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可能大家見過很多使用jquery/js開發的顏色選擇器，今天這里我們將使用HTML5技術來自己實現一個更棒的顏色選擇器。希望大家喜歡！

HTML代碼

<!-- 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>

代碼很簡單，包含了2個部分，一個點擊元素，一個用來展示顏色選擇器的元素。

Javascript代碼

$(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，這是一個非常短的js代碼，用來創建新的畫布和對象，然后我們畫出一個圓形的顏色板。你可以選擇不同顏色底板。 這里使用一個參數來設定不同的選擇。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>

<canvas id="picker" var="4" width="300" height="300"></canvas> 

<canvas id="picker" var="5" width="300" height="300"></canvas>

下面我們添加事件：mousemove，click事件。這里使用jQuery來實現選擇器的展現和隱藏。

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

當我們的鼠標移動到選擇對象上，我們需要刷新信息，例如，目前顏色

$('#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代碼

不同顏色底板的CSS：

/* 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;
}

希望大家喜歡！

via script-tutorials