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No res-include for rpmspec wx24dsp
[wxWidgets.git] / src / tiff / tif_luv.c
index 67577399ccac2a990a11484ee6c59eeda99bba8c..4c3d06e44932a793d2bb454dd29d9bc8c2b3447c 100644 (file)
  * of conversion to and from LogLuv, though the application is still
  * responsible for interpreting the TIFFTAG_STONITS calibration factor.
  *
- * The information is compressed into one of two basic encodings, depending on
- * the setting of the compression tag, which is one of COMPRESSION_SGILOG
+ * By definition, a CIE XYZ vector of [1 1 1] corresponds to a neutral white
+ * point of (x,y)=(1/3,1/3).  However, most color systems assume some other
+ * white point, such as D65, and an absolute color conversion to XYZ then
+ * to another color space with a different white point may introduce an
+ * unwanted color cast to the image.  It is often desirable, therefore, to
+ * perform a white point conversion that maps the input white to [1 1 1]
+ * in XYZ, then record the original white point using the TIFFTAG_WHITEPOINT
+ * tag value.  A decoder that demands absolute color calibration may use
+ * this white point tag to get back the original colors, but usually it
+ * will be ignored and the new white point will be used instead that
+ * matches the output color space.
+ *
+ * Pixel information is compressed into one of two basic encodings, depending
+ * on the setting of the compression tag, which is one of COMPRESSION_SGILOG
  * or COMPRESSION_SGILOG24.  For COMPRESSION_SGILOG, greyscale data is
  * stored as:
  *
  * scheme by separating the logL, u and v bytes for each row and applying
  * a PackBits type of compression.  Since the 24-bit encoding is not
  * adaptive, the 32-bit color format takes less space in many cases.
+ *
+ * Further control is provided over the conversion from higher-resolution
+ * formats to final encoded values through the pseudo tag
+ * TIFFTAG_SGILOGENCODE:
+ *  SGILOGENCODE_NODITHER     = do not dither encoded values
+ *  SGILOGENCODE_RANDITHER    = apply random dithering during encoding
+ *
+ * The default value of this tag is SGILOGENCODE_NODITHER for
+ * COMPRESSION_SGILOG to maximize run-length encoding and
+ * SGILOGENCODE_RANDITHER for COMPRESSION_SGILOG24 to turn
+ * quantization errors into noise.
  */
 
 #include <stdio.h>
@@ -135,10 +158,11 @@ typedef   struct logLuvState LogLuvState;
 
 struct logLuvState {
        int                     user_datafmt;   /* user data format */
+       int                     encode_meth;    /* encoding method */
        int                     pixel_size;     /* bytes per pixel */
 
        tidata_t*               tbuf;           /* translation buffer */
-       short                   tbuflen;        /* buffer length */
+       int                     tbuflen;        /* buffer length */
        void (*tfunc)(LogLuvState*, tidata_t, int);
 
