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<a href="/plan9/">Plan 9 from Bell Labs</a>’s /usr/web/sources/contrib/rsc/draw.c


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Copyright © 2009 Alcatel-Lucent. 
Distributed under the
<a href="/plan9/license.html">Lucent Public License version 1.02</a>.
 
<a href="/plan9/download.html">Download the Plan 9 distribution.</a>

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#include <u.h>
#include <libc.h>
#include <draw.h>
#include <memdraw.h>

int drawdebug;
static int tablesbuilt;

/* perfect approximation to NTSC = .299r+.587g+.114b when 0 ≤ r,g,b < 256 */
#define RGB2K(r,g,b) ((156763*(r)+307758*(g)+59769*(b))>>19)

/*
* For 16-bit values, x / 255 == (t = x+1, (t+(t>>8)) >> 8).
* We add another 127 to round to the nearest value rather
* than truncate.
*
* CALCxy does x bytewise calculations on y input images (x=1,4; y=1,2).
* CALC2x does two parallel 16-bit calculations on y input images (y=1,2).
*/
#define CALC11(a, v, tmp) \
(tmp=(a)*(v)+128, (tmp+(tmp>>8))>>8)

#define CALC12(a1, v1, a2, v2, tmp) \
(tmp=(a1)*(v1)+(a2)*(v2)+128, (tmp+(tmp>>8))>>8)

#define MASK 0xFF00FF

#define CALC21(a, vvuu, tmp) \
(tmp=(a)*(vvuu)+0x00800080, ((tmp+((tmp>>8)&MASK))>>8)&MASK)

#define CALC41(a, rgba, tmp1, tmp2) \
(CALC21(a, rgba & MASK, tmp1) | \
(CALC21(a, (rgba>>8)&MASK, tmp2)<<8))

#define CALC22(a1, vvuu1, a2, vvuu2, tmp) \
(tmp=(a1)*(vvuu1)+(a2)*(vvuu2)+0x00800080, ((tmp+((tmp>>8)&MASK))>>8)&MASK)

#define CALC42(a1, rgba1, a2, rgba2, tmp1, tmp2) \
(CALC22(a1, rgba1 & MASK, a2, rgba2 & MASK, tmp1) | \
(CALC22(a1, (rgba1>>8) & MASK, a2, (rgba2>>8) & MASK, tmp2)<<8))

static void mktables(void);
typedef int Subdraw(Memdrawparam*);
static Subdraw chardraw, alphadraw, memoptdraw;

static Memimage* memones;
static Memimage* memzeros;
Memimage *memwhite;
Memimage *memblack;
Memimage *memtransparent;
Memimage *memopaque;

int __ifmt(Fmt*);

void
memimageinit(void)
{
static int didinit = 0;

if(didinit)
return;

didinit = 1;

mktables();
_memmkcmap();

fmtinstall('R', Rfmt);
fmtinstall('P', Pfmt);
fmtinstall('b', __ifmt);

memones = allocmemimage(Rect(0,0,1,1), GREY1);
memones->flags |= Frepl;
memones->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
*byteaddr(memones, ZP) = ~0;

memzeros = allocmemimage(Rect(0,0,1,1), GREY1);
memzeros->flags |= Frepl;
memzeros->clipr = Rect(-0x3FFFFFF, -0x3FFFFFF, 0x3FFFFFF, 0x3FFFFFF);
*byteaddr(memzeros, ZP) = 0;

if(memones == nil || memzeros == nil)
assert(0 /*cannot initialize memimage library */); /* RSC BUG */

memwhite = memones;
memblack = memzeros;
memopaque = memones;
memtransparent = memzeros;
}

u32int _imgtorgba(Memimage*, u32int);
u32int _rgbatoimg(Memimage*, u32int);
u32int _pixelbits(Memimage*, Point);

#define DBG if(drawdebug)
static Memdrawparam par;

Memdrawparam*
_memimagedrawsetup(Memimage *dst, Rectangle r, Memimage *src, Point p0, Memimage *mask, Point p1, int op)
{
if(mask == nil)
mask = memopaque;

DBG print("memimagedraw %p/%luX %R @ %p %p/%luX %P %p/%luX %P... ", dst, dst->chan, r, dst->data->bdata, src, src->chan, p0, mask, mask->chan, p1);

if(drawclip(dst, &r, src, &p0, mask, &p1, &par.sr, &par.mr) == 0){
/* if(drawdebug) */
/* iprint("empty clipped rectangle\n"); */
return nil;
}

if(op < Clear || op > SoverD){
/* if(drawdebug) */
/* iprint("op out of range: %d\n", op); */
return nil;
}

par.op = op;
par.dst = dst;
par.r = r;
par.src = src;
/* par.sr set by drawclip */
par.mask = mask;
/* par.mr set by drawclip */

par.state = 0;
if(src->flags&Frepl){
par.state |= Replsrc;
if(Dx(src->r)==1 && Dy(src->r)==1){
par.sval = pixelbits(src, src->r.min);
par.state |= Simplesrc;
par.srgba = _imgtorgba(src, par.sval);
par.sdval = _rgbatoimg(dst, par.srgba);
if((par.srgba&0xFF) == 0 && (op&DoutS)){
/* if (drawdebug) iprint("fill with transparent source\n"); */
return nil; /* no-op successfully handled */
}
if((par.srgba&0xFF) == 0xFF)
par.state |= Fullsrc;
}
}

if(mask->flags & Frepl){
par.state |= Replmask;
if(Dx(mask->r)==1 && Dy(mask->r)==1){
par.mval = pixelbits(mask, mask->r.min);
if(par.mval == 0 && (op&DoutS)){
/* if(drawdebug) iprint("fill with zero mask\n"); */
return nil; /* no-op successfully handled */
}
par.state |= Simplemask;
if(par.mval == ~0)
par.state |= Fullmask;
par.mrgba = _imgtorgba(mask, par.mval);
}
}

/* if(drawdebug) */
/* iprint("dr %R sr %R mr %R...", r, par.sr, par.mr); */
DBG print("draw dr %R sr %R mr %R %lux\n", r, par.sr, par.mr, par.state);

return &par;
}

void
_memimagedraw(Memdrawparam *par)
{
/*
* Now that we've clipped the parameters down to be consistent, we
* simply try sub-drawing routines in order until we find one that was able
* to handle us. If the sub-drawing routine returns zero, it means it was
* unable to satisfy the request, so we do not return.
*/

/*
* Hardware support. Each video driver provides this function,
* which checks to see if there is anything it can help with.
* There could be an if around this checking to see if dst is in video memory.
*/
DBG print("test hwdraw\n");
if(hwdraw(par)){
/*if(drawdebug) iprint("hw handled\n"); */
DBG print("hwdraw handled\n");
return;
}
/*
* Optimizations using memmove and memset.
*/
DBG print("test memoptdraw\n");
if(memoptdraw(par)){
/*if(drawdebug) iprint("memopt handled\n"); */
DBG print("memopt handled\n");
return;
}

/*
* Character drawing.
* Solid source color being painted through a boolean mask onto a high res image.
*/
DBG print("test chardraw\n");
if(chardraw(par)){
/*if(drawdebug) iprint("chardraw handled\n"); */
DBG print("chardraw handled\n");
return;
}

/*
* General calculation-laden case that does alpha for each pixel.
*/
DBG print("do alphadraw\n");
alphadraw(par);
/*if(drawdebug) iprint("alphadraw handled\n"); */
DBG print("alphadraw handled\n");
}
#undef DBG

/*
* Clip the destination rectangle further based on the properties of the
* source and mask rectangles. Once the destination rectangle is properly
* clipped, adjust the source and mask rectangles to be the same size.
* Then if source or mask is replicated, move its clipped rectangle
* so that its minimum point falls within the repl rectangle.
*
* Return zero if the final rectangle is null.
*/
int
drawclip(Memimage *dst, Rectangle *r, Memimage *src, Point *p0, Memimage *mask, Point *p1, Rectangle *sr, Rectangle *mr)
{
Point rmin, delta;
int splitcoords;
Rectangle omr;

if(r->min.x>=r->max.x || r->min.y>=r->max.y)
return 0;
splitcoords = (p0->x!=p1->x) || (p0->y!=p1->y);
/* clip to destination */
rmin = r->min;
if(!rectclip(r, dst->r) || !rectclip(r, dst->clipr))
return 0;
/* move mask point */
p1->x += r->min.x-rmin.x;
p1->y += r->min.y-rmin.y;
/* move source point */
p0->x += r->min.x-rmin.x;
p0->y += r->min.y-rmin.y;
/* map destination rectangle into source */
sr->min = *p0;
sr->max.x = p0->x+Dx(*r);
sr->max.y = p0->y+Dy(*r);
/* sr is r in source coordinates; clip to source */
if(!(src->flags&Frepl) && !rectclip(sr, src->r))
return 0;
if(!rectclip(sr, src->clipr))
return 0;
/* compute and clip rectangle in mask */
if(splitcoords){
/* move mask point with source */
p1->x += sr->min.x-p0->x;
p1->y += sr->min.y-p0->y;
mr->min = *p1;
mr->max.x = p1->x+Dx(*sr);
mr->max.y = p1->y+Dy(*sr);
omr = *mr;
/* mr is now rectangle in mask; clip it */
if(!(mask->flags&Frepl) && !rectclip(mr, mask->r))
return 0;
if(!rectclip(mr, mask->clipr))
return 0;
/* reflect any clips back to source */
sr->min.x += mr->min.x-omr.min.x;
sr->min.y += mr->min.y-omr.min.y;
sr->max.x += mr->max.x-omr.max.x;
sr->max.y += mr->max.y-omr.max.y;
*p1 = mr->min;
}else{
if(!(mask->flags&Frepl) && !rectclip(sr, mask->r))
return 0;
if(!rectclip(sr, mask->clipr))
return 0;
*p1 = sr->min;
}

