--- CV/CV.xs	2003/11/12 23:54:54	1.7
+++ CV/CV.xs	2004/04/05 20:55:10	1.8
@@ -57,6 +57,7 @@
     
 }
 
+static void
 a85_finish (PerlIO *fp)
 {
   while (a85_cnt != 4)
@@ -69,6 +70,33 @@
   PerlIO_write (fp, a85_buf, a85_ptr - a85_buf);
 }
 
+static void
+rgb_to_hsv (unsigned int  r, unsigned int  g, unsigned int  b,
+            unsigned int *h, unsigned int *s, unsigned int *v)
+{
+  unsigned int mx = r; if (g > mx) mx = g; if (b > mx) mx = b;
+  unsigned int mn = r; if (g < mn) mn = g; if (b < mn) mn = b;
+  unsigned int delta = mx - mn;
+
+  *v = mx;
+
+  *s = mx ? delta * 255 / mx : 0;
+
+  if (delta == 0)
+    *h = 0;
+  else
+    {
+      if (r == mx)
+        *h = ((int)g - (int)b) * 255 / (int)(delta * 3);
+      else if (g == mx)
+        *h = ((int)b - (int)r) * 255 / (int)(delta * 3) + 52;
+      else if (b == mx)
+        *h = ((int)r - (int)g) * 255 / (int)(delta * 3) + 103;
+
+      *h &= 255;
+    }
+}
+
 /////////////////////////////////////////////////////////////////////////////
 
 MODULE = Gtk2::CV PACKAGE = Gtk2::CV::ImageWindow
@@ -254,6 +282,71 @@
               PerlIO_putc (fp, src [x * bpp + y * sstr + i]);
 }
 
+#############################################################################
+
+MODULE = Gtk2::CV PACKAGE = Gtk2::CV
+
+SV *
+pb_to_hv84 (GdkPixbuf *pb)
+	CODE:
+{
+	int w = gdk_pixbuf_get_width  (pb);
+	int h = gdk_pixbuf_get_height (pb);
+	int x, y;
+        guchar *dst;
+        int bpp = gdk_pixbuf_get_n_channels (pb);
+        guchar *src = gdk_pixbuf_get_pixels (pb);
+        int sstr = gdk_pixbuf_get_rowstride (pb);
+
+	RETVAL = newSV (6 * 8 * 12 / 8);
+        SvPOK_only (RETVAL);
+        SvCUR_set (RETVAL, 6 * 8 * 12 / 8);
+
+        dst = SvPVX (RETVAL);
+
+        /* some primitive error distribution + random dithering */
+
+        for (y = 0; y < h; y++)
+          {
+            guchar *p = src + y * sstr;
+
+            for (x = 0; x < w; x += 2)
+              {
+                unsigned int r, g, b, h, s, v, H, V1, V2;
+
+                if (bpp == 3)
+                  r = *p++, g = *p++, b = *p++;
+                else if (bpp == 1)
+                  r = g = b = *p++;
+                else
+                  abort ();
+
+                rgb_to_hsv (r, g, b, &h, &s, &v);
+
+                H = (h * 15 / 255) << 4;
+                V1 = v;
+
+                if (bpp == 3)
+                  r = *p++, g = *p++, b = *p++;
+                else if (bpp == 1)
+                  r = g = b = *p++;
+                else
+                  abort ();
+
+                rgb_to_hsv (r, g, b, &h, &s, &v);
+
+                H |= h * 15 / 255;
+                V2 = v;
+
+                *dst++ = H;
+                *dst++ = V1;
+                *dst++ = V2;
+              }
+          }
+}
+	OUTPUT:
+        RETVAL
+