        TIFFVSetMethod          vgetparent;     /* super-class method */
@@ -186,13 +210,13 @@ LogL16Decode(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
                for (i = 0; i < npixels && cc > 0; )
                        if (*bp >= 128) {               /* run */
                                rc = *bp++ + (2-128);
-                               b = (int16)*bp++ << shft;
+                               b = (int16)(*bp++ << shft);
                                cc -= 2;
-                               while (rc--)
+                               while (rc-- && i < npixels)
                                        tp[i++] |= b;
                        } else {                        /* non-run */
                                rc = *bp++;             /* nul is noop */
-                               while (--cc && rc--)
+                               while (--cc && rc-- && i < npixels)
                                        tp[i++] |= (int16)*bp++ << shft;
                        }
                if (i != npixels) {
@@ -232,7 +256,6 @@ LogLuvDecode24(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
                assert(sp->tbuflen >= npixels);
                tp = (uint32 *) sp->tbuf;
        }
-       _TIFFmemset((tdata_t) tp, 0, npixels*sizeof (tp[0]));
                                        /* copy to array of uint32 */
        bp = (u_char*) tif->tif_rawcp;
        cc = tif->tif_rawcc;
@@ -289,11 +312,11 @@ LogLuvDecode32(TIFF* tif, tidata_t op, tsize_t occ, tsample_t s)
                                rc = *bp++ + (2-128);
                                b = (uint32)*bp++ << shft;
                                cc -= 2;
-                               while (rc--)
+                               while (rc-- && i < npixels)
                                        tp[i++] |= b;
                        } else {                        /* non-run */
                                rc = *bp++;             /* nul is noop */
-                               while (--cc && rc--)
+                               while (--cc && rc-- && i < npixels)
                                        tp[i++] |= (uint32)*bp++ << shft;
                        }
                if (i != npixels) {
@@ -382,7 +405,7 @@ LogL16Encode(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
                        }
                        mask = 0xff << shft;            /* find next run */
                        for (beg = i; beg < npixels; beg += rc) {
-                               b = tp[beg] & mask;
+                               b = (int16) (tp[beg] & mask);
                                rc = 1;
                                while (rc < 127+2 && beg+rc < npixels &&
                                                (tp[beg+rc] & mask) == b)
@@ -391,36 +414,36 @@ LogL16Encode(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
                                        break;          /* long enough */
                        }
                        if (beg-i > 1 && beg-i < MINRUN) {
-                               b = tp[i] & mask;       /* check short run */
+                               b = (int16) (tp[i] & mask);/*check short run */
                                j = i+1;
                                while ((tp[j++] & mask) == b)
-                                       if (j == beg) {
-                                               *op++ = 128-2+j-i;
-                                               *op++ = b >> shft;
-                                               occ -= 2;
-                                               i = beg;
-                                               break;
-                                       }
+                                    if (j == beg) {
+                                        *op++ = (tidataval_t)(128-2+j-i);
+                                        *op++ = (tidataval_t) (b >> shft);
+                                        occ -= 2;
+                                        i = beg;
+                                        break;
+                                    }
                        }
                        while (i < beg) {               /* write out non-run */
                                if ((j = beg-i) > 127) j = 127;
                                if (occ < j+3) {
-                                       tif->tif_rawcp = op;
-                                       tif->tif_rawcc = tif->tif_rawdatasize - occ;
-                                       if (!TIFFFlushData1(tif))
-                                               return (-1);
-                                       op = tif->tif_rawcp;
-                                       occ = tif->tif_rawdatasize - tif->tif_rawcc;
+                                    tif->tif_rawcp = op;
+                                    tif->tif_rawcc = tif->tif_rawdatasize - occ;
+                                    if (!TIFFFlushData1(tif))
+                                        return (-1);
+                                    op = tif->tif_rawcp;
+                                    occ = tif->tif_rawdatasize - tif->tif_rawcc;
                                }
-                               *op++ = j; occ--;
+                               *op++ = (tidataval_t) j; occ--;
                                while (j--) {
-                                       *op++ = tp[i++] >> shft & 0xff;
+                                       *op++ = (tidataval_t) (tp[i++] >> shft & 0xff);
                                        occ--;
                                }
                        }
                        if (rc >= MINRUN) {             /* write out run */
-                               *op++ = 128-2+rc;
-                               *op++ = tp[beg] >> shft & 0xff;
+                               *op++ = (tidataval_t) (128-2+rc);
+                               *op++ = (tidataval_t) (tp[beg] >> shft & 0xff);
                                occ -= 2;
                        } else
                                rc = 0;
@@ -465,9 +488,9 @@ LogLuvEncode24(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
                        op = tif->tif_rawcp;
                        occ = tif->tif_rawdatasize - tif->tif_rawcc;
                }
-               *op++ = *tp >> 16;
-               *op++ = *tp >> 8 & 0xff;
-               *op++ = *tp++ & 0xff;
+               *op++ = (tidataval_t)(*tp >> 16);
+               *op++ = (tidataval_t)(*tp >> 8 & 0xff);
+               *op++ = (tidataval_t)(*tp++ & 0xff);
                occ -= 3;
        }
        tif->tif_rawcp = op;
@@ -529,8 +552,8 @@ LogLuvEncode32(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
                                j = i+1;
                                while ((tp[j++] & mask) == b)
                                        if (j == beg) {
-                                               *op++ = 128-2+j-i;
-                                               *op++ = b >> shft;
+                                               *op++ = (tidataval_t)(128-2+j-i);
+                                               *op++ = (tidataval_t)(b >> shft);
                                                occ -= 2;
                                                i = beg;
                                                break;
@@ -546,15 +569,15 @@ LogLuvEncode32(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
                                        op = tif->tif_rawcp;
                                        occ = tif->tif_rawdatasize - tif->tif_rawcc;
                                }
-                               *op++ = j; occ--;
+                               *op++ = (tidataval_t) j; occ--;
                                while (j--) {
-                                       *op++ = tp[i++] >> shft & 0xff;
+                                       *op++ = (tidataval_t)(tp[i++] >> shft & 0xff);
                                        occ--;
                                }
                        }
                        if (rc >= MINRUN) {             /* write out run */
-                               *op++ = 128-2+rc;
-                               *op++ = tp[beg] >> shft & 0xff;
+                               *op++ = (tidataval_t) (128-2+rc);
+                               *op++ = (tidataval_t)(tp[beg] >> shft & 0xff);
                                occ -= 2;
                        } else
                                rc = 0;
@@ -598,46 +621,57 @@ LogLuvEncodeTile(TIFF* tif, tidata_t bp, tsize_t cc, tsample_t s)
 /*
  * Encode/Decode functions for converting to and from user formats.
  */
+
 #include "uvcode.h"
 