/* move source clipping back to destination */
delta.x = r->min.x - p0->x;
delta.y = r->min.y - p0->y;
r->min.x = sr->min.x + delta.x;
r->min.y = sr->min.y + delta.y;
r->max.x = sr->max.x + delta.x;
r->max.y = sr->max.y + delta.y;

/* move source rectangle so sr->min is in src->r */
if(src->flags&Frepl) {
delta.x = drawreplxy(src->r.min.x, src->r.max.x, sr->min.x) - sr->min.x;
delta.y = drawreplxy(src->r.min.y, src->r.max.y, sr->min.y) - sr->min.y;
sr->min.x += delta.x;
sr->min.y += delta.y;
sr->max.x += delta.x;
sr->max.y += delta.y;
}
*p0 = sr->min;

/* move mask point so it is in mask->r */
*p1 = drawrepl(mask->r, *p1);
mr->min = *p1;
mr->max.x = p1->x+Dx(*sr);
mr->max.y = p1->y+Dy(*sr);

assert(Dx(*sr) == Dx(*mr) && Dx(*mr) == Dx(*r));
assert(Dy(*sr) == Dy(*mr) && Dy(*mr) == Dy(*r));
assert(ptinrect(*p0, src->r));
assert(ptinrect(*p1, mask->r));
assert(ptinrect(r->min, dst->r));

return 1;
}

/*
* Conversion tables.
*/
static uchar replbit[1+8][256]; /* replbit[x][y] is the replication of the x-bit quantity y to 8-bit depth */
static uchar conv18[256][8]; /* conv18[x][y] is the yth pixel in the depth-1 pixel x */
static uchar conv28[256][4]; /* ... */
static uchar conv48[256][2];

/*
* bitmap of how to replicate n bits to fill 8, for 1 ≤ n ≤ 8.
* the X's are where to put the bottom (ones) bit of the n-bit pattern.
* only the top 8 bits of the result are actually used.
* (the lower 8 bits are needed to get bits in the right place
* when n is not a divisor of 8.)
*
* Should check to see if its easier to just refer to replmul than
* use the precomputed values in replbit. On PCs it may well
* be; on machines with slow multiply instructions it probably isn't.
*/
#define a ((((((((((((((((0
#define X *2+1)
#define _ *2)
static int replmul[1+8] = {
0,
a X X X X X X X X X X X X X X X X,
a _ X _ X _ X _ X _ X _ X _ X _ X,
a _ _ X _ _ X _ _ X _ _ X _ _ X _,
a _ _ _ X _ _ _ X _ _ _ X _ _ _ X,
a _ _ _ _ X _ _ _ _ X _ _ _ _ X _,
a _ _ _ _ _ X _ _ _ _ _ X _ _ _ _,
a _ _ _ _ _ _ X _ _ _ _ _ _ X _ _,
a _ _ _ _ _ _ _ X _ _ _ _ _ _ _ X,
};
#undef a
#undef X
#undef _

static void
mktables(void)
{
int i, j, mask, sh, small;

if(tablesbuilt)
return;

fmtinstall('R', Rfmt);
fmtinstall('P', Pfmt);
tablesbuilt = 1;

/* bit replication up to 8 bits */
for(i=0; i<256; i++){
for(j=0; j<=8; j++){ /* j <= 8 [sic] */
small = i & ((1<<j)-1);
replbit[j][i] = (small*replmul[j])>>8;
}
}

/* bit unpacking up to 8 bits, only powers of 2 */
for(i=0; i<256; i++){
for(j=0, sh=7, mask=1; j<8; j++, sh--)
conv18[i][j] = replbit[1][(i>>sh)&mask];

for(j=0, sh=6, mask=3; j<4; j++, sh-=2)
conv28[i][j] = replbit[2][(i>>sh)&mask];

for(j=0, sh=4, mask=15; j<2; j++, sh-=4)
conv48[i][j] = replbit[4][(i>>sh)&mask];
}
}

static uchar ones = 0xff;

/*
* General alpha drawing case. Can handle anything.
*/
typedef struct Buffer Buffer;
struct Buffer {
/* used by most routines */
uchar *red;
uchar *grn;
uchar *blu;
uchar *alpha;
uchar *grey;
u32int *rgba;
int delta; /* number of bytes to add to pointer to get next pixel to the right */

/* used by boolcalc* for mask data */
uchar *m; /* ptr to mask data r.min byte; like p->bytermin */
int mskip; /* no. of left bits to skip in *m */
uchar *bm; /* ptr to mask data img->r.min byte; like p->bytey0s */
int bmskip; /* no. of left bits to skip in *bm */
uchar *em; /* ptr to mask data img->r.max.x byte; like p->bytey0e */
int emskip; /* no. of right bits to skip in *em */
};

typedef struct Param Param;
typedef Buffer Readfn(Param*, uchar*, int);
typedef void Writefn(Param*, uchar*, Buffer);
typedef Buffer Calcfn(Buffer, Buffer, Buffer, int, int, int);

enum {
MAXBCACHE = 16
};

/* giant rathole to customize functions with */
struct Param {
Readfn *replcall;
Readfn *greymaskcall;
Readfn *convreadcall;
Writefn *convwritecall;

Memimage *img;
Rectangle r;
int dx; /* of r */
int needbuf;
int convgrey;
int alphaonly;

uchar *bytey0s; /* byteaddr(Pt(img->r.min.x, img->r.min.y)) */
uchar *bytermin; /* byteaddr(Pt(r.min.x, img->r.min.y)) */
uchar *bytey0e; /* byteaddr(Pt(img->r.max.x, img->r.min.y)) */
int bwidth;

int replcache; /* if set, cache buffers */
Buffer bcache[MAXBCACHE];
u32int bfilled;
uchar *bufbase;
int bufoff;
int bufdelta;

int dir;

int convbufoff;
uchar *convbuf;
Param *convdpar;
int convdx;
};

static uchar *drawbuf;
static int ndrawbuf;
static int mdrawbuf;
static Param spar, mpar, dpar; /* easier on the stacks */
static Readfn greymaskread, replread, readptr;
static Writefn nullwrite;
static Calcfn alphacalc0, alphacalc14, alphacalc2810, alphacalc3679, alphacalc5, alphacalc11, alphacalcS;
static Calcfn boolcalc14, boolcalc236789, boolcalc1011;

static Readfn* readfn(Memimage*);
static Readfn* readalphafn(Memimage*);
static Writefn* writefn(Memimage*);

static Calcfn* boolcopyfn(Memimage*, Memimage*);
static Readfn* convfn(Memimage*, Param*, Memimage*, Param*);

static Calcfn *alphacalc[Ncomp] =
{
alphacalc0, /* Clear */
alphacalc14, /* DoutS */
alphacalc2810, /* SoutD */
alphacalc3679, /* DxorS */
alphacalc14, /* DinS */
alphacalc5, /* D */
alphacalc3679, /* DatopS */
alphacalc3679, /* DoverS */
alphacalc2810, /* SinD */
alphacalc3679, /* SatopD */
alphacalc2810, /* S */
alphacalc11, /* SoverD */
};

static Calcfn *boolcalc[Ncomp] =
{
alphacalc0, /* Clear */
boolcalc14, /* DoutS */
boolcalc236789, /* SoutD */
boolcalc236789, /* DxorS */
boolcalc14, /* DinS */
alphacalc5, /* D */
boolcalc236789, /* DatopS */
boolcalc236789, /* DoverS */
boolcalc236789, /* SinD */
boolcalc236789, /* SatopD */
boolcalc1011, /* S */
boolcalc1011, /* SoverD */
};

static int
allocdrawbuf(void)
{
uchar *p;

if(ndrawbuf > mdrawbuf){
p = realloc(drawbuf, ndrawbuf);
if(p == nil){
werrstr("memimagedraw out of memory");
return -1;
}
drawbuf = p;
mdrawbuf = ndrawbuf;
}
return 0;
}

static void
getparam(Param *p, Memimage *img, Rectangle r, int convgrey, int needbuf)
{
int nbuf;

memset(p, 0, sizeof *p);

