油漆帆布不能正常工作 [英] Paint canvas not working properly
问题描述
http:// www .asifslab.com / reveal.js-master /为什么%20does%20wind%20feel%20cold.html#/ 4
为什么绘图画布不能正常工作?绘制的线远离点击的点。但是,如果我使用的画布out.js它的工作完美。 http://codepen.io/anon/pen/eEaKh
此外,当删除函数运行,它在外面留下一个白色边框。如何解决这些问题?
http://www.asifslab.com/reveal.js-master/Why%20does%20wind%20feel%20cold.html#/4 Why doesn't the drawing canvas work properly? The line drawn is away from the point clicked. However, if I use the canvas out of reveal.js it works perfectly. http://codepen.io/anon/pen/eEaKh Also when the erase function is run, it leaves a white border outside. How do I fix these problems?
推荐答案
要计算鼠标位置,您需要减去画布的位置:
To calculate the mouse position you need to subtract the position of the canvas:
这是一种方法(在事件处理程序内部):
Here is one way of doing this (inside the event handler):
var rect = canvas.getBoundingClientRect(),
x = e.clientX - rect.left,
y = e.clientY - rect.top;
现在您的 x
和 y
将相对于画布。
Now your x
and y
will be relative to canvas.
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