Html5: Drawing with text
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2022-05-25 20:51:28
Drawing with text Click and drag to draw! ......
<!doctype html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta charset="utf-8">
<title>drawing with text</title>
<meta name="keywords" content="geovindu">
<meta name="description" content="涂聚文">
<meta name="author" content="tim holman">
<style type="text/css">
@import "compass/css3";
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>
<!--
drawing with text:
- click and drag to draw.
- double click to clear.
ported from java at http://www.generative-gestaltung.de
by tim holman - @twholman
-->
<script type="text/javascript">
//a pen by tim holman
//https://onaircode.com/awesome-html5-canvas-examples-source-code/
// drawing with text. ported from generative design book - http://www.generative-gestaltung.de - original licence: http://www.apache.org/licenses/license-2.0
// application variables
var position = {x: 0, y: window.innerheight/2};
var counter = 0;
var minfontsize = 3;
var angledistortion = 0;
var letters = "中国人民解放了！中国人站起来了！涂聚文(geovin du),明者因事而变，知者随事而制！--《盐铁论》。there was a table set out under a tree in front of the house, and the march hare and the hatter were having tea at it: a dormouse was sitting between them, fast asleep, and the other two were using it as a cushion, resting their elbows on it, and talking over its head. 'very uncomfortable for the dormouse,' thought alice; 'only, as it's asleep, i suppose it doesn't mind.'";
// drawing variables
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);
canvas.addeventlistener('dblclick', doubleclick, 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 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 mousedown( event ){
mouse.down = true;
position.x = event.pagex;
position.y = event.pagey;
document.getelementbyid('info').style.display = 'none';
}
function mouseup( event ){
mouse.down = false;
}
function doubleclick( event ) {
canvas.width = canvas.width;
}
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>
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