p->img = img;
p->r = r;
p->dx = Dx(r);
p->needbuf = needbuf;
p->convgrey = convgrey;

assert(img->r.min.x <= r.min.x && r.min.x < img->r.max.x);

p->bytey0s = byteaddr(img, Pt(img->r.min.x, img->r.min.y));
p->bytermin = byteaddr(img, Pt(r.min.x, img->r.min.y));
p->bytey0e = byteaddr(img, Pt(img->r.max.x, img->r.min.y));
p->bwidth = sizeof(u32int)*img->width;

assert(p->bytey0s <= p->bytermin && p->bytermin <= p->bytey0e);

if(p->r.min.x == p->img->r.min.x)
assert(p->bytermin == p->bytey0s);

nbuf = 1;
if((img->flags&Frepl) && Dy(img->r) <= MAXBCACHE && Dy(img->r) < Dy(r)){
p->replcache = 1;
nbuf = Dy(img->r);
}
p->bufdelta = 4*p->dx;
p->bufoff = ndrawbuf;
ndrawbuf += p->bufdelta*nbuf;
}

static void
clipy(Memimage *img, int *y)
{
int dy;

dy = Dy(img->r);
if(*y == dy)
*y = 0;
else if(*y == -1)
*y = dy-1;
assert(0 <= *y && *y < dy);
}

static void
dumpbuf(char *s, Buffer b, int n)
{
int i;
uchar *p;

print("%s", s);
for(i=0; i<n; i++){
print(" ");
if(p=b.grey){
print(" k%.2uX", *p);
b.grey += b.delta;
}else{
if(p=b.red){
print(" r%.2uX", *p);
b.red += b.delta;
}
if(p=b.grn){
print(" g%.2uX", *p);
b.grn += b.delta;
}
if(p=b.blu){
print(" b%.2uX", *p);
b.blu += b.delta;
}
}
if((p=b.alpha) != &ones){
print(" α%.2uX", *p);
b.alpha += b.delta;
}
}
print("\n");
}

/*
* For each scan line, we expand the pixels from source, mask, and destination
* into byte-aligned red, green, blue, alpha, and grey channels. If buffering is not
* needed and the channels were already byte-aligned (grey8, rgb24, rgba32, rgb32),
* the readers need not copy the data: they can simply return pointers to the data.
* If the destination image is grey and the source is not, it is converted using the NTSC
* formula.
*
* Once we have all the channels, we call either rgbcalc or greycalc, depending on
* whether the destination image is color. This is allowed to overwrite the dst buffer (perhaps
* the actual data, perhaps a copy) with its result. It should only overwrite the dst buffer
* with the same format (i.e. red bytes with red bytes, etc.) A new buffer is returned from
* the calculator, and that buffer is passed to a function to write it to the destination.
* If the buffer is already pointing at the destination, the writing function is a no-op.
*/
#define DBG if(drawdebug)
static int
alphadraw(Memdrawparam *par)
{
int isgrey, starty, endy, op;
int needbuf, dsty, srcy, masky;
int y, dir, dx, dy;
Buffer bsrc, bdst, bmask;
Readfn *rdsrc, *rdmask, *rddst;
Calcfn *calc;
Writefn *wrdst;
Memimage *src, *mask, *dst;
Rectangle r, sr, mr;

if(drawdebug)
print("alphadraw %R\n", par->r);
r = par->r;
dx = Dx(r);
dy = Dy(r);

ndrawbuf = 0;

src = par->src;
mask = par->mask;
dst = par->dst;
sr = par->sr;
mr = par->mr;
op = par->op;

isgrey = dst->flags&Fgrey;

/*
* Buffering when src and dst are the same bitmap is sufficient but not
* necessary. There are stronger conditions we could use. We could
* check to see if the rectangles intersect, and if simply moving in the
* correct y direction can avoid the need to buffer.
*/
needbuf = (src->data == dst->data);

getparam(&spar, src, sr, isgrey, needbuf);
getparam(&dpar, dst, r, isgrey, needbuf);
getparam(&mpar, mask, mr, 0, needbuf);

dir = (needbuf && byteaddr(dst, r.min) > byteaddr(src, sr.min)) ? -1 : 1;
spar.dir = mpar.dir = dpar.dir = dir;

/*
* If the mask is purely boolean, we can convert from src to dst format
* when we read src, and then just copy it to dst where the mask tells us to.
* This requires a boolean (1-bit grey) mask and lack of a source alpha channel.
*
* The computation is accomplished by assigning the function pointers as follows:
* rdsrc - read and convert source into dst format in a buffer
* rdmask - convert mask to bytes, set pointer to it
* rddst - fill with pointer to real dst data, but do no reads
* calc - copy src onto dst when mask says to.
* wrdst - do nothing
* This is slightly sleazy, since things aren't doing exactly what their names say,
* but it avoids a fair amount of code duplication to make this a case here
* rather than have a separate booldraw.
*/
/*if(drawdebug) iprint("flag %lud mchan %lux=?%x dd %d\n", src->flags&Falpha, mask->chan, GREY1, dst->depth); */
if(!(src->flags&Falpha) && mask->chan == GREY1 && dst->depth >= 8 && op == SoverD){
/*if(drawdebug) iprint("boolcopy..."); */
rdsrc = convfn(dst, &dpar, src, &spar);
rddst = readptr;
rdmask = readfn(mask);
calc = boolcopyfn(dst, mask);
wrdst = nullwrite;
}else{
/* usual alphadraw parameter fetching */
rdsrc = readfn(src);
rddst = readfn(dst);
wrdst = writefn(dst);
calc = alphacalc[op];

/*
* If there is no alpha channel, we'll ask for a grey channel
* and pretend it is the alpha.
*/
if(mask->flags&Falpha){
rdmask = readalphafn(mask);
mpar.alphaonly = 1;
}else{
mpar.greymaskcall = readfn(mask);
mpar.convgrey = 1;
rdmask = greymaskread;

/*
* Should really be above, but then boolcopyfns would have
* to deal with bit alignment, and I haven't written that.
*
* This is a common case for things like ellipse drawing.
* When there's no alpha involved and the mask is boolean,
* we can avoid all the division and multiplication.
*/
if(mask->chan == GREY1 && !(src->flags&Falpha))
calc = boolcalc[op];
else if(op == SoverD && !(src->flags&Falpha))
calc = alphacalcS;
}
}

/*
* If the image has a small enough repl rectangle,
* we can just read each line once and cache them.
*/
if(spar.replcache){
spar.replcall = rdsrc;
rdsrc = replread;
}
if(mpar.replcache){
mpar.replcall = rdmask;
rdmask = replread;
}

if(allocdrawbuf() < 0)
return 0;

/*
* Before we were saving only offsets from drawbuf in the parameter
* structures; now that drawbuf has been grown to accomodate us,
* we can fill in the pointers.
*/
spar.bufbase = drawbuf+spar.bufoff;
mpar.bufbase = drawbuf+mpar.bufoff;
dpar.bufbase = drawbuf+dpar.bufoff;
spar.convbuf = drawbuf+spar.convbufoff;

if(dir == 1){
starty = 0;
endy = dy;
}else{
starty = dy-1;
endy = -1;
}

/*
* srcy, masky, and dsty are offsets from the top of their
* respective Rectangles. they need to be contained within
* the rectangles, so clipy can keep them there without division.
*/
srcy = (starty + sr.min.y - src->r.min.y)%Dy(src->r);
masky = (starty + mr.min.y - mask->r.min.y)%Dy(mask->r);
dsty = starty + r.min.y - dst->r.min.y;

assert(0 <= srcy && srcy < Dy(src->r));
assert(0 <= masky && masky < Dy(mask->r));
assert(0 <= dsty && dsty < Dy(dst->r));

if(drawdebug)
print("alphadraw: rdsrc=%p rdmask=%p rddst=%p calc=%p wrdst=%p\n",
rdsrc, rdmask, rddst, calc, wrdst);
for(y=starty; y!=endy; y+=dir, srcy+=dir, masky+=dir, dsty+=dir){
clipy(src, &srcy);
clipy(dst, &dsty);
clipy(mask, &masky);

bsrc = rdsrc(&spar, spar.bufbase, srcy);
DBG print("[");
bmask = rdmask(&mpar, mpar.bufbase, masky);
DBG print("]\n");
bdst = rddst(&dpar, dpar.bufbase, dsty);
DBG dumpbuf("src", bsrc, dx);
DBG dumpbuf("mask", bmask, dx);
DBG dumpbuf("dst", bdst, dx);
bdst = calc(bdst, bsrc, bmask, dx, isgrey, op);
DBG dumpbuf("bdst", bdst, dx);
wrdst(&dpar, dpar.bytermin+dsty*dpar.bwidth, bdst);
}

return 1;
}
#undef DBG

static Buffer
alphacalc0(Buffer bdst, Buffer b1, Buffer b2, int dx, int grey, int op)
{
USED(grey);
USED(op);
memset(bdst.rgba, 0, dx*bdst.delta);
return bdst;
}

