Make bmpcmp adapt to different spot colorant order in psdcmyk files.

When processing the second image file, if the CMYK equivalent color for a
spot color does not match that of the first file check if there was a
colorant with the same CMYK in the first file, and if found, map the
color in the second file to the position used in the first file.

As the second file is stored in the page memory, the color_map is used
to store the colorant in the same position as was used for the first
image file.

Also get rid of the globals and change the psd_read to use (void) for
reading the data when it is going to discard the result (for clarity).
(eliminating the globals for the spots is from Robin Watts, extended
to allow for the addition of a color_map).

1 files changed, 240 insertions, 190 deletions

diff --git a/toolbin/bmpcmp.c b/toolbin/bmpcmp.c
index 78b7ef7be..53361b3c1 100644
--- a/toolbin/bmpcmp.c
+++ b/toolbin/bmpcmp.c
@@ -97,17 +97,30 @@ typedef struct
     int        lab;
 } Params;
 
+typedef struct
+{
+    int            width;
+    int            height;
+    int            span;
+    int            bpp;
+    int            cmyk;
+    void          *lab;
+    /* Below are the entries for handling spot colors and the	*/
+    /* CMYK equivalents (only used for PSD images currently).	*/
+    int           *num_spots;
+    unsigned char *spots;
+    /* used to map the second file colors to the same colorants	*/
+    /* as the first and issue a warning if they did not match.	*/
+    int           *color_map;
+} Image;
+
+
 typedef struct ImageReader
 {
     FILE *file;
     const char* file_name;
     void *(*read)(struct ImageReader *,
-                  int                *w,
-                  int                *h,
-                  int                *s,
-                  int                *bpp,
-                  int                *cmyk,
-                  void               **lab);
+                  Image              *);
 } ImageReader;
 
 /*
@@ -121,10 +134,6 @@ typedef void (DiffFn)(unsigned char *bmp,
                       BBox          *bbox,
                       Params        *params);
 
-/* Nasty (as if the rest of this code isn't!) global variables for holding
- * spot color details. */
-static unsigned char spots[256*4];
-static int spotfill = 0;
 
 static void *Malloc(size_t size) {
     void *block;
@@ -384,12 +393,7 @@ static unsigned char *bmp_load_sub(unsigned char *bmp,
 }
 
 static void *bmp_read(ImageReader *im,
-                      int         *width,
-                      int         *height,
-                      int         *span,
-                      int         *bpp,
-                      int         *cmyk,
-                      void       **lab)
+                      Image       *img)
 {
     int            offset;
     long           filelen, filepos;
@@ -397,8 +401,8 @@ static void *bmp_read(ImageReader *im,
     unsigned char *bmp;
 
     /* No CMYK bmp support */
-    *cmyk = 0;
-    *lab = NULL;
+    img->cmyk = 0;
+    img->lab = NULL;
 
     filepos = ftell(im->file);
     fseek(im->file, 0, SEEK_END);
@@ -415,7 +419,7 @@ static void *bmp_read(ImageReader *im,
     fread(bmp, 1, filelen, im->file);
 
     offset = getdword(bmp+10);
-    data = bmp_load_sub(bmp+14, width, height, span, bpp, offset-14, filelen);
+    data = bmp_load_sub(bmp+14, &img->width, &img->height, &img->span, &img->bpp, offset-14, filelen);
     free(bmp);
     return data;
 }
@@ -465,24 +469,19 @@ static int get_short(FILE *file, int rev)
 }
 
 static void *cups_read(ImageReader *im,
-                       int         *width,
-                       int         *height,
-                       int         *span,
-                       int         *bpp,
-                       int         *cmyk,
-                       int          rev,
-                       void       **lab)
+                       Image       *img,
+                       int          rev)
 {
     unsigned char *data, *d;
     int            c, x, y, b, bpc, bpl;
     int            colspace;
 
