Question

大家好我们可以使用html5 ??

在canvas中放置拖放功能

我的实际要求是将图片拖到应该在画布内完成的文本框中... 请分享您的想法。以下链接我曾经学习拖放但它应该在画布内完成..

http://www.w3schools.com/html5/tryit.asp?filename=tryhtml5_draganddrop

Answer 1

您可以在本教程中了解更多信息：http://html5.litten.com/how-to-drag-and-drop-on-an-html5-canvas/

根据您在问题中的有限描述，听起来像是在画布上拖动项目，本教程可能是最佳匹配。

这是您可以粘贴到文件中并在符合HTML5标准的浏览器中打开的实际代码，它将起作用：

<!doctype html>
<html>
<head>
<meta charset="UTF-8" />
<title>Canvas Drag and Drop Test</title>
</head>
<body>
<section>

<div>
<canvas id="canvas" width="400" height="300">
This text is displayed if your browser does not support HTML5 Canvas.
</canvas>
</div>

<script type="text/javascript">

var canvas;
var ctx;
var x = 75;
var y = 50;
var WIDTH = 400;
var HEIGHT = 300;
var dragok = false;

function rect(x,y,w,h) {
 ctx.beginPath();
 ctx.rect(x,y,w,h);
 ctx.closePath();
 ctx.fill();
}

function clear() {
 ctx.clearRect(0, 0, WIDTH, HEIGHT);
}

function init() {
 canvas = document.getElementById("canvas");
 ctx = canvas.getContext("2d");
 return setInterval(draw, 10);
}

function draw() {
 clear();
 ctx.fillStyle = "#FAF7F8";
 rect(0,0,WIDTH,HEIGHT);
 ctx.fillStyle = "#444444";
 rect(x - 15, y - 15, 30, 30);
}

function myMove(e){
 if (dragok){
  x = e.pageX - canvas.offsetLeft;
  y = e.pageY - canvas.offsetTop;
 }
}

function myDown(e){
 if (e.pageX < x + 15 + canvas.offsetLeft && e.pageX > x - 15 +
 canvas.offsetLeft && e.pageY < y + 15 + canvas.offsetTop &&
 e.pageY > y -15 + canvas.offsetTop){
  x = e.pageX - canvas.offsetLeft;
  y = e.pageY - canvas.offsetTop;
  dragok = true;
  canvas.onmousemove = myMove;
 }
}

function myUp(){
 dragok = false;
 canvas.onmousemove = null;
}

init();
canvas.onmousedown = myDown;
canvas.onmouseup = myUp;

</script>

</section>
</body>
</html>

使用HTML5在画布内拖放功能

1 个答案: