在 HTML 画布中创建链接 [英] Create links in HTML canvas
本文介绍了在 HTML 画布中创建链接的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
是否可以从画布元素中呈现的文本中创建 html 链接?
Is it possible to create html links out of text that is rendered in a canvas element?
推荐答案
没有简单的方法.您必须将链接文本绘制到画布上,然后检查鼠标点击.这是一个演示 html 页面:
There is no easy way. You will have to draw the link text onto the canvas and then check for mouseclicks. Here is a demo html page:
<html>
<head>
<script type="text/javascript">
var canvas = document.getElementById("myCanvas");
var ctx;
var linkText="https://stackoverflow.com";
var linkX=5;
var linkY=15;
var linkHeight=10;
var linkWidth;
var inLink = false;
// draw the balls on the canvas
function draw(){
canvas = document.getElementById("myCanvas");
// check if supported
if(canvas.getContext){
ctx=canvas.getContext("2d");
//clear canvas
ctx.clearRect(0, 0, canvas.width, canvas.height);
//draw the link
ctx.font='10px sans-serif';
ctx.fillStyle = "#0000ff";
ctx.fillText(linkText,linkX,linkY);
linkWidth=ctx.measureText(linkText).width;
//add mouse listeners
canvas.addEventListener("mousemove", on_mousemove, false);
canvas.addEventListener("click", on_click, false);
}
}
//check if the mouse is over the link and change cursor style
function on_mousemove (ev) {
var x, y;
// Get the mouse position relative to the canvas element.
if (ev.layerX || ev.layerX == 0) { //for firefox
x = ev.layerX;
y = ev.layerY;
}
x-=canvas.offsetLeft;
y-=canvas.offsetTop;
//is the mouse over the link?
if(x>=linkX && x <= (linkX + linkWidth) && y<=linkY && y>= (linkY-linkHeight)){
document.body.style.cursor = "pointer";
inLink=true;
}
else{
document.body.style.cursor = "";
inLink=false;
}
}
//if the link has been clicked, go to link
function on_click(e) {
if (inLink) {
window.location = linkText;
}
}
</script>
</head>
<body onload="draw()">
<center>
<canvas id="myCanvas" width="200" height="200" style="border-style:solid;border-width:1px">Canvas not supported.</canvas>
</center>
</body>
</html>
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