local box = require'box2d'Math for 2D rectangles defined as (x, y, w, h).
| representation forms | |
box.corners(x, y, w, h) -> x1, y1, x2, y2 |
left,top and right,bottom corners |
box.rect(x1, y1, x2, y2) -> x, y, w, h |
box given left,top and right,bottom corners |
| layouting | |
box.align(w, h, halign, valign,bx, by, bw, bh) -> x, y, w, h |
align a box in another box |
box.vsplit(i, sh, x, y, w, h) -> x, y, w, h |
slice a box horizontally at a certain height and return the i'th box. if sh is negative, slicing is done from the bottom side. |
box.hsplit(i, sw, x, y, w, h) -> x, y, w, h |
slice a box vertically at a certain width and return the i'th box. if sw is negative, slicing is done from the right side. |
box.nsplit(i, n, direction, x, y, w, h) -> x, y, w, h |
slice a box in n equal slices, vertically or horizontally, and return the i'th box. direction = 'v' or 'h' |
box.translate(x0, y0, x, y, w, h) -> x, y, w, h |
move a box |
box.offset(d, x, y, w, h) -> x, y, w, h |
offset a box by d, outward if d is positive |
box.fit(w, h, bw, bh) -> w, h |
fit a box into another box preserving aspect ratio. use align() to position the box |
| hit testing | |
box.hit(x0, y0, x, y, w, h) -> true | false |
check if a point (x0, y0) is inside rect (x, y, w, h) |
box.hit_edges(x0, y0, d, x, y, w, h)-> hit, left, top, right, bottom |
hit test for edges and corners |
| edge snapping | |
box.snap_edges(d, x, y, w, h, rectangles[, opaque])-> x, y, w, h |
snap the sides of a rectangle against a list of rectangles of form {{x=,y=,w=,h=},...}. if opaque = true, the rectangles are considered opaque, in which case they must be sorted front-to-back. |
box.snap_pos(d, x, y, w, h, rectangles[, opaque])-> x, y, w, h |
snap the position of a rectangle against a list of rectangles. |
box.snapped_edges(d, x1, y1, w1, h1, x2, y2, w2, h2[, opaque])-> snapped, left, top, right, bottom |
check if two boxes are snapped and on which edges. |
| overlapping test | |
box.overlapping(x1, y1, w1, h1, x2, y2, w2, h2) -> true | false |
check if two boxes overlap. |
| clipping | |
box.clip(x, y, w, h, x0, y0, w0, h0) -> x1, y1, w1, h1 |
clip box (x, y, w, h) to fit inside box (x0, y0, w0, h0) |
Operations never mutate the object, instead they return a new one.
box(x, y, w, h) -> box |
create a new box object |
box.x, box.y, box.w, box.h |
box coordinates (for reading and writing) |
box:rect() -> x, y, w, h box() -> x, y, w, h |
coordinates unpacked |
box:corners() -> x1, y1, x2, y2 |
left,top and right,bottom corners |
box:align(halign, valign, parent_box) -> box |
align |
box:vsplit(i, sh) -> box |
split vertically |
box:hsplit(i, sw) -> box |
split horizontally |
box:nsplit(i, n, direction) -> box |
split in equal parts |
box:translate(x0, y0) -> box |
translate |
box:offset(d) -> box |
offset by d (outward if d is positive) |
box:fit(parent_box, halign, valign) -> box |
enlarge/shrink-to-fit and align |
box:hit(x0, y0) -> true | false |
hit test |
box:hit_edges(x0, y0, d) -> hit, left, top, right, bottom |
hit test for edges |
box:snap_edges(d, boxes) -> box |
snap the edges to a list of boxes |
box:snap_pos(d, boxes) -> box |
snap the position |
box:overlapping(box) -> true | false |
overlapping test |
box:clip(box) -> box |
clip box to fit inside another box |