Import sources from 2011-03-30 iso image

1 files changed, 2203 insertions, 0 deletions

diff --git a/sys/src/9/port/devdraw.c b/sys/src/9/port/devdraw.c
new file mode 100755
index 000000000..d11ab05a2
--- /dev/null
+++ b/sys/src/9/port/devdraw.c
@@ -0,0 +1,2203 @@
+#include	"u.h"
+#include	"../port/lib.h"
+#include	"mem.h"
+#include	"dat.h"
+#include	"fns.h"
+#include	"../port/error.h"
+
+#define	Image	IMAGE
+#include	<draw.h>
+#include	<memdraw.h>
+#include	<memlayer.h>
+#include	<cursor.h>
+#include	"screen.h"
+
+enum
+{
+	Qtopdir		= 0,
+	Qnew,
+	Qwinname,
+	Q3rd,
+	Q2nd,
+	Qcolormap,
+	Qctl,
+	Qdata,
+	Qrefresh,
+};
+
+/*
+ * Qid path is:
+ *	 4 bits of file type (qids above)
+ *	24 bits of mux slot number +1; 0 means not attached to client
+ */
+#define	QSHIFT	4	/* location in qid of client # */
+
+#define	QID(q)		((((ulong)(q).path)&0x0000000F)>>0)
+#define	CLIENTPATH(q)	((((ulong)q)&0x7FFFFFF0)>>QSHIFT)
+#define	CLIENT(q)	CLIENTPATH((q).path)
+
+#define	NHASH		(1<<5)
+#define	HASHMASK	(NHASH-1)
+#define	IOUNIT		(64*1024)
+
+typedef struct Client Client;
+typedef struct Draw Draw;
+typedef struct DImage DImage;
+typedef struct DScreen DScreen;
+typedef struct CScreen CScreen;
+typedef struct FChar FChar;
+typedef struct Refresh Refresh;
+typedef struct Refx Refx;
+typedef struct DName DName;
+
+ulong blanktime = 30;	/* in minutes; a half hour */
+
+struct Draw
+{
+	int		clientid;
+	int		nclient;
+	Client**	client;
+	int		nname;
+	DName*		name;
+	int		vers;
+	int		softscreen;
+	int		blanked;	/* screen turned off */
+	ulong		blanktime;	/* time of last operation */
+	ulong		savemap[3*256];
+};
+
+struct Client
+{
+	Ref		r;
+	DImage*		dimage[NHASH];
+	CScreen*	cscreen;
+	Refresh*	refresh;
+	Rendez		refrend;
+	uchar*		readdata;
+	int		nreaddata;
+	int		busy;
+	int		clientid;
+	int		slot;
+	int		refreshme;
+	int		infoid;
+	int		op;
+};
+
+struct Refresh
+{
+	DImage*		dimage;
+	Rectangle	r;
+	Refresh*	next;
+};
+
+struct Refx
+{
+	Client*		client;
+	DImage*		dimage;
+};
+
+struct DName
+{
+	char		*name;
+	Client		*client;
+	DImage*		dimage;
+	int		vers;
+};
+
+struct FChar
+{
+	int		minx;	/* left edge of bits */
+	int		maxx;	/* right edge of bits */
+	uchar		miny;	/* first non-zero scan-line */
+	uchar		maxy;	/* last non-zero scan-line + 1 */
+	schar		left;	/* offset of baseline */
+	uchar		width;	/* width of baseline */
+};
+
+/*
+ * Reference counts in DImages:
+ *	one per open by original client
+ *	one per screen image or fill
+ * 	one per image derived from this one by name
+ */
+struct DImage
+{
+	int		id;
+	int		ref;
+	char		*name;
+	int		vers;
+	Memimage*	image;
+	int		ascent;
+	int		nfchar;
+	FChar*		fchar;
+	DScreen*	dscreen;	/* 0 if not a window */
+	DImage*		fromname;	/* image this one is derived from, by name */
+	DImage*		next;
+};
+
+struct CScreen
+{
+	DScreen*	dscreen;
+	CScreen*	next;
+};
+
+struct DScreen
+{
+	int		id;
+	int		public;
+	int		ref;
+	DImage		*dimage;
+	DImage		*dfill;
+	Memscreen*	screen;
+	Client*		owner;
+	DScreen*	next;
+};
+
+static	Draw		sdraw;
+	QLock	drawlock;
+
+static	Memimage	*screenimage;
+static	DImage*	screendimage;
+static	char	screenname[40];
+static	int	screennameid;
+
+static	Rectangle	flushrect;
+static	int		waste;
+static	DScreen*	dscreen;
+extern	void		flushmemscreen(Rectangle);
+	void		drawmesg(Client*, void*, int);
+	void		drawuninstall(Client*, int);
+	void		drawfreedimage(DImage*);
+	Client*		drawclientofpath(ulong);
+	DImage*	allocdimage(Memimage*);
+
+static	char Enodrawimage[] =	"unknown id for draw image";
+static	char Enodrawscreen[] =	"unknown id for draw screen";
+static	char Eshortdraw[] =	"short draw message";
+static	char Eshortread[] =	"draw read too short";
+static	char Eimageexists[] =	"image id in use";
+static	char Escreenexists[] =	"screen id in use";
+static	char Edrawmem[] =	"image memory allocation failed";
+static	char Ereadoutside[] =	"readimage outside image";
+static	char Ewriteoutside[] =	"writeimage outside image";
+static	char Enotfont[] =	"image not a font";
+static	char Eindex[] =		"character index out of range";
+static	char Enoclient[] =	"no such draw client";
+static	char Edepth[] =		"image has bad depth";
+static	char Enameused[] =	"image name in use";
+static	char Enoname[] =	"no image with that name";
+static	char Eoldname[] =	"named image no longer valid";
+static	char Enamed[] = 	"image already has name";
+static	char Ewrongname[] = 	"wrong name for image";
+
+static void
+dlock(void)
+{
+	qlock(&drawlock);
+}
+
+static int
+candlock(void)
+{
+	return canqlock(&drawlock);
+}
+
+static void
+dunlock(void)
+{
+	qunlock(&drawlock);
+}
+
+static int
+drawgen(Chan *c, char*, Dirtab*, int, int s, Dir *dp)
+{
+	int t;
+	Qid q;
+	ulong path;
+	Client *cl;
+
+	q.vers = 0;
+
+	if(s == DEVDOTDOT){
+		switch(QID(c->qid)){
+		case Qtopdir:
+		case Q2nd:
+			mkqid(&q, Qtopdir, 0, QTDIR);
+			devdir(c, q, "#i", 0, eve, 0500, dp);
+			break;
+		case Q3rd:
+			cl = drawclientofpath(c->qid.path);
+			if(cl == nil)
+				strcpy(up->genbuf, "??");
+			else
+				sprint(up->genbuf, "%d", cl->clientid);
+			mkqid(&q, Q2nd, 0, QTDIR);
+			devdir(c, q, up->genbuf, 0, eve, 0500, dp);
+			break;
+		default:
+			panic("drawwalk %llux", c->qid.path);
+		}
+		return 1;
+	}
+
+	/*
+	 * Top level directory contains the name of the device.
+	 */
+	t = QID(c->qid);
+	if(t == Qtopdir){
+		switch(s){
+		case 0:
+			mkqid(&q, Q2nd, 0, QTDIR);
+			devdir(c, q, "draw", 0, eve, 0555, dp);
+			break;
+		case 1:
+			mkqid(&q, Qwinname, 0, 0);
+			devdir(c, q, "winname", 0, eve, 0444, dp);
+			break;
+		default:
+			return -1;
+		}
+		return 1;
+	}
+
+	/*
+	 * Second level contains "new" plus all the clients.
+	 */
+	if(t == Q2nd || t == Qnew){
+		if(s == 0){
+			mkqid(&q, Qnew, 0, QTFILE);
+			devdir(c, q, "new", 0, eve, 0666, dp);
+		}
+		else if(s <= sdraw.nclient){
+			cl = sdraw.client[s-1];
+			if(cl == 0)
+				return 0;
+			sprint(up->genbuf, "%d", cl->clientid);
+			mkqid(&q, (s<<QSHIFT)|Q3rd, 0, QTDIR);
+			devdir(c, q, up->genbuf, 0, eve, 0555, dp);
+			return 1;
+		}
+		else
+			return -1;
+		return 1;
+	}
+
+	/*
+	 * Third level.