-#define U_NEU  0.210526316
-#define V_NEU  0.473684211
+#ifndef UVSCALE
+#define U_NEU          0.210526316
+#define V_NEU          0.473684211
+#define UVSCALE                410.
+#endif
 
-#ifdef M_LN2
-#define        LOGOF2          M_LN2
-#else
-#define LOGOF2         0.69314718055994530942
+#ifndef        M_LN2
+#define M_LN2          0.69314718055994530942
+#endif
+#ifndef M_PI
+#define M_PI           3.14159265358979323846
 #endif
-#define log2(x)                ((1./LOGOF2)*log(x))
-#define exp2(x)                exp(LOGOF2*(x))
+#define log2(x)                ((1./M_LN2)*log(x))
+#define exp2(x)                exp(M_LN2*(x))
 
-#define UVSCALE                410.
+#define itrunc(x,m)    ((m)==SGILOGENCODE_NODITHER ? \
+                               (int)(x) : \
+                               (int)((x) + rand()*(1./RAND_MAX) - .5))
 
-static double
-pix16toY(int p16)
+#if !LOGLUV_PUBLIC
+static
+#endif
+double
+LogL16toY(int p16)             /* compute luminance from 16-bit LogL */
 {
        int     Le = p16 & 0x7fff;
        double  Y;
 
        if (!Le)
                return (0.);
-       Y = exp(LOGOF2/256.*(Le+.5) - LOGOF2*64.);
-       if (p16 & 0x8000)
-               return (-Y);
-       return (Y);
+       Y = exp(M_LN2/256.*(Le+.5) - M_LN2*64.);
+       return (!(p16 & 0x8000) ? Y : -Y);
 }
 
-static int
-pix16fromY(double Y)
+#if !LOGLUV_PUBLIC
+static
+#endif
+int
+LogL16fromY(double Y, int em)  /* get 16-bit LogL from Y */
 {
-       if (Y >= 1.84467e19)
+       if (Y >= 1.8371976e19)
                return (0x7fff);
-       if (Y <= -1.84467e19)
+       if (Y <= -1.8371976e19)
                return (0xffff);
-       if (Y > 5.43571e-20)
-               return (int)(256.*(log2(Y) + 64.));
-       if (Y < -5.43571e-20)
-               return (~0x7fff | (int)(256.*(log2(-Y) + 64.)));
+       if (Y > 5.4136769e-20)
+               return itrunc(256.*(log2(Y) + 64.), em);
+       if (Y < -5.4136769e-20)
+               return (~0x7fff | itrunc(256.*(log2(-Y) + 64.), em));
        return (0);
 }
 
@@ -648,7 +682,7 @@ L16toY(LogLuvState* sp, tidata_t op, int n)
        float* yp = (float*) op;
 
        while (n-- > 0)
-               *yp++ = pix16toY(*l16++);
+               *yp++ = (float)LogL16toY(*l16++);
 }
 
 static void
@@ -658,8 +692,8 @@ L16toGry(LogLuvState* sp, tidata_t op, int n)
        uint8* gp = (uint8*) op;
 
        while (n-- > 0) {
-               double Y = pix16toY(*l16++);
-               *gp++ = (Y <= 0.) ? 0 : (Y >= 1.) ? 255 : (int)(256.*sqrt(Y));
+               double Y = LogL16toY(*l16++);
+               *gp++ = (uint8) ((Y <= 0.) ? 0 : (Y >= 1.) ? 255 : (int)(256.*sqrt(Y)));
        }
 }
 
@@ -670,10 +704,13 @@ L16fromY(LogLuvState* sp, tidata_t op, int n)
        float* yp = (float*) op;
 
        while (n-- > 0)
-               *l16++ = pix16fromY(*yp++);
+               *l16++ = (int16) (LogL16fromY(*yp++, sp->encode_meth));
 }
 
