title: 純javascript--簡單的colorPicker取色器
date: 2018-04-26 00:04:45
tags:

功能需求

• 取色板可點擊遭贸，長按移動火惊，獲取顏色
• 取色條拖動改變色相
• 可修改十六進制值隅很，RGB，HSL桐猬，HSV值改變所有顯示數(shù)據(jù)
• 用戶輸入的數(shù)據(jù)進行校驗（十六進制自動補全冷离；不正確的十六進制自動顯示為黑色；rgb值的極限范圍澡谭，S,V,L 小數(shù)點輸入的實時校驗并糾正）

主思路

一愿题、三部分組成：取色板，取色條蛙奖，輸入框
二潘酗、hsv rgb hsl 三者關(guān)系
HSVL：
H: 色相，0°-360°雁仲，每隔60°有不同的主色相
S: 飽和度崎脉，0-100%，越低越灰暗
V: 明度伯顶，L: 亮度 0-100%
s隨著水平軸的向右從0-1囚灼，v隨著垂直軸的向上從0-1骆膝，所以可以用鼠標(biāo)在取色板中的位置(width, height)與整個面板的width和height的比例求出(s, v)，h值可根據(jù)在取色條上的高度灶体，求出hsv值阅签，再來個轉(zhuǎn)換公式rgb，hsl也呼之欲出~

image.png

取色板驮履，取色條渲染

///先完成取色板鱼辙，取色條的渲染
    <div class="main-panel">
        <div class="main">
            <canvas width="460" height="400" id="selectColor">You browser is not support canvas</canvas>
            <span id="main-handle" class="handle"></span>
        </div>
        <div class="bar">
            <canvas width="12" height="400" id="dragColor"></canvas>
            <span id="drag-handle" class="handle"></span>
        </div>
    </div>

////取色板渲染
        PickerPanel.prototype.render = function (color) {
              ///一層是透明灰層
            var lightLinear = this.ctxPicker.createLinearGradient(0, 0, 0, this.height);
            lightLinear.addColorStop(0, 'rgba(0, 0, 0, 0)');
            lightLinear.addColorStop(1, 'rgba(0, 0, 0, 1)');
              ///一層是顏色層，通過傳進來的color決定色相
            var colorLinear = this.ctxPicker.createLinearGradient(0, 0, this.width, 0);
            colorLinear.addColorStop(0, 'rgba(255, 255, 255, 1)');
            colorLinear.addColorStop(1, color);

            this.ctxPicker.fillStyle = colorLinear;
            this.ctxPicker.fillRect(0, 0, this.width, this.height);
            this.ctxPicker.fillStyle = lightLinear;
            this.ctxPicker.fillRect(0, 0, this.width, this.height);
            
        }


////取色器渲染
        BarPanel.prototype.render = function () {

            var dragLinear = this.ctxPicker.createLinearGradient(0, 0, 0, this.height);
         ////整個取色器分成6等分玫镐，每等分的增量 1 / 6
            dragLinear.addColorStop(0, '#ff0000');
            dragLinear.addColorStop(0.167, '#ffff00');
            dragLinear.addColorStop(0.334, '#00ff00');
            dragLinear.addColorStop(0.501, '#00ffff');
            dragLinear.addColorStop(0.668, '#0000ff');
            dragLinear.addColorStop(0.835, '#ff00ff');
            dragLinear.addColorStop(1, '#ff0000');  

            this.ctxPicker.fillStyle = dragLinear;
            this.ctxPicker.fillRect(0, 0, this.width, this.height);

        }

確定顏色坐標(biāo)(HSV)

///通過取色條的位置與總高度比獲取h
///通過鼠標(biāo)x與總width之比獲取s倒戏，鼠標(biāo)y與總height之比獲取v
    function getHSV() {
        var h = barIns.y * 360 / barIns.height,
            s = pickerIns.x * 1 / pickerIns.width,
            v = 1 - ( pickerIns.y * 1 / pickerIns.height );
        return {
            h: parseInt(h) === 360? 0 : parseInt(h),
            s: s.toFixed(2),
            v: v.toFixed(2)
        }
    }

HSV 轉(zhuǎn)換成 RGB HSL

var colorConvert = {
    hsv2rbg: function (h, s, v) {
        var r, g, b;

        var i = Math.floor(h / 60),
            f = h / 60 - i,
            p = v * (1 - s),
            q = v * (1 - f * s),
            t = v * (1 - (1 - f) * s);

        switch (i % 6) {
            case 0:
                r = v, g = t, b = p;
                break;
            case 1:
                r = q, g = v, b = p;
                break;
            case 2:
                r = p, g = v, b = t;
                break;
            case 3:
                r = p, g = q, b = v;
                break;
            case 4:
                r = t, g = p, b = v;
                break;
            case 5:
                r = v, g = p, b = q;
                break;
        }

        return {
            r: parseInt(r * 255),
            g: parseInt(g * 255),
            b: parseInt(b * 255)
        }
    },

    rgb2hsv: function (r, g, b) {
        r /= 255, g /= 255, b /= 255;