-    *lab = NULL;
+    img->lab = NULL;
 
     if (skip_bytes(im->file, 372) == EOF)
         return NULL;
-    *width  = get_int(im->file, rev);
-    *height = get_int(im->file, rev);
+    img->width  = get_int(im->file, rev);
+    img->height = get_int(im->file, rev);
     if (skip_bytes(im->file, 4) == EOF)
         return NULL;
     bpc  = get_int(im->file, rev);
@@ -513,14 +512,14 @@ static void *cups_read(ImageReader *im,
     if (skip_bytes(im->file, 1796-424) == EOF)
         return NULL;
 
-    data = Malloc(*width * *height * 4);
-    *span = *width * 4;
-    *bpp = 32;
-    for (y = *height; y > 0; y--) {
+    data = Malloc(img->width * img->height * 4);
+    img->span = img->width * 4;
+    img->bpp = 32;
+    for (y = img->height; y > 0; y--) {
         b = 0;
         c = 0;
-        d = data + (y - 1) * *span;
-        for (x = *width; x > 0; x--) {
+        d = data + (y - 1) * img->span;
+        for (x = img->width; x > 0; x--) {
             b >>= 1;
             if (b == 0) {
                 c = fgetc(im->file);
@@ -540,35 +539,25 @@ static void *cups_read(ImageReader *im,
                 *d++ = 0;
             }
         }
-        skip_bytes(im->file, bpl-((*width+7)>>3));
+        skip_bytes(im->file, bpl-((img->width+7)>>3));
     }
 
     /* No CMYK cups support */
-    *cmyk = 0;
+    img->cmyk = 0;
 
     return data;
 }
 
 static void *cups_read_le(ImageReader *im,
-                          int         *width,
-                          int         *height,
-                          int         *span,
-                          int         *bpp,
-                          int         *cmyk,
-                          void       **lab)
+                          Image       *img)
 {
-    return cups_read(im, width, height, span, bpp, cmyk, 0, lab);
+    return cups_read(im, img, 0);
 }
 
 static void *cups_read_be(ImageReader *im,
-                          int         *width,
-                          int         *height,
-                          int         *span,
-                          int         *bpp,
-                          int         *cmyk,
-                          void       **lab)
+                          Image       *img)
 {
-    return cups_read(im, width, height, span, bpp, cmyk, 1, lab);
+    return cups_read(im, img, 1);
 }
 
 static void skip_to_eol(FILE *file)
@@ -981,18 +970,13 @@ static int pam_header_read(FILE *file,
 }
 
 static void *pnm_read(ImageReader *im,
-                      int         *width,
-                      int         *height,
-                      int         *span,
-                      int         *bpp,
-                      int         *cmyk,
-                      void        **lab)
+                      Image       *img)
 {
     unsigned char *bmp;
     int            c, maxval;
     void          (*read)(FILE *, int, int, int, unsigned char *);
 
-    *lab = NULL;
+    img->lab = NULL;
 
     c = fgetc(im->file);
     /* Skip over any white space before the P */
@@ -1001,7 +985,7 @@ static void *pnm_read(ImageReader *im,
     }
     if (c == EOF)
         return NULL;
-    *cmyk = 0;
+    img->cmyk = 0;
     switch (get_pnm_num(im->file))
     {
         case 1:
@@ -1031,22 +1015,22 @@ static void *pnm_read(ImageReader *im,
             return NULL;
     }
     if (read == pam_read) {
-        *cmyk = pam_header_read(im->file, width, height, &maxval);
+        img->cmyk = pam_header_read(im->file, &img->width, &img->height, &maxval);
     } else {
-        *width  = get_pnm_num(im->file);
-        *height = get_pnm_num(im->file);
+        img->width  = get_pnm_num(im->file);
+        img->height = get_pnm_num(im->file);
         if (read != pbm_read)
             maxval = get_pnm_num(im->file);
         else
             maxval = 1;
     }
 
-    *span   = *width * 4;
-    *bpp = 32; /* We always convert to 32bpp */
+    img->span   = img->width * 4;
+    img->bpp = 32; /* We always convert to 32bpp */
 
