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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
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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
$('.colorpicker').fadeToggle("slow", "linear");
bCanPreview = true;
});
});
大家可以看到，这是一个非常短的js代码，用来创建新的画布和对象，然后我们画出一个圆形的颜色板。你可以选择不同的颜色底板。这里使用一个参数来设定不同的选择。如下：
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代码如下:<canvas id="picker" var="1" width="300" height="300"></canvas>
<canvas id="picker" var="2" width="300" height="300"></canvas>
<canvas id="picker" var="3" width="300" height="300"></canvas>
<pre class="html" name="code"> </pre>
下面我们添加事件：mousemove，click事件。这里使用jQuery来实现选择器的展现和隐藏。
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代码如下:$('.preview').click(function(e) { // preview click $('.colorpicker').fadeToggle("slow", "linear"); bCanPreview = true; });
当我们的鼠标移动到选择对象上，我们需要刷新信息，例如，目前颜色
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代码如下:$('#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：
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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;
}
希望大家喜欢
