ref: c116550e6a41572796e4db65e4f6acbcb3d9d6f8
dir: /appl/grid/readjpg.b/
implement Readjpg; include "sys.m"; sys: Sys; include "draw.m"; draw: Draw; Display, Image: import draw; include "grid/readjpg.m"; display: ref Display; slowread: int; zeroints := array[64] of { * => 0 }; init(disp: ref Draw->Display) { sys = load Sys Sys->PATH; draw = load Draw Draw->PATH; display = disp; init_tabs(); } fjpg2img(fd: ref sys->FD, cachepath: string, chanin, chanout: chan of string): ref Image { if (fd == nil) return nil; sync := chan of int; imgchan := chan of ref Image; is := newImageSource(0,0); spawn slowreads(is,fd,cachepath, sync, chanout); srpid := <- sync; if (srpid == -1) return nil; spawn getjpegimg(is, chanout, imgchan, sync); gjipid := <- sync; for (;;) alt { ctl := <- chanin => if (ctl == "kill") { if (srpid != -1) kill(srpid); kill(gjipid); return nil; } img := <- imgchan => if (srpid != -1) kill(srpid); return img; err := <- sync => if (err == 0) srpid = -1; else { kill(gjipid); return nil; } } } jpg2img(filename, cachepath: string, chanin, chanout: chan of string): ref Image { fd := sys->open(filename, sys->OREAD); return fjpg2img(fd, cachepath, chanin, chanout); } kill(pid: int) { pctl := sys->open("/prog/" + string pid + "/ctl", Sys->OWRITE); if (pctl != nil) sys->write(pctl, array of byte "kill", len "kill"); } filelength(fd : ref sys->FD): int { (n, dir) := sys->fstat(fd); if (n == -1) return -1; filelen := int dir.length; return filelen; } slowreads(is: ref ImageSource, fd : ref sys->FD, cachepath: string, sync: chan of int, chanout: chan of string) { filelen := filelength(fd); if (filelen < 1) { sync <-= -1; return; } is.data = array[filelen] of byte; slowread = 0; sync <-= sys->pctl(0, nil); cachefd : ref sys->FD = nil; if (cachepath != "") cachefd = sys->create(cachepath, sys->OWRITE, 8r666); if (chanout != nil) { chanout <-= "l2 Loading..."; chanout <-= "pc 0"; } i : int; for (;;) { i = sys->read(fd,is.data[slowread:], 8192); if (i < 1) break; if (cachefd != nil) sys->write(cachefd, is.data[slowread:],i); slowread += i; if (chanout != nil) chanout <-= "pc "+string ((slowread*100)/filelen); sys->sleep(0); } if (i == -1 || slowread == 0) { sync <-= -1; return; } newdata := array[slowread] of byte; newdata = is.data[:slowread]; is.data = newdata; if (cachepath != "" && slowread < filelen) sys->remove(cachepath); sync <-= 0; } wait4data(n: int) { for(;;) { if (slowread > n) break; sys->sleep(100); } } newImageSource(w, h: int) : ref ImageSource { is := ref ImageSource( w,h, # width, height 0,0, # origw, origh 0, # i nil, # jhdr nil # data ); return is; } getjpeghdr(is: ref ImageSource) { h := ref Jpegstate( 0, 0, # sr, cnt 0, # Nf nil, # comp byte 0, # mode, 0, 0, # X, Y nil, # qt nil, nil, # dcht, acht 0, # Ns nil, # scomp 0, 0, # Ss, Se 0, 0, # Ah, Al 0, 0, # ri, nseg nil, # nblock nil, nil, # dccoeff, accoeff 0, 0, 0, 0 # nacross, ndown, Hmax, Vmax ); is.jstate = h; if(jpegmarker(is) != SOI) sys->print("Error: Jpeg expected SOI marker\n"); (m, n) := jpegtabmisc(is); if(!