ref: c4ecd0fee0f0cef485a223d6e638a56bafd5bbda
dir: /sys/src/libmemlayer/lorigin.c/
#include <u.h>
#include <libc.h>
#include <draw.h>
#include <memdraw.h>
#include <memlayer.h>
/*
* Place i so i->r.min = log, i->layer->screenr.min == scr.
*/
int
memlorigin(Memimage *i, Point log, Point scr)
{
Memlayer *l;
Memscreen *s;
Memimage *t, *shad, *nsave;
Rectangle x, newr, oldr;
Point delta;
int overlap, eqlog, eqscr, wasclear;
l = i->layer;
s = l->screen;
oldr = l->screenr;
newr = Rect(scr.x, scr.y, scr.x+Dx(oldr), scr.y+Dy(oldr));
eqscr = eqpt(scr, oldr.min);
eqlog = eqpt(log, i->r.min);
if(eqscr && eqlog)
return 0;
nsave = nil;
if(eqlog==0 && l->save!=nil){
nsave = allocmemimage(Rect(log.x, log.y, log.x+Dx(oldr), log.y+Dy(oldr)), i->chan);
if(nsave == nil)
return -1;
}
/*
* Bring it to front and move logical coordinate system.
*/
memltofront(i);
wasclear = l->clear;
if(nsave){
if(!wasclear)
memimagedraw(nsave, nsave->r, l->save, l->save->r.min, nil, Pt(0,0), S);
freememimage(l->save);
l->save = nsave;
}
delta = subpt(log, i->r.min);
i->r = rectaddpt(i->r, delta);
i->clipr = rectaddpt(i->clipr, delta);
l->delta = subpt(l->screenr.min, i->r.min);
if(eqscr)
return 0;
/*
* To clean up old position, make a shadow window there, don't paint it,
* push it behind this one, and (later) delete it. Because the refresh function
* for this fake window is a no-op, this will cause no graphics action except
* to restore the background and expose the windows previously hidden.
*/
shad = memlalloc(s, oldr, memlnorefresh, nil, DNofill);
if(shad == nil)
return -1;
s->frontmost = i;
if(s->rearmost == i)
s->rearmost = shad;
else
l->rear->layer->front = shad;
shad->layer->front = i;
shad->layer->rear = l->rear;
l->rear = shad;
l->front = nil;
shad->layer->clear = 0;
/*
* Shadow is now holding down the fort at the old position.
* Move the window and hide things obscured by new position.
*/
for(t=l->rear->layer->rear; t!=nil; t=t->layer->rear){
x = newr;
overlap = rectclip(&x, t->layer->screenr);
if(overlap){
memlhide(t, x);
t->layer->clear = 0;
}
}
l->screenr = newr;
l->delta = subpt(scr, i->r.min);
l->clear = rectinrect(newr, l->screen->image->clipr);
/*
* Everything's covered. Copy to new position and delete shadow window.
*/
if(wasclear)
memdraw(s->image, newr, s->image, oldr.min, nil, Pt(0,0), S);
else
memlexpose(i, newr);
memldelete(shad);
return 1;
}
void
memlnorefresh(Memimage *l, Rectangle r, void *v)
{
USED(l);
USED(r.min.x);
USED(v);
}