/*
* Do the channels in the buffers match enough
* that we can do word-at-a-time operations
* on the pixels?
*/
static int
chanmatch(Buffer *bdst, Buffer *bsrc)
{
uchar *drgb, *srgb;

/*
* first, r, g, b must be in the same place
* in the rgba word.
*/
drgb = (uchar*)bdst->rgba;
srgb = (uchar*)bsrc->rgba;
if(bdst->red - drgb != bsrc->red - srgb
|| bdst->blu - drgb != bsrc->blu - srgb
|| bdst->grn - drgb != bsrc->grn - srgb)
return 0;

/*
* that implies alpha is in the same place,
* if it is there at all (it might be == &ones).
* if the destination is &ones, we can scribble
* over the rgba slot just fine.
*/
if(bdst->alpha == &ones)
return 1;

/*
* if the destination is not ones but the src is,
* then the simultaneous calculation will use
* bogus bytes from the src's rgba. no good.
*/
if(bsrc->alpha == &ones)
return 0;

/*
* otherwise, alphas are in the same place.
*/
return 1;
}

static Buffer
alphacalc14(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int fd, sadelta;
int i, sa, ma, q;
u32int t, t1;

obdst = bdst;
sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);

for(i=0; i<dx; i++){
sa = *bsrc.alpha;
ma = *bmask.alpha;
fd = CALC11(sa, ma, t);
if(op == DoutS)
fd = 255-fd;

if(grey){
*bdst.grey = CALC11(fd, *bdst.grey, t);
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
if(q){
*bdst.rgba = CALC41(fd, *bdst.rgba, t, t1);
bsrc.rgba++;
bdst.rgba++;
bsrc.alpha += sadelta;
bmask.alpha += bmask.delta;
continue;
}
*bdst.red = CALC11(fd, *bdst.red, t);
*bdst.grn = CALC11(fd, *bdst.grn, t);
*bdst.blu = CALC11(fd, *bdst.blu, t);
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
if(bdst.alpha != &ones){
*bdst.alpha = CALC11(fd, *bdst.alpha, t);
bdst.alpha += bdst.delta;
}
bmask.alpha += bmask.delta;
bsrc.alpha += sadelta;
}
return obdst;
}

static Buffer
alphacalc2810(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int fs, sadelta;
int i, ma, da, q;
u32int t, t1;

obdst = bdst;
sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);

for(i=0; i<dx; i++){
ma = *bmask.alpha;
da = *bdst.alpha;
if(op == SoutD)
da = 255-da;
fs = ma;
if(op != S)
fs = CALC11(fs, da, t);

if(grey){
*bdst.grey = CALC11(fs, *bsrc.grey, t);
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
if(q){
*bdst.rgba = CALC41(fs, *bsrc.rgba, t, t1);
bsrc.rgba++;
bdst.rgba++;
bmask.alpha += bmask.delta;
bdst.alpha += bdst.delta;
continue;
}
*bdst.red = CALC11(fs, *bsrc.red, t);
*bdst.grn = CALC11(fs, *bsrc.grn, t);
*bdst.blu = CALC11(fs, *bsrc.blu, t);
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
if(bdst.alpha != &ones){
*bdst.alpha = CALC11(fs, *bsrc.alpha, t);
bdst.alpha += bdst.delta;
}
bmask.alpha += bmask.delta;
bsrc.alpha += sadelta;
}
return obdst;
}

static Buffer
alphacalc3679(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int fs, fd, sadelta;
int i, sa, ma, da, q;
u32int t, t1;

obdst = bdst;
sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);

for(i=0; i<dx; i++){
sa = *bsrc.alpha;
ma = *bmask.alpha;
da = *bdst.alpha;
if(op == SatopD)
fs = CALC11(ma, da, t);
else
fs = CALC11(ma, 255-da, t);
if(op == DoverS)
fd = 255;
else{
fd = CALC11(sa, ma, t);
if(op != DatopS)
fd = 255-fd;
}

if(grey){
*bdst.grey = CALC12(fs, *bsrc.grey, fd, *bdst.grey, t);
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
if(q){
*bdst.rgba = CALC42(fs, *bsrc.rgba, fd, *bdst.rgba, t, t1);
bsrc.rgba++;
bdst.rgba++;
bsrc.alpha += sadelta;
bmask.alpha += bmask.delta;
bdst.alpha += bdst.delta;
continue;
}
*bdst.red = CALC12(fs, *bsrc.red, fd, *bdst.red, t);
*bdst.grn = CALC12(fs, *bsrc.grn, fd, *bdst.grn, t);
*bdst.blu = CALC12(fs, *bsrc.blu, fd, *bdst.blu, t);
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
if(bdst.alpha != &ones){
*bdst.alpha = CALC12(fs, sa, fd, da, t);
bdst.alpha += bdst.delta;
}
bmask.alpha += bmask.delta;
bsrc.alpha += sadelta;
}
return obdst;
}

static Buffer
alphacalc5(Buffer bdst, Buffer b1, Buffer b2, int dx, int grey, int op)
{
USED(dx);
USED(grey);
USED(op);
return bdst;
}

static Buffer
alphacalc11(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int fd, sadelta;
int i, sa, ma, q;
u32int t, t1;

USED(op);
obdst = bdst;
sadelta = bsrc.alpha == &ones ? 0 : bsrc.delta;
q = bsrc.delta == 4 && bdst.delta == 4 && chanmatch(&bdst, &bsrc);

for(i=0; i<dx; i++){
sa = *bsrc.alpha;
ma = *bmask.alpha;
fd = 255-CALC11(sa, ma, t);

if(grey){
*bdst.grey = CALC12(ma, *bsrc.grey, fd, *bdst.grey, t);
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
if(q){
*bdst.rgba = CALC42(ma, *bsrc.rgba, fd, *bdst.rgba, t, t1);
bsrc.rgba++;
bdst.rgba++;
bsrc.alpha += sadelta;
bmask.alpha += bmask.delta;
continue;
}
*bdst.red = CALC12(ma, *bsrc.red, fd, *bdst.red, t);
*bdst.grn = CALC12(ma, *bsrc.grn, fd, *bdst.grn, t);
*bdst.blu = CALC12(ma, *bsrc.blu, fd, *bdst.blu, t);
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
if(bdst.alpha != &ones){
*bdst.alpha = CALC12(ma, sa, fd, *bdst.alpha, t);
bdst.alpha += bdst.delta;
}
bmask.alpha += bmask.delta;
bsrc.alpha += sadelta;
}
return obdst;
}

/*
not used yet
source and mask alpha 1
static Buffer
alphacalcS0(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int i;

USED(op);
obdst = bdst;
if(bsrc.delta == bdst.delta){
memmove(bdst.rgba, bsrc.rgba, dx*bdst.delta);
return obdst;
}
for(i=0; i<dx; i++){
if(grey){
*bdst.grey = *bsrc.grey;
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
*bdst.red = *bsrc.red;
*bdst.grn = *bsrc.grn;
*bdst.blu = *bsrc.blu;
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
if(bdst.alpha != &ones){
*bdst.alpha = 255;
bdst.alpha += bdst.delta;
}
}
return obdst;
}
*/

/* source alpha 1 */
static Buffer
alphacalcS(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int fd;
int i, ma;
u32int t;

USED(op);
obdst = bdst;

for(i=0; i<dx; i++){
ma = *bmask.alpha;
fd = 255-ma;

if(grey){
*bdst.grey = CALC12(ma, *bsrc.grey, fd, *bdst.grey, t);
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
*bdst.red = CALC12(ma, *bsrc.red, fd, *bdst.red, t);
*bdst.grn = CALC12(ma, *bsrc.grn, fd, *bdst.grn, t);
*bdst.blu = CALC12(ma, *bsrc.blu, fd, *bdst.blu, t);
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
if(bdst.alpha != &ones){
*bdst.alpha = ma+CALC11(fd, *bdst.alpha, t);
bdst.alpha += bdst.delta;
}
bmask.alpha += bmask.delta;
}
return obdst;
}

static Buffer
boolcalc14(Buffer bdst, Buffer b1, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int i, ma, zero;

obdst = bdst;

for(i=0; i<dx; i++){
ma = *bmask.alpha;
zero = ma ? op == DoutS : op == DinS;

if(grey){
if(zero)
*bdst.grey = 0;
bdst.grey += bdst.delta;
}else{
if(zero)
*bdst.red = *bdst.grn = *bdst.blu = 0;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
bmask.alpha += bmask.delta;
if(bdst.alpha != &ones){
if(zero)
*bdst.alpha = 0;
bdst.alpha += bdst.delta;
}
}
return obdst;
}

static Buffer
boolcalc236789(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int fs, fd;
int i, ma, da, zero;
u32int t;

obdst = bdst;
zero = !(op&1);

for(i=0; i<dx; i++){
ma = *bmask.alpha;
da = *bdst.alpha;
fs = da;
if(op&2)
fs = 255-da;
fd = 0;
if(op&4)
fd = 255;

