鼠标滑过文字跟随效果
2020-11-27 本文已影响0人
zkzhengmeng
1.鼠标滑动文字跟随效果,可自定义文字
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>Canvas文字跟随特效</title>
<style type="text/css">
html,
body {
width: 100%;
height: 100%;
margin: 0px;
overflow: hidden;
&:hover {
span {
display: none;
}
}
}
canvas {
cursor: crosshair;
}
span {
font-family: 'Georgia', cursive;
font-size: 40px;
position: fixed;
top: 50%;
left: 50%;
color: #000;
margin-top: -40px;
margin-left: -200px;
}
</style>
</head>
<body>
<canvas id='canvas'></canvas>
<span id='info'>Click and drag to draw!<span>
<script type="text/javascript">
var position = {x: 0, y: window.innerHeight/2};
var counter = 0;
var minFontSize = 3;
var angleDistortion = 0;
var letters = "我是一只小鸟,在天空自由自在的翱翔!";
var canvas;
var context;
var mouse = {x: 0, y: 0, down: false}
function init() {
canvas = document.getElementById( 'canvas' );
context = canvas.getContext( '2d' );
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
canvas.addEventListener('mousemove', mouseMove, false);
canvas.addEventListener('mousedown', mouseDown, false);
canvas.addEventListener('mouseup', mouseUp, false);
canvas.addEventListener('mouseout', mouseUp, false);
window.onresize = function(event) {
canvas.width = window.innerWidth;
canvas.height = window.innerHeight;
}
}
function mouseMove ( event ){
mouse.x = event.pageX;
mouse.y = event.pageY;
draw();
}
function mouseDown( event ){
mouse.down = true;
position.x = event.pageX;
position.y = event.pageY;
document.getElementById('info').style.display = 'none';
}
function mouseUp( event ){
canvas.width = canvas.width;
}
function draw() {
if ( mouse.down ) {
var d = distance( position, mouse );
var fontSize = minFontSize + d/2;
var letter = letters[counter];
var stepSize = textWidth( letter, fontSize );
if (d > stepSize) {
var angle = Math.atan2(mouse.y-position.y, mouse.x-position.x);
context.font = fontSize + "px Georgia";
context.save();
context.translate( position.x, position.y);
context.rotate( angle );
context.fillText(letter,0,0);
context.restore();
counter++;
if (counter > letters.length-1) {
counter = 0;
}
//console.log (position.x + Math.cos( angle ) * stepSize)
position.x = position.x + Math.cos(angle) * stepSize;
position.y = position.y + Math.sin(angle) * stepSize;
}
}
}
function distance( pt, pt2 ){
var xs = 0;
var ys = 0;
xs = pt2.x - pt.x;
xs = xs * xs;
ys = pt2.y - pt.y;
ys = ys * ys;
return Math.sqrt( xs + ys );
}
function textWidth( string, size ) {
context.font = size + "px Georgia";
if ( context.fillText ) {
return context.measureText( string ).width;
} else if ( context.mozDrawText) {
return context.mozMeasureText( string );
}
};
init();
</script>
</body>
</html>
