pro-docs/libs/codemirror/addon/scroll/simplescrollbars.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'

    function Bar(cls, orientation, scroll) {
        this.orientation = orientation
        this.scroll = scroll
        this.screen = this.total = this.size = 1
        this.pos = 0

        this.node = document.createElement('div')
        this.node.className = cls + '-' + orientation
        this.inner = this.node.appendChild(document.createElement('div'))

        var self = this
        CodeMirror.on(this.inner, 'mousedown', function (e) {
            if (e.which != 1) return
            CodeMirror.e_preventDefault(e)
            var axis = self.orientation == 'horizontal' ? 'pageX' : 'pageY'
            var start = e[axis],
                startpos = self.pos
            function done() {
                CodeMirror.off(document, 'mousemove', move)
                CodeMirror.off(document, 'mouseup', done)
            }
            function move(e) {
                if (e.which != 1) return done()
                self.moveTo(startpos + (e[axis] - start) * (self.total / self.size))
            }
            CodeMirror.on(document, 'mousemove', move)
            CodeMirror.on(document, 'mouseup', done)
        })

        CodeMirror.on(this.node, 'click', function (e) {
            CodeMirror.e_preventDefault(e)
            var innerBox = self.inner.getBoundingClientRect(),
                where
            if (self.orientation == 'horizontal') where = e.clientX < innerBox.left ? -1 : e.clientX > innerBox.right ? 1 : 0
            else where = e.clientY < innerBox.top ? -1 : e.clientY > innerBox.bottom ? 1 : 0
            self.moveTo(self.pos + where * self.screen)
        })

        function onWheel(e) {
            var moved = CodeMirror.wheelEventPixels(e)[self.orientation == 'horizontal' ? 'x' : 'y']
            var oldPos = self.pos
            self.moveTo(self.pos + moved)
            if (self.pos != oldPos) CodeMirror.e_preventDefault(e)
        }
        CodeMirror.on(this.node, 'mousewheel', onWheel)
        CodeMirror.on(this.node, 'DOMMouseScroll', onWheel)
    }

    Bar.prototype.setPos = function (pos, force) {
        if (pos < 0) pos = 0
        if (pos > this.total - this.screen) pos = this.total - this.screen
        if (!force && pos == this.pos) return false
        this.pos = pos
        this.inner.style[this.orientation == 'horizontal' ? 'left' : 'top'] = pos * (this.size / this.total) + 'px'
        return true
    }

    Bar.prototype.moveTo = function (pos) {
        if (this.setPos(pos)) this.scroll(pos, this.orientation)
    }

    var minButtonSize = 10

    Bar.prototype.update = function (scrollSize, clientSize, barSize) {
        var sizeChanged = this.screen != clientSize || this.total != scrollSize || this.size != barSize
        if (sizeChanged) {
            this.screen = clientSize
            this.total = scrollSize
            this.size = barSize
        }

        var buttonSize = this.screen * (this.size / this.total)
        if (buttonSize < minButtonSize) {
            this.size -= minButtonSize - buttonSize
            buttonSize = minButtonSize
        }
        this.inner.style[this.orientation == 'horizontal' ? 'width' : 'height'] = buttonSize + 'px'
        this.setPos(this.pos, sizeChanged)
    }

    function SimpleScrollbars(cls, place, scroll) {
        this.addClass = cls
        this.horiz = new Bar(cls, 'horizontal', scroll)
        place(this.horiz.node)
        this.vert = new Bar(cls, 'vertical', scroll)
        place(this.vert.node)
        this.width = null
    }

    SimpleScrollbars.prototype.update = function (measure) {
        if (this.width == null) {
            var style = window.getComputedStyle ? window.getComputedStyle(this.horiz.node) : this.horiz.node.currentStyle
            if (style) this.width = parseInt(style.height)
        }
        var width = this.width || 0

        var needsH = measure.scrollWidth > measure.clientWidth + 1
        var needsV = measure.scrollHeight > measure.clientHeight + 1
        this.vert.node.style.display = needsV ? 'block' : 'none'
        this.horiz.node.style.display = needsH ? 'block' : 'none'

        if (needsV) {
            this.vert.update(measure.scrollHeight, measure.clientHeight, measure.viewHeight - (needsH ? width : 0))
            this.vert.node.style.bottom = needsH ? width + 'px' : '0'
        }
        if (needsH) {
            this.horiz.update(measure.scrollWidth, measure.clientWidth, measure.viewWidth - (needsV ? width : 0) - measure.barLeft)
            this.horiz.node.style.right = needsV ? width + 'px' : '0'
            this.horiz.node.style.left = measure.barLeft + 'px'
        }

        return { right: needsV ? width : 0, bottom: needsH ? width : 0 }
    }

    SimpleScrollbars.prototype.setScrollTop = function (pos) {
        this.vert.setPos(pos)
    }

    SimpleScrollbars.prototype.setScrollLeft = function (pos) {
        this.horiz.setPos(pos)
    }

    SimpleScrollbars.prototype.clear = function () {
        var parent = this.horiz.node.parentNode
        parent.removeChild(this.horiz.node)
        parent.removeChild(this.vert.node)
    }

    CodeMirror.scrollbarModel.simple = function (place, scroll) {
        return new SimpleScrollbars('CodeMirror-simplescroll', place, scroll)
    }
    CodeMirror.scrollbarModel.overlay = function (place, scroll) {
        return new SimpleScrollbars('CodeMirror-overlayscroll', place, scroll)
    }
})