rulerGenerator.js

/* jshint asi: true*/
var ruler = {}


var limitTickQty = function(){
    //Prevent it from crashing if it tries to render too many linest
    ruler.ticksPerUnit = Math.pow(ruler.subUnitBase,ruler.subUnitExponent)
    ruler.masterTickQty = ruler.ticksPerUnit * ruler.width
    if(ruler.height>100){
        console.info("Unreasonable ruler height: "+ ruler.height + " reducing height")
         ruler.height= 15
         document.getElementById("rulerHeight").value = ruler.height;
    }
    if(ruler.width>1000){
        console.info("Unreasonable tick quantity: "+ ruler.masterTickQty + " reducing width")
         ruler.width= 500
         document.getElementById("rulerWidth").value = ruler.width;
    }
     if(ruler.masterTickQty > 10000){
        console.info("Unreasonable tick quantity: "+ ruler.masterTickQty + " reducing exponent")
        if(ruler.subUnitExponent>1){
        ruler.subUnitExponent = ruler.subUnitExponent -1
        document.getElementById("subUnitExponent")[ruler.subUnitExponent].selected = true;
        }
     }
    if(ruler.ticksPerUnit > 100){
        console.info("Unreasonable exponent: "+ ruler.ticksPerUnit+ " resetting to reasonable")
        ruler.subUnitExponent = 1
        document.getElementById("subUnitExponent")[ruler.subUnitExponent].selected = true;//selects resonable
    }
}

var checkUnit = function(){
    var pixelsPerInch = 72//I don't think this needs to be in the object....
    var pixelsPerCM  =  pixelsPerInch / ruler.cmPerInch

    if (ruler.units === "inches"){
        ruler.pixelsPerUnit = pixelsPerInch
        ruler.unitsAbbr= "\"in."
    }
    else if (ruler.units === "centimeters"){
        ruler.unitsAbbr= "cm."
        ruler.pixelsPerUnit = pixelsPerCM
    }
    else{
        ruler.pixelsPerUnit = 0
        console.error("Unexpected unit value. Unit value: "+rulerUnits)
    }
    ruler.heightPixels = ruler.height * ruler.pixelsPerUnit
}

var checkSubUnitBase = function(){
    // if it is fractional, make the fractional dropdown appear
    // if it is decimal, likewise
    var suffix = " " + ruler.unitsAbbr

    var subLabelsDec = [
   "1"  +suffix,
   "1/10th"  +suffix,
   "1/100th"  +suffix,
   "1/1000th"  +suffix,
   "1/10000th"  +suffix,
   "1/100000th"  +suffix,
   "1/1000000th"  +suffix,
    ]

    var subLabelsFrac = [
   "1"  +suffix,
   "1/2"  +suffix,
   "1/4"  +suffix,
   "1/8"  +suffix,
   "1/16"  +suffix,
   "1/32"  +suffix,
   "1/64"  +suffix,
    ]

    if (ruler.subUnitBase === '10'){//Decimal!
    ruler.subLabels = subLabelsDec
        document.getElementById("subUnitExponent")[3].disabled = true;
        document.getElementById("subUnitExponent")[4].disabled = true;//disable the ones that crash.
        document.getElementById("subUnitExponent")[5].disabled = true;
        document.getElementById("subUnitExponent")[6].disabled = true;

        for (var i = ruler.subLabels.length - 1; i >= 0; i--) {
            document.getElementById("subUnitExponent")[i].text =ruler.subLabels[i]
        }
    }
    else if (ruler.subUnitBase === '2'){//Fractional!
        ruler.subLabels = subLabelsFrac

        document.getElementById("subUnitExponent")[3].disabled = false;
        document.getElementById("subUnitExponent")[4].disabled = false;
        document.getElementById("subUnitExponent")[5].disabled = false;//re-enable the ones that dont crash
        document.getElementById("subUnitExponent")[6].disabled = false;

            for (var j = ruler.subLabels.length - 1; j >= 0; j--) {
                document.getElementById("subUnitExponent")[j].text =ruler.subLabels[j]
            }
    }
    else{
        console.error("Impossible subUnitBase. Must be 2 or 10. is:  "+ ruler.subUnitBase)
    }
}

var resizeCanvas = function(){
    document.getElementById("myCanvas").width = ruler.width*ruler.pixelsPerUnit;
    heightAddend = 50
    document.getElementById("myCanvas").height = heightAddend+ ruler.height*ruler.pixelsPerUnit;
}

var constructRuler = function(){
    ruler.tickArray = [];//for prevention of redunancy, an member for each tick
    var layerArray = new Array(ruler.subUnitExponent)//Layers in the SVG file.

    for (var exponentIndex = 0;  exponentIndex <= ruler.subUnitExponent ;  exponentIndex++) {
        //loop thru each desired level of ticks, inches, halves, quarters, etc....
        var tickQty = ruler.width * Math.pow(ruler.subUnitBase,exponentIndex)
        layerArray[exponentIndex]= new paper.Layer();
        layerArray[exponentIndex].name = ruler.subLabels[exponentIndex] + " Tick Group";

        var startNo = $('#startNo').val() ;

        highestTickDenomonatorMultiplier = ruler.ticksPerUnit / Math.pow(ruler.subUnitBase,exponentIndex)
        //to prevent reduntant ticks, this multiplier is applied to crrent units to ensure consistent indexing of ticks.
        for (var tickIndex = 0;  tickIndex <= tickQty ;  tickIndex++) {
            ruler.masterTickIndex = highestTickDenomonatorMultiplier * tickIndex
            // levelToLevelMultiplier =0.7
            var tickHeight
            tickHeight = ruler.heightPixels*Math.pow(ruler.levelToLevelMultiplier,exponentIndex)

            var tickSpacing = ruler.pixelsPerUnit/(Math.pow(ruler.subUnitBase,exponentIndex))
            //spacing between ticks, the fundemental datum on a ruler :-)
            var finalTick = false
            if(tickIndex === tickQty){finalTick = true}

            var offsetTickIndex = parseInt(tickIndex) + parseInt(startNo)
            tick(tickHeight,0, tickIndex, offsetTickIndex, exponentIndex, tickSpacing,finalTick);
            //draws the ticks
        }
    }
}

var tick = function(tickHeight, horizPosition, tickIndex, offsetTickIndex, exponentIndex, tickSpacing,finalTick){
    //exponentIndex is 0-6, how small it is, 6 being smallest
    var x1 = horizPosition + (tickSpacing * tickIndex)
    var x2 = x1 //x === x because lines are vertical
    var y1 = 0//all lines start at top of screen
    var y2 = tickHeight//downward

    if (ruler.tickArray[ruler.masterTickIndex]===undefined || ruler.redundant) {
        // if no tick exists already, or if we want redundant lines, draw the tick.
        var line = new paper.Path.Line([x1, y1], [x2, y2]);//actual line instance
        line.name = ruler.subLabels[exponentIndex]+ " Tick no. " + tickIndex //label for SVG editor
        line.strokeColor = "black";//color of ruler line
        line.strokeWidth = "1";//width of ruler line in pixels

        ruler.tickArray[ruler.masterTickIndex]=true //register the tick so it is not duplicated
            if (exponentIndex === 0) {//if is a primary tick, it needs a label
                tickLabel(x1,y2,finalTick,offsetTickIndex,exponentIndex)
            }
    }   
}

var tickLabel = function(x1,y2,finalTick,tickIndex,exponentIndex){
    //label the tick
            var labelTextSize
            var labelTextSizeInches = 18
            var labelTextSizeCm = Math.round(labelTextSizeInches/ruler.cmPerInch)
            if(ruler.units === "inches"){labelTextSize = labelTextSizeInches;}
            else{labelTextSize = labelTextSizeCm;}
            var xLabelOffset = 4
            var yLabelOffset = 1
            if (finalTick) {xLabelOffset = -1* xLabelOffset}//last label is right justified
            var text = new paper.PointText(new paper.Point(x1+ xLabelOffset, y2+yLabelOffset));
            text.justification = 'left';
            if (finalTick) {text.justification = 'right';}//last label is right justified
            text.fillColor = 'black';
            text.content = tickIndex;
            text.style = {
            // fontFamily: 'Helvetica',
            fontFamily: 'monospace',
            fontWeight: 'bold',
            fontSize: labelTextSize}
            text.name = ruler.subLabels[exponentIndex] + " label no. " +tickIndex //label for SVG editor
}

var debug = function(){
    console.info("--All the variables---")
    console.info(ruler)//prints all attributes of ruler object
}

var updateVariables = function(){
    ruler.units =  $("input:radio[name=rulerUnits]:checked'").val();
    ruler.subUnitBase = $("input:radio[name=subUnits]:checked'").val();
    ruler.redundant =  $("input:checkbox[name=redundant]:checked'").val();
    ruler.width = $('#rulerWidth').val() ;
    ruler.height = $('#rulerHeight').val() ;
    ruler.subUnitExponent = $('#subUnitExponent').val() ;
    ruler.levelToLevelMultiplier = $('#levelToLevelMultiplier').val();
    ruler.cmPerInch = 2.54
}

var build = function(){
    // Get a reference to the canvas object
    var canvas = document.getElementById('myCanvas');
    // Create an empty project and a view for the canvas:
    paper.setup(canvas);


    updateVariables()
    checkUnit()
    checkSubUnitBase()
    limitTickQty()
    resizeCanvas()
    constructRuler()

    paper.view.draw();
}

var exportSvg = function(){
    //* I referenced the excellent SVG export example here: http://paperjs.org/features/#svg-import-and-export
    document.getElementById("svgexpbutton").onclick = 
    function(){
        exportWidth = document.getElementById("myCanvas").width
        exportHeight = document.getElementById("myCanvas").height
        viewBox ='viewBox="0 0 '+exportWidth+' '+exportHeight+'"'
        dims = ' width= "'+exportWidth+'" height="'+exportHeight+' " '
        var svgPrefix = '<svg x="0" y="0"'+dims+viewBox+' version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">';
        // var svgPostfix = '</svg>';
        var svg =   paper.project.exportSVG({ asString: true, size: { width: exportWidth, height: exportHeight } });

        var elem = document.getElementById("svgexpdata");
        elem.value = 'data:image/svg+xml;base64,' + btoa(svg);
        //btoa Creates a base-64 encoded ASCII string from a "string" of binary data
        document.getElementById("svgexpform").submit();
};

}

$(document).ready(function(){ 
    console.log("\t Welcome to the Ruler Generator │╵│╵│╵│╵│╵│╵│")
    //When document is loaded, call build once
    build()
    debug()//prints all values to browser console

    $( "#rulerParameters" ).change(function(  ) {
        //anytime anything within the form is altered, call build again
        build()
        debug()//prints all values to browser console
    });

    exportSvg()

});