-    bmp = Malloc(*width * *height * 4);
+    bmp = Malloc(img->width * img->height * 4);
 
-    read(im->file, *width, *height, maxval, bmp);
+    read(im->file, img->width, img->height, maxval, bmp);
     return bmp;
 }
 
@@ -1093,12 +1077,7 @@ static toff_t tiff_csize(thandle_t im_)
 }
 
 static void* tif_read(ImageReader* im,
-    int* im_width,
-    int* im_height,
-    int* span,
-    int* bpp,
-    int* cmyk,
-    void **lab)
+                      Image       *img)
 {
     TIFF* tif;
     uint16 compression;
@@ -1118,7 +1097,7 @@ static void* tif_read(ImageReader* im,
     cmsContext ctx;
 #endif
 
-    *lab = NULL;
+    img->lab = NULL;
 
     /* There is only one image in each file */
     if (ftell(im->file) != 0)
@@ -1222,7 +1201,7 @@ static void* tif_read(ImageReader* im,
 
         /* Do calloc just to make sure alpha value is known */
         data_lab = Calloc(height * width * 4);
-        *lab = data_lab;
+        img->lab = data_lab;
     }
 #endif
 
@@ -1287,11 +1266,11 @@ static void* tif_read(ImageReader* im,
     _TIFFfree(buf);
     TIFFClose(tif);
 
-    *im_width = width;
-    *im_height = height;
-    *span = width * 4;
-    *bpp = 32;
-    *cmyk = num_comps == 4;
+    img->width = width;
+    img->height = height;
+    img->span = width * 4;
+    img->bpp = 32;
+    img->cmyk = num_comps == 4;
 
     return data;
 }
@@ -1299,12 +1278,7 @@ static void* tif_read(ImageReader* im,
 
 #ifdef HAVE_LIBPNG
 static void *png_read(ImageReader *im,
-                      int         *width,
-                      int         *height,
-                      int         *span,
-                      int         *bpp,
-                      int         *cmyk,
-                      void        **lab)
+                      Image       *img)
 {
     png_structp png;
     png_infop info;
@@ -1313,7 +1287,7 @@ static void *png_read(ImageReader *im,
     unsigned char *data;
     int expand = 0;
 
-    *lab = NULL;
+    img->lab = NULL;
 
     /* There is only one image in each file */
     if (ftell(im->file) != 0)
@@ -1370,28 +1344,23 @@ static void *png_read(ImageReader *im,
     png_read_end(png, NULL);
     png_destroy_read_struct(&png, &info, NULL);
 
-    *width = w;
-    *height = h;
-    *span = (int) stride;
-    *bpp = (int) (stride * 8) / w;
-    *cmyk = 0;
+    img->width = w;
+    img->height = h;
+    img->span = (int) stride;
+    img->bpp = (int) (stride * 8) / w;
+    img->cmyk = 0;
     return data;
 }
 #endif
 
 static void *psd_read(ImageReader *im,
-                      int         *width,
-                      int         *height,
-                      int         *span,
-                      int         *bpp,
-                      int         *cmyk,
-                      void       **lab)
-{
-    int c, ir_len, w, h, n, x, y, z, N;
+                      Image       *img)
+{
+    int c, ir_len, w, h, span, n, x, y, z, N;
     unsigned char *bmp, *line, *ptr;
     int bpc;
 
-    *lab = NULL;
+    img->lab = NULL;
 
     if (feof(im->file))
         return NULL;
@@ -1404,14 +1373,14 @@ static void *psd_read(ImageReader *im,
     }
 
     /* Skip zeros */
-    c = get_short(im->file, 1);
-    c = get_int(im->file, 1);
+    (void)get_short(im->file, 1);
+    (void)get_int(im->file, 1);
 
     n = get_short(im->file, 1);
-    *bpp = n * 8;
+    img->bpp = n * 8;
 