-static void
+#if !LOGLUV_PUBLIC
+static
+#endif
+void
 XYZtoRGB24(float xyz[3], uint8 rgb[3])
 {
        double  r, g, b;
@@ -683,68 +720,161 @@ XYZtoRGB24(float xyz[3], uint8 rgb[3])
        b =  0.061*xyz[0] + -0.224*xyz[1] +  1.163*xyz[2];
                                        /* assume 2.0 gamma for speed */
        /* could use integer sqrt approx., but this is probably faster */
-       rgb[0] = (r <= 0.) ? 0 : (r >= 1.) ? 255 : (int)(256.*sqrt(r));
-       rgb[1] = (g <= 0.) ? 0 : (g >= 1.) ? 255 : (int)(256.*sqrt(g));
-       rgb[2] = (b <= 0.) ? 0 : (b >= 1.) ? 255 : (int)(256.*sqrt(b));
+       rgb[0] = (uint8)((r<=0.) ? 0 : (r >= 1.) ? 255 : (int)(256.*sqrt(r)));
+       rgb[1] = (uint8)((g<=0.) ? 0 : (g >= 1.) ? 255 : (int)(256.*sqrt(g)));
+       rgb[2] = (uint8)((b<=0.) ? 0 : (b >= 1.) ? 255 : (int)(256.*sqrt(b)));
+}
+
+#if !LOGLUV_PUBLIC
+static
+#endif
+double
+LogL10toY(int p10)             /* compute luminance from 10-bit LogL */
+{
+       if (p10 == 0)
+               return (0.);
+       return (exp(M_LN2/64.*(p10+.5) - M_LN2*12.));
+}
+
+#if !LOGLUV_PUBLIC
+static
+#endif
+int
+LogL10fromY(double Y, int em)  /* get 10-bit LogL from Y */
+{
+       if (Y >= 15.742)
+               return (0x3ff);
+       else if (Y <= .00024283)
+               return (0);
+       else
+               return itrunc(64.*(log2(Y) + 12.), em);
 }
 
+#define NANGLES                100
+#define uv2ang(u, v)   ( (NANGLES*.499999999/M_PI) \
+                               * atan2((v)-V_NEU,(u)-U_NEU) + .5*NANGLES )
+
 static int
-uv_encode(double u, double v)          /* encode (u',v') coordinates */
+oog_encode(double u, double v)         /* encode out-of-gamut chroma */
+{
+       static int      oog_table[NANGLES];
+       static int      initialized = 0;
+       register int    i;
+       
+       if (!initialized) {             /* set up perimeter table */
+               double  eps[NANGLES], ua, va, ang, epsa;
+               int     ui, vi, ustep;
+               for (i = NANGLES; i--; )
+                       eps[i] = 2.;
+               for (vi = UV_NVS; vi--; ) {
+                       va = UV_VSTART + (vi+.5)*UV_SQSIZ;
+                       ustep = uv_row[vi].nus-1;
+                       if (vi == UV_NVS-1 || vi == 0 || ustep <= 0)
+                               ustep = 1;
+                       for (ui = uv_row[vi].nus-1; ui >= 0; ui -= ustep) {
+                               ua = uv_row[vi].ustart + (ui+.5)*UV_SQSIZ;
+                               ang = uv2ang(ua, va);
+                                i = (int) ang;
+                               epsa = fabs(ang - (i+.5));
+                               if (epsa < eps[i]) {
+                                       oog_table[i] = uv_row[vi].ncum + ui;
+                                       eps[i] = epsa;
+                               }
+                       }
+               }
+               for (i = NANGLES; i--; )        /* fill any holes */
+                       if (eps[i] > 1.5) {
+                               int     i1, i2;
+                               for (i1 = 1; i1 < NANGLES/2; i1++)
+                                       if (eps[(i+i1)%NANGLES] < 1.5)
+                                               break;
+                               for (i2 = 1; i2 < NANGLES/2; i2++)
+                                       if (eps[(i+NANGLES-i2)%NANGLES] < 1.5)
+                                               break;
+                               if (i1 < i2)
+                                       oog_table[i] =
+                                               oog_table[(i+i1)%NANGLES];
+                               else
+                                       oog_table[i] =
+                                               oog_table[(i+NANGLES-i2)%NANGLES];
+                       }
+               initialized = 1;
+       }
+       i = (int) uv2ang(u, v);         /* look up hue angle */
+       return (oog_table[i]);
+}
+
+#undef uv2ang
+#undef NANGLES
+
+#if !LOGLUV_PUBLIC
+static
+#endif
+int
+uv_encode(double u, double v, int em)  /* encode (u',v') coordinates */
 {
        register int    vi, ui;
 
        if (v < UV_VSTART)
-               return(-1);
-       vi = (v - UV_VSTART)*(1./UV_SQSIZ);
+               return oog_encode(u, v);
+       vi = itrunc((v - UV_VSTART)*(1./UV_SQSIZ), em);
        if (vi >= UV_NVS)
-               return(-1);
+               return oog_encode(u, v);
        if (u < uv_row[vi].ustart)
-               return(-1);
-       ui = (u - uv_row[vi].ustart)*(1./UV_SQSIZ);
+               return oog_encode(u, v);
+       ui = itrunc((u - uv_row[vi].ustart)*(1./UV_SQSIZ), em);
        if (ui >= uv_row[vi].nus)
-               return(-1);
-       return(uv_row[vi].ncum + ui);
+               return oog_encode(u, v);
+
+       return (uv_row[vi].ncum + ui);
 }
 