if(grey){
if(ma)
*bdst.grey = CALC12(fs, *bsrc.grey, fd, *bdst.grey, t);
else if(zero)
*bdst.grey = 0;
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
if(ma){
*bdst.red = CALC12(fs, *bsrc.red, fd, *bdst.red, t);
*bdst.grn = CALC12(fs, *bsrc.grn, fd, *bdst.grn, t);
*bdst.blu = CALC12(fs, *bsrc.blu, fd, *bdst.blu, t);
}
else if(zero)
*bdst.red = *bdst.grn = *bdst.blu = 0;
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
bmask.alpha += bmask.delta;
if(bdst.alpha != &ones){
if(ma)
*bdst.alpha = fs+CALC11(fd, da, t);
else if(zero)
*bdst.alpha = 0;
bdst.alpha += bdst.delta;
}
}
return obdst;
}

static Buffer
boolcalc1011(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int grey, int op)
{
Buffer obdst;
int i, ma, zero;

obdst = bdst;
zero = !(op&1);

for(i=0; i<dx; i++){
ma = *bmask.alpha;

if(grey){
if(ma)
*bdst.grey = *bsrc.grey;
else if(zero)
*bdst.grey = 0;
bsrc.grey += bsrc.delta;
bdst.grey += bdst.delta;
}else{
if(ma){
*bdst.red = *bsrc.red;
*bdst.grn = *bsrc.grn;
*bdst.blu = *bsrc.blu;
}
else if(zero)
*bdst.red = *bdst.grn = *bdst.blu = 0;
bsrc.red += bsrc.delta;
bsrc.blu += bsrc.delta;
bsrc.grn += bsrc.delta;
bdst.red += bdst.delta;
bdst.blu += bdst.delta;
bdst.grn += bdst.delta;
}
bmask.alpha += bmask.delta;
if(bdst.alpha != &ones){
if(ma)
*bdst.alpha = 255;
else if(zero)
*bdst.alpha = 0;
bdst.alpha += bdst.delta;
}
}
return obdst;
}
/*
* Replicated cached scan line read. Call the function listed in the Param,
* but cache the result so that for replicated images we only do the work once.
*/
static Buffer
replread(Param *p, uchar *s, int y)
{
Buffer *b;

USED(s);
b = &p->bcache[y];
if((p->bfilled & (1<<y)) == 0){
p->bfilled |= 1<<y;
*b = p->replcall(p, p->bufbase+y*p->bufdelta, y);
}
return *b;
}

/*
* Alpha reading function that simply relabels the grey pointer.
*/
static Buffer
greymaskread(Param *p, uchar *buf, int y)
{
Buffer b;

b = p->greymaskcall(p, buf, y);
b.alpha = b.grey;
return b;
}

#define DBG if(0)
static Buffer
readnbit(Param *p, uchar *buf, int y)
{
Buffer b;
Memimage *img;
uchar *repl, *r, *w, *ow, bits;
int i, n, sh, depth, x, dx, npack, nbits;

memset(&b, 0, sizeof b);
b.rgba = (u32int*)buf;
b.grey = w = buf;
b.red = b.blu = b.grn = w;
b.alpha = &ones;
b.delta = 1;

dx = p->dx;
img = p->img;
depth = img->depth;
repl = &replbit[depth][0];
npack = 8/depth;
sh = 8-depth;

/* copy from p->r.min.x until end of repl rectangle */
x = p->r.min.x;
n = dx;
if(n > p->img->r.max.x - x)
n = p->img->r.max.x - x;

r = p->bytermin + y*p->bwidth;
DBG print("readnbit dx %d %p=%p+%d*%d, *r=%d fetch %d ", dx, r, p->bytermin, y, p->bwidth, *r, n);
bits = *r++;
nbits = 8;
if(i=x&(npack-1)){
DBG print("throwaway %d...", i);
bits <<= depth*i;
nbits -= depth*i;
}
for(i=0; i<n; i++){
if(nbits == 0){
DBG print("(%.2ux)...", *r);
bits = *r++;
nbits = 8;
}
*w++ = repl[bits>>sh];
DBG print("bit %x...", repl[bits>>sh]);
bits <<= depth;
nbits -= depth;
}
dx -= n;
if(dx == 0)
return b;

assert(x+i == p->img->r.max.x);

/* copy from beginning of repl rectangle until where we were before. */
x = p->img->r.min.x;
n = dx;
if(n > p->r.min.x - x)
n = p->r.min.x - x;

r = p->bytey0s + y*p->bwidth;
DBG print("x=%d r=%p...", x, r);
bits = *r++;
nbits = 8;
if(i=x&(npack-1)){
bits <<= depth*i;
nbits -= depth*i;
}
DBG print("nbits=%d...", nbits);
for(i=0; i<n; i++){
if(nbits == 0){
bits = *r++;
nbits = 8;
}
*w++ = repl[bits>>sh];
DBG print("bit %x...", repl[bits>>sh]);
bits <<= depth;
nbits -= depth;
DBG print("bits %x nbits %d...", bits, nbits);
}
dx -= n;
if(dx == 0)
return b;

assert(dx > 0);
/* now we have exactly one full scan line: just replicate the buffer itself until we are done */
ow = buf;
while(dx--)
*w++ = *ow++;

return b;
}
#undef DBG

#define DBG if(0)
static void
writenbit(Param *p, uchar *w, Buffer src)
{
uchar *r;
u32int bits;
int i, sh, depth, npack, nbits, x, ex;

assert(src.grey != nil && src.delta == 1);

x = p->r.min.x;
ex = x+p->dx;
depth = p->img->depth;
npack = 8/depth;

i=x&(npack-1);
bits = i ? (*w >> (8-depth*i)) : 0;
nbits = depth*i;
sh = 8-depth;
r = src.grey;

for(; x<ex; x++){
bits <<= depth;
DBG print(" %x", *r);
bits |= (*r++ >> sh);
nbits += depth;
if(nbits == 8){
*w++ = bits;
nbits = 0;
}
}

if(nbits){
sh = 8-nbits;
bits <<= sh;
bits |= *w & ((1<<sh)-1);
*w = bits;
}
DBG print("\n");
return;
}
#undef DBG

static Buffer
readcmap(Param *p, uchar *buf, int y)
{
Buffer b;
int a, convgrey, copyalpha, dx, i, m;
uchar *q, *cmap, *begin, *end, *r, *w;

memset(&b, 0, sizeof b);
begin = p->bytey0s + y*p->bwidth;
r = p->bytermin + y*p->bwidth;
end = p->bytey0e + y*p->bwidth;
cmap = p->img->cmap->cmap2rgb;
convgrey = p->convgrey;
copyalpha = (p->img->flags&Falpha) ? 1 : 0;

w = buf;
dx = p->dx;
if(copyalpha){
b.alpha = buf++;
a = p->img->shift[CAlpha]/8;
m = p->img->shift[CMap]/8;
for(i=0; i<dx; i++){
*w++ = r[a];
q = cmap+r[m]*3;
r += 2;
if(r == end)
r = begin;
if(convgrey){
*w++ = RGB2K(q[0], q[1], q[2]);
}else{
*w++ = q[2]; /* blue */
*w++ = q[1]; /* green */
*w++ = q[0]; /* red */
}
}
}else{
b.alpha = &ones;
for(i=0; i<dx; i++){
q = cmap+*r++*3;
if(r == end)
r = begin;
if(convgrey){
*w++ = RGB2K(q[0], q[1], q[2]);
}else{
*w++ = q[2]; /* blue */
*w++ = q[1]; /* green */
*w++ = q[0]; /* red */
}
}
}

b.rgba = (u32int*)(buf-copyalpha);

if(convgrey){
b.grey = buf;
b.red = b.blu = b.grn = buf;
b.delta = 1+copyalpha;
}else{
b.blu = buf;
b.grn = buf+1;
b.red = buf+2;
b.grey = nil;
b.delta = 3+copyalpha;
}
return b;
}

static void
writecmap(Param *p, uchar *w, Buffer src)
{
uchar *cmap, *red, *grn, *blu;
int i, dx, delta;

cmap = p->img->cmap->rgb2cmap;

delta = src.delta;
red= src.red;
grn = src.grn;
blu = src.blu;

dx = p->dx;
for(i=0; i<dx; i++, red+=delta, grn+=delta, blu+=delta)
*w++ = cmap[(*red>>4)*256+(*grn>>4)*16+(*blu>>4)];
}

#define DBG if(drawdebug)
static Buffer
readbyte(Param *p, uchar *buf, int y)
{
Buffer b;
Memimage *img;
int dx, isgrey, convgrey, alphaonly, copyalpha, i, nb;
uchar *begin, *end, *r, *w, *rrepl, *grepl, *brepl, *arepl, *krepl;
uchar ured, ugrn, ublu;
u32int u;

img = p->img;
begin = p->bytey0s + y*p->bwidth;
r = p->bytermin + y*p->bwidth;
end = p->bytey0e + y*p->bwidth;

w = buf;
dx = p->dx;
nb = img->depth/8;

convgrey = p->convgrey; /* convert rgb to grey */
isgrey = img->flags&Fgrey;
alphaonly = p->alphaonly;
copyalpha = (img->flags&Falpha) ? 1 : 0;

/* if we can, avoid processing everything */
if(!(img->flags&Frepl) && !convgrey && (img->flags&Fbytes)){
memset(&b, 0, sizeof b);
if(p->needbuf){
memmove(buf, r, dx*nb);
r = buf;
}
b.rgba = (u32int*)r;
if(copyalpha)
b.alpha = r+img->shift[CAlpha]/8;
else
b.alpha = &ones;
if(isgrey){
b.grey = r+img->shift[CGrey]/8;
b.red = b.grn = b.blu = b.grey;
}else{
b.red = r+img->shift[CRed]/8;
b.grn = r+img->shift[CGreen]/8;
b.blu = r+img->shift[CBlue]/8;
}
b.delta = nb;
return b;
}

rrepl = replbit[img->nbits[CRed]];
grepl = replbit[img->nbits[CGreen]];
brepl = replbit[img->nbits[CBlue]];
arepl = replbit[img->nbits[CAlpha]];
krepl = replbit[img->nbits[CGrey]];

for(i=0; i<dx; i++){
u = r[0] | (r[1]<<8) | (r[2]<<16) | (r[3]<<24);
if(copyalpha)
*w++ = arepl[(u>>img->shift[CAlpha]) & img->mask[CAlpha]];

if(isgrey)
*w++ = krepl[(u >> img->shift[CGrey]) & img->mask[CGrey]];
else if(!alphaonly){
ured = rrepl[(u >> img->shift[CRed]) & img->mask[CRed]];
ugrn = grepl[(u >> img->shift[CGreen]) & img->mask[CGreen]];
ublu = brepl[(u >> img->shift[CBlue]) & img->mask[CBlue]];
if(convgrey){
*w++ = RGB2K(ured, ugrn, ublu);
}else{
*w++ = brepl[(u >> img->shift[CBlue]) & img->mask[CBlue]];
*w++ = grepl[(u >> img->shift[CGreen]) & img->mask[CGreen]];
*w++ = rrepl[(u >> img->shift[CRed]) & img->mask[CRed]];
}
}
r += nb;
if(r == end)
r = begin;
}

b.alpha = copyalpha ? buf : &ones;
b.rgba = (u32int*)buf;
if(alphaonly){
b.red = b.grn = b.blu = b.grey = nil;
if(!copyalpha)
b.rgba = nil;
b.delta = 1;
}else if(isgrey || convgrey){
b.grey = buf+copyalpha;
b.red = b.grn = b.blu = buf+copyalpha;
b.delta = copyalpha+1;
}else{
b.blu = buf+copyalpha;
b.grn = buf+copyalpha+1;
b.grey = nil;
b.red = buf+copyalpha+2;
b.delta = copyalpha+3;
}
return b;
}
#undef DBG

#define DBG if(drawdebug)
static void
writebyte(Param *p, uchar *w, Buffer src)
{
Memimage *img;
int i, isalpha, isgrey, nb, delta, dx, adelta;
uchar ff, *red, *grn, *blu, *grey, *alpha;
u32int u, mask;

img = p->img;

red = src.red;
grn = src.grn;
blu = src.blu;
alpha = src.alpha;
delta = src.delta;
grey = src.grey;
dx = p->dx;

nb = img->depth/8;
mask = (nb==4) ? 0 : ~((1<<img->depth)-1);

isalpha = img->flags&Falpha;
isgrey = img->flags&Fgrey;
adelta = src.delta;

if(isalpha && (alpha == nil || alpha == &ones)){
ff = 0xFF;
alpha = &ff;
adelta = 0;
}

for(i=0; i<dx; i++){
u = w[0] | (w[1]<<8) | (w[2]<<16) | (w[3]<<24);
DBG print("u %.8lux...", u);
u &= mask;
DBG print("&mask %.8lux...", u);
if(isgrey){
u |= ((*grey >> (8-img->nbits[CGrey])) & img->mask[CGrey]) << img->shift[CGrey];
DBG print("|grey %.8lux...", u);
grey += delta;
}else{
u |= ((*red >> (8-img->nbits[CRed])) & img->mask[CRed]) << img->shift[CRed];
u |= ((*grn >> (8-img->nbits[CGreen])) & img->mask[CGreen]) << img->shift[CGreen];
u |= ((*blu >> (8-img->nbits[CBlue])) & img->mask[CBlue]) << img->shift[CBlue];
red += delta;
grn += delta;
blu += delta;
DBG print("|rgb %.8lux...", u);
}

if(isalpha){
u |= ((*alpha >> (8-img->nbits[CAlpha])) & img->mask[CAlpha]) << img->shift[CAlpha];
alpha += adelta;
DBG print("|alpha %.8lux...", u);
}

w[0] = u;
w[1] = u>>8;
w[2] = u>>16;
w[3] = u>>24;
DBG print("write back %.8lux...", u);
w += nb;
}
}
#undef DBG

static Readfn*
readfn(Memimage *img)
{
if(img->depth < 8)
return readnbit;
if(img->nbits[CMap] == 8)
return readcmap;
return readbyte;
}

static Readfn*
readalphafn(Memimage *m)
{
USED(m);
return readbyte;
}

static Writefn*
writefn(Memimage *img)
{
if(img->depth < 8)
return writenbit;
if(img->chan == CMAP8)
return writecmap;
return writebyte;
}

static void
nullwrite(Param *p, uchar *s, Buffer b)
{
USED(p);
USED(s);
}

static Buffer
readptr(Param *p, uchar *s, int y)
{
Buffer b;
uchar *q;

USED(s);
memset(&b, 0, sizeof b);
q = p->bytermin + y*p->bwidth;
b.red = q; /* ptr to data */
b.grn = b.blu = b.grey = b.alpha = nil;
b.rgba = (u32int*)q;
b.delta = p->img->depth/8;
return b;
}

static Buffer
boolmemmove(Buffer bdst, Buffer bsrc, Buffer b1, int dx, int i, int o)
{
USED(i);
USED(o);
memmove(bdst.red, bsrc.red, dx*bdst.delta);
return bdst;
}

static Buffer
boolcopy8(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
{
uchar *m, *r, *w, *ew;

USED(i);
USED(o);
m = bmask.grey;
w = bdst.red;
r = bsrc.red;
ew = w+dx;
for(; w < ew; w++,r++)
if(*m++)
*w = *r;
return bdst; /* not used */
}

static Buffer
boolcopy16(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
{
uchar *m;
ushort *r, *w, *ew;

USED(i);
USED(o);
m = bmask.grey;
w = (ushort*)bdst.red;
r = (ushort*)bsrc.red;
ew = w+dx;
for(; w < ew; w++,r++)
if(*m++)
*w = *r;
return bdst; /* not used */
}

static Buffer
boolcopy24(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
{
uchar *m;
uchar *r, *w, *ew;

USED(i);
USED(o);
m = bmask.grey;
w = bdst.red;
r = bsrc.red;
ew = w+dx*3;
while(w < ew){
if(*m++){
*w++ = *r++;
*w++ = *r++;
*w++ = *r++;
}else{
w += 3;
r += 3;
}
}
return bdst; /* not used */
}

static Buffer
boolcopy32(Buffer bdst, Buffer bsrc, Buffer bmask, int dx, int i, int o)
{
uchar *m;
u32int *r, *w, *ew;

USED(i);
USED(o);
m = bmask.grey;
w = (u32int*)bdst.red;
r = (u32int*)bsrc.red;
ew = w+dx;
for(; w < ew; w++,r++)
if(*m++)
*w = *r;
return bdst; /* not used */
}

static Buffer
genconv(Param *p, uchar *buf, int y)
{
Buffer b;
int nb;
uchar *r, *w, *ew;

/* read from source into RGB format in convbuf */
b = p->convreadcall(p, p->convbuf, y);

/* write RGB format into dst format in buf */
p->convwritecall(p->convdpar, buf, b);

if(p->convdx){
nb = p->convdpar->img->depth/8;
r = buf;
w = buf+nb*p->dx;
ew = buf+nb*p->convdx;
while(w<ew)
*w++ = *r++;
}

b.red = buf;
b.blu = b.grn = b.grey = b.alpha = nil;
b.rgba = (u32int*)buf;
b.delta = 0;

return b;
}

static Readfn*
convfn(Memimage *dst, Param *dpar, Memimage *src, Param *spar)
{
if(dst->chan == src->chan && !(src->flags&Frepl)){
/*if(drawdebug) iprint("readptr..."); */
return readptr;
}

if(dst->chan==CMAP8 && (src->chan==GREY1||src->chan==GREY2||src->chan==GREY4)){
/* cheat because we know the replicated value is exactly the color map entry. */
/*if(drawdebug) iprint("Readnbit..."); */
return readnbit;
}

spar->convreadcall = readfn(src);
spar->convwritecall = writefn(dst);
spar->convdpar = dpar;