(m == SOF || m == SOF2)) sys->print("Error: Jpeg expected Frame marker"); nil = getc(is); # sample precision h.Y = getbew(is); h.X = getbew(is); h.Nf = getc(is); h.comp = array[h.Nf] of Framecomp; h.nblock = array[h.Nf] of int; for(i:=0; i<h.Nf; i++) { h.comp[i].C = getc(is); (H, V) := nibbles(getc(is)); h.comp[i].H = H; h.comp[i].V = V; h.comp[i].Tq = getc(is); h.nblock[i] =H*V; } h.mode = byte m; is.origw = h.X; is.origh = h.Y; setdims(is); if(n != 6+3*h.Nf) sys->print("Error: Jpeg bad SOF length"); } setdims(is: ref ImageSource) { sw := is.origw; sh := is.origh; dw := is.width; dh := is.height; if(dw == 0 && dh == 0) { dw = sw; dh = sh; } else if(dw == 0 || dh == 0) { if(dw == 0) { dw = int ((real sw) * (real dh/real sh)); if(dw == 0) dw = 1; } else { dh = int ((real sh) * (real dw/real sw)); if(dh == 0) dh = 1; } } is.width = dw; is.height = dh; } jpegmarker(is: ref ImageSource) : int { if(getc(is) != 16rFF) sys->print("Error: Jpeg expected marker"); return getc(is); } getbew(is: ref ImageSource) : int { c0 := getc(is); c1 := getc(is); return (c0<<8) + c1; } getn(is: ref ImageSource, n: int) : (array of byte, int) { if (is.i + n > slowread - 1) wait4data(is.i + n); a := is.data; i := is.i; if(i + n <= len a) is.i += n; # else # sys->print("Error: premature eof"); return (a, i); } # Consume tables and miscellaneous marker segments, # returning the marker id and length of the first non-such-segment # (after having consumed the marker). # May raise "premature eof" or other exception. jpegtabmisc(is: ref ImageSource) : (int, int) { h := is.jstate; m, n : int; Loop: for(;;) { h.nseg++; m = jpegmarker(is); n = 0; if(m != EOI) n = getbew(is) - 2; case m { SOF or SOF2 or SOS or EOI => break Loop; APPn+0 => if(h.nseg==1 && n >= 6) { (buf, i) := getn(is, 6); n -= 6; if(string buf[i:i+4]=="JFIF") { vers0 := int buf[i+5]; vers1 := int buf[i+6]; if(vers0>1 || vers1>2) sys->print("Error: Jpeg unimplemented version"); } } APPn+1 to APPn+15 => ; DQT => jpegquanttables(is, n); n = 0; DHT => jpeghuffmantables(is, n); n = 0; DRI => h.ri =getbew(is); n -= 2; COM => ; * => sys->print("Error: Jpeg unexpected marker"); } if(n > 0) getn(is, n); } return (m, n); } # Consume huffman tables, raising exception on error. jpeghuffmantables(is: ref ImageSource, n: int) { h := is.jstate; if(h.dcht == nil) { h.dcht = array[4] of ref Huffman; h.acht = array[4] of ref Huffman; } for(l:= 0; l < n; ) l += jpeghuffmantable(is); if(l != n) sys->print("Error: Jpeg huffman table bad length"); } jpeghuffmantable(is: ref ImageSource) : int { t := ref Huffman; h := is.jstate; (Tc, th) := nibbles(getc(is)); if(Tc > 1) sys->print("Error: Jpeg unknown Huffman table class"); if(th>3 || (h.mode==byte SOF && th>1)) sys->print("Error: Jpeg unknown Huffman table index"); if(Tc == 0) h.dcht[th] = t; else h.acht[th] = t; # flow chart C-2 (b, bi) := getn(is, 16); numcodes := array[16] of int; nsize := 0; for(i:=0; i<16; i++) nsize += (numcodes[i] = int b[bi+i]); t.size = array[nsize+1] of int; k := 0; for(i=1; i<=16; i++) { n :=numcodes[i-1]; for(j:=0; j<n; j++) t.size[k++] = i; } t.size[k] = 0; # initialize HUFFVAL t.val = array[nsize] of int; (b, bi) = getn(is, nsize); for(i=0; i<nsize; i++) t.val[i] = int b[bi++]; # flow chart C-3 t.code = array[nsize+1] of int; k = 