Difference between revisions of "The HSV color scheme"

From JSXGraph Wiki
Jump to navigationJump to search
Line 5: Line 5:
 
Here, you can experiment with these values.
 
Here, you can experiment with these values.
 
<jsxgraph width=600 height=500>
 
<jsxgraph width=600 height=500>
        var brd = JXG.JSXGraph.initBoard('jxgbox', {boundingbox:[-4,4,4,-4], keepaspectratio:true});
+
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 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 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 V = brd.createElement('slider',[[-3,2.5],[2,2.5],[0,1,1]], {name:'V',fillColor:'black',strokeColor:'black'});
 
          
 
          
        var r1 = 2;
+
var r1 = 2;
        var r2 = 1/4.75;
+
var r2 = 1/4.75;
        var lambda = 8;
+
var lambda = 8;
        var phi = 0;
+
var phi = 0;
 +
 
 
var c = brd.createElement('curve',[
 
var c = 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);},
Line 21: Line 22:
 
           highlightFillcolor: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});
 
           strokeColor:'black',strokeWidth:3});
            
+
 
        var p = brd.createElement('point',[0,-0.5],{visible:false});
+
var c2 = brd.createElement('curve',[
        var ci = brd.createElement('circle',[p,1],  
+
          function(t){return r1*Math.sin(t);},
                {fillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
+
          function(t){return r1*Math.cos(t)-0.5;},
                highlightFillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
+
           0, 2*Math.PI],
                strokewidth:3,
+
          {fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
                strokeColor:'black'
+
          highlightFillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); },
                });             
+
          strokeColor:'black',strokeWidth:3});
 +
/*         
 +
var p = brd.createElement('point',[0,-0.5],{visible:false});
 +
var ci = brd.createElement('circle',[p,1],  
 +
          {fillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
 +
          highlightFillcolor:function(){ return JXG.hsv2rgb(180+H.Value(),S.Value(),V.Value()); },
 +
          strokewidth:3,
 +
          strokeColor:'black'
 +
          });             
 +
*/
 
</jsxgraph>
 
</jsxgraph>
  

Revision as of 18:08, 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:[-2,4,8,-4]});
var H = brd.createElement('slider',[[0,3.5],[5,3.5],[0,1,360]], {name:'H'});
var S = brd.createElement('slider',[[0,3],[5,3],[0,1,1]], {name:'S'});
var V = brd.createElement('slider',[[0,2.5],[5,2.5],[0,1,1]], {name:'V'});
var rct = brd.createElement('curve',[[-1,-1,5,5,-1],[-2,2,2,-2,-2]],
                 {strokeColor:'black', 
                  fillcolor:function(){ return JXG.hsv2rgb(H.Value(),S.Value(),V.Value()); }
                 }
          );
</jsxgraph>

External links