像素点 --------思路

最新推荐文章于 2025-11-28 04:56:28 发布

原创最新推荐文章于 2025-11-28 04:56:28 发布 · 270 阅读

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文章标签：

#javascript #html #html5

本文介绍了一种使用HTML5 Canvas技术从一张龙的图片中提取关键信息，并利用这些信息在网页上通过DIV元素模拟绘制龙的过程。该方法首先将图片加载到Canvas中，然后读取像素颜色信息，最后根据特定条件生成一系列DOM元素来模仿原图。

需求：产品经理：你能不能用div给我画条龙

链接掘金出处记录下怕删除哈哈

将图片绘制到canvas中

var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");

var image = new Image();
image.src = "dragon.jpg";
image.onload = function(){
        canvas.width = image.width;
        canvas.height = image.height;

        ctx.drawImage(image,0,0);
}

获取并裁剪画布的点阵信息

var imageData = ctx.getImageData(0,0,image.width,image.height).data;
ctx.fillStyle = "#ffffff";
ctx.fillRect(0,0,image.width,image.height);

var gap = 6;

for (var h = 0; h < image.height; h+=gap) {
    for(var w = 0; w < image.width; w+=gap){
            var position = (image.width * h + w) * 4;
            var r = imageData[position], g = imageData[position + 1], b = imageData[position + 2];

            if(r+g+b==0){
                    ctx.fillStyle = "#000";
                    ctx.fillRect(w,h,4,4);
                }
    }
}

通过点阵信息生成气泡dom

var dragonContainer = document.getElementById("container");
var dragonScale = 2;

for (var h = 0; h < image.height; h+=gap) {
    for(var w = 0; w < image.width; w+=gap){
            var position = (image.width * h + w) * 4;
            var r = imageData[position], g = imageData[position + 1], b = imageData[position + 2];

            if(r+g+b==0){
                    var bubble = document.createElement("img");
                    bubble.src = "bubble.png";
                    bubble.setAttribute("class","bubble");

                    var bubbleSize = Math.random()*10+20;
                    bubble.style.left = (w*dragonScale-bubbleSize/2) + "px";
                    bubble.style.top = (h*dragonScale-bubbleSize/2) + "px";
                    bubble.style.width = bubble.style.height = bubbleSize+"px";
                    bubble.style.animationDuration = Math.random()*6+4 + "s";

                    dragonContainer.appendChild(bubble);
                }
    }
}