+	 */
+	path = c->qid.path&~((1<<QSHIFT)-1);	/* slot component */
+	q.vers = c->qid.vers;
+	q.type = QTFILE;
+	switch(s){
+	case 0:
+		q.path = path|Qcolormap;
+		devdir(c, q, "colormap", 0, eve, 0600, dp);
+		break;
+	case 1:
+		q.path = path|Qctl;
+		devdir(c, q, "ctl", 0, eve, 0600, dp);
+		break;
+	case 2:
+		q.path = path|Qdata;
+		devdir(c, q, "data", 0, eve, 0600, dp);
+		break;
+	case 3:
+		q.path = path|Qrefresh;
+		devdir(c, q, "refresh", 0, eve, 0400, dp);
+		break;
+	default:
+		return -1;
+	}
+	return 1;
+}
+
+static
+int
+drawrefactive(void *a)
+{
+	Client *c;
+
+	c = a;
+	return c->refreshme || c->refresh!=0;
+}
+
+static
+void
+drawrefreshscreen(DImage *l, Client *client)
+{
+	while(l != nil && l->dscreen == nil)
+		l = l->fromname;
+	if(l != nil && l->dscreen->owner != client)
+		l->dscreen->owner->refreshme = 1;
+}
+
+static
+void
+drawrefresh(Memimage*, Rectangle r, void *v)
+{
+	Refx *x;
+	DImage *d;
+	Client *c;
+	Refresh *ref;
+
+	if(v == 0)
+		return;
+	x = v;
+	c = x->client;
+	d = x->dimage;
+	for(ref=c->refresh; ref; ref=ref->next)
+		if(ref->dimage == d){
+			combinerect(&ref->r, r);
+			return;
+		}
+	ref = malloc(sizeof(Refresh));
+	if(ref){
+		ref->dimage = d;
+		ref->r = r;
+		ref->next = c->refresh;
+		c->refresh = ref;
+	}
+}
+
+static void
+addflush(Rectangle r)
+{
+	int abb, ar, anbb;
+	Rectangle nbb;
+
+	if(sdraw.softscreen==0 || !rectclip(&r, screenimage->r))
+		return;
+
+	if(flushrect.min.x >= flushrect.max.x){
+		flushrect = r;
+		waste = 0;
+		return;
+	}
+	nbb = flushrect;
+	combinerect(&nbb, r);
+	ar = Dx(r)*Dy(r);
+	abb = Dx(flushrect)*Dy(flushrect);
+	anbb = Dx(nbb)*Dy(nbb);
+	/*
+	 * Area of new waste is area of new bb minus area of old bb,
+	 * less the area of the new segment, which we assume is not waste.
+	 * This could be negative, but that's OK.
+	 */
+	waste += anbb-abb - ar;
+	if(waste < 0)
+		waste = 0;
+	/*
+	 * absorb if:
+	 *	total area is small
+	 *	waste is less than half total area
+	 * 	rectangles touch
+	 */
+	if(anbb<=1024 || waste*2<anbb || rectXrect(flushrect, r)){
+		flushrect = nbb;
+		return;
+	}
+	/* emit current state */
+	if(flushrect.min.x < flushrect.max.x)
+		flushmemscreen(flushrect);
+	flushrect = r;
+	waste = 0;
+}
+
+static
+void
+dstflush(int dstid, Memimage *dst, Rectangle r)
+{
+	Memlayer *l;
+
+	if(dstid == 0){
+		combinerect(&flushrect, r);
+		return;
+	}
+	/* how can this happen? -rsc, dec 12 2002 */
+	if(dst == 0){
+		print("nil dstflush\n");
+		return;
+	}
+	l = dst->layer;
+	if(l == nil)
+		return;
+	do{
+		if(l->screen->image->data != screenimage->data)
+			return;
+		r = rectaddpt(r, l->delta);
+		l = l->screen->image->layer;
+	}while(l);
+	addflush(r);
+}
+
+void
+drawflush(void)
+{
+	if(flushrect.min.x < flushrect.max.x)
+		flushmemscreen(flushrect);
+	flushrect = Rect(10000, 10000, -10000, -10000);
+}
+
+static
+int
+drawcmp(char *a, char *b, int n)
+{
+	if(strlen(a) != n)
+		return 1;
+	return memcmp(a, b, n);
+}
+
+DName*
+drawlookupname(int n, char *str)
+{
+	DName *name, *ename;
+
+	name = sdraw.name;
+	ename = &name[sdraw.nname];
+	for(; name<ename; name++)
+		if(drawcmp(name->name, str, n) == 0)
+			return name;
+	return 0;
+}
+
+int
+drawgoodname(DImage *d)
+{
+	DName *n;
+
+	/* if window, validate the screen's own images */
+	if(d->dscreen)
+		if(drawgoodname(d->dscreen->dimage) == 0
+		|| drawgoodname(d->dscreen->dfill) == 0)
+			return 0;
+	if(d->name == nil)
+		return 1;
+	n = drawlookupname(strlen(d->name), d->name);
+	if(n==nil || n->vers!=d->vers)
+		return 0;
+	return 1;
+}
+
+DImage*
+drawlookup(Client *client, int id, int checkname)
+{
+	DImage *d;
+
+	d = client->dimage[id&HASHMASK];
+	while(d){
+		if(d->id == id){
+			if(checkname && !drawgoodname(d))
+				error(Eoldname);
+			return d;
+		}
+		d = d->next;
+	}
+	return 0;
+}
+
+DScreen*
+drawlookupdscreen(int id)
+{
+	DScreen *s;
+
+	s = dscreen;
+	while(s){
+		if(s->id == id)
+			return s;
+		s = s->next;
+	}
+	return 0;
+}
+
+DScreen*
+drawlookupscreen(Client *client, int id, CScreen **cs)
+{
+	CScreen *s;
+
+	s = client->cscreen;
+	while(s){
+		if(s->dscreen->id == id){
+			*cs = s;
+			return s->dscreen;
+		}
+		s = s->next;
+	}
+	error(Enodrawscreen);
+	return 0;
+}
+
+DImage*
+allocdimage(Memimage *i)
+{
+	DImage *d;
+
+	d = malloc(sizeof(DImage));
+	if(d == 0)
+		return 0;
+	d->ref = 1;
+	d->name = 0;
+	d->vers = 0;
+	d->image = i;
+	d->nfchar = 0;
+	d->fchar = 0;
+	d->fromname = 0;
+	return d;
+}
+
+Memimage*
+drawinstall(Client *client, int id, Memimage *i, DScreen *dscreen)
+{
+	DImage *d;
+
+	d = allocdimage(i);
+	if(d == 0)
+		return 0;
+	d->id = id;
+	d->dscreen = dscreen;
+	d->next = client->dimage[id&HASHMASK];
+	client->dimage[id&HASHMASK] = d;
+	return i;
+}
+
+Memscreen*
+drawinstallscreen(Client *client, DScreen *d, int id, DImage *dimage, DImage *dfill, int public)
+{
+	Memscreen *s;
+	CScreen *c;
+
+	c = malloc(sizeof(CScreen));
+	if(dimage && dimage->image && dimage->image->chan == 0)
+		panic("bad image %p in drawinstallscreen", dimage->image);
+
+	if(c == 0)
+		return 0;
+	if(d == 0){
+		d = malloc(sizeof(DScreen));
+		if(d == 0){
+			free(c);
+			return 0;
+		}
+		s = malloc(sizeof(Memscreen));
+		if(s == 0){
+			free(c);
+			free(d);
+			return 0;
+		}
+		s->frontmost = 0;
+		s->rearmost = 0;
+		d->dimage = dimage;
+		if(dimage){
+			s->image = dimage->image;
+			dimage->ref++;
+		}
+		d->dfill = dfill;
+		if(dfill){
+			s->fill = dfill->image;
+			dfill->ref++;
+		}
+		d->ref = 0;
+		d->id = id;
+		d->screen = s;
+		d->public = public;
+		d->next = dscreen;
+		d->owner = client;
+		dscreen = d;
+	}
+	c->dscreen = d;
+	d->ref++;
+	c->next = client->cscreen;