-    h = *height = get_int(im->file, 1);
-    w = *width = get_int(im->file, 1);
+    h = img->height = get_int(im->file, 1);
+    w = img->width = get_int(im->file, 1);
     bpc = get_short(im->file, 1);
     if (bpc != 8 && bpc != 16) {
         fprintf(stderr, "bmpcmp: We only support 8bpp or 16bpp psd files!\n");
@@ -1419,19 +1388,19 @@ static void *psd_read(ImageReader *im,
     }
     c = get_short(im->file, 1);
     if (c == 4) {
-        *cmyk = 1;
+        img->cmyk = 1;
         if (n < 4) {
             fprintf(stderr, "bmpcmp: Unexpected number of components (%d) in a CMYK (+spots) PSD file!\n", n);
             exit(1);
         }
     } else if (c == 3) {
-        *cmyk = 0; /* RGB */
+        img->cmyk = 0; /* RGB */
         if (n != 3) {
             fprintf(stderr, "bmpcmp: Unexpected number of components (%d) in a RGB PSD file!\n", n);
             exit(1);
         }
     } else if (c == 1) {
-        *cmyk = 0; /* Greyscale */
+        img->cmyk = 0; /* Greyscale */
         if (n != 1) {
             fprintf(stderr, "bmpcmp: Unexpected number of components (%d) in a Greyscale PSD file!\n", n);
             exit(1);
@@ -1449,64 +1418,100 @@ static void *psd_read(ImageReader *im,
     }
 
