Difference between revisions of "The HSV color scheme"

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Line 15: Line 15:
 
var phi = 0;
 
var phi = 0;
  
var c = brd.createElement('curve',[
+
var c1 = brd.createElement('curve',[
 
           function(t){return r1*Math.sin(t)+r2*Math.sin(lambda*t+phi);},
 
           function(t){return r1*Math.sin(t)+r2*Math.sin(lambda*t+phi);},
           function(t){return r1*Math.cos(t)+r2*Math.cos(lambda*t+phi)-0.5;},
+
           function(t){return r1*Math.cos(t)+r2*Math.cos(lambda*t+phi)-0.2;},
 
           0, 2*Math.PI],
 
           0, 2*Math.PI],
 
           {fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
 
           {fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
Line 25: Line 25:
 
var c2 = brd.createElement('curve',[
 
var c2 = brd.createElement('curve',[
 
           function(t){return Math.sin(t);},
 
           function(t){return Math.sin(t);},
           function(t){return Math.cos(t)-0.5;},
+
           function(t){return Math.cos(t)-0.2;},
 
           0, 2*Math.PI],
 
           0, 2*Math.PI],
 
           {fillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
 
           {fillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
Line 35: Line 35:
 
<source lang="xml">
 
<source lang="xml">
 
<jsxgraph width=600 height=500>
 
<jsxgraph width=600 height=500>
var brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-2,4,8,-4]});
+
var brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-4,4,4,-4], keepaspectratio:true});
var H = brd.createElement('slider',[[0,3.5],[5,3.5],[0,1,360]], {name:'H'});
+
var H = brd.createElement('slider',[[-3,3.5],[2,3.5],[0,1,360]], {name:'H',fillColor:'black',strokeColor:'black'});
var S = brd.createElement('slider',[[0,3],[5,3],[0,1,1]], {name:'S'});
+
var S = brd.createElement('slider',[[-3,3],[2,3],[0,1,1]], {name:'S',fillColor:'black',strokeColor:'black'});
var V = brd.createElement('slider',[[0,2.5],[5,2.5],[0,1,1]], {name:'V'});
+
var V = brd.createElement('slider',[[-3,2.5],[2,2.5],[0,1,1]], {name:'V',fillColor:'black',strokeColor:'black'});
var rct = brd.createElement('curve',[[-1,-1,5,5,-1],[-2,2,2,-2,-2]],
+
       
                {strokeColor:'black',  
+
var r1 = 2;
                  fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); }
+
var r2 = 1/4.75;
                }
+
var lambda = 8;
          );
+
var phi = 0;
 +
 
 +
var c1 = brd.createElement('curve',[
 +
          function(t){return r1*Math.sin(t)+r2*Math.sin(lambda*t+phi);},
 +
          function(t){return r1*Math.cos(t)+r2*Math.cos(lambda*t+phi)-0.2;},
 +
          0, 2*Math.PI],
 +
          {fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
 +
          highlightFillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
 +
          strokeColor:'black',strokeWidth:3});
 +
 
 +
var c2 = brd.createElement('curve',[
 +
          function(t){return Math.sin(t);},
 +
          function(t){return Math.cos(t)-0.2;},
 +
          0, 2*Math.PI],
 +
          {fillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
 +
          highlightFillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
 +
          strokeColor:'black',strokeWidth:3});
 
</jsxgraph>
 
</jsxgraph>
 
</source>
 
</source>

Revision as of 18:10, 24 September 2009

The HSV color scheme consists of three values:

  • Hue (base color): between 0 and 360
  • Saturation (purity): between 0 and 1
  • Value (brightness): between 0 and 1

Here, you can experiment with these values.

The underlying JavaScript code

<jsxgraph width=600 height=500>
var brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-4,4,4,-4], keepaspectratio:true});
var H = brd.createElement('slider',[[-3,3.5],[2,3.5],[0,1,360]], {name:'H',fillColor:'black',strokeColor:'black'});
var S = brd.createElement('slider',[[-3,3],[2,3],[0,1,1]], {name:'S',fillColor:'black',strokeColor:'black'});
var V = brd.createElement('slider',[[-3,2.5],[2,2.5],[0,1,1]], {name:'V',fillColor:'black',strokeColor:'black'});
        
var r1 = 2;
var r2 = 1/4.75;
var lambda = 8;
var phi = 0;

var c1 = brd.createElement('curve',[
          function(t){return r1*Math.sin(t)+r2*Math.sin(lambda*t+phi);},
          function(t){return r1*Math.cos(t)+r2*Math.cos(lambda*t+phi)-0.2;},
          0, 2*Math.PI],
          {fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
           highlightFillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
           strokeColor:'black',strokeWidth:3});

var c2 = brd.createElement('curve',[
          function(t){return Math.sin(t);},
          function(t){return Math.cos(t)-0.2;},
          0, 2*Math.PI],
          {fillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
           highlightFillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
           strokeColor:'black',strokeWidth:3});
</jsxgraph>

External links