0; code := 0; si := t.size[0]; for(;;) { do t.code[k++] = code++; while(t.size[k] == si); if(t.size[k] == 0) break; do { code <<= 1; si++; } while(t.size[k] != si); } # flow chart F-25 t.mincode = array[17] of int; t.maxcode = array[17] of int; t.valptr = array[17] of int; i = 0; j := 0; F25: for(;;) { for(;;) { i++; if(i > 16) break F25; if(numcodes[i-1] != 0) break; t.maxcode[i] = -1; } t.valptr[i] = j; t.mincode[i] = t.code[j]; j += int numcodes[i-1]-1; t.maxcode[i] = t.code[j]; j++; } # create byte-indexed fast path tables t.value = array[256] of int; t.shift = array[256] of int; maxcode := t.maxcode; # stupid startup algorithm: just run machine for each byte value Bytes: for(v:=0; v<256; v++){ cnt := 7; m := 1<<7; code = 0; sr := v; i = 1; for(;;i++){ if(sr & m) code |= 1; if(code <= maxcode[i]) break; code <<= 1; m >>= 1; if(m == 0){ t.shift[v] = 0; t.value[v] = -1; continue Bytes; } cnt--; } t.shift[v] = 8-cnt; t.value[v] = t.val[t.valptr[i]+(code-t.mincode[i])]; } return nsize+17; } jpegquanttables(is: ref ImageSource, n: int) { h := is.jstate; if(h.qt == nil) h.qt = array[4] of array of int; for(l:=0; l<n; ) l += jpegquanttable(is); if(l != n) sys->print("Error: Jpeg quant table bad length"); } jpegquanttable(is: ref ImageSource): int { (pq, tq) := nibbles(getc(is)); if(pq > 1) sys->print("Error: Jpeg unknown quantization table class"); if(tq > 3) sys->print("Error: Jpeg bad quantization table index"); q := array[64] of int; is.jstate.qt[tq] = q; for(i:=0; i<64; i++) { if(pq == 0) q[i] =getc(is); else q[i] = getbew(is); } return 1+(64*(1+pq));; } # Have just read Frame header. # Now expect: # ((tabl/misc segment(s))* (scan header) (entropy coded segment)+)+ EOI getjpegimg(is:ref ImageSource,chanout:chan of string,imgchan: chan of ref Image,sync: chan of int) { sync <-= sys->pctl(0, nil); getjpeghdr(is); h := is.jstate; chans: array of array of byte = nil; for(;;) { (m, n) := jpegtabmisc(is); if(m == EOI) break; if(m != SOS) sys->print("Error: Jpeg expected start of scan"); h.Ns = getc(is); scomp := array[h.Ns] of Scancomp; for(i := 0; i < h.Ns; i++) { scomp[i].C = getc(is); (scomp[i].tdc, scomp[i].tac) = nibbles(getc(is)); } h.scomp = scomp; h.Ss = getc(is); h.Se = getc(is); (h.Ah, h.Al) = nibbles(getc(is)); if(n != 4+h.Ns*2) sys->print("Error: Jpeg SOS header wrong length"); if(h.mode == byte SOF) { if(chans != nil) sys->print("Error: Jpeg baseline has > 1 scan"); chans = jpegbaselinescan(is, chanout); } } if(chans == nil) sys->print("Error: jpeg has no image"); width := is.width; height := is.height; if(width != h.X || height != h.Y) { for(k := 0; k < len chans; k++) chans[k] = resample(chans[k], h.X, h.Y, width, height); } r := remapYCbCr(chans, chanout); im := newimage24(width, height); im.writepixels(im.r, r); imgchan <-= im; } newimage24(w, h: int) : ref Image { im := display.newimage(((0,0),(w,h)), Draw->RGB24, 0, Draw->White); if(im == nil) sys->print("Error: out of memory"); return im; } remapYCbCr(chans: array of array of byte, chanout: chan of string): array of byte { Y := chans[0]; Cb := chans[1]; Cr := chans[2]; rgb := array [3*len Y] of byte; bix := 0; lY := len Y; n := lY / 