+	client->cscreen = c;
+	return d->screen;
+}
+
+void
+drawdelname(DName *name)
+{
+	int i;
+
+	i = name-sdraw.name;
+	memmove(name, name+1, (sdraw.nname-(i+1))*sizeof(DName));
+	sdraw.nname--;
+}
+
+void
+drawfreedscreen(DScreen *this)
+{
+	DScreen *ds, *next;
+
+	this->ref--;
+	if(this->ref < 0)
+		print("negative ref in drawfreedscreen\n");
+	if(this->ref > 0)
+		return;
+	ds = dscreen;
+	if(ds == this){
+		dscreen = this->next;
+		goto Found;
+	}
+	while(next = ds->next){	/* assign = */
+		if(next == this){
+			ds->next = this->next;
+			goto Found;
+		}
+		ds = next;
+	}
+	error(Enodrawimage);
+
+    Found:
+	if(this->dimage)
+		drawfreedimage(this->dimage);
+	if(this->dfill)
+		drawfreedimage(this->dfill);
+	free(this->screen);
+	free(this);
+}
+
+void
+drawfreedimage(DImage *dimage)
+{
+	int i;
+	Memimage *l;
+	DScreen *ds;
+
+	dimage->ref--;
+	if(dimage->ref < 0)
+		print("negative ref in drawfreedimage\n");
+	if(dimage->ref > 0)
+		return;
+
+	/* any names? */
+	for(i=0; i<sdraw.nname; )
+		if(sdraw.name[i].dimage == dimage)
+			drawdelname(sdraw.name+i);
+		else
+			i++;
+	if(dimage->fromname){	/* acquired by name; owned by someone else*/
+		drawfreedimage(dimage->fromname);
+		goto Return;
+	}
+//	if(dimage->image == screenimage)	/* don't free the display */
+//		goto Return;
+	ds = dimage->dscreen;
+	if(ds){
+		l = dimage->image;
+		if(l->data == screenimage->data)
+			addflush(l->layer->screenr);
+		if(l->layer->refreshfn == drawrefresh)	/* else true owner will clean up */
+			free(l->layer->refreshptr);
+		l->layer->refreshptr = nil;
+		if(drawgoodname(dimage))
+			memldelete(l);
+		else
+			memlfree(l);
+		drawfreedscreen(ds);
+	}else
+		freememimage(dimage->image);
+    Return:
+	free(dimage->fchar);
+	free(dimage);
+}
+
+void
+drawuninstallscreen(Client *client, CScreen *this)
+{
+	CScreen *cs, *next;
+
+	cs = client->cscreen;
+	if(cs == this){
+		client->cscreen = this->next;
+		drawfreedscreen(this->dscreen);
+		free(this);
+		return;
+	}
+	while(next = cs->next){	/* assign = */
+		if(next == this){
+			cs->next = this->next;
+			drawfreedscreen(this->dscreen);
+			free(this);
+			return;
+		}
+		cs = next;
+	}
+}
+
+void
+drawuninstall(Client *client, int id)
+{
+	DImage *d, *next;
+
+	d = client->dimage[id&HASHMASK];
+	if(d == 0)
+		error(Enodrawimage);
+	if(d->id == id){
+		client->dimage[id&HASHMASK] = d->next;
+		drawfreedimage(d);
+		return;
+	}
+	while(next = d->next){	/* assign = */
+		if(next->id == id){
+			d->next = next->next;
+			drawfreedimage(next);
+			return;
+		}
+		d = next;
+	}
+	error(Enodrawimage);
+}
+
+void
+drawaddname(Client *client, DImage *di, int n, char *str)
+{
+	DName *name, *ename, *new, *t;
+
+	name = sdraw.name;
+	ename = &name[sdraw.nname];
+	for(; name<ename; name++)
+		if(drawcmp(name->name, str, n) == 0)
+			error(Enameused);
+	t = smalloc((sdraw.nname+1)*sizeof(DName));
+	memmove(t, sdraw.name, sdraw.nname*sizeof(DName));
+	free(sdraw.name);
+	sdraw.name = t;
+	new = &sdraw.name[sdraw.nname++];
+	new->name = smalloc(n+1);
+	memmove(new->name, str, n);
+	new->name[n] = 0;
+	new->dimage = di;
+	new->client = client;
+	new->vers = ++sdraw.vers;
+}
+
+Client*
+drawnewclient(void)
+{
+	Client *cl, **cp;
+	int i;
+
+	for(i=0; i<sdraw.nclient; i++){
+		cl = sdraw.client[i];
+		if(cl == 0)
+			break;
+	}
+	if(i == sdraw.nclient){
+		cp = malloc((sdraw.nclient+1)*sizeof(Client*));
+		if(cp == 0)
+			return 0;
+		memmove(cp, sdraw.client, sdraw.nclient*sizeof(Client*));
+		free(sdraw.client);
+		sdraw.client = cp;
+		sdraw.nclient++;
+		cp[i] = 0;
+	}
+	cl = malloc(sizeof(Client));
+	if(cl == 0)
+		return 0;
+	memset(cl, 0, sizeof(Client));
+	cl->slot = i;
+	cl->clientid = ++sdraw.clientid;
+	cl->op = SoverD;
+	sdraw.client[i] = cl;
+	return cl;
+}
+
+static int
+drawclientop(Client *cl)
+{
+	int op;
+
+	op = cl->op;
+	cl->op = SoverD;
+	return op;
+}
+
+int
+drawhasclients(void)
+{
+	/*
+	 * if draw has ever been used, we can't resize the frame buffer,
+	 * even if all clients have exited (nclients is cumulative); it's too
+	 * hard to make work.
+	 */
+	return sdraw.nclient != 0;
+}
+
+Client*
+drawclientofpath(ulong path)
+{
+	Client *cl;
+	int slot;
+
+	slot = CLIENTPATH(path);
+	if(slot == 0)
+		return nil;
+	cl = sdraw.client[slot-1];
+	if(cl==0 || cl->clientid==0)
+		return nil;
+	return cl;
+}
+
+
+Client*
+drawclient(Chan *c)
+{
+	Client *client;
+
+	client = drawclientofpath(c->qid.path);
+	if(client == nil)
+		error(Enoclient);
+	return client;
+}
+
+Memimage*
+drawimage(Client *client, uchar *a)
+{
+	DImage *d;
+
+	d = drawlookup(client, BGLONG(a), 1);
+	if(d == nil)
+		error(Enodrawimage);
+	return d->image;
+}
+
+void
+drawrectangle(Rectangle *r, uchar *a)
+{
+	r->min.x = BGLONG(a+0*4);
+	r->min.y = BGLONG(a+1*4);
+	r->max.x = BGLONG(a+2*4);
+	r->max.y = BGLONG(a+3*4);
+}
+
+void
+drawpoint(Point *p, uchar *a)
+{
+	p->x = BGLONG(a+0*4);
+	p->y = BGLONG(a+1*4);
+}
+
+Point
+drawchar(Memimage *dst, Memimage *rdst, Point p, Memimage *src, Point *sp, DImage *font, int index, int op)
+{
+	FChar *fc;
+	Rectangle r;
+	Point sp1;
+	static Memimage *tmp;
+
+	fc = &font->fchar[index];
+	r.min.x = p.x+fc->left;
+	r.min.y = p.y-(font->ascent-fc->miny);
+	r.max.x = r.min.x+(fc->maxx-fc->minx);
+	r.max.y = r.min.y+(fc->maxy-fc->miny);
+	sp1.x = sp->x+fc->left;
+	sp1.y = sp->y+fc->miny;
+
+	/*
+	 * If we're drawing greyscale fonts onto a VGA screen,
+	 * it's very costly to read the screen memory to do the
+	 * alpha blending inside memdraw.  If this is really a stringbg,
+	 * then rdst is the bg image (in main memory) which we can
+	 * refer to for the underlying dst pixels instead of reading dst
+	 * directly.
