Beregn farve interval

F.eks. sådan her:

<script type='text/javascript'>
maxColorIdx = 25;

textcolor = new Array();
textcolor[0]          = "0000FF";  // Blå
textcolor[maxColorIdx] = "FFFF00";  // Gul

rStart = "0x" + textcolor[0].substr(0, 2);
gStart = "0x" + textcolor[0].substr(2, 2);
bStart = "0x" + textcolor[0].substr(4, 2);

rEnd = "0x" + textcolor[maxColorIdx].substr(0, 2);
gEnd = "0x" + textcolor[maxColorIdx].substr(2, 2);
bEnd = "0x" + textcolor[maxColorIdx].substr(4, 2);

for (i=1; i<maxColorIdx; i++)
{
    r = Math.round(((maxColorIdx-i) * parseInt(rStart) + i * parseInt(rEnd))/maxColorIdx);
    g = Math.round(((maxColorIdx-i) * parseInt(gStart) + i * parseInt(gEnd))/maxColorIdx);
    b = Math.round(((maxColorIdx-i) * parseInt(bStart) + i * parseInt(bEnd))/maxColorIdx);

    r = Dec2Hex(r);
    g = Dec2Hex(g);
    b = Dec2Hex(b);

    textcolor[i] = r + g + b;
}

function Dec2Hex(Dec)
{
    var hexChars = "0123456789ABCDEF";
    var a = Dec % 16;
    var b = (Dec - a)/16;
    hex = "" + hexChars.charAt(b) + hexChars.charAt(a);
    return hex;
}

for (i=0; i<=maxColorIdx; i++)
{
    showColor(textcolor[i]);
}

function showColor(color)
{
    document.write("<div style='background: " + color + "'>" + color + "</div>");
}
</script>

... eller en smule kønnere:

<script type='text/javascript'>
maxColorIdx = 25;

textcolor = new Array();
textcolor[0]          = "0000FF";  // Blå
textcolor[maxColorIdx] = "FFFF00";  // Gul

rStart = Hex2Dec(textcolor[0].substr(0, 2));
gStart = Hex2Dec(textcolor[0].substr(2, 2));
bStart = Hex2Dec(textcolor[0].substr(4, 2));

rEnd = Hex2Dec(textcolor[maxColorIdx].substr(0, 2));
gEnd = Hex2Dec(textcolor[maxColorIdx].substr(2, 2));
bEnd = Hex2Dec(textcolor[maxColorIdx].substr(4, 2));

for (i=1; i<maxColorIdx; i++)
{
    r = Math.round(((maxColorIdx-i)*rStart + i*rEnd)/maxColorIdx);
    g = Math.round(((maxColorIdx-i)*gStart + i*gEnd)/maxColorIdx);
    b = Math.round(((maxColorIdx-i)*bStart + i*bEnd)/maxColorIdx);

    r = Dec2Hex(r);
    g = Dec2Hex(g);
    b = Dec2Hex(b);

    textcolor[i] = r + g + b;
}

function Hex2Dec(Hex)
{
    return parseInt("0x" + Hex);
}

function Dec2Hex(Dec)
{
    var hexChars = "0123456789ABCDEF";
    var a = Dec % 16;
    var b = (Dec - a)/16;
    hex = "" + hexChars.charAt(b) + hexChars.charAt(a);
    return hex;
}

for (i=0; i<=maxColorIdx; i++)
{
    showColor(textcolor[i]);
}

function showColor(color)
{
    document.write("<div style='background: " + color + "'>" + color + "</div>");
}
</script>

Hi, det virker. Perfekt

Svar :^)