20; count := 0; for (i := 0; i < lY; i++) { if ((count == 0 || count >= n ) && chanout != nil) { chanout <-= "l2 Processing..."; chanout <-= "pc "+string ((100*i)/ lY); count = 0; } count++; y := int Y[i]; cb := int Cb[i]; cr := int Cr[i]; r := y + Cr2r[cr]; g := y - Cr2g[cr] - Cb2g[cb]; b := y + Cb2b[cb]; rgb[bix++] = clampb[b+CLAMPBOFF]; rgb[bix++] = clampb[g+CLAMPBOFF]; rgb[bix++] = clampb[r+CLAMPBOFF]; } if (chanout != nil) chanout <-= "pc 100"; return rgb; } zig := array[64] of { 0, 1, 8, 16, 9, 2, 3, 10, 17, # 0-7 24, 32, 25, 18, 11, 4, 5, # 8-15 12, 19, 26, 33, 40, 48, 41, 34, # 16-23 27, 20, 13, 6, 7, 14, 21, 28, # 24-31 35, 42, 49, 56, 57, 50, 43, 36, # 32-39 29, 22, 15, 23, 30, 37, 44, 51, # 40-47 58, 59, 52, 45, 38, 31, 39, 46, # 48-55 53, 60, 61, 54, 47, 55, 62, 63 # 56-63 }; jpegbaselinescan(is: ref ImageSource,chanout: chan of string) : array of array of byte { h := is.jstate; Ns := h.Ns; if(Ns != h.Nf) sys->print("Error: Jpeg baseline needs Ns==Nf"); if(!(Ns==3 || Ns==1)) sys->print("Error: Jpeg baseline needs Ns==1 or 3"); chans := array[h.Nf] of array of byte; for(k:=0; k<h.Nf; k++) chans[k] = array[h.X*h.Y] of byte; # build per-component arrays Td := array[Ns] of int; Ta := array[Ns] of int; data := array[Ns] of array of array of int; H := array[Ns] of int; V := array[Ns] of int; DC := array[Ns] of int; # compute maximum H and V Hmax := 0; Vmax := 0; for(comp:=0; comp<Ns; comp++) { if(h.comp[comp].H > Hmax) Hmax = h.comp[comp].H; if(h.comp[comp].V > Vmax) Vmax = h.comp[comp].V; } # initialize data structures allHV1 := 1; for(comp=0; comp<Ns; comp++) { # JPEG requires scan components to be in same order as in frame, # so if both have 3 we know scan is Y Cb Cr and there's no need to # reorder Td[comp] = h.scomp[comp].tdc; Ta[comp] = h.scomp[comp].tac; H[comp] = h.comp[comp].H; V[comp] = h.comp[comp].V; nblock := H[comp]*V[comp]; if(nblock != 1) allHV1 = 0; # data[comp]: needs (3+nblock)*4 + nblock*(3+8*8)*4 bytes data[comp] = array[nblock] of array of int; DC[comp] = 0; for(m:=0; m<nblock; m++) data[comp][m] = array[8*8] of int; } ri := h.ri; h.cnt = 0; h.sr = 0; nacross := ((h.X+(8*Hmax-1))/(8*Hmax)); nmcu := ((h.Y+(8*Vmax-1))/(8*Vmax))*nacross; n1 := 0; n2 := nmcu / 20; for(mcu:=0; mcu<nmcu; ) { if ((n1 == 0 || n1 >= n2) && chanout != nil && slowread == len is.data) { chanout <-= "l2 Scanning... "; chanout <-= "pc "+string ((100*mcu)/nmcu); n1 = 0; } n1 ++; for(comp=0; comp<Ns; comp++) { dcht := h.dcht[Td[comp]]; acht := h.acht[Ta[comp]]; qt := h.qt[h.comp[comp].Tq]; for(block:=0; block<H[comp]*V[comp]; block++) { # F-22 t := jdecode(is, dcht); diff := jreceive(is, t); DC[comp] += diff; # F-23 zz := data[comp][block]; zz[0:] = zeroints; zz[0] = qt[0]*DC[comp]; k = 1; for(;;) { rs := jdecode(is, acht); (rrrr, ssss) := nibbles(rs); if(ssss == 0){ if(rrrr != 15) break; k += 16; }else{ k += rrrr; z := jreceive(is, ssss); zz[zig[k]] = z*qt[k]; if(k == 63) break; k++; } } idct(zz); } } # rotate colors to RGB and assign to bytes colormap(h, chans, data[0], data[1], data[2], mcu, nacross, Hmax, Vmax, H, V); # process restart marker, if present mcu++; if(ri>0 && mcu<nmcu && mcu%ri==0){ jrestart(is, mcu); for(comp=0; comp<Ns; comp++) DC[comp] = 0; } } if (chanout != nil) chanout <-= "pc 100"; return chans; } jrestart(is: ref ImageSource, mcu: int) { h := is.jstate; ri := h.ri; restart := mcu/ri-1; rst, nskip: int; nskip = 0; do { do{ rst = jnextborm(is); nskip++; }while(rst>=0 && rst!