可能大家见过很多使用jquery/js开发的颜色选择器，今天这里我们将使用HTML5技术来自己实现一个更棒的颜色选择器。希望大家喜欢！
<!–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
$(function(){
var bCanPreview = true; // can preview
// create canvas and context objects
var canvas = document.getElementById(‘picker’);
var ctx = canvas.getContext(‘2d’);
// drawing active image
var image = new Image();
image.onload = function () {
ctx.drawImage(image, 0, 0, image.width, image.height); // draw the image on the canvas
}
// select desired colorwheel
var imagesrc=”images/colorwheel1.png”;
switch ($(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