-static int
+#if !LOGLUV_PUBLIC
+static
+#endif
+int
 uv_decode(double *up, double *vp, int c)       /* decode (u',v') index */
 {
        int     upper, lower;
        register int    ui, vi;
 
        if (c < 0 || c >= UV_NDIVS)
-               return(-1);
-       lower = 0;                      /* binary search */
+               return (-1);
+       lower = 0;                              /* binary search */
        upper = UV_NVS;
-       do {
+       while (upper - lower > 1) {
                vi = (lower + upper) >> 1;
                ui = c - uv_row[vi].ncum;
                if (ui > 0)
                        lower = vi;
                else if (ui < 0)
                        upper = vi;
-               else
+               else {
+                       lower = vi;
                        break;
-       } while (upper - lower > 1);
+               }
+       }
        vi = lower;
        ui = c - uv_row[vi].ncum;
        *up = uv_row[vi].ustart + (ui+.5)*UV_SQSIZ;
        *vp = UV_VSTART + (vi+.5)*UV_SQSIZ;
-       return(0);
+       return (0);
 }
 
-static void
-pix24toXYZ(uint32 p, float XYZ[3])
+#if !LOGLUV_PUBLIC
+static
+#endif
+void
+LogLuv24toXYZ(uint32 p, float XYZ[3])
 {
-       int     Le, Ce;
+       int     Ce;
        double  L, u, v, s, x, y;
                                        /* decode luminance */
-       Le = p >> 14 & 0x3ff;
-       if (Le == 0) {
+       L = LogL10toY(p>>14 & 0x3ff);
+       if (L <= 0.) {
                XYZ[0] = XYZ[1] = XYZ[2] = 0.;
                return;
        }
-       L = exp(LOGOF2/64.*(Le+.5) - LOGOF2*12.);
                                        /* decode color */
        Ce = p & 0x3fff;
        if (uv_decode(&u, &v, Ce) < 0) {
@@ -754,36 +884,33 @@ pix24toXYZ(uint32 p, float XYZ[3])
        x = 9.*u * s;
        y = 4.*v * s;
                                        /* convert to XYZ */
-       XYZ[0] = x/y * L;
-       XYZ[1] = L;
-       XYZ[2] = (1.-x-y)/y * L;
+       XYZ[0] = (float)(x/y * L);
+       XYZ[1] = (float)L;
+       XYZ[2] = (float)((1.-x-y)/y * L);
 }
 
-static uint32
-pix24fromXYZ(float XYZ[3])
+#if !LOGLUV_PUBLIC
+static
+#endif
+uint32
+LogLuv24fromXYZ(float XYZ[3], int em)
 {
        int     Le, Ce;
-       double  L, u, v, s;
+       double  u, v, s;
                                        /* encode luminance */
-       L = XYZ[1];
-       if (L >= 16.)
-               Le = 0x3ff;
-       else if (L <= 1./4096.)
-               Le = 0;
-       else
-               Le = 64.*(log2(L) + 12.);
+       Le = LogL10fromY(XYZ[1], em);
                                        /* encode color */
        s = XYZ[0] + 15.*XYZ[1] + 3.*XYZ[2];
-       if (s == 0.) {
+       if (!Le || s <= 0.) {
                u = U_NEU;
                v = V_NEU;
        } else {
                u = 4.*XYZ[0] / s;
                v = 9.*XYZ[1] / s;
        }
-       Ce = uv_encode(u, v);
-       if (Ce < 0)
-               Ce = uv_encode(U_NEU, V_NEU);
+       Ce = uv_encode(u, v, em);
+       if (Ce < 0)                     /* never happens */
+               Ce = uv_encode(U_NEU, V_NEU, SGILOGENCODE_NODITHER);
                                        /* combine encodings */
        return (Le << 14 | Ce);
 }
@@ -795,7 +922,7 @@ Luv24toXYZ(LogLuvState* sp, tidata_t op, int n)
        float* xyz = (float*) op;
 
        while (n-- > 0) {
-               pix24toXYZ(*luv, xyz);
+               LogLuv24toXYZ(*luv, xyz);
                xyz += 3;
                luv++;
        }
@@ -810,13 +937,13 @@ Luv24toLuv48(LogLuvState* sp, tidata_t op, int n)
        while (n-- > 0) {
                double u, v;
 