=16rFF); if(rst == 16rFF){ rst = jnextborm(is); nskip++; } } while(rst>=0 && (rst&~7)!= RST); if(nskip != 2 || rst < 0 || ((rst&7) != (restart&7))) sys->print("Error: Jpeg restart problem"); h.cnt = 0; h.sr = 0; } jc1: con 2871; # 1.402 * 2048 jc2: con 705; # 0.34414 * 2048 jc3: con 1463; # 0.71414 * 2048 jc4: con 3629; # 1.772 * 2048 CLAMPBOFF: con 300; NCLAMPB: con CLAMPBOFF+256+CLAMPBOFF; CLAMPNOFF: con 64; NCLAMPN: con CLAMPNOFF+256+CLAMPNOFF; clampb: array of byte; # clamps byte values init_tabs() { j: int; clampb = array[NCLAMPB] of byte; for(j=0; j<CLAMPBOFF; j++) clampb[j] = byte 0; for(j=0; j<256; j++) clampb[CLAMPBOFF+j] = byte j; for(j=0; j<CLAMPBOFF; j++) clampb[CLAMPBOFF+256+j] = byte 16rFF; } # Fills in pixels (x,y) for x = minx=8*Hmax*(mcu%nacross), minx+1, ..., minx+8*Hmax-1 (or h.X-1, if less) # and for y = miny=8*Vmax*(mcu/nacross), miny+1, ..., miny+8*Vmax-1 (or h.Y-1, if less) colormap(h: ref Jpegstate, chans: array of array of byte, data0, data1, data2: array of array of int, mcu, nacross, Hmax, Vmax: int, H, V: array of int) { rpic := chans[0]; gpic := chans[1]; bpic := chans[2]; minx := 8*Hmax*(mcu%nacross); dx := 8*Hmax; if(minx+dx > h.X) dx = h.X-minx; miny := 8*Vmax*(mcu/nacross); dy := 8*Vmax; if(miny+dy > h.Y) dy = h.Y-miny; pici := miny*h.X+minx; H0 := H[0]; H1 := H[1]; H2 := H[2]; for(y:=0; y<dy; y++) { t := y*V[0]; b0 := H0*(t/(8*Vmax)); y0 := 8*((t/Vmax)&7); t = y*V[1]; b1 := H1*(t/(8*Vmax)); y1 := 8*((t/Vmax)&7); t = y*V[2]; b2 := H2*(t/(8*Vmax)); y2 := 8*((t/Vmax)&7); x0 := 0; x1 := 0; x2 := 0; for(x:=0; x<dx; x++) { rpic[pici+x] = clampb[data0[b0][y0+x0++*H0/Hmax] + 128 + CLAMPBOFF]; gpic[pici+x] = clampb[data1[b1][y1+x1++*H1/Hmax] + 128 + CLAMPBOFF]; bpic[pici+x] = clampb[data2[b2][y2+x2++*H2/Hmax] + 128 + CLAMPBOFF]; if(x0*H0/Hmax >= 8){ x0 = 0; b0++; } if(x1*H1/Hmax >= 8){ x1 = 0; b1++; } if(x2*H2/Hmax >= 8){ x2 = 0; b2++; } } pici += h.X; } } # decode next 8-bit value from entropy-coded input. chart F-26 jdecode(is: ref ImageSource, t: ref Huffman): int { h := is.jstate; maxcode := t.maxcode; if(h.cnt < 8) jnextbyte(is); # fast lookup code := (h.sr>>(h.cnt-8))&16rFF; v := t.value[code]; if(v >= 0){ h.cnt -= t.shift[code]; return v; } h.cnt -= 8; if(h.cnt == 0) jnextbyte(is); h.cnt--; cnt := h.cnt; m := 1<<cnt; sr := h.sr; code <<= 1; i := 9; for(;;i++){ if(sr & m) code |= 1; if(code <= maxcode[i]) break; code <<= 1; m >>= 1; if(m == 0){ sr = jnextbyte(is); m = 16r80; cnt = 8; } cnt--; } h.cnt = cnt; return t.val[t.valptr[i]+(code-t.mincode[i])]; } # load next byte of input jnextbyte(is: ref ImageSource): int { b :=getc(is); if(b == 16rFF) { b2 :=getc(is); if(b2 != 0) { if(b2 == int DNL) sys->print("Error: Jpeg DNL marker unimplemented"); # decoder is reading into marker; satisfy it and restore state ungetc2(is, byte b); } } h := is.jstate; h.cnt += 8; h.sr = (h.sr<<8)| b; return