     /* Image Resources section */
-    spotfill = 0;
     ir_len = get_int(im->file, 1);
     while (ir_len > 0)
     {
-        int data_len, pad;
-        c  = fgetc(im->file)<<24; if (--ir_len == 0) break;
-        c |= fgetc(im->file)<<16; if (--ir_len == 0) break;
-        c |= fgetc(im->file)<<8;  if (--ir_len == 0) break;
-        c |= fgetc(im->file);     if (--ir_len == 0) break;
+        int data_len;
+
+        if (ir_len < 12)	/* enough for "8BIM", short data_type (0x3ef), 2-byte pad, int data_len */
+            break;	/* not enough data */
+        c = get_int(im->file, 1);
         /* c == 8BIM */
-        c  = fgetc(im->file)<<8; if (--ir_len == 0) break;
-        c |= fgetc(im->file);    if (--ir_len == 0) break;
+        c  = get_short(im->file, 1);
         /* Skip the padded id (which will always be 00 00) */
-        pad  = fgetc(im->file);    if (--ir_len == 0) break;
-        pad |= fgetc(im->file)<<8; if (--ir_len == 0) break;
-        /* Get the data len */
-        data_len  = fgetc(im->file)<<24; if (--ir_len == 0) break;
-        data_len |= fgetc(im->file)<<16; if (--ir_len == 0) break;
-        data_len |= fgetc(im->file)<<8;  if (--ir_len == 0) break;
-        data_len |= fgetc(im->file);     if (--ir_len == 0) break;
+        (void)get_short(im->file, 1);
+        data_len = get_int(im->file, 1);
+        ir_len -= 12;
         if (c == 0x3ef) {
-          while (data_len > 0) {
+            int spotnum = 0;
+            int i;
+
+            while (data_len > 0) {
+                unsigned char spot[4];
+
+                if (ir_len < 14)	/* enough for short colorspace, and CMYK data */
+                    break;
                 /* Read the colorspace */
-                c  = fgetc(im->file)<<8;  if (--ir_len == 0) break;
-                c |= fgetc(im->file);     if (--ir_len == 0) break;
+                c  = get_short(im->file, 1);
                 /* We only support CMYK spots! */
                 if (c != 2) {
                     fprintf(stderr, "bmpcmp: Spot color equivalent not CMYK! (%d)\n", c);
                     exit(EXIT_FAILURE);
                 }
                 /* c == 2 = COLORSPACE = CMYK */
-                /* 16 bits C, 16 bits M, 16 bits Y, 16 bits K */
-                spots[spotfill++] = 0xff - fgetc(im->file);  if (--ir_len == 0) break;
-                c = fgetc(im->file);  if (--ir_len == 0) break;
-                spots[spotfill++] = 0xff - fgetc(im->file);  if (--ir_len == 0) break;
-                c = fgetc(im->file);  if (--ir_len == 0) break;
-                spots[spotfill++] = 0xff - fgetc(im->file);  if (--ir_len == 0) break;
-                c = fgetc(im->file);  if (--ir_len == 0) break;
-                spots[spotfill++] = 0xff - fgetc(im->file);  if (--ir_len == 0) break;
-                c = fgetc(im->file);  if (--ir_len == 0) break;
+                /* 16 bits C, 16 bits M, 16 bits Y, 16 bits K, ignore the low byte */
+                spot[0] = 0xff - fgetc(im->file);	/* high byte of Cyan */
+                (void)fgetc(im->file);		/* ignore low byte */
+                spot[1] = 0xff - fgetc(im->file);	/* high byte of Magenta */
+                (void)fgetc(im->file);		/* ignore low byte */
+                spot[2] = 0xff - fgetc(im->file);	/* high byte of Yellow */
+                (void)fgetc(im->file);		/* ignore low byte */
+                spot[3] = 0xff - fgetc(im->file);	/* high byte of Black */
+                (void)fgetc(im->file);		/* ignore low byte */
                 /* 2 bytes opacity (always seems to be 0) */
-                c = fgetc(im->file);  if (--ir_len == 0) break;
-                c = fgetc(im->file);  if (--ir_len == 0) break;
+                (void)get_short(im->file, 1);
                 /* 1 byte 'kind' (0 = selected, 1 = protected) */
-                c = fgetc(im->file);  if (--ir_len == 0) break;
+                (void)fgetc(im->file);
                 /* 1 byte padding */
-                c = fgetc(im->file);  if (--ir_len == 0) break;
+                (void)fgetc(im->file);
                 data_len -= 14;
-            }
-        }
-        if (ir_len > 0)
-        {
-            while (data_len > 0)
-            {
-                c = fgetc(im->file); if (--ir_len == 0) break;
-                data_len--;
-            }
+                ir_len -= 14;
+
+                /* Check if the spot colorants were filled in by the first image and	*/
+                /* if so, fill in the color_map with the matching spot number.		*/
+                if (*(img->num_spots) == 0) {	/* num_spots not updated until finished with this file */
+                    /* Spots not seen, this must be the first image */
+                    img->spots[spotnum*4 + 0] = spot[0];
+                    img->spots[spotnum*4 + 1] = spot[1];
+                    img->spots[spotnum*4 + 2] = spot[2];
+                    img->spots[spotnum*4 + 3] = spot[3];
+                    img->color_map[spotnum + 4] = spotnum + 4;	/* default, map to self */
+                } else {
+                    /* spots were set by the first file. See if the colorant order matches */
+                    if (img->spots[spotnum*4 + 0] != spot[0] || img->spots[spotnum*4 + 1] != spot[1] ||
+                        img->spots[spotnum*4 + 2] != spot[2] || img->spots[spotnum*4 + 3] != spot[3] ) {
+                        /* This spot didn't match, issue a warning and see if we can map */
+                        fprintf(stderr, "bmpcmp: spot colorant number %d did not match.\n", spotnum);
+                        for (i=(*(img->num_spots)-1); i >= 0 ; --i) {
+                            if (img->spots[i*4 + 0] == spot[0] && img->spots[i*4 + 1] == spot[1] &&
+                                img->spots[i*4 + 2] == spot[2] && img->spots[i*4 + 3] == spot[3]) {
+                                img->color_map[spotnum + 4] = i + 4;
+                                fprintf(stderr, "bmpcmp: spot colorant %d in file 2 matches colorant %d.\n",
+                                        spotnum, i);
+                                break;
+                            }
+                        }
+                        if (i < 0) {
+                            /* a match was not found. stop */
+                            fprintf(stderr, "bmpcmp: no matching colorant found for color_map\n");
+                            exit(1);
+                        }
+                    }
+                }
+                spotnum++;
+            }
+            *(img->num_spots) = spotnum;	/* save for the next image file */
+#ifdef VERBOSE
+            fprintf(stderr, "color map:");
+            for (i=0; i < 4+nimg->um_spots; i++)
+                fprintf(stderr, " %d->%d,", i, color_map[i]);
+            fprintf(stderr, "\n");
+#endif
         }
+        /* skip any remaining data */
+        ir_len -= data_len;
+        while (data_len-- > 0)
+            (void)fgetc(im->file);
     }
 