+	 */
+	if(ishwimage(dst) && !ishwimage(rdst) && font->image->depth > 1){
+		if(tmp == nil || tmp->chan != dst->chan || Dx(tmp->r) < Dx(r) || Dy(tmp->r) < Dy(r)){
+			if(tmp)
+				freememimage(tmp);
+			tmp = allocmemimage(Rect(0,0,Dx(r),Dy(r)), dst->chan);
+			if(tmp == nil)
+				goto fallback;
+		}
+		memdraw(tmp, Rect(0,0,Dx(r),Dy(r)), rdst, r.min, memopaque, ZP, S);
+		memdraw(tmp, Rect(0,0,Dx(r),Dy(r)), src, sp1, font->image, Pt(fc->minx, fc->miny), op);
+		memdraw(dst, r, tmp, ZP, memopaque, ZP, S);
+	}else{
+	fallback:
+		memdraw(dst, r, src, sp1, font->image, Pt(fc->minx, fc->miny), op);
+	}
+
+	p.x += fc->width;
+	sp->x += fc->width;
+	return p;
+}
+
+static DImage*
+makescreenimage(void)
+{
+	int width, depth;
+	ulong chan;
+	DImage *di;
+	Memdata *md;
+	Memimage *i;
+	Rectangle r;
+
+	md = malloc(sizeof *md);
+	if(md == nil)
+		return nil;
+	md->allocd = 1;
+	md->base = nil;
+	md->bdata = attachscreen(&r, &chan, &depth, &width, &sdraw.softscreen);
+	if(md->bdata == nil){
+		free(md);
+		return nil;
+	}
+	md->ref = 1;
+	i = allocmemimaged(r, chan, md);
+	if(i == nil){
+		free(md);
+		return nil;
+	}
+	i->width = width;
+	i->clipr = r;
+
+	di = allocdimage(i);
+	if(di == nil){
+		freememimage(i);	/* frees md */
+		return nil;
+	}
+	if(!waserror()){
+		snprint(screenname, sizeof screenname, "noborder.screen.%d", ++screennameid);
+		drawaddname(nil, di, strlen(screenname), screenname);
+		poperror();
+	}
+	return di;
+}
+
+static int
+initscreenimage(void)
+{
+	if(screenimage != nil)
+		return 1;
+
+	screendimage = makescreenimage();
+	if(screendimage == nil)
+		return 0;
+	screenimage = screendimage->image;
+// iprint("initscreenimage %p %p\n", screendimage, screenimage);
+	mouseresize();
+	return 1;
+}
+
+void
+deletescreenimage(void)
+{
+	dlock();
+	if(screenimage){
+		/* will be freed via screendimage; disable */
+		screenimage->clipr = ZR;
+		screenimage = nil;
+	}
+	if(screendimage){
+		drawfreedimage(screendimage);
+		screendimage = nil;
+	}
+	dunlock();
+}
+
+void
+resetscreenimage(void)
+{
+	dlock();
+	initscreenimage();
+	dunlock();
+}
+
+static Chan*
+drawattach(char *spec)
+{
+	dlock();
+	if(!initscreenimage()){
+		dunlock();
+		error("no frame buffer");
+	}
+	dunlock();
+	return devattach('i', spec);
+}
+
+static Walkqid*
+drawwalk(Chan *c, Chan *nc, char **name, int nname)
+{
+	if(screenimage == nil)
+		error("no frame buffer");
+	return devwalk(c, nc, name, nname, 0, 0, drawgen);
+}
+
+static int
+drawstat(Chan *c, uchar *db, int n)
+{
+	return devstat(c, db, n, 0, 0, drawgen);
+}
+
+static Chan*
+drawopen(Chan *c, int omode)
+{
+	Client *cl;
+	DName *dn;
+	DImage *di;
+
+	if(c->qid.type & QTDIR){
+		c = devopen(c, omode, 0, 0, drawgen);
+		c->iounit = IOUNIT;
+	}
+
+	dlock();
+	if(waserror()){
+		dunlock();
+		nexterror();
+	}
+
+	if(QID(c->qid) == Qnew){
+		cl = drawnewclient();
+		if(cl == 0)
+			error(Enodev);
+		c->qid.path = Qctl|((cl->slot+1)<<QSHIFT);
+	}
+
+	switch(QID(c->qid)){
+	case Qwinname:
+		break;
+
+	case Qnew:
+		break;
+
+	case Qctl:
+		cl = drawclient(c);
+		if(cl->busy)
+			error(Einuse);
+		cl->busy = 1;
+		flushrect = Rect(10000, 10000, -10000, -10000);
+		dn = drawlookupname(strlen(screenname), screenname);
+		if(dn == 0)
+			error("draw: cannot happen 2");
+		if(drawinstall(cl, 0, dn->dimage->image, 0) == 0)
+			error(Edrawmem);
+		di = drawlookup(cl, 0, 0);
+		if(di == 0)
+			error("draw: cannot happen 1");
+		di->vers = dn->vers;
+		di->name = smalloc(strlen(screenname)+1);
+		strcpy(di->name, screenname);
+		di->fromname = dn->dimage;
+		di->fromname->ref++;
+		incref(&cl->r);
+		break;
+
+	case Qcolormap:
+	case Qdata:
+	case Qrefresh:
+		cl = drawclient(c);
+		incref(&cl->r);
+		break;
+	}
+	dunlock();
+	poperror();
+	c->mode = openmode(omode);
+	c->flag |= COPEN;
+	c->offset = 0;
+	c->iounit = IOUNIT;
+	return c;
+}
+
+static void
+drawclose(Chan *c)
+{
+	int i;
+	DImage *d, **dp;
+	Client *cl;
+	Refresh *r;
+
+	if(QID(c->qid) < Qcolormap)	/* Qtopdir, Qnew, Q3rd, Q2nd have no client */
+		return;
+	dlock();
+	if(waserror()){
+		dunlock();
+		nexterror();
+	}
+
+	cl = drawclient(c);
+	if(QID(c->qid) == Qctl)
+		cl->busy = 0;
+	if((c->flag&COPEN) && (decref(&cl->r)==0)){
+		while(r = cl->refresh){	/* assign = */
+			cl->refresh = r->next;
+			free(r);
+		}
+		/* free names */
+		for(i=0; i<sdraw.nname; )
+			if(sdraw.name[i].client == cl)
+				drawdelname(sdraw.name+i);
+			else
+				i++;
+		while(cl->cscreen)
+			drawuninstallscreen(cl, cl->cscreen);
+		/* all screens are freed, so now we can free images */
+		dp = cl->dimage;
+		for(i=0; i<NHASH; i++){
+			while((d = *dp) != nil){
+				*dp = d->next;
+				drawfreedimage(d);
+			}
+			dp++;
+		}
+		sdraw.client[cl->slot] = 0;
+		drawflush();	/* to erase visible, now dead windows */
+		free(cl);
+	}
+	dunlock();
+	poperror();
+}
+
+long
+drawread(Chan *c, void *a, long n, vlong off)
+{
+	int index, m;
+	ulong red, green, blue;
+	Client *cl;
+	uchar *p;
+	Refresh *r;
+	DImage *di;
+	Memimage *i;
+	ulong offset = off;
+	char buf[16];
+
+	if(c->qid.type & QTDIR)
+		return devdirread(c, a, n, 0, 0, drawgen);
+	if(QID(c->qid) == Qwinname)
+		return readstr(off, a, n, screenname);
+
+	cl = drawclient(c);
+	dlock();
+	if(waserror()){
+		dunlock();
+		nexterror();
+	}
+	switch(QID(c->qid)){
+	case Qctl:
+		if(n < 12*12)
+			error(Eshortread);
+		if(cl->infoid < 0)
+			error(Enodrawimage);
+		if(cl->infoid == 0){
+			i = screenimage;
+			if(i == nil)
+				error(Enodrawimage);
+		}else{
+			di = drawlookup(cl, cl->infoid, 1);
+			if(di == nil)
+				error(Enodrawimage);
+			i = di->image;
+		}
+		n = sprint(a, "%11d %11d %11s %11d %11d %11d %11d %11d %11d %11d %11d %11d ",
+			cl->clientid, cl->infoid, chantostr(buf, i->chan), (i->flags&Frepl)==Frepl,
+			i->r.min.x, i->r.min.y, i->r.max.x, i->r.max.y,
+			i->clipr.min.x, i->clipr.min.y, i->clipr.max.x, i->clipr.max.y);
+		cl->infoid = -1;
