Posted in Javascript onFebruary 18, 2016
滑动拼图就是把一张图片分成几等份,打乱顺序(下图),然后通过滑动拼凑成一张完整的图片。
要实现一个拼图游戏,需要考虑怎样随机的打乱顺序,怎样交换两张图片的位置,等等。但是,使用了Flexbox布局以后,这都不需要你去考虑,浏览器会帮你做,Flexbox就是这么的强大。关于Flexbox的介绍可以点击这里。
这个游戏中要用的是Flexbox布局的order属性,order属性可以用来控制Flex项目的顺序。
这里我用九个canvas元素来把图片分成九等分,也可以用其他方法,比如背景图片定位:
<div class="wrap"> <canvas></canvas> <canvas></canvas> <canvas></canvas> <canvas></canvas> <canvas></canvas> <canvas></canvas> <canvas></canvas> <canvas></canvas> <canvas></canvas> </div>
如果不仅限于九宫格,还要十六宫格等,上面的元素完全可以动态生成。
下面是生成打乱顺序的九张图代码:
var drawImage = function (url) { return new Promise(function (resolve, reject) { var img = new Image(); img.onload = function () { resolve(img); }; img.src = url; }) }; drawImage("2.jpg").then(function (img) { var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9]; var random = arr.sort(function() {return Math.random() > 0.5}); [].forEach.call(document.querySelectorAll("canvas"), function (item, i) { item.width = $(".wrap").clientWidth / 3; item.height = $(".wrap").clientHeight / 3; item.style.order = random[i]; var ctx = item.getContext("2d"); ctx.drawImage(img, img.width * (i % 3) / 3, img.height * Math.floor(i / 3) / 3, img.width / 3, img.height / 3, 0, 0, item.width, item.height); }); });
上面的关键代码是:
item.style.order = random[i];
通过将数字打乱顺序,随机赋值给每个canvas元素的order属性,这样浏览器就自动帮你排序了。
关于代码的其他细节就不讲了,这里说一下怎样交换两张图片的位置,真是出乎意料的简单:
var order1 = item.style.order; var order2 = target.style.order;
只需要交换双方的order属性值就可以了。
完整代码
<!DOCTYPE html> <html> <head lang="en"> <meta charset="UTF-8"> <meta content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=0" name="viewport" /> <meta content="yes" name="apple-mobile-web-app-capable" /> <meta content="black" name="apple-mobile-web-app-status-bar-style" /> <meta content="telephone=no" name="format-detection" /> <title></title> <style> html, body { height: 100%; } body { margin: 0; padding: 0; overflow: hidden; } .wrap { display: flex; flex-wrap: wrap; width: 100%; height: 100%; overflow: hidden; } .wrap canvas { width: 33.3333%; height: 33.3333%; border: 1px solid red; box-sizing: border-box; } </style> </head> <body> <div class="wrap"> <canvas data-value="1"></canvas> <canvas data-value="2"></canvas> <canvas data-value="3"></canvas> <canvas data-value="4"></canvas> <canvas data-value="5"></canvas> <canvas data-value="6"></canvas> <canvas data-value="7"></canvas> <canvas data-value="8"></canvas> <canvas data-value="9"></canvas> </div> <script> var $ = function (el) { return document.querySelector(el); }; var touchMove, touchEnd; var drawImage = function (url) { return new Promise(function (resolve, reject) { var img = new Image(); img.onload = function () { resolve(img); }; img.src = url; }) }; drawImage("2.jpg").then(function (img) { var arr = [1, 2, 3, 4, 5, 6, 7, 8, 9]; var random = arr.sort(function() {return Math.random() > 0.5}); [].forEach.call(document.querySelectorAll("canvas"), function (item, i) { item.width = $(".wrap").clientWidth / 3; item.height = $(".wrap").clientHeight / 3; item.style.order = random[i]; var ctx = item.getContext("2d"); ctx.drawImage(img, img.width * (i % 3) / 3, img.height * Math.floor(i / 3) / 3, img.width / 3, img.height / 3, 0, 0, item.width, item.height); }); }); document.addEventListener("touchstart", function (e) { var target = e.target; if (e.target.tagName.toLowerCase() !== "canvas") { return; } var ctx = target.getContext("2d"); var image = ctx.getImageData(0, 0, target.width, target.height); var obj = target.cloneNode(true); obj.getContext("2d").putImageData(image, 0, 0); var top = target.getBoundingClientRect().top, left = target.getBoundingClientRect().left; obj.style.cssText = "position: absolute; top: " + top + "px; left: " + left + "px"; document.body.appendChild(obj); var point = {"x": e.touches[0].pageX, "y": e.touches[0].pageY}; document.addEventListener("touchmove", touchMove = function (e) { obj.style.cssText = "position: absolute; top:" + (e.touches[0].pageY - point.y + top) + "px; left: " + (e.touches[0].pageX - point.x + left) + "px"; }); document.addEventListener("touchend", touchEnd = function (e) { var pos = {"x": e.changedTouches[0].pageX, "y": e.changedTouches[0].pageY}; [].forEach.call(document.querySelectorAll(".wrap canvas"), function (item, i) { var offset = item.getBoundingClientRect(); if (pos.x > offset.left && pos.x < (offset.left + item.width) && pos.y > offset.top && pos.y < (offset.top + item.height)) { var order1 = item.style.order; var order2 = target.style.order; if (obj.parentNode) { document.body.removeChild(obj); } item.style.order = order2; target.style.order = order1; } }); document.removeEventListener("touchmove", touchMove); document.removeEventListener("touchend", touchEnd); }) }) </script> </body> </html>
大家做测试的时候,最好用谷歌模拟器或者手机打开,因为只支持移动端触摸事件。
代码中只实现了基本功能,并没有实现完整功能。
javascript结合Flexbox简单实现滑动拼图游戏
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