        var max = Math.max(r, g, b),
            min = Math.min(r, g, b);
        var h, s, v;
        v = max;

        var d = max - min;
        s = max == 0 ? 0 : d / max;

        if (max == min) {
            h = 0;
        } else {
            switch (max) {
                case r:
                    h = 60 * ((g - b) / d + (g < b ? 6 : 0));
                    break;
                case g:
                    h = 60 * ((b - r) / d + 2);
                    break;
                case b:
                    h = 60 * ((r - g) / d + 4);
                    break;
            }
        }

        return {
            h: parseInt(h),
            s: s.toFixed(2),
            v: v.toFixed(2)
        }
    },

    hsl2rgb: function (h, s, l) {
        h /= 360;

        var r, g, b;

        if (s == 0) {
            r = g = b = l; // achromatic
        } else {
            function hue2rgb(p, q, t) {
                if (t < 0) t += 1;
                if (t > 1) t -= 1;
                if (t < 1 / 6) return p + (q - p) * 6 * t;
                if (t < 1 / 2) return q;
                if (t < 2 / 3) return p + (q - p) * (2 / 3 - t) * 6;
                return p;
            }

            var q = l < 0.5 ? l * (1 + s) : l + s - l * s;
            var p = 2 * l - q;

            r = hue2rgb(p, q, h + 1 / 3);
            g = hue2rgb(p, q, h);
            b = hue2rgb(p, q, h - 1 / 3);
        }   

        return {
            r: parseInt(r * 255),
            g: parseInt(g * 255),
            b: parseInt(b * 255)
        }   
    },

    rgb2hsl: function (r, g, b) {
        r /= 255, g /= 255, b /= 255;

        var max = Math.max(r, g, b),
            min = Math.min(r, g, b);
        var h, s, l = (max + min) / 2;

        if (max == min) {
            h = s = 0; // achromatic
        } else {
            var d = max - min;
            s = l > 0.5 ? d / (2 - max - min) : d / (max + min);

            switch (max) {
                case r:
                    h = 60 * ((g - b) / d + (g < b ? 6 : 0));
                    break;
                case g:
                    h = 60 * ((b - r) / d + 2);
                    break;
                case b:
                    h = 60 * ((r - g) / d + 4);
                    break;
            }
        }

        return {
            h: parseInt(h),
            s: s.toFixed(2),
            l: l.toFixed(2)
        }
    },

    hsv2hsl: function (h, s, v) {
        var rgb = this.hsv2rbg(h, s, v);
        return this.rgb2hsl(rgb.r, rgb.g, rgb.b);
    },

    hsl2hsv: function (h, s, l) {
        var rgb = this.hsl2rgb(h, s, l);
        return this.rgb2hsv(rgb.r, rgb.g, rgb.b);
    }
}

var DecimalConvert = {
    d2h: function (value) {
        var hArr = [], a = ['A', 'B', 'C', 'D', 'E', 'F'];
        if (value === 0) {
            hArr.unshift(0);
        }
        while (value !== 0) {
            var mol = value % 16;
            mol = mol - 9 > 0? a[mol - 10] : mol;
            hArr.unshift(mol);
            value = parseInt(value / 16);
        }

        ////////////////////////////
        //////////應(yīng)用于顏色十進制轉(zhuǎn)換成十六進制 //
        /////////////////////////s///
        if (hArr.length < 2) {
            hArr.unshift(0);
        }

        return hArr.join('');
    },
    h2d: function (value) {
        var hArr = value.split(/(\d\d)|(\w\w)/).filter(h => !!h).map(h => parseInt(h, 16));
        return {
            r: hArr[0],
            g: hArr[1],
            b: hArr[2]
        }
    }

}

輸入數(shù)據(jù)的校驗，用正則表達(dá)式處理

        InputPanel.prototype.dataFormat = function(e, id, value) {

            switch (id) {
                case 'R':
                case 'G':
                case 'B':
                    value = Number(value);
                    if (value > 255) value = 255;
                    e.target.value = isNaN(value)? 0 : value;
                    pickByRGB();
                    break;
                case 'H':
                    value = Number(value);
                    if (value >= 360) value = 360;
                    e.target.value = isNaN(value)? 0 : value;
                    pickByHSL();
                    break;
                case 'S':
                case 'L':
                    value = value.replace(/^[^01]/, '').replace(/([01])\d?(\.)*(\d)?(\d)?.?/, '$1$2$3$4');
                    e.target.value = (value * 100) > 100? '1.00' : value;
                    if (value.charAt(value.length - 1) !== '.') {
                        pickByHSL();
                    }
                    break;
                default: break;
            }
        }

剩下的就主要是一些dom的事件綁定和數(shù)據(jù)的更新~

1.gif

gif質(zhì)量有點差哈哈恐似，各位看官將就看吧~

參考：https://zh.wikipedia.org/wiki/HSL%E5%92%8CHSV%E8%89%B2%E5%BD%A9%E7%A9%BA%E9%97%B4