+		break;
+
+	case Qcolormap:
+		drawactive(1);	/* to restore map from backup */
+		p = malloc(4*12*256+1);
+		if(p == 0)
+			error(Enomem);
+		m = 0;
+		for(index = 0; index < 256; index++){
+			getcolor(index, &red, &green, &blue);
+			m += sprint((char*)p+m, "%11d %11lud %11lud %11lud\n", index, red>>24, green>>24, blue>>24);
+		}
+		n = readstr(offset, a, n, (char*)p);
+		free(p);
+		break;
+
+	case Qdata:
+		if(cl->readdata == nil)
+			error("no draw data");
+		if(n < cl->nreaddata)
+			error(Eshortread);
+		n = cl->nreaddata;
+		memmove(a, cl->readdata, cl->nreaddata);
+		free(cl->readdata);
+		cl->readdata = nil;
+		break;
+
+	case Qrefresh:
+		if(n < 5*4)
+			error(Ebadarg);
+		for(;;){
+			if(cl->refreshme || cl->refresh)
+				break;
+			dunlock();
+			if(waserror()){
+				dlock();	/* restore lock for waserror() above */
+				nexterror();
+			}
+			sleep(&cl->refrend, drawrefactive, cl);
+			poperror();
+			dlock();
+		}
+		p = a;
+		while(cl->refresh && n>=5*4){
+			r = cl->refresh;
+			BPLONG(p+0*4, r->dimage->id);
+			BPLONG(p+1*4, r->r.min.x);
+			BPLONG(p+2*4, r->r.min.y);
+			BPLONG(p+3*4, r->r.max.x);
+			BPLONG(p+4*4, r->r.max.y);
+			cl->refresh = r->next;
+			free(r);
+			p += 5*4;
+			n -= 5*4;
+		}
+		cl->refreshme = 0;
+		n = p-(uchar*)a;
+		break;
+	}
+	dunlock();
+	poperror();
+	return n;
+}
+
+void
+drawwakeall(void)
+{
+	Client *cl;
+	int i;
+
+	for(i=0; i<sdraw.nclient; i++){
+		cl = sdraw.client[i];
+		if(cl && (cl->refreshme || cl->refresh))
+			wakeup(&cl->refrend);
+	}
+}
+
+static long
+drawwrite(Chan *c, void *a, long n, vlong)
+{
+	char buf[128], *fields[4], *q;
+	Client *cl;
+	int i, m, red, green, blue, x;
+
+	if(c->qid.type & QTDIR)
+		error(Eisdir);
+	cl = drawclient(c);
+	dlock();
+	if(waserror()){
+		drawwakeall();
+		dunlock();
+		nexterror();
+	}
+	switch(QID(c->qid)){
+	case Qctl:
+		if(n != 4)
+			error("unknown draw control request");
+		cl->infoid = BGLONG((uchar*)a);
+		break;
+
+	case Qcolormap:
+		drawactive(1);	/* to restore map from backup */
+		m = n;
+		n = 0;
+		while(m > 0){
+			x = m;
+			if(x > sizeof(buf)-1)
+				x = sizeof(buf)-1;
+			q = memccpy(buf, a, '\n', x);
+			if(q == 0)
+				break;
+			i = q-buf;
+			n += i;
+			a = (char*)a + i;
+			m -= i;
+			*q = 0;
+			if(tokenize(buf, fields, nelem(fields)) != 4)
+				error(Ebadarg);
+			i = strtoul(fields[0], 0, 0);
+			red = strtoul(fields[1], 0, 0);
+			green = strtoul(fields[2], 0, 0);
+			blue = strtoul(fields[3], &q, 0);
+			if(fields[3] == q)
+				error(Ebadarg);
+			if(red>255 || green>255 || blue>255 || i<0 || i>255)
+				error(Ebadarg);
+			red |= red<<8;
+			red |= red<<16;
+			green |= green<<8;
+			green |= green<<16;
+			blue |= blue<<8;
+			blue |= blue<<16;
+			setcolor(i, red, green, blue);
+		}
+		break;
+
+	case Qdata:
+		drawmesg(cl, a, n);
+		drawwakeall();
+		break;
+
+	default:
+		error(Ebadusefd);
+	}
+	dunlock();
+	poperror();
+	return n;
+}
+
+uchar*
+drawcoord(uchar *p, uchar *maxp, int oldx, int *newx)
+{
+	int b, x;
+
+	if(p >= maxp)
+		error(Eshortdraw);
+	b = *p++;
+	x = b & 0x7F;
+	if(b & 0x80){
+		if(p+1 >= maxp)
+			error(Eshortdraw);
+		x |= *p++ << 7;
+		x |= *p++ << 15;
+		if(x & (1<<22))
+			x |= ~0<<23;
+	}else{
+		if(b & 0x40)
+			x |= ~0<<7;
+		x += oldx;
+	}
+	*newx = x;
+	return p;
+}
+
+static void
+printmesg(char *fmt, uchar *a, int plsprnt)
+{
+	char buf[256];
+	char *p, *q;
+	int s;
+
+	if(1|| plsprnt==0){
+		SET(s,q,p);
+		USED(fmt, a, buf, p, q, s);
+		return;
+	}
+	q = buf;
+	*q++ = *a++;
+	for(p=fmt; *p; p++){
+		switch(*p){
+		case 'l':
+			q += sprint(q, " %ld", (long)BGLONG(a));
+			a += 4;
+			break;
+		case 'L':
+			q += sprint(q, " %.8lux", (ulong)BGLONG(a));
+			a += 4;
+			break;
+		case 'R':
+			q += sprint(q, " [%d %d %d %d]", BGLONG(a), BGLONG(a+4), BGLONG(a+8), BGLONG(a+12));
+			a += 16;
+			break;
+		case 'P':
+			q += sprint(q, " [%d %d]", BGLONG(a), BGLONG(a+4));
+			a += 8;
+			break;
+		case 'b':
+			q += sprint(q, " %d", *a++);
+			break;
+		case 's':
+			q += sprint(q, " %d", BGSHORT(a));
+			a += 2;
+			break;
+		case 'S':
+			q += sprint(q, " %.4ux", BGSHORT(a));
+			a += 2;
+			break;
+		}
+	}
+	*q++ = '\n';
+	*q = 0;
+	iprint("%.*s", (int)(q-buf), buf);
+}
+
+void
+drawmesg(Client *client, void *av, int n)
+{
+	int c, repl, m, y, dstid, scrnid, ni, ci, j, nw, e0, e1, op, ox, oy, oesize, esize, doflush;
+	uchar *u, *a, refresh;
+	char *fmt;
+	ulong value, chan;
+	Rectangle r, clipr;
+	Point p, q, *pp, sp;
+	Memimage *i, *bg, *dst, *src, *mask;
+	Memimage *l, **lp;
+	Memscreen *scrn;
+	DImage *font, *ll, *di, *ddst, *dsrc;
+	DName *dn;
+	DScreen *dscrn;
+	FChar *fc;
+	Refx *refx;
+	CScreen *cs;
+	Refreshfn reffn;
+
+	a = av;
+	m = 0;
+	fmt = nil;
+	if(waserror()){
+		if(fmt) printmesg(fmt, a, 1);
+	/*	iprint("error: %s\n", up->errstr);	*/
+		nexterror();
+	}
+	while((n-=m) > 0){
+		USED(fmt);
+		a += m;
+		switch(*a){
+		default:
+			error("bad draw command");
+		/* new allocate: 'b' id[4] screenid[4] refresh[1] chan[4] repl[1] R[4*4] clipR[4*4] rrggbbaa[4] */
+		case 'b':
+			printmesg(fmt="LLbLbRRL", a, 0);
+			m = 1+4+4+1+4+1+4*4+4*4+4;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			scrnid = BGSHORT(a+5);
+			refresh = a[9];
+			chan = BGLONG(a+10);
+			repl = a[14];
+			drawrectangle(&r, a+15);
+			drawrectangle(&clipr, a+31);
+			value = BGLONG(a+47);
+			if(drawlookup(client, dstid, 0))
+				error(Eimageexists);
+			if(scrnid){
+				dscrn = drawlookupscreen(client, scrnid, &cs);
+				scrn = dscrn->screen;
+				if(repl || chan!=scrn->image->chan)
+					error("image parameters incompatible with screen");
+				reffn = nil;
+				switch(refresh){
+				case Refbackup:
+					break;
+				case Refnone:
+					reffn = memlnorefresh;
+					break;
+				case Refmesg:
+					reffn = drawrefresh;
+					break;
+				default:
+					error("unknown refresh method");
+				}
+				l = memlalloc(scrn, r, reffn, 0, value);