b; } ungetc2(is: ref ImageSource, nil: byte) { if(is.i < 2) { if(is.i != 1) sys->print("Error: EXInternal: ungetc2 past beginning of buffer"); is.i = 0; } else is.i -= 2; } getc(is: ref ImageSource) : int { if(is.i >= len is.data) { sys->print("Error: premature eof"); } if (is.i >= slowread) wait4data(is.i); return int is.data[is.i++]; } # like jnextbyte, but look for marker too jnextborm(is: ref ImageSource): int { b :=getc(is); if(b == 16rFF) return b; h := is.jstate; h.cnt += 8; h.sr = (h.sr<<8)| b; return b; } # return next s bits of input, MSB first, and level shift it jreceive(is: ref ImageSource, s: int): int { h := is.jstate; while(h.cnt < s) jnextbyte(is); h.cnt -= s; v := h.sr >> h.cnt; m := (1<<s); v &= m-1; # level shift if(v < (m>>1)) v += ~(m-1)+1; return v; } nibbles(c: int) : (int, int) { return (c>>4, c&15); } # Scaled integer implementation. # inverse two dimensional DCT, Chen-Wang algorithm # (IEEE ASSP-32, pp. 803-816, Aug. 1984) # 32-bit integer arithmetic (8 bit coefficients) # 11 mults, 29 adds per DCT # # coefficients extended to 12 bit for IEEE1180-1990 # compliance W1: con 2841; # 2048*sqrt(2)*cos(1*pi/16) W2: con 2676; # 2048*sqrt(2)*cos(2*pi/16) W3: con 2408; # 2048*sqrt(2)*cos(3*pi/16) W5: con 1609; # 2048*sqrt(2)*cos(5*pi/16) W6: con 1108; # 2048*sqrt(2)*cos(6*pi/16) W7: con 565; # 2048*sqrt(2)*cos(7*pi/16) W1pW7: con 3406; # W1+W7 W1mW7: con 2276; # W1-W7 W3pW5: con 4017; # W3+W5 W3mW5: con 799; # W3-W5 W2pW6: con 3784; # W2+W6 W2mW6: con 1567; # W2-W6 R2: con 181; # 256/sqrt(2) idct(b: array of int) { # transform horizontally for(y:=0; y<8; y++){ eighty := y<<3; # if all non-DC components are zero, just propagate the DC term if(b[eighty+1]==0) if(b[eighty+2]==0 && b[eighty+3]==0) if(b[eighty+4]==0 && b[eighty+5]==0) if(b[eighty+6]==0 && b[eighty+7]==0){ v := b[eighty]<<3; b[eighty+0] = v; b[eighty+1] = v; b[eighty+2] = v; b[eighty+3] = v; b[eighty+4] = v; b[eighty+5] = v; b[eighty+6] = v; b[eighty+7] = v; continue; } # prescale x0 := (b[eighty+0]<<11)+128; x1 := b[eighty+4]<<11; x2 := b[eighty+6]; x3 := b[eighty+2]; x4 := b[eighty+1]; x5 := b[eighty+7]; x6 := b[eighty+5]; x7 := b[eighty+3]; # first stage x8 := W7*(x4+x5); x4 = x8 + W1mW7*x4; x5 = x8 - W1pW7*x5; x8 = W3*(x6+x7); x6 = x8 - W3mW5*x6; x7 = x8 - W3pW5*x7; # second stage x8 = x0 + x1; x0 -= x1; x1 = W6*(x3+x2); x2 = x1 - W2pW6*x2; x3 = x1 + W2mW6*x3; x1 = x4 + x6; x4 -= x6; x6 = x5 + x7; x5 -= x7; # third stage x7 = x8 + x3; x8 -= x3; x3 = x0 + x2; x0 -= x2; x2 = (R2*(x4+x5)+128)>>8; x4 = (R2*(x4-x5)+128)>>8; # fourth stage b[eighty+0] = (x7+x1)>>8; b[eighty+1] = (x3+x2)>>8; b[eighty+2] = (x0+x4)>>8; b[eighty+3] = (x8+x6)>>8; b[eighty+4] = (x8-x6)>>8; b[eighty+5] = (x0-x4)>>8; b[eighty+6] = (x3-x2)>>8; b[eighty+7] = (x7-x1)>>8; } # transform vertically for(x:=0; x<8; x++){ # if all non-DC components are zero, just propagate the DC term if(b[x+8*1]==0) if(b[x+8*2]==0 && b[x+8*3]==0) if(b[x+8*4]==0 && b[x+8*5]==0) if(b[x+8*6]==0 && b[x+8*7]==0){ v := (b[x+8*0]+32)>>6; b[x+8*0] = v; b[x+8*1] = v; b[x+8*2] = v; b[x+8*3] = v; b[x+8*4] = v; b[x+8*5] = v; b[x+8*6] = v; b[x+8*7] = v; continue; } # prescale x0 := (b[x+8*0]<<8)+8192; x1 := b[x+8*4]<<8; x2 := b[x+8*6]; x3 := b[x+8*2]; x4 := b[x+8*1]; x5 := b[x+8*7]; x6 := b[x+8*5]; x7 := b[x+8*3]; # first stage x8 := W7*(x4+x5) + 4; x4 = (x8+W1mW7*x4)>>3; x5 = (x8-W1pW7*x5)>>3; x8 = W3*(x6+x7) + 4; x6 = (x8-W3mW5*x6)>>3; x7 = (x8-W3pW5*x7)>>3; # second stage x8 = x0 + x1; x0 -= x1; x1 = W6*(x3+x2) + 4; x2 = (x1-W2pW6*x2)>>3; x3 = (x1+W2mW6*x3)>>3; x1 = x4 + x6; x4 -= x6; x6 = x5 + x7; x5 -= x7; # third stage x7 = x8 + x3; x8 -= x3; x3 = x0 + x2; x0 -= x2; x2 = (R2*(x4+x5)+128)>>8; x4 = (R2*(x4-x5)+128)>>8; # fourth stage b[x+8*0] = (x7+x1)>>14; b[x+8*1] = (x3+x2)>>14; b[x+8*2] = (x0+x4)>>14; b[x+8*3] = (x8+x6)>>14; b[x+8*4] = (x8-x6)>>14; b[x+8*5] = (x0-x4)>>14; b[x+8*6] = (x3-x2)>>14; b[x+8*7] = (x7-x1)>>14; } } resample(src: array of byte, sw, sh: int, dw, dh: int) : array of byte { if(src == nil || sw == 0 || sh == 0 || dw == 0 || dh == 0) return src; xfac := real sw / real dw; yfac := real sh / real dh; totpix := dw*dh; dst := array[totpix] of byte; dindex := 0; # precompute index in src row corresponding to each index in dst row sindices := array[dw] of int; dx := 0.0; for(x := 0; x < dw; x++) { sx := int dx; dx += xfac; if(sx >= sw) sx = sw-1; sindices[x] = sx; } dy := 0.0; for(y := 0; y < dh; y++) { sy := int dy; dy += yfac; if(sy >= sh) sy = sh-1; soffset := sy * sw; for(x = 0; x < dw; x++) dst[dindex++] = src[soffset + sindices[x]]; } return dst; } Cr2r := array [256] of { -179, -178, -177, -175, -174, -172, -171, -170, -168, -167, -165, -164, -163, -161, -160, -158, -157, -156, -154, -153, -151, -150, -149, -147, -146, -144, -143, -142, -140, -139, -137, -136, -135, -133, -132, -130, -129, -128, -126, -125, -123, -122, -121, -119, -118, -116, -115, -114, -112, -111, -109, -108, -107, -105, -104, -102, -101, -100, -98, -97, -95, -94, -93, -91, -90, -88, -87, -86, -84, -83, -81, -80, -79, -77, -76, -74, -73, -72, -70, -69, -67, -66, -64, -63, -62, -60, -59, -57, -56, -55, -53, -52, -50, -49, -48, -46, -45, -43, -42, -41, -39, -38, -36, -35, -34, -32, -31, -29, -28, -27, -25, -24, -22, -21, -20, -18, -17, -15, -14, -13, -11, -10, -8, -7, -6, -4, -3, -1, 0, 1, 3, 4, 6, 7, 8, 10, 11, 13, 14, 15, 17, 18, 20, 21, 22, 24, 25, 27, 28, 29, 31, 32, 34, 35, 36, 38, 39, 41, 42, 43, 45, 46, 48, 49, 50, 52, 53, 55, 56, 57, 59, 60, 62, 63, 64, 66, 67, 69, 70, 72, 73, 74, 76, 77, 79, 80, 81, 83, 84, 86, 87, 88, 90, 91, 93, 94, 95, 97, 98, 100, 101, 102, 104, 105, 107, 108, 109, 111, 112, 114, 115, 116, 118, 119, 121, 122, 123, 125, 126, 128, 129, 130, 132, 133, 135, 136, 137, 139, 140, 142, 143, 144, 146, 147, 149, 150, 151, 153, 154, 156, 157, 158, 160, 161, 163, 164, 165, 167, 168, 170, 171, 172, 174, 175, 177, 178, }; Cr2g := array [256] of { -91, -91, -90, -89, -89, -88, -87, -86, -86, -85, -84, -84, -83, -82, -81, -81, -80, -79, -79, -78, -77, -76, -76, -75, -74, -74, -73, -72, -71, -71, -70, -69, -69, -68, -67, -66, -66, -65, -64, -64, -63, -62, -61, -61, -60, -59, -59, -58, -57, -56, -56, -55, -54, -54, -53, -52, -51, -51, -50, -49, -49, -48, -47, -46, -46, -45, -44, -44, -43, -42, -41, -41, -40, -39, -39, -38, -37, -36, -36, -35, -34, -34, -33, -32, -31, -31, -30, -29, -29, -28, -27, -26, -26, -25, -24, -24, -23, -22, -21, -21, -20, -19, -19, -18, -17, -16, -16, -15, -14, -14, -13, -12, -11, -11, -10, -9, -9, -8, -7, -6, -6, -5, -4, -4, -3, -2, -1, -1, 