     /* Skip Layer and Mask section */
@@ -1526,10 +1531,10 @@ static void *psd_read(ImageReader *im,
     N = n;
     if (N < 4)
         N = 4;
-    *span = (w * N + 3) & ~3;
-    bmp = Malloc(*span * h);
+    img->span = span = (w * N + 3) & ~3;
+    bmp = Malloc(span * h);
     line = Malloc(w * (bpc>>3));
-    ptr = bmp + *span * (h-1);
+    ptr = bmp + span * (h-1);
     if (bpc == 8) {
         if (n == 1) {
             /* Greyscale */
@@ -1544,10 +1549,10 @@ static void *psd_read(ImageReader *im,
                     *ptr++ = val;
                     *ptr++ = 0;
                 }
-                ptr -= w*N + *span;
+                ptr -= w*N + span;
                 line -= w;
             }
-            ptr += *span * h + 1;
+            ptr += span * h + 1;
         } else if (n == 3) {
             /* RGB (reverse to get BGR) */
             ptr += 2;
@@ -1561,10 +1566,10 @@ static void *psd_read(ImageReader *im,
                         *ptr = *line++;
                         ptr += N;
                     }
-                    ptr -= w*N + *span;
+                    ptr -= w*N + span;
                     line -= w;
                 }
-                ptr += *span * h - 1;
+                ptr += span * h - 1;
             }
             ptr += 4;
             for (y = 0; y < h; y++)
@@ -1574,13 +1579,14 @@ static void *psd_read(ImageReader *im,
                     *ptr = 0;
                     ptr += N;
                 }
-                ptr -= w*N + *span;
+                ptr -= w*N + span;
             }
-            ptr += *span * h + 1;
+            ptr += span * h + 1;
         } else {
             /* CMYK + (maybe) spots */
             for (z = 0; z < n; z++)
             {
+                ptr = bmp + img->color_map[z] + span * (h-1);
                 for (y = 0; y < h; y++)
                 {
                     fread(line, 1, w, im->file);
@@ -1589,10 +1595,9 @@ static void *psd_read(ImageReader *im,
                         *ptr = 255 - *line++;
                         ptr += n;
                     }
-                    ptr -= w*n + *span;
+                    ptr -= w*n + span;
                     line -= w;
                 }
-                ptr += *span * h + 1;
             }
         }
     } else {
@@ -1611,10 +1616,10 @@ static void *psd_read(ImageReader *im,
                     *ptr++ = val;
                     *ptr++ = 0;
                 }
-                ptr -= w*N + *span;
+                ptr -= w*N + span;
                 line -= w*2;
             }
-            ptr += *span * h + 1;
+            ptr += span * h + 1;
         } else if (n == 3) {
             /* RGB (reverse to get BGR) */
             ptr += 2;
@@ -1629,10 +1634,10 @@ static void *psd_read(ImageReader *im,
                         line++;
                         ptr += N;
                     }
-                    ptr -= w*N + *span;
+                    ptr -= w*N + span;
                     line -= w*2;
                 }
-                ptr += *span * h - 1;
+                ptr += span * h - 1;
             }
             ptr += 4;
             for (y = 0; y < h; y++)
@@ -1642,26 +1647,26 @@ static void *psd_read(ImageReader *im,
                     *ptr = 0;
                     ptr += N;
                 }
-                ptr -= w*N + *span;
+                ptr -= w*N + span;
             }
-            ptr += *span * h + 1;
+            ptr += span * h + 1;
         } else {
             /* CMYK + (maybe) spots */
             for (z = 0; z < n; z++)
             {
+                ptr = bmp + img->color_map[z] + span * (h-1);
                 for (y = 0; y < h; y++)
                 {
                     fread(line, 2, w, im->file);
                     for (x = 0; x < w; x++)
                     {
                         *ptr = 255 - *line++;
-                        line++;
+                        line++;		/* skip the low byte of data */
                         ptr += n;
                     }
-                    ptr -= w*n + *span;
+                    ptr -= w*n + span;
                     line -= 2*w;
                 }
-                ptr += *span * h + 1;
             }
         }
     }
@@ -1669,13 +1674,13 @@ static void *psd_read(ImageReader *im,
 