/* allocate a conversion buffer */
spar->convbufoff = ndrawbuf;
ndrawbuf += spar->dx*4;

if(spar->dx > Dx(spar->img->r)){
spar->convdx = spar->dx;
spar->dx = Dx(spar->img->r);
}

/*if(drawdebug) iprint("genconv..."); */
return genconv;
}

/*
* Do NOT call this directly. pixelbits is a wrapper
* around this that fetches the bits from the X server
* when necessary.
*/
u32int
_pixelbits(Memimage *i, Point pt)
{
uchar *p;
u32int val;
int off, bpp, npack;

val = 0;
p = byteaddr(i, pt);
switch(bpp=i->depth){
case 1:
case 2:
case 4:
npack = 8/bpp;
off = pt.x%npack;
val = p[0] >> bpp*(npack-1-off);
val &= (1<<bpp)-1;
break;
case 8:
val = p[0];
break;
case 16:
val = p[0]|(p[1]<<8);
break;
case 24:
val = p[0]|(p[1]<<8)|(p[2]<<16);
break;
case 32:
val = p[0]|(p[1]<<8)|(p[2]<<16)|(p[3]<<24);
break;
}
while(bpp<32){
val |= val<<bpp;
bpp *= 2;
}
return val;
}

static Calcfn*
boolcopyfn(Memimage *img, Memimage *mask)
{
if(mask->flags&Frepl && Dx(mask->r)==1 && Dy(mask->r)==1 && pixelbits(mask, mask->r.min)==~0)
return boolmemmove;

switch(img->depth){
case 8:
return boolcopy8;
case 16:
return boolcopy16;
case 24:
return boolcopy24;
case 32:
return boolcopy32;
default:
assert(0 /* boolcopyfn */);
}
return 0;
}

/*
* Optimized draw for filling and scrolling; uses memset and memmove.
*/
static void
memsets(void *vp, ushort val, int n)
{
ushort *p, *ep;

p = vp;
ep = p+n;
while(p<ep)
*p++ = val;
}

static void
memsetl(void *vp, u32int val, int n)
{
u32int *p, *ep;

p = vp;
ep = p+n;
while(p<ep)
*p++ = val;
}

static void
memset24(void *vp, u32int val, int n)
{
uchar *p, *ep;
uchar a,b,c;

p = vp;
ep = p+3*n;
a = val;
b = val>>8;
c = val>>16;
while(p<ep){
*p++ = a;
*p++ = b;
*p++ = c;
}
}

u32int
_imgtorgba(Memimage *img, u32int val)
{
uchar r, g, b, a;
int nb, ov, v;
u32int chan;
uchar *p;

a = 0xFF;
r = g = b = 0xAA; /* garbage */
for(chan=img->chan; chan; chan>>=8){
nb = NBITS(chan);
ov = v = val&((1<<nb)-1);
val >>= nb;

while(nb < 8){
v |= v<<nb;
nb *= 2;
}
v >>= (nb-8);

switch(TYPE(chan)){
case CRed:
r = v;
break;
case CGreen:
g = v;
break;
case CBlue:
b = v;
break;
case CAlpha:
a = v;
break;
case CGrey:
r = g = b = v;
break;
case CMap:
p = img->cmap->cmap2rgb+3*ov;
r = *p++;
g = *p++;
b = *p;
break;
}
}
return (r<<24)|(g<<16)|(b<<8)|a;
}

u32int
_rgbatoimg(Memimage *img, u32int rgba)
{
u32int chan;
int d, nb;
u32int v;
uchar *p, r, g, b, a, m;

v = 0;
r = rgba>>24;
g = rgba>>16;
b = rgba>>8;
a = rgba;
d = 0;
for(chan=img->chan; chan; chan>>=8){
nb = NBITS(chan);
switch(TYPE(chan)){
case CRed:
v |= (r>>(8-nb))<<d;
break;
case CGreen:
v |= (g>>(8-nb))<<d;
break;
case CBlue:
v |= (b>>(8-nb))<<d;
break;
case CAlpha:
v |= (a>>(8-nb))<<d;
break;
case CMap:
p = img->cmap->rgb2cmap;
m = p[(r>>4)*256+(g>>4)*16+(b>>4)];
v |= (m>>(8-nb))<<d;
break;
case CGrey:
m = RGB2K(r,g,b);
v |= (m>>(8-nb))<<d;
break;
}
d += nb;
}
/* print("rgba2img %.8lux = %.*lux\n", rgba, 2*d/8, v); */
return v;
}

#define DBG if(0)
static int
memoptdraw(Memdrawparam *par)
{
int m, y, dy, dx, op;
u32int v;
Memimage *src;
Memimage *dst;

dx = Dx(par->r);
dy = Dy(par->r);
src = par->src;
dst = par->dst;
op = par->op;

DBG print("state %lux mval %lux dd %d\n", par->state, par->mval, dst->depth);
/*
* If we have an opaque mask and source is one opaque pixel we can convert to the
* destination format and just replicate with memset.
*/
m = Simplesrc|Simplemask|Fullmask;
if((par->state&m)==m && (par->srgba&0xFF) == 0xFF && (op ==S || op == SoverD)){
uchar *dp, p[4];
int d, dwid, ppb, np, nb;
uchar lm, rm;

DBG print("memopt, dst %p, dst->data->bdata %p\n", dst, dst->data->bdata);
dwid = dst->width*sizeof(u32int);
dp = byteaddr(dst, par->r.min);
v = par->sdval;
DBG print("sdval %lud, depth %d\n", v, dst->depth);
switch(dst->depth){
case 1:
case 2:
case 4:
for(d=dst->depth; d<8; d*=2)
v |= (v<<d);
ppb = 8/dst->depth; /* pixels per byte */
m = ppb-1;
/* left edge */
np = par->r.min.x&m; /* no. pixels unused on left side of word */
dx -= (ppb-np);
nb = 8 - np * dst->depth; /* no. bits used on right side of word */
lm = (1<<nb)-1;
DBG print("np %d x %d nb %d lm %ux ppb %d m %ux\n", np, par->r.min.x, nb, lm, ppb, m);

/* right edge */
np = par->r.max.x&m; /* no. pixels used on left side of word */
dx -= np;
nb = 8 - np * dst->depth; /* no. bits unused on right side of word */
rm = ~((1<<nb)-1);
DBG print("np %d x %d nb %d rm %ux ppb %d m %ux\n", np, par->r.max.x, nb, rm, ppb, m);

DBG print("dx %d Dx %d\n", dx, Dx(par->r));
/* lm, rm are masks that are 1 where we should touch the bits */
if(dx < 0){ /* just one byte */
lm &= rm;
for(y=0; y<dy; y++, dp+=dwid)
*dp ^= (v ^ *dp) & lm;
}else if(dx == 0){ /* no full bytes */
if(lm)
dwid--;

for(y=0; y<dy; y++, dp+=dwid){
if(lm){
DBG print("dp %p v %lux lm %ux (v ^ *dp) & lm %lux\n", dp, v, lm, (v^*dp)&lm);
*dp ^= (v ^ *dp) & lm;
dp++;
}
*dp ^= (v ^ *dp) & rm;
}
}else{ /* full bytes in middle */
dx /= ppb;
if(lm)
dwid--;
dwid -= dx;

for(y=0; y<dy; y++, dp+=dwid){
if(lm){
*dp ^= (v ^ *dp) & lm;
dp++;
}
memset(dp, v, dx);
dp += dx;
*dp ^= (v ^ *dp) & rm;
}
}
return 1;
case 8:
for(y=0; y<dy; y++, dp+=dwid)
memset(dp, v, dx);
return 1;
case 16:
p[0] = v; /* make little endian */
p[1] = v>>8;
v = *(ushort*)p;
DBG print("dp=%p; dx=%d; for(y=0; y<%d; y++, dp+=%d)\nmemsets(dp, v, dx);\n",
dp, dx, dy, dwid);
for(y=0; y<dy; y++, dp+=dwid)
memsets(dp, v, dx);
return 1;
case 24:
for(y=0; y<dy; y++, dp+=dwid)
memset24(dp, v, dx);
return 1;
case 32:
p[0] = v; /* make little endian */
p[1] = v>>8;
p[2] = v>>16;
p[3] = v>>24;
v = *(u32int*)p;
for(y=0; y<dy; y++, dp+=dwid)
memsetl(dp, v, dx);
return 1;
default:
assert(0 /* bad dest depth in memoptdraw */);
}
}