0, 1, 1, 2, 3, 4, 4, 5, 6, 6, 7, 8, 9, 9, 10, 11, 11, 12, 13, 14, 14, 15, 16, 16, 17, 18, 19, 19, 20, 21, 21, 22, 23, 24, 24, 25, 26, 26, 27, 28, 29, 29, 30, 31, 31, 32, 33, 34, 34, 35, 36, 36, 37, 38, 39, 39, 40, 41, 41, 42, 43, 44, 44, 45, 46, 46, 47, 48, 49, 49, 50, 51, 51, 52, 53, 54, 54, 55, 56, 56, 57, 58, 59, 59, 60, 61, 61, 62, 63, 64, 64, 65, 66, 66, 67, 68, 69, 69, 70, 71, 71, 72, 73, 74, 74, 75, 76, 76, 77, 78, 79, 79, 80, 81, 81, 82, 83, 84, 84, 85, 86, 86, 87, 88, 89, 89, 90, 91, }; Cb2g := array [256] of { -44, -44, -43, -43, -43, -42, -42, -42, -41, -41, -41, -40, -40, -40, -39, -39, -39, -38, -38, -38, -37, -37, -36, -36, -36, -35, -35, -35, -34, -34, -34, -33, -33, -33, -32, -32, -32, -31, -31, -31, -30, -30, -30, -29, -29, -29, -28, -28, -28, -27, -27, -26, -26, -26, -25, -25, -25, -24, -24, -24, -23, -23, -23, -22, -22, -22, -21, -21, -21, -20, -20, -20, -19, -19, -19, -18, -18, -18, -17, -17, -17, -16, -16, -15, -15, -15, -14, -14, -14, -13, -13, -13, -12, -12, -12, -11, -11, -11, -10, -10, -10, -9, -9, -9, -8, -8, -8, -7, -7, -7, -6, -6, -6, -5, -5, -4, -4, -4, -3, -3, -3, -2, -2, -2, -1, -1, -1, 0, 0, 0, 1, 1, 1, 2, 2, 2, 3, 3, 3, 4, 4, 4, 5, 5, 6, 6, 6, 7, 7, 7, 8, 8, 8, 9, 9, 9, 10, 10, 10, 11, 11, 11, 12, 12, 12, 13, 13, 13, 14, 14, 14, 15, 15, 15, 16, 16, 17, 17, 17, 18, 18, 18, 19, 19, 19, 20, 20, 20, 21, 21, 21, 22, 22, 22, 23, 23, 23, 24, 24, 24, 25, 25, 25, 26, 26, 26, 27, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30, 31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34, 35, 35, 35, 36, 36, 36, 37, 37, 38, 38, 38, 39, 39, 39, 40, 40, 40, 41, 41, 41, 42, 42, 42, 43, 43, 43, 44, }; Cb2b := array [256] of { -227, -225, -223, -222, -220, -218, -216, -214, -213, -211, -209, -207, -206, -204, -202, -200, -198, -197, -195, -193, -191, -190, -188, -186, -184, -183, -181, -179, -177, -175, -174, -172, -170, -168, -167, -165, -163, -161, -159, -158, -156, -154, -152, -151, -149, -147, -145, -144, -142, -140, -138, -136, -135, -133, -131, -129, -128, -126, -124, -122, -120, -119, -117, -115, -113, -112, -110, -108, -106, -105, -103, -101, -99, -97, -96, -94, -92, -90, -89, -87, -85, -83, -82, -80, -78, -76, -74, -73, -71, -69, -67, -66, -64, -62, -60, -58, -57, -55, -53, -51, -50, -48, -46, -44, -43, -41, -39, -37, -35, -34, -32, -30, -28, -27, -25, -23, -21, -19, -18, -16, -14, -12, -11, -9, -7, -5, -4, -2, 0, 2, 4, 5, 7, 9, 11, 12, 14, 16, 18, 19, 21, 23, 25, 27, 28, 30, 32, 34, 35, 37, 39, 41, 43, 44, 46, 48, 50, 51, 53, 55, 57, 58, 60, 62, 64, 66, 67, 69, 71, 73, 74, 76, 78, 80, 82, 83, 85, 87, 89, 90, 92, 94, 96, 97, 99, 101, 103, 105, 106, 108, 110, 112, 113, 115, 117, 119, 120, 122, 124, 126, 128, 129, 131, 133, 135, 136, 138, 140, 142, 144, 145, 147, 149, 151, 152, 154, 156, 158, 159, 161, 163, 165, 167, 168, 170, 172, 174, 175, 177, 179, 181, 183, 184, 186, 188, 190, 191, 193, 195, 197, 198, 200, 202, 204, 206, 207, 209, 211, 213, 214, 216, 218, 220, 222, 223, 225, };