     /* Skip over any following header */
     if (!feof(im->file))
-        c = fgetc(im->file);
+        (void)fgetc(im->file);
     if (!feof(im->file))
-        c = fgetc(im->file);
+        (void)fgetc(im->file);
     if (!feof(im->file))
-        c = fgetc(im->file);
+        (void)fgetc(im->file);
     if (!feof(im->file))
-        c = fgetc(im->file);
+        (void)fgetc(im->file);
 
     return bmp;
 }
@@ -3631,8 +3636,13 @@ static void rediff(unsigned char *map,
     *global = local;
 }
 
-static void unspot(unsigned char *bmp, int w, int h, int span, int bpp)
+static void unspot(unsigned char *bmp, Image *img)
 {
+    int w = img->width;
+    int h = img->height;
+    int span = img->span;
+    int bpp = img->bpp;
+    unsigned char *spots = img->spots;
     int x, y, z, n = bpp>>3;
     unsigned char *p = bmp;
 
@@ -3671,10 +3681,12 @@ static void unspot(unsigned char *bmp, int w, int h, int span, int bpp)
 int main(int argc, char *argv[])
 {
     int            w,  h,  s,  bpp,  cmyk;
-    int            w2, h2, s2, bpp2, cmyk2;
+    int            w2, h2;
     int            nx, ny, n;
     int            xstep, ystep;
     int            imagecount;
+    Image          im1 = { 0 };
+    Image          im2 = { 0 };
     unsigned char *bmp;
     unsigned char *bmp2;
     unsigned char *map;
@@ -3691,6 +3703,19 @@ int main(int argc, char *argv[])
     int            can_compare = 1;
     void           *lab1, *lab2;
 
+    /* The following is for CMYK+spots (currently only PSD */
+    int           num_spots = 0;
+    unsigned char spots[256*4] = { 0 };		/* shared between both images */
+    int           color_map[256] = { 0, 1, 2, 3, 0 };
+
+    im1.spots = (unsigned char *)&spots;
+    im2.spots = (unsigned char *)&spots;
+    im1.num_spots = &num_spots;
+    im2.num_spots = &num_spots;
+    im1.color_map = (int *)&color_map;
+    im2.color_map = (int *)&color_map;
+    /* end CMYK+spots section */
+
     parseArgs(argc, argv, &params);
     if (params.window <= 1 && params.threshold == 0) {
         diffFn = simple_diff;
@@ -3711,22 +3736,47 @@ int main(int argc, char *argv[])
     image_open(&image2, params.filename2);
 
