columnWidths.js

// Calc whole pixel widths using Bresenham's line algorithm (useful thing, innit?)
    function distributeWidthAsColumns(width, numColumns) {

        var columnWidths = [];
        var columnWidthIdeal = width / numColumns;
        var totalWholePixels = 0;
        var errorTotal = 0;
        var pixelWidth = Math.floor(columnWidthIdeal);
        var errorPerColumn = columnWidthIdeal - pixelWidth;

        var i,w;
        for (i=0; i < numColumns; i++) {

            if (columnWidthIdeal < minColWidth) { // Set at the top of the file
                w = minColWidth;
            } else {
                w = pixelWidth; // Default to rounded-down value
                errorTotal += errorPerColumn;

                if (errorTotal >= 1) {
                    w++; // If we've got a whole pixel of error, add it to the current width
                    errorTotal--; // And take it off our total error
                }

                if (i == numColumns - 1 && (totalWholePixels + w) < width ) {
                    w++; // If it's the last column and we're missing a partial pixel, add a whole one.
                }
            }

            totalWholePixels += w;
            columnWidths.push(w);
        }

        columnWidths.totalWholePixels = totalWholePixels;
        return columnWidths;
    }