+				if(l == 0)
+					error(Edrawmem);
+				addflush(l->layer->screenr);
+				l->clipr = clipr;
+				rectclip(&l->clipr, r);
+				if(drawinstall(client, dstid, l, dscrn) == 0){
+					memldelete(l);
+					error(Edrawmem);
+				}
+				dscrn->ref++;
+				if(reffn){
+					refx = nil;
+					if(reffn == drawrefresh){
+						refx = malloc(sizeof(Refx));
+						if(refx == 0){
+							drawuninstall(client, dstid);
+							error(Edrawmem);
+						}
+						refx->client = client;
+						refx->dimage = drawlookup(client, dstid, 1);
+					}
+					memlsetrefresh(l, reffn, refx);
+				}
+				continue;
+			}
+			i = allocmemimage(r, chan);
+			if(i == 0)
+				error(Edrawmem);
+			if(repl)
+				i->flags |= Frepl;
+			i->clipr = clipr;
+			if(!repl)
+				rectclip(&i->clipr, r);
+			if(drawinstall(client, dstid, i, 0) == 0){
+				freememimage(i);
+				error(Edrawmem);
+			}
+			memfillcolor(i, value);
+			continue;
+
+		/* allocate screen: 'A' id[4] imageid[4] fillid[4] public[1] */
+		case 'A':
+			printmesg(fmt="LLLb", a, 1);
+			m = 1+4+4+4+1;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			if(dstid == 0)
+				error(Ebadarg);
+			if(drawlookupdscreen(dstid))
+				error(Escreenexists);
+			ddst = drawlookup(client, BGLONG(a+5), 1);
+			dsrc = drawlookup(client, BGLONG(a+9), 1);
+			if(ddst==0 || dsrc==0)
+				error(Enodrawimage);
+			if(drawinstallscreen(client, 0, dstid, ddst, dsrc, a[13]) == 0)
+				error(Edrawmem);
+			continue;
+
+		/* set repl and clip: 'c' dstid[4] repl[1] clipR[4*4] */
+		case 'c':
+			printmesg(fmt="LbR", a, 0);
+			m = 1+4+1+4*4;
+			if(n < m)
+				error(Eshortdraw);
+			ddst = drawlookup(client, BGLONG(a+1), 1);
+			if(ddst == nil)
+				error(Enodrawimage);
+			if(ddst->name)
+				error("cannot change repl/clipr of shared image");
+			dst = ddst->image;
+			if(a[5])
+				dst->flags |= Frepl;
+			drawrectangle(&dst->clipr, a+6);
+			continue;
+
+		/* draw: 'd' dstid[4] srcid[4] maskid[4] R[4*4] P[2*4] P[2*4] */
+		case 'd':
+			printmesg(fmt="LLLRPP", a, 0);
+			m = 1+4+4+4+4*4+2*4+2*4;
+			if(n < m)
+				error(Eshortdraw);
+			dst = drawimage(client, a+1);
+			dstid = BGLONG(a+1);
+			src = drawimage(client, a+5);
+			mask = drawimage(client, a+9);
+			drawrectangle(&r, a+13);
+			drawpoint(&p, a+29);
+			drawpoint(&q, a+37);
+			op = drawclientop(client);
+			memdraw(dst, r, src, p, mask, q, op);
+			dstflush(dstid, dst, r);
+			continue;
+
+		/* toggle debugging: 'D' val[1] */
+		case 'D':
+			printmesg(fmt="b", a, 0);
+			m = 1+1;
+			if(n < m)
+				error(Eshortdraw);
+			drawdebug = a[1];
+			continue;
+
+		/* ellipse: 'e' dstid[4] srcid[4] center[2*4] a[4] b[4] thick[4] sp[2*4] alpha[4] phi[4]*/
+		case 'e':
+		case 'E':
+			printmesg(fmt="LLPlllPll", a, 0);
+			m = 1+4+4+2*4+4+4+4+2*4+2*4;
+			if(n < m)
+				error(Eshortdraw);
+			dst = drawimage(client, a+1);
+			dstid = BGLONG(a+1);
+			src = drawimage(client, a+5);
+			drawpoint(&p, a+9);
+			e0 = BGLONG(a+17);
+			e1 = BGLONG(a+21);
+			if(e0<0 || e1<0)
+				error("invalid ellipse semidiameter");
+			j = BGLONG(a+25);
+			if(j < 0)
+				error("negative ellipse thickness");
+			drawpoint(&sp, a+29);
+			c = j;
+			if(*a == 'E')
+				c = -1;
+			ox = BGLONG(a+37);
+			oy = BGLONG(a+41);
+			op = drawclientop(client);
+			/* high bit indicates arc angles are present */
+			if(ox & (1<<31)){
+				if((ox & (1<<30)) == 0)
+					ox &= ~(1<<31);
+				memarc(dst, p, e0, e1, c, src, sp, ox, oy, op);
+			}else
+				memellipse(dst, p, e0, e1, c, src, sp, op);
+			dstflush(dstid, dst, Rect(p.x-e0-j, p.y-e1-j, p.x+e0+j+1, p.y+e1+j+1));
+			continue;
+
+		/* free: 'f' id[4] */
+		case 'f':
+			printmesg(fmt="L", a, 1);
+			m = 1+4;
+			if(n < m)
+				error(Eshortdraw);
+			ll = drawlookup(client, BGLONG(a+1), 0);
+			if(ll && ll->dscreen && ll->dscreen->owner != client)
+				ll->dscreen->owner->refreshme = 1;
+			drawuninstall(client, BGLONG(a+1));
+			continue;
+
+		/* free screen: 'F' id[4] */
+		case 'F':
+			printmesg(fmt="L", a, 1);
+			m = 1+4;
+			if(n < m)
+				error(Eshortdraw);
+			drawlookupscreen(client, BGLONG(a+1), &cs);
+			drawuninstallscreen(client, cs);
+			continue;
+
+		/* initialize font: 'i' fontid[4] nchars[4] ascent[1] */
+		case 'i':
+			printmesg(fmt="Llb", a, 1);
+			m = 1+4+4+1;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			if(dstid == 0)
+				error("cannot use display as font");
+			font = drawlookup(client, dstid, 1);
+			if(font == 0)
+				error(Enodrawimage);
+			if(font->image->layer)
+				error("cannot use window as font");
+			ni = BGLONG(a+5);
+			if(ni<=0 || ni>4096)
+				error("bad font size (4096 chars max)");
+			free(font->fchar);	/* should we complain if non-zero? */
+			font->fchar = malloc(ni*sizeof(FChar));
+			if(font->fchar == 0)
+				error("no memory for font");
+			memset(font->fchar, 0, ni*sizeof(FChar));
+			font->nfchar = ni;
+			font->ascent = a[9];
+			continue;
+
+		/* load character: 'l' fontid[4] srcid[4] index[2] R[4*4] P[2*4] left[1] width[1] */
+		case 'l':
+			printmesg(fmt="LLSRPbb", a, 0);
+			m = 1+4+4+2+4*4+2*4+1+1;
+			if(n < m)
+				error(Eshortdraw);
+			font = drawlookup(client, BGLONG(a+1), 1);
+			if(font == 0)
+				error(Enodrawimage);
+			if(font->nfchar == 0)
+				error(Enotfont);
+			src = drawimage(client, a+5);
+			ci = BGSHORT(a+9);
+			if(ci >= font->nfchar)
+				error(Eindex);
+			drawrectangle(&r, a+11);
+			drawpoint(&p, a+27);
+			memdraw(font->image, r, src, p, memopaque, p, S);
+			fc = &font->fchar[ci];
+			fc->minx = r.min.x;
+			fc->maxx = r.max.x;
+			fc->miny = r.min.y;
+			fc->maxy = r.max.y;
+			fc->left = a[35];
+			fc->width = a[36];
+			continue;
+
+		/* draw line: 'L' dstid[4] p0[2*4] p1[2*4] end0[4] end1[4] radius[4] srcid[4] sp[2*4] */
+		case 'L':
+			printmesg(fmt="LPPlllLP", a, 0);
+			m = 1+4+2*4+2*4+4+4+4+4+2*4;
+			if(n < m)
+				error(Eshortdraw);
+			dst = drawimage(client, a+1);
