ref: df03eca7e7cbfadf1cf8c8c5a94390eaa5013a8b
dir: /appl/lib/winplace.b/
implement Winplace;
#
# Copyright © 2003 Vita Nuova Holdings Limited
#
include "sys.m";
sys: Sys;
include "draw.m";
draw: Draw;
Rect, Point: import draw;
include "winplace.m";
Delta: adt {
d: int; # +1 or -1
wid: int; # index into wr
coord: int; # x/y coord
};
EW, NS: con iota;
Lay: adt {
d: int;
x: fn(l: self Lay, p: Point): int;
y: fn(l: self Lay, p: Point): int;
mkr: fn(l: self Lay, r: Rect): Rect;
};
init()
{
sys = load Sys Sys->PATH;
draw = load Draw Draw->PATH;
}
place(wins: list of Rect, scr, lastrect: Rect, minsize: Point): Rect
{
found := find(wins, scr);
if(found != nil){
# first look for any spaces big enough to hold minsize;
# choose top-left of those available.
(ok, best) := findfit(found, minsize);
if (ok){
if(minsize.x == 0)
return best;
return (best.min, best.min.add(minsize));
}
if(minsize.x == 0)
minsize = scr.size().div(2);
}
# no big enough space; try to avoid covering titlebars
tfound := find(titlebarrects(wins), scr);
(ok, best) := findfit(tfound, minsize);
if (ok)
return (best.min, best.min.add(minsize));
tfound = nil;
# no areas available - just find somewhere.
if(found == nil)
return somespace(scr, lastrect, minsize);
# no big enough space found; find the largest area available
# that will fit within minsize
best = clipsize(hd found, minsize);
area := best.dx() * best.dy();
for (fl := tl found; fl != nil; fl = tl fl) {
r := clipsize(hd fl, minsize);
rarea := r.dx() * r.dy();
if (rarea > area || (rarea == area && better(r, best)))
(area, best) = (rarea, r);
}
best.max = best.min.add(minsize);
return checkrect(best, scr);
}
findfit(found: list of Rect, minsize: Point): (int, Rect)
{
best: Rect;
ok := 0;
for (fl := found; fl != nil; fl = tl fl) {
r := hd fl;
if (r.dx() < minsize.x || r.dy() < minsize.y)
continue;
if (!ok || better(r, best)) {
best = r;
ok++;
}
}
return (ok, best);
}
TBARWIDTH: con 100;
TBARHEIGHT: con 20;
titlebarrects(rl: list of Rect): list of Rect
{
nl: list of Rect;
for (; rl != nil; rl = tl rl) {
r := hd rl;
tr := Rect((r.max.x - TBARWIDTH, r.min.y),
(r.max.x, r.min.y + TBARHEIGHT));
if (tr.min.x < r.min.x)
tr.min.x = r.min.x;
if (tr.max.y > r.max.y)
tr.max.y = r.max.y;
nl = tr :: nl;
}
return nl;
}
somespace(scr, lastrect: Rect, minsize: Point): Rect
{
r := Rect(lastrect.min, lastrect.min.add(minsize)).addpt((20, 20));
if (r.max.x > scr.max.x || r.max.y > scr.max.y)
r = Rect(scr.min, scr.min.add(minsize));
return r;
}
checkrect(r, scr: Rect): Rect
{
# make sure it's all on screen
if (r.max.x > scr.max.x) {
dx := r.max.x - scr.max.x;
r.max.x -= dx;
r.min.x -= dx;
}
if (r.max.y > scr.max.y) {
dy := r.max.y - scr.max.y;
r.max.y -= dy;
r.min.y -= dy;
}
# make sure origin is on screen.
off := r.min.sub(scr.min);
if (off.x > 0)
off.x = 0;
if (off.y > 0)
off.y = 0;
r = r.subpt(off);
return r;
}
# return true if r1 is ``better'' placed than r2, all other things
# being equal.
# currently we choose top-most, left-most, in that order.
better(r1, r2: Rect): int
{
return r1.min.y < r2.min.y ||
(r1.min.y == r2.min.y && r1.min.x < r2.min.x);
}
clipsize(r: Rect, size: Point): Rect
{
if (r.dx() > size.x)
r.max.x = r.min.x + size.x;
if (r.dy() > size.y)
r.max.y = r.min.y + size.y;
return r;
}
find(wins: list of Rect, scr: Rect): list of Rect
{
n := len wins + 4;
wr := array[n] of Rect;
for (; wins != nil; wins = tl wins)
wr[--n] = hd wins;
scr2 := scr.inset(-1);
# border sentinels
wr[3] = Rect((scr.min.x,scr2.min.y), (scr.max.x, scr.min.y)); # top
wr[2] = Rect((scr2.min.x, scr2.min.y), (scr.min.x, scr2.max.y)); # left
wr[1] = Rect((scr.min.x, scr.max.y), (scr.max.x, scr2.max.y)); # bottom
wr[0] = Rect((scr.max.x, scr2.min.y), (scr2.max.x, scr2.max.y)); # right
found := sweep(wr, Lay(EW), nil);
return sweep(wr, Lay(NS), found);
