将HTML5 Canvas的内容保存为图片借助toDataURL实现

2020-03-24 16:22:40

字体：大中小

来源：转载

供稿：网友

主要思想是借助Canvas自己的API - toDataURL()来实现，整个实现
HTML + JavaScript的代码很简单。

复制代码代码如下:
html
meta http-equiv="X-UA-Compatible" content="chrome=1"
head
script
window.onload = function() {
draw();
var saveButton = document.getElementById("saveImageBtn");
bindButtonEvent(saveButton, "click", saveImageInfo);
var dlButton = document.getElementById("downloadImageBtn");
bindButtonEvent(dlButton, "click", saveAsLocalImage);
};
function draw(){
var canvas = document.getElementById("thecanvas");
var ctx = canvas.getContext("2d");
ctx.fillStyle = "rgba(125, 46, 138, 0.5)";
ctx.fillRect(25,25,100,100);
ctx.fillStyle = "rgba( 0, 146, 38, 0.5)";
ctx.fillRect(58, 74, 125, 100);
ctx.fillStyle = "rgba( 0, 0, 0, 1)"; // black color
ctx.fillText("Gloomyfish - Demo", 50, 50);
}
function bindButtonEvent(element, type, handler)
{
if(element.addEventListener) {
element.addEventListener(type, handler, false);
} else {
element.attachEvent('on'+type, handler);
}
}
function saveImageInfo ()
{
var mycanvas = document.getElementById("thecanvas");
var image = mycanvas.toDataURL("image/png");
var w=window.open('about:blank','image from canvas');
w.document.write(" img src='"+image+"' alt='from canvas'/
}
function saveAsLocalImage () {
var myCanvas = document.getElementById("thecanvas");
// here is the most important part because if you dont replace you will get a DOM 18 exception.
// var image = myCanvas.toDataURL("image/png").replace("image/png", "image/octet-stream;Content-Disposition: attachment;filename=foobar.png");
var image = myCanvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
window.location.href=image; // it will save locally
}
/script
/head
body bgcolor="#E6E6FA"
div
canvas width=200 height=200 id="thecanvas" /canvas
button id="saveImageBtn" Save Image /button
button id="downloadImageBtn" Download Image /button
/div
/body
/html

运行效果如下：
html教程

郑重声明：本文版权归原作者所有，转载文章仅为传播更多信息之目的，如作者信息标记有误，请第一时间联系我们修改或删除，多谢。

上一篇：HTML注释有何作用

下一篇：HTML属性的作用（代码）