-               *luv3++ = (*luv >> 12 & 0xffd) + 13314;
+               *luv3++ = (int16)((*luv >> 12 & 0xffd) + 13314);
                if (uv_decode(&u, &v, *luv&0x3fff) < 0) {
                        u = U_NEU;
                        v = V_NEU;
                }
-               *luv3++ = u * (1L<<15);
-               *luv3++ = v * (1L<<15);
+               *luv3++ = (int16)(u * (1L<<15));
+               *luv3++ = (int16)(v * (1L<<15));
                luv++;
        }
 }
@@ -830,7 +957,7 @@ Luv24toRGB(LogLuvState* sp, tidata_t op, int n)
        while (n-- > 0) {
                float xyz[3];
 
-               pix24toXYZ(*luv++, xyz);
+               LogLuv24toXYZ(*luv++, xyz);
                XYZtoRGB24(xyz, rgb);
                rgb += 3;
        }
@@ -843,7 +970,7 @@ Luv24fromXYZ(LogLuvState* sp, tidata_t op, int n)
        float* xyz = (float*) op;
 
        while (n-- > 0) {
-               *luv++ = pix24fromXYZ(xyz);
+               *luv++ = LogLuv24fromXYZ(xyz, sp->encode_meth);
                xyz += 3;
        }
 }
@@ -861,23 +988,30 @@ Luv24fromLuv48(LogLuvState* sp, tidata_t op, int n)
                        Le = 0;
                else if (luv3[0] >= (1<<12)+3314)
                        Le = (1<<10) - 1;
-               else
+               else if (sp->encode_meth == SGILOGENCODE_NODITHER)
                        Le = (luv3[0]-3314) >> 2;
-               Ce = uv_encode((luv[1]+.5)/(1<<15), (luv[2]+.5)/(1<<15));
-               if (Ce < 0)
-                       Ce = uv_encode(U_NEU, V_NEU);
+               else
+                       Le = itrunc(.25*(luv3[0]-3314.), sp->encode_meth);
+
+               Ce = uv_encode((luv3[1]+.5)/(1<<15), (luv3[2]+.5)/(1<<15),
+                                       sp->encode_meth);
+               if (Ce < 0)     /* never happens */
+                       Ce = uv_encode(U_NEU, V_NEU, SGILOGENCODE_NODITHER);
                *luv++ = (uint32)Le << 14 | Ce;
                luv3 += 3;
        }
 }
 
-static void
-pix32toXYZ(uint32 p, float XYZ[3])
+#if !LOGLUV_PUBLIC
+static
+#endif
+void
+LogLuv32toXYZ(uint32 p, float XYZ[3])
 {
        double  L, u, v, s, x, y;
                                        /* decode luminance */
-       L = pix16toY((int)p >> 16);
-       if (L == 0.) {
+       L = LogL16toY((int)p >> 16);
+       if (L <= 0.) {
                XYZ[0] = XYZ[1] = XYZ[2] = 0.;
                return;
        }
@@ -888,21 +1022,24 @@ pix32toXYZ(uint32 p, float XYZ[3])
        x = 9.*u * s;
        y = 4.*v * s;
                                        /* convert to XYZ */
-       XYZ[0] = x/y * L;
-       XYZ[1] = L;
-       XYZ[2] = (1.-x-y)/y * L;
+       XYZ[0] = (float)(x/y * L);
+       XYZ[1] = (float)L;
+       XYZ[2] = (float)((1.-x-y)/y * L);
 }
 
-static uint32
-pix32fromXYZ(float XYZ[3])
+#if !LOGLUV_PUBLIC
+static
+#endif
+uint32
+LogLuv32fromXYZ(float XYZ[3], int em)
 {
        unsigned int    Le, ue, ve;
        double  u, v, s;
                                        /* encode luminance */
-       Le = (unsigned int)pix16fromY(XYZ[1]);
+       Le = (unsigned int)LogL16fromY(XYZ[1], em);
                                        /* encode color */
        s = XYZ[0] + 15.*XYZ[1] + 3.*XYZ[2];
-       if (s == 0.) {
+       if (!Le || s <= 0.) {
                u = U_NEU;
                v = V_NEU;
        } else {
@@ -910,10 +1047,10 @@ pix32fromXYZ(float XYZ[3])
                v = 9.*XYZ[1] / s;
        }
        if (u <= 0.) ue = 0;
-       else ue = UVSCALE * u;
+       else ue = itrunc(UVSCALE*u, em);
        if (ue > 255) ue = 255;
        if (v <= 0.) ve = 0;
-       else ve = UVSCALE * v;
+       else ve = itrunc(UVSCALE*v, em);
        if (ve > 255) ve = 255;
                                        /* combine encodings */
        return (Le << 16 | ue << 8 | ve);
@@ -926,7 +1063,7 @@ Luv32toXYZ(LogLuvState* sp, tidata_t op, int n)
        float* xyz = (float*) op;
 