/*
* If no source alpha, an opaque mask, we can just copy the
* source onto the destination. If the channels are the same and
* the source is not replicated, memmove suffices.
*/
m = Simplemask|Fullmask;
if((par->state&(m|Replsrc))==m && src->depth >= 8
&& src->chan == dst->chan && !(src->flags&Falpha) && (op == S || op == SoverD)){
uchar *sp, *dp;
long swid, dwid, nb;
int dir;

if(src->data == dst->data && byteaddr(dst, par->r.min) > byteaddr(src, par->sr.min))
dir = -1;
else
dir = 1;

swid = src->width*sizeof(u32int);
dwid = dst->width*sizeof(u32int);
sp = byteaddr(src, par->sr.min);
dp = byteaddr(dst, par->r.min);
if(dir == -1){
sp += (dy-1)*swid;
dp += (dy-1)*dwid;
swid = -swid;
dwid = -dwid;
}
nb = (dx*src->depth)/8;
for(y=0; y<dy; y++, sp+=swid, dp+=dwid)
memmove(dp, sp, nb);
return 1;
}

/*
* If we have a 1-bit mask, 1-bit source, and 1-bit destination, and
* they're all bit aligned, we can just use bit operators. This happens
* when we're manipulating boolean masks, e.g. in the arc code.
*/
if((par->state&(Simplemask|Simplesrc|Replmask|Replsrc))==0
&& dst->chan==GREY1 && src->chan==GREY1 && par->mask->chan==GREY1
&& (par->r.min.x&7)==(par->sr.min.x&7) && (par->r.min.x&7)==(par->mr.min.x&7)){
uchar *sp, *dp, *mp;
uchar lm, rm;
long swid, dwid, mwid;
int i, x, dir;

sp = byteaddr(src, par->sr.min);
dp = byteaddr(dst, par->r.min);
mp = byteaddr(par->mask, par->mr.min);
swid = src->width*sizeof(u32int);
dwid = dst->width*sizeof(u32int);
mwid = par->mask->width*sizeof(u32int);

if(src->data == dst->data && byteaddr(dst, par->r.min) > byteaddr(src, par->sr.min)){
dir = -1;
}else
dir = 1;

lm = 0xFF>>(par->r.min.x&7);
rm = 0xFF<<(8-(par->r.max.x&7));
dx -= (8-(par->r.min.x&7)) + (par->r.max.x&7);

if(dx < 0){ /* one byte wide */
lm &= rm;
if(dir == -1){
dp += dwid*(dy-1);
sp += swid*(dy-1);
mp += mwid*(dy-1);
dwid = -dwid;
swid = -swid;
mwid = -mwid;
}
for(y=0; y<dy; y++){
*dp ^= (*dp ^ *sp) & *mp & lm;
dp += dwid;
sp += swid;
mp += mwid;
}
return 1;
}

dx /= 8;
if(dir == 1){
i = (lm!=0)+dx+(rm!=0);
mwid -= i;
swid -= i;
dwid -= i;
for(y=0; y<dy; y++, dp+=dwid, sp+=swid, mp+=mwid){
if(lm){
*dp ^= (*dp ^ *sp++) & *mp++ & lm;
dp++;
}
for(x=0; x<dx; x++){
*dp ^= (*dp ^ *sp++) & *mp++;
dp++;
}
if(rm){
*dp ^= (*dp ^ *sp++) & *mp++ & rm;
dp++;
}
}
return 1;
}else{
/* dir == -1 */
i = (lm!=0)+dx+(rm!=0);
dp += dwid*(dy-1)+i-1;
sp += swid*(dy-1)+i-1;
mp += mwid*(dy-1)+i-1;
dwid = -dwid+i;
swid = -swid+i;
mwid = -mwid+i;
for(y=0; y<dy; y++, dp+=dwid, sp+=swid, mp+=mwid){
if(rm){
*dp ^= (*dp ^ *sp--) & *mp-- & rm;
dp--;
}
for(x=0; x<dx; x++){
*dp ^= (*dp ^ *sp--) & *mp--;
dp--;
}
if(lm){
*dp ^= (*dp ^ *sp--) & *mp-- & lm;
dp--;
}
}
}
return 1;
}
return 0;
}
#undef DBG

/*
* Boolean character drawing.
* Solid opaque color through a 1-bit greyscale mask.
*/
#define DBG if(0)
static int
chardraw(Memdrawparam *par)
{
u32int bits;
int i, ddepth, dy, dx, x, bx, ex, y, npack, bsh, depth, op;
u32int v, maskwid, dstwid;
uchar *wp, *rp, *q, *wc;
ushort *ws;
u32int *wl;
uchar sp[4];
Rectangle r, mr;
Memimage *mask, *src, *dst;

if(0) if(drawdebug) iprint("chardraw? mf %lux md %d sf %lux dxs %d dys %d dd %d ddat %p sdat %p\n",
par->mask->flags, par->mask->depth, par->src->flags,
Dx(par->src->r), Dy(par->src->r), par->dst->depth, par->dst->data, par->src->data);

mask = par->mask;
src = par->src;
dst = par->dst;
r = par->r;
mr = par->mr;
op = par->op;

if((par->state&(Replsrc|Simplesrc|Fullsrc|Replmask)) != (Replsrc|Simplesrc|Fullsrc)
|| mask->depth != 1 || dst->depth<8 || dst->data==src->data
|| op != SoverD)
return 0;

/*if(drawdebug) iprint("chardraw..."); */

depth = mask->depth;
maskwid = mask->width*sizeof(u32int);
rp = byteaddr(mask, mr.min);
npack = 8/depth;
bsh = (mr.min.x % npack) * depth;

wp = byteaddr(dst, r.min);
dstwid = dst->width*sizeof(u32int);
DBG print("bsh %d\n", bsh);
dy = Dy(r);
dx = Dx(r);

ddepth = dst->depth;

/*
* for loop counts from bsh to bsh+dx
*
* we want the bottom bits to be the amount
* to shift the pixels down, so for n≡0 (mod 8) we want
* bottom bits 7. for n≡1, 6, etc.
* the bits come from -n-1.
*/

bx = -bsh-1;
ex = -bsh-1-dx;
SET(bits);
v = par->sdval;

/* make little endian */
sp[0] = v;
sp[1] = v>>8;
sp[2] = v>>16;
sp[3] = v>>24;

/*print("sp %x %x %x %x\n", sp[0], sp[1], sp[2], sp[3]); */
for(y=0; y<dy; y++, rp+=maskwid, wp+=dstwid){
q = rp;
if(bsh)
bits = *q++;
switch(ddepth){
case 8:
/*if(drawdebug) iprint("8loop..."); */
wc = wp;
for(x=bx; x>ex; x--, wc++){
i = x&7;
if(i == 8-1)
bits = *q++;
DBG print("bits %lux sh %d...", bits, i);
if((bits>>i)&1)
*wc = v;
}
break;
case 16:
ws = (ushort*)wp;
v = *(ushort*)sp;
for(x=bx; x>ex; x--, ws++){
i = x&7;
if(i == 8-1)
bits = *q++;
DBG print("bits %lux sh %d...", bits, i);
if((bits>>i)&1)
*ws = v;
}
break;
case 24:
wc = wp;
for(x=bx; x>ex; x--, wc+=3){
i = x&7;
if(i == 8-1)
bits = *q++;
DBG print("bits %lux sh %d...", bits, i);
if((bits>>i)&1){
wc[0] = sp[0];
wc[1] = sp[1];
wc[2] = sp[2];
}
}
break;
case 32:
wl = (u32int*)wp;
v = *(u32int*)sp;
for(x=bx; x>ex; x--, wl++){
i = x&7;
if(i == 8-1)
bits = *q++;
DBG iprint("bits %lux sh %d...", bits, i);
if((bits>>i)&1)
*wl = v;
}
break;
}
}

DBG print("\n");
return 1;
}
#undef DBG

/*
* Fill entire byte with replicated (if necessary) copy of source pixel,
* assuming destination ldepth is >= source ldepth.
*
* This code is just plain wrong for >8bpp.
*
u32int
membyteval(Memimage *src)
{
int i, val, bpp;
uchar uc;

unloadmemimage(src, src->r, &uc, 1);
bpp = src->depth;
uc <<= (src->r.min.x&(7/src->depth))*src->depth;
uc &= ~(0xFF>>bpp);
* pixel value is now in high part of byte. repeat throughout byte
val = uc;
for(i=bpp; i<8; i<<=1)
val |= val>>i;
return val;
}
*
*/

void
_memfillcolor(Memimage *i, u32int val)
{
u32int bits;
int d, y;
uchar p[4];

if(val == DNofill)
return;

bits = _rgbatoimg(i, val);
switch(i->depth){
case 24: /* 24-bit images suck */
for(y=i->r.min.y; y<i->r.max.y; y++)
memset24(byteaddr(i, Pt(i->r.min.x, y)), bits, Dx(i->r));
break;
default: /* 1, 2, 4, 8, 16, 32 */
for(d=i->depth; d<32; d*=2)
bits = (bits << d) | bits;
p[0] = bits; /* make little endian */
p[1] = bits>>8;
p[2] = bits>>16;
p[3] = bits>>24;
bits = *(u32int*)p;
memsetl(wordaddr(i, i->r.min), bits, i->width*Dy(i->r));
break;
}
}


</pre>
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