make example a bit nicer

Reals/Grapher.mch

@@ -8,10 +8,18 @@ DEFINITIONS
                                 FORMAT_TO_STRING("~w,~w ",[real(i), points(i)])));
  
   // the function to be plotted:                                                          
- myfunction(x) == 2.0*RSQRT(x)-0.5*RSIN(2.0*x);
+  myfunction(x) == 1.5*RSQRT(x)-0.5*RSIN(2.0*x);
 
- mypoints(scale) == %x.(x:1..500| 300.0-scale*myfunction(RDIV(real(x),scale)));
+  // proportions of the SVG frame
+  WIDTH == 500;
+  HEIGHT == 300;
 
- // graph plotted in rectangle (0,0) to (300,300)
- visb_graph == svg_points2str(mypoints(30.0))
+  mx_x == 10.0; // maximum x value computed
+ 
+  // compute a sequence of function values:
+  mypoints(scale) == %x.(x:1..WIDTH| real(HEIGHT) - 
+                                     scale*myfunction(RDIV(real(x),scale)));
+ 
+ // graph plotted in rectangle (0,0) to (500,300)
+ visb_graph == svg_points2str(mypoints(RDIV(real(WIDTH),mx_x)))
 END
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