}
sweep(wr: array of Rect, lay: Lay, found: list of Rect): list of Rect
{
# sweep through in the direction of lay,
# adding and removing end points of rectangles
# as we pass them, and maintaining list of current viable rectangles.
maj := sortcoords(wr, lay);
(cr, ncr) := (array[len wr * 2] of Delta, 0);
rl: list of Rect; # ordered by lay.y(min)
for (i := 0; i < len maj; i++) {
wid := maj[i].wid;
if (maj[i].d > 0)
ncr = addwin(cr, ncr, wid, lay.y(wr[wid].min), lay.y(wr[wid].max));
else
ncr = removewin(cr, ncr, wid, lay.y(wr[wid].min), lay.y(wr[wid].max));
nrl: list of Rect = nil;
count := 0;
for (j := 0; j < ncr - 1; j++) {
count += cr[j].d;
(start, end) := (cr[j].coord, cr[j+1].coord);
if (count == 0 && end > start) {
nf: list of Rect;
(rl, nrl, nf) = select(rl, nrl, maj[i].coord, start, end);
for (; nf != nil; nf = tl nf)
found = addfound(found, lay.mkr(hd nf));
}
}
for (; rl != nil; rl = tl rl) {
r := hd rl;
r.max.x = maj[i].coord;
found = addfound(found, lay.mkr(r));
}
for (; nrl != nil; nrl = tl nrl)
rl = hd nrl :: rl;
nrl = nil;
}
return found;
}
addfound(found: list of Rect, r: Rect): list of Rect
{
if (r.max.x - r.min.x < 1 ||
r.max.y - r.min.y < 1)
return found;
return r :: found;
}
select(rl, nrl: list of Rect, xcoord, start, end: int): (list of Rect, list of Rect, list of Rect)
{
found: list of Rect;
made := 0;
while (rl != nil) {
r := hd rl;
r.max.x = xcoord;
(rstart, rend) := (r.min.y, r.max.y);
if (rstart >= end)
break;
addit := 1;
if (rstart == start && rend == end) {
made = 1;
} else {
if (!made && rstart > start) {
nrl = ((xcoord, start), (xcoord, end)) :: nrl;
made = 1;
}
if (rend > end || rstart < start) {
found = r :: found;
if (rend > end)
rend = end;
if (rstart < start)
rstart = start;
if (rstart >= rend)
addit = 0;
(r.min.y, r.max.y) = (rstart, rend);
}
}
if (addit)
nrl = r :: nrl;
rl = tl rl;
}
if (!made)
nrl = ((xcoord, start), (xcoord, end)) :: nrl;
return (rl, nrl, found);
}
removewin(d: array of Delta, nd: int, wid: int, min, max: int): int
{
minidx := finddelta(d, nd, Delta(+1, wid, min));
maxidx := finddelta(d, nd, Delta(-1, wid, max));
if (minidx == -1 || maxidx == -1 || minidx == maxidx) {
sys->fprint(sys->fildes(2),
"bad delta find; minidx: %d; maxidx: %d; wid: %d; min: %d; max: %d\n",
minidx, maxidx, wid, min, max);
raise "panic";
}
d[minidx:] = d[minidx + 1:maxidx];
d[maxidx - 1:] = d[maxidx + 1:nd];
return nd - 2;
}
addwin(d: array of Delta, nd: int, wid: int, min, max: int): int
{
(minidx, maxidx) := (findcoord(d, nd, min), findcoord(d, nd, max));
d[maxidx + 2:] = d[maxidx:nd];
d[maxidx + 1] = Delta(-1, wid, max);
d[minidx + 1:] = d[minidx:maxidx];
d[minidx] = Delta(+1, wid, min);
return nd + 2;
}
finddelta(d: array of Delta, nd: int, df: Delta): int
{
idx := findcoord(d, nd, df.coord);
for (i := idx; i < nd && d[i].coord == df.coord; i++)
if (d[i].wid == df.wid && d[i].d == df.d)
return i;
for (i = idx - 1; i >= 0 && d[i].coord == df.coord; i--)
if (d[i].wid == df.wid && d[i].d == df.d)
return i;
return -1;
}
findcoord(d: array of Delta, nd: int, coord: int): int
{
(lo, hi) := (0, nd - 1);
while (lo <= hi) {
mid := (lo + hi) / 2;
if (coord < d[mid].coord)
hi = mid - 1;
else if (coord > d[mid].coord)
lo = mid + 1;
else
return mid;
}
return lo;
}
sortcoords(wr: array of Rect, lay: Lay): array of Delta
{
a := array[len wr * 2] of Delta;
j := 0;
for (i := 0; i < len wr; i++) {
a[j++] = (+1, i, lay.x(wr[i].min));
a[j++] = (-1, i, lay.x(wr[i].max));
}
sortdelta(a);
return a;
}
sortdelta(a: array of Delta)
{
n := len a;
for(m := n; m > 1; ) {
if(m < 5)
m = 1;
else
m = (5*m-1)/11;
for(i := n-m-1; i >= 0; i--) {
tmp := a[i];
for(j := i+m; j <= n-1 && tmp.coord > a[j].coord; j += m)
a[j-m] = a[j];
a[j-m] = tmp;
}
}
}
Lay.x(l: self Lay, p: Point): int
{
if (l.d == EW)
return p.x;
return p.y;
}
Lay.y(l: self Lay, p: Point): int
{
if (l.d == EW)
return p.y;
return p.x;
}
Lay.mkr(l: self Lay, r: Rect): Rect
{
if (l.d == EW)
return r;
return ((r.min.y, r.min.x), (r.max.y, r.max.x));
}