js如何自动获取指定像素的颜色

Question

以下代码为鼠标点击某点获取颜色，如何改为自动获取像素为X,Y=1,1的颜色？

Answer 1

var draw = function(img) {

    var canvas = document.getElementById("canvas");

    var context = canvas.getContext("2d");

    context.shadowBlur = 20;

    context.shadowColor = "#000000";

    context.drawImage(img, 0, 0);

    var colorData = canvas.getPixelColor(1, 1); // 获取x=1,y=1像素处的颜色

    var color = colorData.rgba;

    $("body").css("backgroundColor", color);

    $("#currentColor").html("当前像素(1, 1)颜色为: " + color);

}

$(document).ready(function () {

    var img = new Image();

    img.src = "images/demo.jpg";

    $(img).load(function () {

        draw(img);

    });

});