用JavaScript在div中画线 [英] Drawing line in a div with Javascript
本文介绍了用JavaScript在div中画线的处理方法，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
使用画布，您可以使用javascript画一条线，
With a canvas you can draw a line with javascript like this,
<html>
<canvas id="myCanvas" width="500" height="300" style="border:1px solid #d3d3d3;"></canvas>
<script>
var c=document.getElementById("myCanvas");
var ctx = c.getContext("2d");
ctx.moveTo(20,20);
ctx.lineTo(100,100);
ctx.stroke();
</script>
</html>
我如何做同样的事情，但是使用div标签而不是画布？
之所以要这样做，是因为画布似乎无法在IE上运行，而且我知道Google图形使用div标签而不是画布来绘制图形，所以这是可能的。
How can i do the same thing, but by using a div tag instead of a canvas? The reason i want to do this is beacuse the canvas does not seem to work on IE and i know that Google graphs make use of div tags and not canvases to draw graphs, so it might be possible.
我尝试用div替换画布，但是它不起作用。
I tried replacing the canvas with a div, but it does not work.
推荐答案
使用Jquery：
<div id='rPaper'></div>
jQuery
x1 = 50, y1 = 50,
x2 = 350, y2 = 50;
drawnode(x1, y1);
drawnode(x2, y2);
drawline(x1, y1, x2, y2);
function drawnode(x, y) {
var ele = ""
var style = "";
style += "position:absolute;";
style += "z-index:100;"
ele += "<div class='relNode' style=" + style + ">";
ele += "<span> Test Node</span>"
ele += "<div>"
$('#rPaper').show();
var node = $(ele).appendTo('#rPaper');
var width = node.width();
var height = node.height();
var centerX = width / 2;
var centerY = height / 2;
var startX = x - centerX;
var startY = y - centerY;
node.css("left", startX).css("top", startY);
}
function drawline(ax, ay, bx, by) {
console.log('ax: ' + ax);
console.log('ay: ' + ay);
console.log('bx: ' + bx);
console.log('by: ' + by);
if (ax > bx) {
bx = ax + bx;
ax = bx - ax;
bx = bx - ax;
by = ay + by;
ay = by - ay;
by = by - ay;
}
console.log('ax: ' + ax);
console.log('ay: ' + ay);
console.log('bx: ' + bx);
console.log('by: ' + by);
var angle = Math.atan((ay - by) / (bx - ax));
console.log('angle: ' + angle);
angle = (angle * 180 / Math.PI);
console.log('angle: ' + angle);
angle = -angle;
console.log('angle: ' + angle);
var length = Math.sqrt((ax - bx) * (ax - bx) + (ay - by) * (ay - by));
console.log('length: ' + length);
var style = ""
style += "left:" + (ax) + "px;"
style += "top:" + (ay) + "px;"
style += "width:" + length + "px;"
style += "height:1px;"
style += "background-color:black;"
style += "position:absolute;"
style += "transform:rotate(" + angle + "deg);"
style += "-ms-transform:rotate(" + angle + "deg);"
style += "transform-origin:0% 0%;"
style += "-moz-transform:rotate(" + angle + "deg);"
style += "-moz-transform-origin:0% 0%;"
style += "-webkit-transform:rotate(" + angle + "deg);"
style += "-webkit-transform-origin:0% 0%;"
style += "-o-transform:rotate(" + angle + "deg);"
style += "-o-transform-origin:0% 0%;"
style += "-webkit-box-shadow: 0px 0px 2px 2px rgba(0, 0, 0, .1);"
style += "box-shadow: 0px 0px 2px 2px rgba(0, 0, 0, .1);"
style += "z-index:99;"
$("<div style='" + style + "'></div>").appendTo('#rPaper');
}
Demo
// right top -> left bottom
x1 = 850, y1 = 150,
x2 = 550, y2 = 250;
drawnode(x1, y1);
drawnode(x2, y2);
drawline(x1, y1, x2, y2);
Demo
// right bottom -> left top
x1 = 750, y1 = 150,
x2 = 550, y2 = 50;
drawnode(x1, y1);
drawnode(x2, y2);
drawline(x1, y1, x2, y2);
Demo
// left top -> right bottom
x1 = 150, y1 = 150,
x2 = 350, y2 = 350;
drawnode(x1, y1);
drawnode(x2, y2);
drawline(x1, y1, x2, y2);
Demo
// vertical line: down -> up
x1 = 150, y1 = 350,
x2 = 150, y2 = 150;
drawnode(x1, y1);
drawnode(x2, y2);
drawline(x1, y1, x2, y2);
Demo
这篇关于用JavaScript在div中画线的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
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