224ae540c3d74e53f308c2
dir: lua9/doc/README.md
# lua9 Documentation lua9 is a custom [lua](http://lua.org) interpreter including bindings to various plan9 libraries. This document is not meant to replace the plan9 documentation, please refer to the man pages in [section 2](http://man.9front.org/2/) for the documentation of individual functions. ## Notes The API is mostly a one-for-one translation of the C API with some slight changes to make the API feel more "lua-ish". The most significant differences are: * The API is split across several modules (draw, event, etc.). * Naming respects lua conventions instead of their original C name. * Functions that take pointers as out parameters (e.g. event) instead return the value and may return multiple values (e.g. icossin). * In lua, indices start at one not zero. The API respects the lua convention for function returning indices (e.g. emenuhit) * Value types (e.g. Point, Rectangle) are mapped as lua tables, reference types (e.g. Image, Font) as userdata. ## API Reference ### Module `draw` #### `draw.init(title)` This is the C `initdraw` function. The important difference is that it does not handle the additional parameters allowed by `initdraw`. When called, `init` will check for the existence of an `eresized` function as with the C API. Upon success, three global variables are defined: `display`, `screen` and `font`. #### `draw.draw(dst, r, src, mask, p)` #### `draw.replxy(min, max, x)` #### `draw.repl(r, p)` #### `draw.replclipr(i, r, clipr)` #### `draw.line(dst, p0, p1, end0, end1, thick, src, sp)` #### `draw.poly(dst, pts, end0, end1, radius, src, sp)` #### `draw.fillpoly(dst, pts, wind, src, sp)` #### `draw.bezier(dst, p0, p1, p2, p3, end0, end1, radius, src, sp)` #### `draw.fillbezier(dst, p0, p1, p2, p3, w, src, sp)` #### `draw.bezspline(dst, pts, end0, end1, radius, src, sp)` #### `draw.fillbezspline(dst, pts, w, src, sp)` #### `draw.ellipse(dst, c, a, b, thick, src, sp)` #### `draw.fillellipse(dst, c, a, b, src, sp)` #### `draw.arc(dst, c, a, b, thick, src, sp, alpha, phi)` #### `draw.fillarc(dst, c, a, b, src, sp, alpha, phi)` #### `draw.icossin(deg)` Returns two values: `cosp` and `sinp` #### `draw.icossin2(x, y)` Returns two values: `cosp` and `sinp` #### `draw.border(dst, r, i, color, sp)` #### `draw.string(dst, p, src, sp, f, s)` #### `draw.stringn(dst, p, src, sp, f, s, len)` #### `draw.stringbg(dst, p, src, sp, f, s, bg, bgp)` #### `draw.stringnbg(dst, p, src, sp, f, s, len, bg, bgp)` #### `draw.allocimage(d, r, chan, repl, col)` #### `draw.allocimagemix(d, one, three)` #### Constants The following constants are exported: * `END_SQUARE`, `END_DISC`, `END_ARROW`, `END_MASK` ### Module `event` #### `event.init(keys)` Initialize event handling. This is the `einit` C function. #### `event.event()` Returns: * The event key * The event structure #### `event.kbd()` #### `event.canmouse()` #### `event.cankbd()` #### `event.timer(key, n)` #### `event.enter(ask, s, m)` The `s` parameter is used as an initial value in the text field. #### `event.menuhit(but, m, menu)` The `menu` is expected to be a table of strings. The generation of menu items is not supported currently. Returns: - Selected index (starting at 1) or `nil` #### Constants The following constants are exported: * `MOUSE`, `KEYBOARD` ### Module `g` Geometry related functions. #### `g.pt(x, y)` #### `g.rect(x0, y0, x1, y1)` #### `g.rpt(p, q)` #### `g.addpt(p, q)` #### `g.subpt(p, q)` #### `g.mulpt(p, a)` #### `g.divpt(p, a)` #### `g.rectaddpt(r, p)` #### `g.rectsubpt(r, p)` #### `g.insetrect(r, n)` #### `g.canonrect(r)` #### `g.eqpt(p, q)` #### `g.eqrect(r, s)` #### `g.ptinrect(p, r)` #### `g.rectinrect(r, s)` #### `g.rectxrect(r, s)` #### `g.badrect(r)` #### `g.dx(r)` #### `g.dy(r)` ### Module `key` #### `key.eq(k, str)` Checks whether k is equal to str. This is a convenience function to help with lua not having a character type. #### Constants The following constants are exported: * `HOME`, `UP`, `DOWN`, `PGUP`, `PRINT`, `LEFT`, `RIGHT`, `PGDOWN`, `INS`, `END`, `SOH`, `STX`, `ETX`, `EOF`, `ENQ`, `ACK`, `BS`, `NACK`, `ETB`, `DEL`, `ESC`. ### Module `color` #### Constants The following constants are exported: * `OPAQUE`, `TRANSPARENT`, `BLACK`, `WHITE`, `RED`, `GREEN`, `BLUE`, `CYAN`, `MAGENTA`, `YELLOW`, `PALE_YELLOW`, `DARK_YELLOW`, `PALE_GREEN`, `DARK_GREEN`, `MED_GREEN`, `DARK_BLUE`, `PALE_BLUE_GREEN`, `PALE_BLUE`, `BLUE_GREEN`, `GREY_GREEN`, `PALE_GREY_GREEN`, `YELLOW_GREEN`, `MED_BLUE`, `GREY_BLUE`, `PALE_GREY_BLUE`, `PURPLE_BLUE`, `NOT_A_COLOR`, `NO_FILL`