        while (n-- > 0) {
-               pix32toXYZ(*luv++, xyz);
+               LogLuv32toXYZ(*luv++, xyz);
                xyz += 3;
        }
 }
@@ -940,11 +1077,11 @@ Luv32toLuv48(LogLuvState* sp, tidata_t op, int n)
        while (n-- > 0) {
                double u, v;
 
-               *luv3++ = *luv >> 16;
+               *luv3++ = (int16)(*luv >> 16);
                u = 1./UVSCALE * ((*luv>>8 & 0xff) + .5);
                v = 1./UVSCALE * ((*luv & 0xff) + .5);
-               *luv3++ = u * (1L<<15);
-               *luv3++ = v * (1L<<15);
+               *luv3++ = (int16)(u * (1L<<15));
+               *luv3++ = (int16)(v * (1L<<15));
                luv++;
        }
 }
@@ -958,7 +1095,7 @@ Luv32toRGB(LogLuvState* sp, tidata_t op, int n)
        while (n-- > 0) {
                float xyz[3];
 
-               pix32toXYZ(*luv++, xyz);
+               LogLuv32toXYZ(*luv++, xyz);
                XYZtoRGB24(xyz, rgb);
                rgb += 3;
        }
@@ -971,7 +1108,7 @@ Luv32fromXYZ(LogLuvState* sp, tidata_t op, int n)
        float* xyz = (float*) op;
 
        while (n-- > 0) {
-               *luv++ = pix32fromXYZ(xyz);
+               *luv++ = LogLuv32fromXYZ(xyz, sp->encode_meth);
                xyz += 3;
        }
 }
@@ -982,10 +1119,19 @@ Luv32fromLuv48(LogLuvState* sp, tidata_t op, int n)
        uint32* luv = (uint32*) sp->tbuf;
        int16* luv3 = (int16*) op;
 
+       if (sp->encode_meth == SGILOGENCODE_NODITHER) {
+               while (n-- > 0) {
+                       *luv++ = (uint32)luv3[0] << 16 |
+                               (luv3[1]*(uint32)(UVSCALE+.5) >> 7 & 0xff00) |
+                               (luv3[2]*(uint32)(UVSCALE+.5) >> 15 & 0xff);
+                       luv3 += 3;
+               }
+               return;
+       }
        while (n-- > 0) {
                *luv++ = (uint32)luv3[0] << 16 |
-                       (luv3[1]*(uint32)(UVSCALE+.5) >> 7 & 0xff00) |
-                       (luv3[2]*(uint32)(UVSCALE+.5) >> 15 & 0xff);
+       (itrunc(luv3[1]*(UVSCALE/(1<<15)), sp->encode_meth) << 8 & 0xff00) |
+               (itrunc(luv3[2]*(UVSCALE/(1<<15)), sp->encode_meth) & 0xff);
                luv3 += 3;
        }
 }
@@ -1015,6 +1161,17 @@ LogL16GuessDataFmt(TIFFDirectory *td)
        return (SGILOGDATAFMT_UNKNOWN);
 }
 
