HTML5Canvas颜色选择器

来源：懂视网责编：小采时间：2020-11-27 15:16:11

HTML5Canvas颜色选择器

HTML5Canvas颜色选择器:这段代码是用HTML5来创建一个网页颜色选择器。首先在Canvas画一幅图，然后添加鼠标事件鼠标移动，鼠标点击。在鼠标移动的时候，显示当前划过的颜色预览，在鼠标点击的时候，选中当前颜色，显示颜色的细节。 DEMO： http://www.oschina.

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导读HTML5Canvas颜色选择器:这段代码是用HTML5来创建一个网页颜色选择器。首先在Canvas画一幅图，然后添加鼠标事件鼠标移动，鼠标点击。在鼠标移动的时候，显示当前划过的颜色预览，在鼠标点击的时候，选中当前颜色，显示颜色的细节。 DEMO： http://www.oschina.

这段代码是用HTML5来创建一个网页颜色选择器。首先在Canvas画一幅图，然后添加鼠标事件 “鼠标移动”，“鼠标点击”。在鼠标移动的时候，显示当前划过的颜色预览，在鼠标点击的时候，选中当前颜色，显示颜色的细节。

DEMO： http://www.oschina.net/uploads/demo/example158/

[代码] [HTML]代码

<html lang="en" > <head> <meta charset="utf-8" /> <title><A title=HTML5 href="http://www.xyhtml5.com/"

>HTML5A> canvas - Image color picker | Script Tutorialstitle>  <link href="http://www.xyhtml5.com/css3">cssA>/main.<A title=css href="http://www.xyhtml5.com/css3">cssA>" rel="stylesheet" type="text/css" />  <script type="text/http://www.xyhtml5.com/javascript">javascriptA>" src="js/jquery-1.5.2.min.js">script>  <script type="text/http://www.xyhtml5.com/javascript">javascriptA>" src="js/script.js">script>  head>  <body>  <div class="container">  <div class="column1">  <canvas id="panel" width="500" height="333">canvas>  div>  <div class="column2">  <div><input type="button" value="Next image" id="swImage" />div>  <div>Preview:div>  <div id="preview">div>  <div>Color:div>  <div>R: <input type="text" id="rVal" />div>  <div>G: <input type="text" id="gVal" />div>  <div>B: <input type="text" id="bVal" />div>  <div>RGB: <input type="text" id="rgbVal" />div>  <div>RGBA: <input type="text" id="rgbaVal" />div>  <div>HEX: <input type="text" id="hexVal" />div>  <hr />  div>  <div style="clear:both;">div>  div>  <footer>  <h2>HTML5 canvas - Image color pickerh2>  <a href="http://www.script-tutorials.com/html5-canvas-image-color-picker/" class="stuts">Back to original tutorial on <span>Script Tutorialsspan>a>  footer>  body> html>

[CSS]代码

*{ margin:0; padding:0; } body { background-color:#bababa; color:#fff; font:14px/1.3 Arial,sans-serif; } footer { background-color:#212121; bottom:0; box-shadow: 0 -1px 2px #111111; display:block; height:70px; left:0; position:fixed; width:100%; z-index:100; } footer h2{ font-size:22px; font-weight:normal; left:50%; margin-left:-400px; padding:22px 0; position:absolute; width:540px; } footer a.stuts,a.stuts:visited{ border:none; text-decoration:none; color:#fcfcfc; font-size:14px; left:50%; line-height:31px; margin:23px 0 0 110px; position:absolute; top:0; } footer .stuts span { font-size:22px; font-weight:bold; margin-left:5px; } .container { color:#000; margin:20px auto; position:relative; width:730px; } .column1 { float:left; width:500px; } .column2 { float:left; padding-left:20px; width:170px; } #panel { border:1px #000 solid; box-shadow:4px 6px 6px #444444; cursor:crosshair; } .column2 > div { margin-bottom:10px; } #swImage { border:1px #000 solid; box-shadow:2px 3px 3px #444444; cursor:pointer; height:25px; line-height:25px; border-radius:3px; -moz-border-radius:3px; -webkit-border-radius:3px; } #swImage:hover { margin-left:2px; } #preview { border:1px #000 solid; box-shadow:2px 3px 3px #444444; height:80px; width:80px; border-radius:3px; -moz-border-radius:3px; -webkit-border-radius:3px; } .column2 input[type=text] { float:right; width:110px; }

[JavaScript]代码

var canvas; var ctx; var images = [ // predefined array of used images 'images/pic1.jpg', 'images/pic2.jpg', 'images/pic3.jpg', 'images/pic4.jpg', 'images/pic5.jpg', 'images/pic6.jpg', 'images/pic7.jpg', 'images/pic8.jpg', 'images/pic9.jpg', 'images/pic10.jpg']; var iActiveImage = 0; $(function(){ // 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 } image.src = images[iActiveImage]; // creating canvas object canvas = document.getElementById('panel'); ctx = canvas.getContext('2d'); $('#panel').mousemove(function(e) { // mouse move handler var canvasOffset = $(canvas).offset(); var canvasX = Math.floor(e.pageX - canvasOffset.left); var canvasY = Math.floor(e.pageY - canvasOffset.top); var imageData = ctx.getImageData(canvasX, canvasY, 1, 1); var pixel = imageData.data; var pixelColor = "rgba("+pixel[0]+", "+pixel[1]+", "+pixel[2]+", "+pixel[3]+")"; $('#preview').css('backgroundColor', pixelColor); }); $('#panel').click(function(e) { // mouse click handler var canvasOffset = $(canvas).offset(); var canvasX = Math.floor(e.pageX - canvasOffset.left); var canvasY = Math.floor(e.pageY - canvasOffset.top); var imageData = ctx.getImageData(canvasX, canvasY, 1, 1); var pixel = imageData.data; $('#rVal').val(pixel[0]); $('#gVal').val(pixel[1]); $('#bVal').val(pixel[2]); $('#rgbVal').val(pixel[0]+','+pixel[1]+','+pixel[2]); $('#rgbaVal').val(pixel[0]+','+pixel[1]+','+pixel[2]+','+pixel[3]); var dColor = pixel[2] + 256 * pixel[1] + 65536 * pixel[0]; $('#hexVal').val( '#' + dColor.toString(16) ); }); $('#swImage').click(function(e) { // switching images iActiveImage++; if (iActiveImage >= 10) iActiveImage = 0; image.src = images[iActiveImage]; }); });

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