pro-docs/libs/codemirror/addon/display/rulers.js

// CodeMirror, copyright (c) by Marijn Haverbeke and others
// Distributed under an MIT license: https://codemirror.net/LICENSE

;(function (mod) {
    if (typeof exports == 'object' && typeof module == 'object')
        // CommonJS
        mod(require('../../lib/codemirror'))
    else if (typeof define == 'function' && define.amd)
        // AMD
        define(['../../lib/codemirror'], mod)
    // Plain browser env
    else mod(CodeMirror)
})(function (CodeMirror) {
    'use strict'

    CodeMirror.defineOption('rulers', false, function (cm, val) {
        if (cm.state.rulerDiv) {
            cm.state.rulerDiv.parentElement.removeChild(cm.state.rulerDiv)
            cm.state.rulerDiv = null
            cm.off('refresh', drawRulers)
        }
        if (val && val.length) {
            cm.state.rulerDiv = cm.display.lineSpace.parentElement.insertBefore(document.createElement('div'), cm.display.lineSpace)
            cm.state.rulerDiv.className = 'CodeMirror-rulers'
            drawRulers(cm)
            cm.on('refresh', drawRulers)
        }
    })

    function drawRulers(cm) {
        cm.state.rulerDiv.textContent = ''
        var val = cm.getOption('rulers')
        var cw = cm.defaultCharWidth()
        var left = cm.charCoords(CodeMirror.Pos(cm.firstLine(), 0), 'div').left
        cm.state.rulerDiv.style.minHeight = cm.display.scroller.offsetHeight + 30 + 'px'
        for (var i = 0; i < val.length; i++) {
            var elt = document.createElement('div')
            elt.className = 'CodeMirror-ruler'
            var col,
                conf = val[i]
            if (typeof conf == 'number') {
                col = conf
            } else {
                col = conf.column
                if (conf.className) elt.className += ' ' + conf.className
                if (conf.color) elt.style.borderColor = conf.color
                if (conf.lineStyle) elt.style.borderLeftStyle = conf.lineStyle
                if (conf.width) elt.style.borderLeftWidth = conf.width
            }
            elt.style.left = left + col * cw + 'px'
            cm.state.rulerDiv.appendChild(elt)
        }
    }
})