+static uint32
+multiply(size_t m1, size_t m2)
+{
+       uint32  bytes = m1 * m2;
+
+       if (m1 && bytes / m1 != m2)
+               bytes = 0;
+
+       return bytes;
+}
+
 static int
 LogL16InitState(TIFF* tif)
 {
@@ -1043,9 +1200,9 @@ LogL16InitState(TIFF* tif)
                    "No support for converting user data format to LogL");
                return (0);
        }
-       sp->tbuflen = td->td_imagewidth * td->td_rowsperstrip;
-       sp->tbuf = (tidata_t*) _TIFFmalloc(sp->tbuflen * sizeof (int16));
-       if (sp->tbuf == NULL) {
+       sp->tbuflen = multiply(td->td_imagewidth, td->td_rowsperstrip);
+       if (multiply(sp->tbuflen, sizeof (int16)) == 0 ||
+           (sp->tbuf = (tidata_t*) _TIFFmalloc(sp->tbuflen * sizeof (int16))) == NULL) {
                TIFFError(module, "%s: No space for SGILog translation buffer",
                    tif->tif_name);
                return (0);
@@ -1141,9 +1298,9 @@ LogLuvInitState(TIFF* tif)
                    "No support for converting user data format to LogLuv");
                return (0);
        }
-       sp->tbuflen = td->td_imagewidth * td->td_rowsperstrip;
-       sp->tbuf = (tidata_t*) _TIFFmalloc(sp->tbuflen * sizeof (uint32));
-       if (sp->tbuf == NULL) {
+       sp->tbuflen = multiply(td->td_imagewidth, td->td_rowsperstrip);
+       if (multiply(sp->tbuflen, sizeof (uint32)) == 0 ||
+           (sp->tbuf = (tidata_t*) _TIFFmalloc(sp->tbuflen * sizeof (uint32))) == NULL) {
                TIFFError(module, "%s: No space for SGILog translation buffer",
                    tif->tif_name);
                return (0);
@@ -1335,6 +1492,7 @@ LogLuvVSetField(TIFF* tif, ttag_t tag, va_list ap)
                        break;
                case SGILOGDATAFMT_RAW:
                        bps = 32, fmt = SAMPLEFORMAT_UINT;
+                       TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, 1);
                        break;
                case SGILOGDATAFMT_8BIT:
                        bps = 8, fmt = SAMPLEFORMAT_UINT;
@@ -1353,6 +1511,16 @@ LogLuvVSetField(TIFF* tif, ttag_t tag, va_list ap)
                tif->tif_tilesize = TIFFTileSize(tif);
                tif->tif_scanlinesize = TIFFScanlineSize(tif);
                return (1);
+       case TIFFTAG_SGILOGENCODE:
+               sp->encode_meth = va_arg(ap, int);
+               if (sp->encode_meth != SGILOGENCODE_NODITHER &&
+                               sp->encode_meth != SGILOGENCODE_RANDITHER) {
+                       TIFFError(tif->tif_name,
+                               "Unknown encoding %d for LogLuv compression",
+                               sp->encode_meth);
+                       return (0);
+               }
+               return (1);
        default:
                return (*sp->vsetparent)(tif, tag, ap);
        }
@@ -1374,7 +1542,9 @@ LogLuvVGetField(TIFF* tif, ttag_t tag, va_list ap)
 
 static const TIFFFieldInfo LogLuvFieldInfo[] = {
     { TIFFTAG_SGILOGDATAFMT,     0, 0, TIFF_SHORT,     FIELD_PSEUDO,
-      TRUE,    FALSE,  "SGILogDataFmt"}
+      TRUE,    FALSE,  "SGILogDataFmt"},
+    { TIFFTAG_SGILOGENCODE,      0, 0, TIFF_SHORT,     FIELD_PSEUDO,
+      TRUE,    FALSE,  "SGILogEncode"}
 };
 
 int
@@ -1392,8 +1562,10 @@ TIFFInitSGILog(TIFF* tif, int scheme)
        if (tif->tif_data == NULL)
                goto bad;
        sp = (LogLuvState*) tif->tif_data;
-       memset(sp, 0, sizeof (*sp));
+       _TIFFmemset((tdata_t)sp, 0, sizeof (*sp));
        sp->user_datafmt = SGILOGDATAFMT_UNKNOWN;
+       sp->encode_meth = (scheme == COMPRESSION_SGILOG24) ?
+                               SGILOGENCODE_RANDITHER : SGILOGENCODE_NODITHER;
        sp->tfunc = _logLuvNop;
 
        /*
@@ -1412,10 +1584,10 @@ TIFFInitSGILog(TIFF* tif, int scheme)
 
        /* override SetField so we can handle our private pseudo-tag */
        _TIFFMergeFieldInfo(tif, LogLuvFieldInfo, N(LogLuvFieldInfo));
-       sp->vgetparent = tif->tif_vgetfield;
-       tif->tif_vgetfield = LogLuvVGetField;   /* hook for codec tags */
-       sp->vsetparent = tif->tif_vsetfield;
-       tif->tif_vsetfield = LogLuvVSetField;   /* hook for codec tags */
+       sp->vgetparent = tif->tif_tagmethods.vgetfield;
+       tif->tif_tagmethods.vgetfield = LogLuvVGetField;   /* hook for codec tags */
+       sp->vsetparent = tif->tif_tagmethods.vsetfield;
+       tif->tif_tagmethods.vsetfield = LogLuvVSetField;   /* hook for codec tags */
 
        return (1);
 bad: