使用jquery/js开发的颜色选择器想必大家都有见到过吧，在本文将为大家介绍下使用HTML5技术来自己实现一个更棒的颜色选择器，感兴趣的朋友可以参考下

代码如下:

<!--preview element -->

<div class="preview"></div>

<!-- colorpicker element -->

<div class="colorpicker" style="display:none">

<canvas id="picker" var="1" width="300" height="300"></canvas>

<div class="controls">

<div><label>R</label> <input type="text" id="rVal" /></div>

<div><label>G</label> <input type="text" id="gVal" /></div>

<div><label>B</label> <input type="text" id="bVal" /></div>

<div><label>RGB</label> <input type="text" id="rgbVal" /></div>

<div><label>HEX</label> <input type="text" id="hexVal" /></div>

</div>

</div>

代码很简单，包含了2个部分，一个点击元素，一个用来展示颜色选择器的元素。

JavaScript代码

代码如下:

$(function(){

var bCanPreview = true; // can preview

// create canvas and context objects

var canvas = document.getElementById('picker');

var ctx = canvas.getContext('2d');

// drawing active image

var image = new Image();

image.onload = function () {

ctx.drawImage(image, 0, 0, image.width, image.height); // draw the image on the canvas

}

// select desired colorwheel

var imagesrc="images/colorwheel1.png";

switch ($(canvas).attr('var')) {

case '2':

imagesrc="images/colorwheel2.png";

break;

case '3':

imagesrc="images/colorwheel3.png";

break;

case '4':

imagesrc="images/colorwheel4.png";

break;

case '5':

imagesrc="images/colorwheel5.png";

break;

}

image.src = imageSrc;

$('#picker').mousemove(function(e) { // mouse move handler

if (bCanPreview) {

// get coordinates of current position

var canvasOffset = $(canvas).offset();

var canvasX = Math.floor(e.pageX - canvasOffset.left);

var canvasY = Math.floor(e.pageY - canvasOffset.top);

// get current pixel

var imageData = ctx.getImageData(canvasX, canvasY, 1, 1);

var pixel = imageData.data;

// update preview color

var pixelColor = "rgb("+pixel[0]+", "+pixel[1]+", "+pixel[2]+")";

$('.preview').css('backgroundColor', pixelColor);

// update controls

$('#rVal').val(pixel[0]);

$('#gVal').val(pixel[1]);

$('#bVal').val(pixel[2]);

$('#rgbVal').val(pixel[0]+','+pixel[1]+','+pixel[2]);

var dColor = pixel[2] + 256 * pixel[1] + 65536 * pixel[0];

$('#hexVal').val('#' + ('0000' + dColor.toString(16)).substr(-6));

}

});

$('#picker').click(function(e) { // click event handler

bCanPreview = !bCanPreview;

});

$('.preview').click(function(e) { // preview click

$('.colorpicker').fadeToggle("slow", "linear");

bCanPreview = true;

});

});

大家可以看到，这是一个非常短的js代码，用来创建新的画布和对象，然后我们画出一个圆形的颜色板。你可以选择不同的颜色底板。这里使用一个参数来设定不同的选择。如下：

代码如下:

<canvas id="picker" var="1" width="300" height="300"></canvas>

<canvas id="picker" var="2" width="300" height="300"></canvas>

<canvas id="picker" var="3" width="300" height="300"></canvas>

<pre class="html" name="code"> </pre>

下面我们添加事件：mousemove，click事件。这里使用jQuery来实现选择器的展现和隐藏。

代码如下:

$('.preview').click(function(e) { // preview click $('.colorpicker').fadeToggle("slow", "linear"); bCanPreview = true; });

当我们的鼠标移动到选择对象上，我们需要刷新信息，例如，目前颜色

代码如下:

$('#picker').mousemove(function(e) { // mouse move handler

if (bCanPreview) {

// get coordinates of current position

var canvasOffset = $(canvas).offset();

var canvasX = Math.floor(e.pageX - canvasOffset.left);

var canvasY = Math.floor(e.pageY - canvasOffset.top);

// get current pixel

var imageData = ctx.getImageData(canvasX, canvasY, 1, 1);

var pixel = imageData.data;

// update preview color

var pixelColor = "rgb("+pixel[0]+", "+pixel[1]+", "+pixel[2]+")";

$('.preview').css('backgroundColor', pixelColor);

// update controls

$('#rVal').val(pixel[0]);

$('#gVal').val(pixel[1]);

$('#bVal').val(pixel[2]);

$('#rgbVal').val(pixel[0]+','+pixel[1]+','+pixel[2]);

var dColor = pixel[2] + 256 * pixel[1] + 65536 * pixel[0];

$('#hexVal').val('#' + ('0000' + dColor.toString(16)).substr(-6));

}

});

$('#picker').click(function(e) { // click event handler

bCanPreview = !bCanPreview;

});

CSS代码

不同颜色底板的CSS：

代码如下:

/* colorpicker styles */

.colorpicker {

background-color: #222222;

border-radius: 5px 5px 5px 5px;

box-shadow: 2px 2px 2px #444444;

color: #FFFFFF;

font-size: 12px;

position: absolute;

width: 460px;

}

#picker {

cursor: crosshair;

float: left;

margin: 10px;

border: 0;

}

.controls {

float: right;

margin: 10px;

}

.controls > div {

border: 1px solid #2F2F2F;

margin-bottom: 5px;

overflow: hidden;

padding: 5px;

}

.controls label {

float: left;

}

.controls > div input {

background-color: #121212;

border: 1px solid #2F2F2F;

color: #DDDDDD;

float: right;

font-size: 10px;

height: 14px;

margin-left: 6px;

text-align: center;

text-transform: uppercase;

width: 75px;

}

.preview {

background: url("../images/select.png") repeat scroll center center transparent;

border-radius: 3px;

box-shadow: 2px 2px 2px #444444;

cursor: pointer;

height: 30px;

width: 30px;

}