Empty diagram for CNV without gene annotation

[pixuenan]

In the line 137 of script cnv_diagram.js, the code is as following:

var maxTextY = Math.max.apply(null, geneTexts.map(l => l.y)) + characterHeight;

I changed the code to something like following:

if (geneTexts.length > 0){
        var maxTextY = Math.max.apply(null, geneTexts.map(l => l.y)) + characterHeight;
    } else {
        var maxTextY = characterHeight;
    }

Otherwise the CNV without overlaping gene annotation will end up with -Infinity height and empty diagram.