使用HTML5技术开发的超酷颜色选择器-H5教程-PHP中文网

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使用HTML5技术开发的超酷颜色选择器

PHP中文网

Mar 30, 2017 am 10:53 AM

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！

HTML代码

<!-- preview element -->
<p class="preview"></p>
<!-- colorpicker element -->
<p class="colorpicker" style="display:none">
    <canvas id="picker" var="1" width="300" height="300"></canvas>
    <p class="controls">
        <p><label>R</label> <input type="text" id="rVal" /></p>
        <p><label>G</label> <input type="text" id="gVal" /></p>
        <p><label>B</label> <input type="text" id="bVal" /></p>
        <p><label>RGB</label> <input type="text" id="rgbVal" /></p>
        <p><label>HEX</label> <input type="text" id="hexVal" /></p>
    </p>
</p>

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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(&#39;picker&#39;);
    var ctx = canvas.getContext(&#39;2d&#39;);

    // 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(&#39;var&#39;)) {
        case &#39;2&#39;:
            imagesrc="images/colorwheel2.png";
            break;
        case &#39;3&#39;:
            imagesrc="images/colorwheel3.png";
            break;
        case &#39;4&#39;:
            imagesrc="images/colorwheel4.png";
            break;
        case &#39;5&#39;:
            imagesrc="images/colorwheel5.png";
            break;
    }
    image.src = imageSrc;

    $(&#39;#picker&#39;).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]+")";
            $(&#39;.preview&#39;).css(&#39;backgroundColor&#39;, pixelColor);

            // update controls
            $(&#39;#rVal&#39;).val(pixel[0]);
            $(&#39;#gVal&#39;).val(pixel[1]);
            $(&#39;#bVal&#39;).val(pixel[2]);
            $(&#39;#rgbVal&#39;).val(pixel[0]+&#39;,&#39;+pixel[1]+&#39;,&#39;+pixel[2]);

            var dColor = pixel[2] + 256 * pixel[1] + 65536 * pixel[0];
            $(&#39;#hexVal&#39;).val(&#39;#&#39; + (&#39;0000&#39; + dColor.toString(16)).substr(-6));
        }
    });
    $(&#39;#picker&#39;).click(function(e) { // click event handler
        bCanPreview = !bCanPreview;
    });
    $(&#39;.preview&#39;).click(function(e) { // preview click
        $(&#39;.colorpicker&#39;).fadeToggle("slow", "linear");
        bCanPreview = true;
    });
});

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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。你可以选择不同颜色底板。这里使用一个参数来设定不同的选择。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>

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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。

$(&#39;.preview&#39;).click(function(e) { // preview click     
$(&#39;.colorpicker&#39;).fadeToggle("slow", "linear");     
bCanPreview = true; });

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$(&#39;#picker&#39;).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]+")";
        $(&#39;.preview&#39;).css(&#39;backgroundColor&#39;, pixelColor);

        // update controls
        $(&#39;#rVal&#39;).val(pixel[0]);
        $(&#39;#gVal&#39;).val(pixel[1]);
        $(&#39;#bVal&#39;).val(pixel[2]);
        $(&#39;#rgbVal&#39;).val(pixel[0]+&#39;,&#39;+pixel[1]+&#39;,&#39;+pixel[2]);

        var dColor = pixel[2] + 256 * pixel[1] + 65536 * pixel[0];
        $(&#39;#hexVal&#39;).val(&#39;#&#39; + (&#39;0000&#39; + dColor.toString(16)).substr(-6));
    }
});
$(&#39;#picker&#39;).click(function(e) { // click event handler
    bCanPreview = !bCanPreview;
});

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CSS代码

不同颜色底板的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 > p {
    border: 1px solid #2F2F2F;
    margin-bottom: 5px;
    overflow: hidden;
    padding: 5px;
}
.controls label {
    float: left;
}
.controls > p 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;
}

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希望大家喜欢！