+			dstid = BGLONG(a+1);
+			drawpoint(&p, a+5);
+			drawpoint(&q, a+13);
+			e0 = BGLONG(a+21);
+			e1 = BGLONG(a+25);
+			j = BGLONG(a+29);
+			if(j < 0)
+				error("negative line width");
+			src = drawimage(client, a+33);
+			drawpoint(&sp, a+37);
+			op = drawclientop(client);
+			memline(dst, p, q, e0, e1, j, src, sp, op);
+			/* avoid memlinebbox if possible */
+			if(dstid==0 || dst->layer!=nil){
+				/* BUG: this is terribly inefficient: update maximal containing rect*/
+				r = memlinebbox(p, q, e0, e1, j);
+				dstflush(dstid, dst, insetrect(r, -(1+1+j)));
+			}
+			continue;
+
+		/* create image mask: 'm' newid[4] id[4] */
+/*
+ *
+		case 'm':
+			printmesg("LL", a, 0);
+			m = 4+4;
+			if(n < m)
+				error(Eshortdraw);
+			break;
+ *
+ */
+
+		/* attach to a named image: 'n' dstid[4] j[1] name[j] */
+		case 'n':
+			printmesg(fmt="Lz", a, 0);
+			m = 1+4+1;
+			if(n < m)
+				error(Eshortdraw);
+			j = a[5];
+			if(j == 0)	/* give me a non-empty name please */
+				error(Eshortdraw);
+			m += j;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			if(drawlookup(client, dstid, 0))
+				error(Eimageexists);
+			dn = drawlookupname(j, (char*)a+6);
+			if(dn == nil)
+				error(Enoname);
+			if(drawinstall(client, dstid, dn->dimage->image, 0) == 0)
+				error(Edrawmem);
+			di = drawlookup(client, dstid, 0);
+			if(di == 0)
+				error("draw: cannot happen");
+			di->vers = dn->vers;
+			di->name = smalloc(j+1);
+			di->fromname = dn->dimage;
+			di->fromname->ref++;
+			memmove(di->name, a+6, j);
+			di->name[j] = 0;
+			client->infoid = dstid;
+			continue;
+
+		/* name an image: 'N' dstid[4] in[1] j[1] name[j] */
+		case 'N':
+			printmesg(fmt="Lbz", a, 0);
+			m = 1+4+1+1;
+			if(n < m)
+				error(Eshortdraw);
+			c = a[5];
+			j = a[6];
+			if(j == 0)	/* give me a non-empty name please */
+				error(Eshortdraw);
+			m += j;
+			if(n < m)
+				error(Eshortdraw);
+			di = drawlookup(client, BGLONG(a+1), 0);
+			if(di == 0)
+				error(Enodrawimage);
+			if(di->name)
+				error(Enamed);
+			if(c)
+				drawaddname(client, di, j, (char*)a+7);
+			else{
+				dn = drawlookupname(j, (char*)a+7);
+				if(dn == nil)
+					error(Enoname);
+				if(dn->dimage != di)
+					error(Ewrongname);
+				drawdelname(dn);
+			}
+			continue;
+
+		/* position window: 'o' id[4] r.min [2*4] screenr.min [2*4] */
+		case 'o':
+			printmesg(fmt="LPP", a, 0);
+			m = 1+4+2*4+2*4;
+			if(n < m)
+				error(Eshortdraw);
+			dst = drawimage(client, a+1);
+			if(dst->layer){
+				drawpoint(&p, a+5);
+				drawpoint(&q, a+13);
+				r = dst->layer->screenr;
+				ni = memlorigin(dst, p, q);
+				if(ni < 0)
+					error("image origin failed");
+				if(ni > 0){
+					addflush(r);
+					addflush(dst->layer->screenr);
+					ll = drawlookup(client, BGLONG(a+1), 1);
+					drawrefreshscreen(ll, client);
+				}
+			}
+			continue;
+
+		/* set compositing operator for next draw operation: 'O' op */
+		case 'O':
+			printmesg(fmt="b", a, 0);
+			m = 1+1;
+			if(n < m)
+				error(Eshortdraw);
+			client->op = a[1];
+			continue;
+
+		/* filled polygon: 'P' dstid[4] n[2] wind[4] ignore[2*4] srcid[4] sp[2*4] p0[2*4] dp[2*2*n] */
+		/* polygon: 'p' dstid[4] n[2] end0[4] end1[4] radius[4] srcid[4] sp[2*4] p0[2*4] dp[2*2*n] */
+		case 'p':
+		case 'P':
+			printmesg(fmt="LslllLPP", a, 0);
+			m = 1+4+2+4+4+4+4+2*4;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			dst = drawimage(client, a+1);
+			ni = BGSHORT(a+5);
+			if(ni < 0)
+				error("negative count in polygon");
+			e0 = BGLONG(a+7);
+			e1 = BGLONG(a+11);
+			j = 0;
+			if(*a == 'p'){
+				j = BGLONG(a+15);
+				if(j < 0)
+					error("negative polygon line width");
+			}
+			src = drawimage(client, a+19);
+			drawpoint(&sp, a+23);
+			drawpoint(&p, a+31);
+			ni++;
+			pp = malloc(ni*sizeof(Point));
+			if(pp == nil)
+				error(Enomem);
+			doflush = 0;
+			if(dstid==0 || (dst->layer && dst->layer->screen->image->data == screenimage->data))
+				doflush = 1;	/* simplify test in loop */
+			ox = oy = 0;
+			esize = 0;
+			u = a+m;
+			for(y=0; y<ni; y++){
+				q = p;
+				oesize = esize;
+				u = drawcoord(u, a+n, ox, &p.x);
+				u = drawcoord(u, a+n, oy, &p.y);
+				ox = p.x;
+				oy = p.y;
+				if(doflush){
+					esize = j;
+					if(*a == 'p'){
+						if(y == 0){
+							c = memlineendsize(e0);
+							if(c > esize)
+								esize = c;
+						}
+						if(y == ni-1){
+							c = memlineendsize(e1);
+							if(c > esize)
+								esize = c;
+						}
+					}
+					if(*a=='P' && e0!=1 && e0 !=~0)
+						r = dst->clipr;
+					else if(y > 0){
+						r = Rect(q.x-oesize, q.y-oesize, q.x+oesize+1, q.y+oesize+1);
+						combinerect(&r, Rect(p.x-esize, p.y-esize, p.x+esize+1, p.y+esize+1));
+					}
+					if(rectclip(&r, dst->clipr))		/* should perhaps be an arg to dstflush */
+						dstflush(dstid, dst, r);
+				}
+				pp[y] = p;
+			}
+			if(y == 1)
+				dstflush(dstid, dst, Rect(p.x-esize, p.y-esize, p.x+esize+1, p.y+esize+1));
+			op = drawclientop(client);
+			if(*a == 'p')
+				mempoly(dst, pp, ni, e0, e1, j, src, sp, op);
+			else
+				memfillpoly(dst, pp, ni, e0, src, sp, op);
+			free(pp);
+			m = u-a;
+			continue;
+
+		/* read: 'r' id[4] R[4*4] */
+		case 'r':
+			printmesg(fmt="LR", a, 0);
+			m = 1+4+4*4;
+			if(n < m)
+				error(Eshortdraw);
+			i = drawimage(client, a+1);
+			drawrectangle(&r, a+5);
+			if(!rectinrect(r, i->r))
+				error(Ereadoutside);
+			c = bytesperline(r, i->depth);
+			c *= Dy(r);
+			free(client->readdata);
+			client->readdata = mallocz(c, 0);
+			if(client->readdata == nil)
+				error("readimage malloc failed");
+			client->nreaddata = memunload(i, r, client->readdata, c);
+			if(client->nreaddata < 0){
+				free(client->readdata);
+				client->readdata = nil;
+				error("bad readimage call");
+			}
+			continue;
+
+		/* string: 's' dstid[4] srcid[4] fontid[4] P[2*4] clipr[4*4] sp[2*4] ni[2] ni*(index[2]) */
