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HTML5Canvas颜色选择器

时间：2021-07-01 10:21:17 帮助过：110人阅读

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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HTML5Canvas颜色选择器

[代码] [HTML]代码

[CSS]代码

[JavaScript]代码

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