Change graph scale to logarithmic

programming flash
1

Hi all,
I have the following script that takes a number and visualizes it on a circular shape much like an odometer/speed meter that a car dashboard has.


var inputVal = 6.70;

var contentMC = _root.createEmptyMovieClip("contentMC", _root.getNextHighestDepth());
var baseMC = contentMC.createEmptyMovieClip("baseMC", contentMC.getNextHighestDepth());

baseMC._x = 150;
baseMC._y = 150;
var dynamicMC = baseMC.duplicateMovieClip("dynamicMC", contentMC.getNextHighestDepth());
var maskMC = baseMC.duplicateMovieClip("maskMC", contentMC.getNextHighestDepth());

var markMC = _root.createEmptyMovieClip("baseMC", _root.getNextHighestDepth());
markMC.lineStyle(0,0xFF0000);
markMC.beginFill(0xFF0000,100);
markMC.moveTo(0,0);
markMC.lineTo(0,12);
markMC.lineTo(-12,0);
markMC.lineTo(0,0);
markMC.endFill();

var startSize = 320*-1;
var startPos = -110;
drawWedge(baseMC,100,startSize,startPos,[0, 0x000000],[0x0033CC, 100]);
drawDoughnut(maskMC,50,100,startSize,startPos,[5, 0xFF0000],[0xFF00FF, 100]);

processsInput(inputVal);
contentMC.setMask(maskMC);

onMouseDown = function () {
    processsInput((1200/Stage.height)*_ymouse);
};
function processsInput(inVal) {
    var wedgeSize = (startSize/1200)*inVal;
    var wedgeStart = startPos;
    drawWedge(dynamicMC,100,wedgeSize,wedgeStart,[0, 0x000000],[0xFF6600, 100]);
    contentMC.setMask(maskMC);
}

function drawDoughnut(mc, radius, radius2, arc, startAngle, lstyle, fstyle) {
    mc.clear();
    var segAngle, theta, angle, angleMid, segs, ax, ay, bx, by, cx, cy;
    arc = (Math.abs(arc)>360) ? 360 : arc;
    segs = Math.ceil(Math.abs(arc)/45);
    segAngle = arc/segs;
    theta = -(segAngle/180)*Math.PI;
    angle = -(startAngle/180)*Math.PI;
    ax = Math.cos(angle)*radius;
    ay = Math.sin(angle)*radius;
    mc.lineStyle.apply(mc,lstyle);
    mc.beginFill.apply(mc,fstyle);
    rx = ax;
    ry = ay;
    mc.moveTo(ax,ay);
    if (segs>0) {
        for (var i = 0; i<segs; i++) {
            angle += theta;
            angleMid = angle-(theta/2);
            bx = Math.cos(angle)*radius;
            by = Math.sin(angle)*radius;
            cx = Math.cos(angleMid)*(radius/Math.cos(theta/2));
            cy = Math.sin(angleMid)*(radius/Math.cos(theta/2));
            mc.curveTo(cx,cy,bx,by);
        }
    }
    startAngle = arc+startAngle;
    arc *= -1;
    segAngle = arc/segs;
    theta = -(segAngle/180)*Math.PI;
    angle = -(startAngle/180)*Math.PI;
    ax = Math.cos(angle)*radius2;
    ay = Math.sin(angle)*radius2;
    mc.lineStyle.apply(mc,lstyle);
    mc.lineTo(ax,ay);
    if (segs>0) {
        for (var j = 0; j<segs; j++) {
            angle += theta;
            angleMid = angle-(theta/2);
            bx = Math.cos(angle)*radius2;
            by = Math.sin(angle)*radius2;
            cx = Math.cos(angleMid)*(radius2/Math.cos(theta/2));
            cy = Math.sin(angleMid)*(radius2/Math.cos(theta/2));
            mc.curveTo(cx,cy,bx,by);
        }
    }
    mc.lineTo(rx,ry);
    mc.endFill();
}
function drawWedge(mc, radius, arc, startAngle, lstyle, fstyle) {
    mc.clear();
    var segAngle, theta, angle, angleMid, segs, ax, ay, bx, by, cx, cy;
    arc = (Math.abs(arc)>360) ? 360 : arc;
    segs = Math.ceil(Math.abs(arc)/45);
    segAngle = arc/segs;
    theta = -(segAngle/180)*Math.PI;
    angle = -(startAngle/180)*Math.PI;
    ax = Math.cos(angle)*radius;
    ay = Math.sin(angle)*radius;
    mc.lineStyle.apply(mc,lstyle);
    mc.beginFill.apply(mc,fstyle);
    mc.moveTo(0,0);
    mc.lineTo(ax,ay);
    if (segs>0) {
        for (var i = 0; i<segs; i++) {
            angle += theta;
            angleMid = angle-(theta/2);
            bx = Math.cos(angle)*radius;
            by = Math.sin(angle)*radius;
            cx = Math.cos(angleMid)*(radius/Math.cos(theta/2));
            cy = Math.sin(angleMid)*(radius/Math.cos(theta/2));
            mc.curveTo(cx,cy,bx,by);
        }
    }
    //  
    markMC._rotation = (startAngle-arc)-90;
    markMC._x = Math.cos(angle)*(radius-50)+baseMC._x;
    markMC._y = Math.sin(angle)*(radius-50)+baseMC._y;
    //
    mc.endFill();
}

The scale is from 0 to 1200 and the problem I have is that the value I want to show is usually so small that it looks like it’s stuck next to zero all the time. So, what I need is change the scale to logarithmic so the values from 1 to 10 take up as much space as those from 10 to 100 etc. and the small values show fluctuation. In the attached image you’ll see on the left how it behaves now and on the right how I need it to become (both show a visualization of a small value, something around 7 or 8). Anyone can tell me how it’s done? Thanks.