     imagecount = 0;
-    while (((bmp2 = NULL,
-        bmp = image1.read(&image1, &w, &h, &s, &bpp, &cmyk, &lab1)) != NULL) &&
-        ((bmp2 = image2.read(&image2, &w2, &h2, &s2, &bpp2, &cmyk2, &lab2)) != NULL))
-    {
+    while (bmp2 == NULL) {
+        /* Reset CMYK+spots values for next image (page) in file */
+        /* NB: Probably not needed since PSD only supports one image==page */
+        num_spots = 0;
+        memset(spots, 0, sizeof(spots));
+        memset(color_map, 0, sizeof(color_map));
+        for (n=0; n < 4; n++)
+            color_map[n] = n;
+
+        if ((bmp = image1.read(&image1, &im1)) == NULL) {
+            fprintf(stderr, "Unable to read image 1, %s, image #%d\n", params.filename1, imagecount+1);
+            continue;	/* try next image??? */
+        }
+
+        if ((bmp2 = image2.read(&image2, &im2)) == NULL) {
+            fprintf(stderr, "Unable to read image 2, %s, image #%d\n", params.filename2, imagecount+1);
+            continue;	/* try next image??? */
+        }
         imagecount++;
         /* Check images are compatible */
-        if ((w != w2) || (h != h2) || (s != s2) || (bpp != bpp2) ||
-            (cmyk != cmyk2))
+        if ((im1.width != im2.width) ||
+            (im1.height != im2.height) ||
+            (im1.span != im2.span) ||
+            (im1.bpp != im2.bpp) ||
+            (im1.cmyk != im2.cmyk))
         {
             fprintf(stderr,
                 "bmpcmp: Page %d: Can't compare images "
                 "(w=%d,%d) (h=%d,%d) (s=%d,%d) (bpp=%d,%d) (cmyk=%d,%d)!\n",
-                imagecount, w, w2, h, h2, s, s2, bpp, bpp2, cmyk, cmyk2);
+                imagecount, im1.width, im2.width, im1.height, im2.height,
+                im1.span, im2.span, im1.bpp, im2.bpp, im1.cmyk, im2.cmyk);
             can_compare = 0;
             continue;
         }
+        w = im1.width;
+        h = im1.height;
+        s = im1.span;
+        bpp = im1.bpp;
+        cmyk = im1.cmyk;
+        lab1 = im1.lab;
+        lab2 = im2.lab;
 
         if (params.lab && (lab1 == NULL || lab2 == NULL)) {
             fprintf(stderr, "bmpcmp: Lab compare failed (only valid for tiffs with icc profiles)\n");
@@ -3821,10 +3871,10 @@ int main(int argc, char *argv[])
             /* bbox */
             boxlist = Malloc(sizeof(*boxlist) * nx * ny);
 
-            if (bpp >= 32)
+            if (bpp > 32)
             {
-                unspot(bmp, w, h, s, bpp);
-                unspot(bmp2, w, h, s, bpp);
+                unspot(bmp, &im1);
+                unspot(bmp2, &im2);
             }
 
             /* Now save the changed bmps */
@@ -3866,25 +3916,25 @@ int main(int argc, char *argv[])
                     default:
                         break;
                     }
-#ifdef HAVE_LIBPNG
+    #ifdef HAVE_LIBPNG
                     sprintf(str1, "%s.%05d.png", params.outroot, n);
                     sprintf(str2, "%s.%05d.png", params.outroot, n+1);
                     sprintf(str3, "%s.%05d.png", params.outroot, n+2);
                     save_png(bmp,  boxlist, s, bpp, str1);
                     save_png(bmp2, boxlist, s, bpp, str2);
-#else
+    #else
                     sprintf(str1, "%s.%05d.bmp", params.outroot, n);
                     sprintf(str2, "%s.%05d.bmp", params.outroot, n+1);
                     sprintf(str3, "%s.%05d.bmp", params.outroot, n+2);
                     save_bmp(bmp,  boxlist, s, bpp, str1);
                     save_bmp(bmp2, boxlist, s, bpp, str2);
-#endif
+    #endif
                     diff_bmp(bmp, map, boxlist, s, w);
-#ifdef HAVE_LIBPNG
+    #ifdef HAVE_LIBPNG
                     save_png(bmp, boxlist, s, bpp, str3);
-#else
+    #else
                     save_bmp(bmp, boxlist, s, bpp, str3);
-#endif
+    #endif
                     sprintf(str4, "%s.%05d.meta", params.outroot, n);
                     save_meta(boxlist, str4, w, h, imagecount, params.threshold, params.window);
                     n += 3;