+		/* stringbg: 'x' dstid[4] srcid[4] fontid[4] P[2*4] clipr[4*4] sp[2*4] ni[2] bgid[4] bgpt[2*4] ni*(index[2]) */
+		case 's':
+		case 'x':
+			printmesg(fmt="LLLPRPs", a, 0);
+			m = 1+4+4+4+2*4+4*4+2*4+2;
+			if(*a == 'x')
+				m += 4+2*4;
+			if(n < m)
+				error(Eshortdraw);
+
+			dst = drawimage(client, a+1);
+			dstid = BGLONG(a+1);
+			src = drawimage(client, a+5);
+			font = drawlookup(client, BGLONG(a+9), 1);
+			if(font == 0)
+				error(Enodrawimage);
+			if(font->nfchar == 0)
+				error(Enotfont);
+			drawpoint(&p, a+13);
+			drawrectangle(&r, a+21);
+			drawpoint(&sp, a+37);
+			ni = BGSHORT(a+45);
+			u = a+m;
+			m += ni*2;
+			if(n < m)
+				error(Eshortdraw);
+			clipr = dst->clipr;
+			dst->clipr = r;
+			op = drawclientop(client);
+			bg = dst;
+			if(*a == 'x'){
+				/* paint background */
+				bg = drawimage(client, a+47);
+				drawpoint(&q, a+51);
+				r.min.x = p.x;
+				r.min.y = p.y-font->ascent;
+				r.max.x = p.x;
+				r.max.y = r.min.y+Dy(font->image->r);
+				j = ni;
+				while(--j >= 0){
+					ci = BGSHORT(u);
+					if(ci<0 || ci>=font->nfchar){
+						dst->clipr = clipr;
+						error(Eindex);
+					}
+					r.max.x += font->fchar[ci].width;
+					u += 2;
+				}
+				memdraw(dst, r, bg, q, memopaque, ZP, op);
+				u -= 2*ni;
+			}
+			q = p;
+			while(--ni >= 0){
+				ci = BGSHORT(u);
+				if(ci<0 || ci>=font->nfchar){
+					dst->clipr = clipr;
+					error(Eindex);
+				}
+				q = drawchar(dst, bg, q, src, &sp, font, ci, op);
+				u += 2;
+			}
+			dst->clipr = clipr;
+			p.y -= font->ascent;
+			dstflush(dstid, dst, Rect(p.x, p.y, q.x, p.y+Dy(font->image->r)));
+			continue;
+
+		/* use public screen: 'S' id[4] chan[4] */
+		case 'S':
+			printmesg(fmt="Ll", a, 0);
+			m = 1+4+4;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			if(dstid == 0)
+				error(Ebadarg);
+			dscrn = drawlookupdscreen(dstid);
+			if(dscrn==0 || (dscrn->public==0 && dscrn->owner!=client))
+				error(Enodrawscreen);
+			if(dscrn->screen->image->chan != BGLONG(a+5))
+				error("inconsistent chan");
+			if(drawinstallscreen(client, dscrn, 0, 0, 0, 0) == 0)
+				error(Edrawmem);
+			continue;
+
+		/* top or bottom windows: 't' top[1] nw[2] n*id[4] */
+		case 't':
+			printmesg(fmt="bsL", a, 0);
+			m = 1+1+2;
+			if(n < m)
+				error(Eshortdraw);
+			nw = BGSHORT(a+2);
+			if(nw < 0)
+				error(Ebadarg);
+			if(nw == 0)
+				continue;
+			m += nw*4;
+			if(n < m)
+				error(Eshortdraw);
+			lp = malloc(nw*sizeof(Memimage*));
+			if(lp == 0)
+				error(Enomem);
+			if(waserror()){
+				free(lp);
+				nexterror();
+			}
+			for(j=0; j<nw; j++)
+				lp[j] = drawimage(client, a+1+1+2+j*4);
+			if(lp[0]->layer == 0)
+				error("images are not windows");
+			for(j=1; j<nw; j++)
+				if(lp[j]->layer->screen != lp[0]->layer->screen)
+					error("images not on same screen");
+			if(a[1])
+				memltofrontn(lp, nw);
+			else
+				memltorearn(lp, nw);
+			if(lp[0]->layer->screen->image->data == screenimage->data)
+				for(j=0; j<nw; j++)
+					addflush(lp[j]->layer->screenr);
+			ll = drawlookup(client, BGLONG(a+1+1+2), 1);
+			drawrefreshscreen(ll, client);
+			poperror();
+			free(lp);
+			continue;
+
+		/* visible: 'v' */
+		case 'v':
+			printmesg(fmt="", a, 0);
+			m = 1;
+			drawflush();
+			continue;
+
+		/* write: 'y' id[4] R[4*4] data[x*1] */
+		/* write from compressed data: 'Y' id[4] R[4*4] data[x*1] */
+		case 'y':
+		case 'Y':
+			printmesg(fmt="LR", a, 0);
+		//	iprint("load %c\n", *a);
+			m = 1+4+4*4;
+			if(n < m)
+				error(Eshortdraw);
+			dstid = BGLONG(a+1);
+			dst = drawimage(client, a+1);
+			drawrectangle(&r, a+5);
+			if(!rectinrect(r, dst->r))
+				error(Ewriteoutside);
+			y = memload(dst, r, a+m, n-m, *a=='Y');
+			if(y < 0)
+				error("bad writeimage call");
+			dstflush(dstid, dst, r);
+			m += y;
+			continue;
+		}
+	}
+	poperror();
+}
+
+Dev drawdevtab = {
+	'i',
+	"draw",
+
+	devreset,
+	devinit,
+	devshutdown,
+	drawattach,
+	drawwalk,
+	drawstat,
+	drawopen,
+	devcreate,
+	drawclose,
+	drawread,
+	devbread,
+	drawwrite,
+	devbwrite,
+	devremove,
+	devwstat,
+};
+
+/*
+ * On 8 bit displays, load the default color map
+ */
+void
+drawcmap(void)
+{
+	int r, g, b, cr, cg, cb, v;
+	int num, den;
+	int i, j;
+
+	drawactive(1);	/* to restore map from backup */
+	for(r=0,i=0; r!=4; r++)
+	    for(v=0; v!=4; v++,i+=16){
+		for(g=0,j=v-r; g!=4; g++)
+		    for(b=0;b!=4;b++,j++){
+			den = r;
+			if(g > den)
+				den = g;
+			if(b > den)
+				den = b;
+			if(den == 0)	/* divide check -- pick grey shades */
+				cr = cg = cb = v*17;
+			else{
+				num = 17*(4*den+v);
+				cr = r*num/den;
+				cg = g*num/den;
+				cb = b*num/den;
+			}
+			setcolor(i+(j&15),
+				cr*0x01010101, cg*0x01010101, cb*0x01010101);
+		    }
+	}
+}
+
+void
+drawblankscreen(int blank)
+{
+	int i, nc;
+	ulong *p;
+
+	if(blank == sdraw.blanked)
+		return;
+	if(!candlock())
+		return;
+	if(screenimage == nil){
+		dunlock();
+		return;
+	}
+	p = sdraw.savemap;
+	nc = screenimage->depth > 8 ? 256 : 1<<screenimage->depth;
+
+	/*
+	 * blankscreen uses the hardware to blank the screen
+	 * when possible.  to help in cases when it is not possible,
+	 * we set the color map to be all black.
+	 */
+	if(blank == 0){	/* turn screen on */
+		for(i=0; i<nc; i++, p+=3)
+			setcolor(i, p[0], p[1], p[2]);
+		blankscreen(0);
+	}else{	/* turn screen off */
+		blankscreen(1);
+		for(i=0; i<nc; i++, p+=3){
+			getcolor(i, &p[0], &p[1], &p[2]);
+			setcolor(i, 0, 0, 0);
+		}
+	}
+	sdraw.blanked = blank;
+	dunlock();
+}
+
+/*
+ * record activity on screen, changing blanking as appropriate
+ */
+void
+drawactive(int active)
+{
+	if(active){
+		drawblankscreen(0);
+		sdraw.blanktime = MACHP(0)->ticks;
+	}else{
+		if(blanktime && sdraw.blanktime && TK2SEC(MACHP(0)->ticks - sdraw.blanktime)/60 >= blanktime)
+			drawblankscreen(1);
+	}
+}
+
+int
+drawidletime(void)
+{
+	return TK2SEC(MACHP(0)->ticks - sdraw.blanktime)/60;
+}