Index fix

src/slang/color/palettes.sl

@@ -111,38 +111,6 @@ private define hpluv_palette (n)
   return rgb2hex(hsluv2rgb(hues, qualifier("s", 0.9), qualifier("l", 0.6)));
 }
 
-private define colormap_palette (n, name)
-%!%+
-%\function{palette--map}
-%\synopsis{Retrieve a set of colors from a colormap}
-%\usage{UInt_Type[] palette = get_color_palette (String_Type name, UInt_Type len);}
-%\qualifiers{
-%  \qualifier{start[=0.0]}{Starting "color" (lowest value)}
-%  \qualifier{range[=1.0]}{Range of "color", larger than one causes repetitions}
-%}
-%\description
-%  This function is useful if a range of colors is required.
-%  It returns \code{len} values from a linear mapping of the
-%  given colormap. If \code{n} is more than 256, repetitions will
-%  occure.
-%!%-
-{
-#ifexists png_add_colormap
-  variable map;
-  try 
-    map = png_get_colormap(name);
-  catch AnyError:
-    throw UsageError, "Unknown palette: '$name'"$;
-
-  variable ind = (qualifier("start", 0.0) + [0:qualifier("range", 1.0):#n]) mod 1.0;
-  ind = int((ind-int(ind))*255);
-
-  return map[ind];
-#else
-  return ColorPalettes[""];
-#endif
-}
-
 % HSL, HSLuv palettes %{{{
 add_color_palette("hsl", &hsl_palette);
 add_color_palette("hsluv", &hsluv_palette);
@@ -378,7 +346,7 @@ private define blend_palette (n)
   mb[winf] = 0.;
 
   weights = weights[[:-2]];
-  variable idx = [0, int(weights*n), n-1];
+  variable idx = [0, int(weights*(n-1)), n-1];
   variable tr = r[[:-2]]-mr*weights;
   variable tg = g[[:-2]]-mg*weights;
   variable tb = b[[:-2]]-mb*weights;
@@ -557,6 +525,45 @@ private define cubehelix_palette (n)
 add_color_palette("cubehelix", &cubehelix_palette);
 %}}}
 
+private define colormap_palette (n, name)
+%!%+
+%\function{palette--map}
+%\synopsis{Retrieve a set of colors from a colormap}
+%\usage{UInt_Type[] palette = get_color_palette (String_Type name, UInt_Type len);}
+%\qualifiers{
+%  \qualifier{start[=0.0]}{Starting "color" (lowest value)}
+%  \qualifier{range[=1.0]}{Range of "color", larger than one causes repetitions}
+%}
+%\description
+%  This function is useful if a range of colors is required.
+%  It returns \code{len} values from a linear mapping of the
+%  given colormap. The colors are constructed from palette--blend
+%  and forwards all qualifiers to this constructor.
+%!%-
+{
+#ifexists png_add_colormap
+  variable map;
+  try
+    map = png_get_colormap(name);
+  catch AnyError:
+    throw UsageError, "Unknown palette: '$name'"$;
+
+  variable start = qualifier("start", 0.0);
+  variable range = qualifier("range", 1.0);
+  while (start<0) start += 1.0;
+
+  start = int(start*(length(map)-1));
+  range = int(range*(length(map)-1));
+
+  variable ind = [start:start+range] mod length(map);
+  vmessage("start: %06x, stop: %06x", (map[ind])[0], (map[ind])[-1]);
+
+  return blend_palette(n;; struct { @__qualifiers(),  colors=map[ind] });
+#else
+  return ColorPalettes[""];
+#endif
+}
+
 define get_color_palette (name, n)
 %!%+
 %\function{get_color_palette}